Science.gov

Sample records for alachlor acetochlor metolachlor

  1. Metolachlor and alachlor breakdown product formation patterns in aquatic field mesocosms

    USGS Publications Warehouse

    Graham, W.H.; Graham, D.W.; DeNoyelles, F.; Smith, V.H.; Larive, C.K.; Thurman, E.M.

    1999-01-01

    The transformation of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)- N-(2-methoxy-1-methyl)ethyl)acetamide] and alachlor [2-chloro-N-(2,6- diethylphenyl)-N-methoxymethyl)acetamide] in aquatic systems was investigated using outdoor tank mesocosms. Metolachlor and alachlor levels and their ethane sulfonic acid (ESA) and oxanillic acid breakdown products were monitored over time under five experimental treatments (each in quadruplicate). Background water conditions were identical in all treatments with each treatment differing based on the level and type(s) of herbicide present. Treatments included a noherbicide control, 10 ??g/L metolachlor, 25 ??g/L metolachlor, 25 ??g/L alachlor, and 25 ??g/L alachlor plus 25 ??g/L metolachlor in combination. The experiment was initiated by adding herbicide(s) to the units to the target concentrations; herbicide and breakdown product levels and other chemical parameters were then monitored for 85 days. In general, metolachlor half-lives were longer than alachlor half-lives under all treatments, although the differences were not statistically significant. Metolachlor half-lives (??95% confidence limits) ranged from 33.0 d (??14.1 d) to 46.2 d (??40.0 d), whereas alachlor half- lives ranged from 18.7 d (??3.5 d) to 21.0 d (??6.5 d) for different treatments. Formation patterns of ESA were similar in all treatments, whereas oxanillic acid formation differed for the two herbicides. Alachlor oxanillic acid was produced in larger quantities than metolachlor oxanillic acid and either ESA under equivalent conditions. Our results suggest that the transformation pathways for alachlor and metolachlor in aquatic systems are similar and resemble the acetochlor pathway in soils proposed by Feng (Pestic. Biochem. Physiol. 1991, 34, 136); however, the oxanillic acid branch of the pathway is favored for alachlor as compared with metolachlor.The transformation of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N- (2-methoxy-1-methylethy

  2. Biodegradation and mineralization of metolachlor and alachlor by Candida xestobii.

    PubMed

    Munoz, Ana; Koskinen, William C; Cox, Lucía; Sadowsky, Michael J

    2011-01-26

    Metolachlor (2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-o-toluidide) is a pre-emergent chloroacetanilide herbicide used to control broadleaf and annual grassy weeds in a variety of crops. The S enantiomer, S-metolachlor, is the most effective form for weed control. Although the degradation of metolachlor in soils is thought to occur primarily by microbial activity, little is known about the microorganisms that carry out this process and the mechanisms by which this occurs. This study examined a silty-clay soil (a Luvisol) from Spain, with 10 and 2 year histories of metolachlor and S-metolachlor applications, respectively, for microorganisms that had the ability to degrade this herbicide. Tis paper reports the isolation and characterization of pure cultures of Candida xestobii and Bacillus simplex that have the ability to use metolachlor as a sole source of carbon for growth. Species assignment was confirmed by morphological and biochemical criteria and by sequence analysis of 18S and 16S rRNA, respectively. High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses indicated that C. xestobii degraded 60% of the added metolachlor after 4 days of growth and converted up to 25% of the compound into CO(2) after 10 days. In contrast, B. simplex biodegraded 30% of metolachlor following 5 days of growth in minimal medium. In contrast, moreover, the yeast degraded other acetanilide compounds and 80% of acetochlor (2-chloro-N-ethoxymethyl-6'-ethylaceto-o-toluidide) and alachlor (2-chloro-2',6'-diethyl-N-methoxymethylacetanilide) were degraded after 15 and 41 h of growth, respectively. The results of these studies indicate that microorganisms comprising two main branches of the tree of life have acquired the ability to degrade the same novel chlorinated herbicide that has been recently added to the biosphere. PMID:21190381

  3. Environmental fate of alachlor and metolachlor.

    PubMed

    Chesters, G; Simsiman, G V; Levy, J; Alhajjar, B J; Fathulla, R N; Harkin, J M

    1989-01-01

    Decision-makers, scientists, and the interested public should be informed what future research and education is needed if a strong pesticide regulatory program is imposed. Recommendations are intended to highlight research gaps. Some may be of general concern and apply to many pesticides. A situation that calls into question the value of many of our management decisions, is the lack of good field-scale experimentation and of logical mechanisms for translating and extrapolating laboratory data to field-scale dimensions. Many experiments were not designed to allow application of basic statistical criteria. High costs often preclude sufficient replication in field-scale experiments so that researchers must make the "no-win" choice between doing one investigation well or doing two or three poorly. The following observations about alachlor and metolachlor are provided: Pysicochemical properties are accurately determined. The herbicides' modes of action and plant selectivity have received a great deal of attention, but gaps remain in defining which of three modes of action are most important. Geographic distribution and extent of residue contamination of surface waters is documented, but groundwater contamination is poorly defined. Any groundwater monitoring protocol should limit the investigation based on sound scientific judgment since a nationwide monitoring network cannot be economically justified. Enough data are needed, however, to allow mathematical model development, verification and validation for a diversity of soil, geographic, climatic, and agricultural management conditions. In view of the importance of adsorption in determining the fate of pesticides, improved methods of determining adsorption coefficients (KD) are needed particularly for very low concentrations. The impact of soil aggregation on adsorption/desorption needs to be examined. The role of temperature and water content in adsorption/desorption processes needs clearer definition. Although

  4. Formation and transport of the sulfonic acid metabolites of alachlor and metolachlor in soil

    USGS Publications Warehouse

    Aga, D.S.; Thurman, E.M.

    2001-01-01

    Alachlor and metolachlor are dechlorinated and transformed into their corresponding ethane sulfonic acid (ESA) metabolites in soil. In a field-disappearance study, it was shown that alachlor ESA was formed at a faster rate and at concentrations 2-4 times higher than metolachlor ESA, conforming with the observed longer disappearance half-life of metolachlor (15.5 d) in the field as compared to alachlor (8 d). Runoff data also showed higher concentrations of alachlor ESA as compared to metolachlor ESA, even though they were applied at the same levels. Data from soil cores showed transport of the ESA compounds in soil to as far down as 75-90 cm below the surface, at concentrations ranging from less than 0.5 ??g/L to about 50 ??g/L. In contrast, no parent herbicide was detected at these depths. This observation correlates with the higher log KOC values for alachlor (3.33) and metolachlor (3.01) relative to their corresponding ESA metabolites, alachlor ESA (2.26), and metolachlor ESA (2.29).

  5. Biodegradation and mineralization of metolachlor and alachlor by Candida xestobii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metolachlor (2-chloro-6’-ethyl-N-(2-methoxy-1-methylethyl) aceto-o-toluidide) is a pre-emergent chloroacetanilide herbicide used to control broadleaf and annual grassy weeds in a variety of crops. The S enantiomer of metolachlor, S-metolachlor, is the most effective form for weed control. While the ...

  6. Derived Reference Doses (RfDs) for the environmental degradates of the herbicides alachlor and acetochlor: results of an independent expert panel deliberation.

    PubMed

    Gadagbui, Bernard; Maier, Andrew; Dourson, Michael; Parker, Ann; Willis, Alison; Christopher, John P; Hicks, Lebelle; Ramasamy, Santhini; Roberts, Stephen M

    2010-01-01

    An independent peer expert panel was convened under the auspices of the Alliance for Risk Assessment (ARA) to review toxicology data and derive oral Reference Doses (RfDs) for four environmental degradates of the acetanilide herbicides, alachlor and acetochlor. The degradates included in this evaluation were (1) alachlor tertiary-ethanesulfonic acid (ESA), (2) alachlor tertiary-oxanilic acid (OXA), (3) acetochlor ESA, and (4) acetochlor OXA. Each degradate was judged to have sufficient data for developing low to medium confidence RfD, with use of an additional uncertainty factor (UF) to cover data gaps. Body weight decreases were identified as the most sensitive treatment-related adverse effect for RfD development. A composite UF of 1000 (10 for human variability in sensitivity, 10 for interspecies differences in sensitivity, and 10 for subchronic to chronic and database deficiency combined; i.e., 10(A)x10(H)x10(S&D)) for each degradate was considered reasonable, while noting that an argument could be made for an UF of 3000 (10(A)x10(H)x30(S&D)). Based on the available data, an oral RfD of 0.2 mg/kg-day is recommended for both acetochlor ESA and acetochlor OXA and an oral RfD of 0.8 mg/kg-day is recommended for both alachlor ESA and alachlor OXA. PMID:20206657

  7. Accurate mass analysis of ethanesulfonic acid degradates of acetochlor and alachlor using high-performance liquid chromatography and time-of-flight mass spectrometry

    USGS Publications Warehouse

    Thurman, E.M.; Ferrer, I.; Parry, R.

    2002-01-01

    Degradates of acetochlor and alachlor (ethanesulfonic acids, ESAs) were analyzed in both standards and in a groundwater sample using high-performance liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. The negative pseudomolecular ion of the secondary amide of acetochlor ESA and alachlor ESA gave average masses of 256.0750??0.0049 amu and 270.0786??0.0064 amu respectively. Acetochlor and alachlor ESA gave similar masses of 314.1098??0.0061 amu and 314.1153??0.0048 amu; however, they could not be distinguished by accurate mass because they have the same empirical formula. On the other hand, they may be distinguished using positive-ion electrospray because of different fragmentation spectra, which did not occur using negative-ion electrospray.

  8. Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

    USGS Publications Warehouse

    Fairchild, James F.; Ruessler, Shane; Carlson, A. Ron

    1998-01-01

    This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.

  9. Effect of crop competition and herbicides on yellow nutsedge (Cyperus esculentus L. ) and root absorption, translocation, and metabolism of alachlor and metolachlor by yellow nutsedge

    SciTech Connect

    Chamblee, R.W.

    1985-01-01

    Field studies were conducted in 1980, 1981, and 1982 to compare management programs involving different cultural practices, at-planting herbicides, and postemergence herbicides to reduce yellow nutsedge (Cyperus esculentus L.) populations, in a soybean (Glycine max (L.) Merr. Ransom)-corn (Zea mays L. Pioneer 3161 and Pioneer 3358) rotation. In laboratory studies, alachlor and metolachlor toxicity, absorption, translocation, and metabolism were investigated in different sized yellow nutsedge plants. Exposure to herbicides was restricted to plant roots. Plant sizes evaluated were 4 to 6, 10 to 15, and 18 to 22-cm tall at experiment initiation. Concentrations of greater than 0.1 ppm of both alachlor and metolachlor reduced small yellow nutsedge plant size by more than 50%. At concentrations greater than 0.2 ppm increased growth reduction was seen from metolachlor but not from alachlor. Ten to 15-cm plants exposed to 1.6 ppm of alachlor and metolachlor had plant size reductions of 48 and 62%, respectively, after 12 days. There was no difference in root absorption of /sup 14/C alachlor or /sup 14/C metolachlor from nutrient solutions. After 8 days, greater than 40, 58, and 76% of available /sup 14/C was absorbed by small, medium and large plants, respectively. After 4 and 8 days of exposure, small yellow nutsedge plants had translocated 2.6 times as much /sup 14/C metolachlor to plant shoots than /sup 14/C alachlor. Larger plants translocated the herbicides equally. Small sized plants treated with /sup 14/C metolachlor retained greater than 23% of the parent material.

  10. Simultaneous determination of alachlor, metolachlor, atrazine, and simazine in water and soil by isotope dilution gas chromatography/mass spectrometry

    SciTech Connect

    Huang, L.Q.

    1989-03-01

    A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of /sup 15/N,/sup 13/C-alachlor and /sup 2/H/sub 5/-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.

  11. Acetochlor

    Integrated Risk Information System (IRIS)

    Acetochlor ; CASRN 34256 - 82 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effe

  12. METHOD DEVELOPMENT FOR ALACHLOR ESA AND OTHER ACENTANILIDE HERBICIDE DEGRADATION PRODUCTS

    EPA Science Inventory

    Introduction: Acetanilide herbicides are frequently applied in the U.S. on crops (corn, soybeans, popcorn, etc.) to control broadleaf and annual weeds. The acetanilide and acetamide herbicides currently registered for use in the U.S. are alachlor, acetochlor, metolachlor, propa...

  13. Alachlor

    Integrated Risk Information System (IRIS)

    Alachlor ; CASRN 15972 - 60 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  14. Leaching of Br-, metolachlor, alachlor, atrazine, deethylatrazine and deisopropylatrazine in clayey vadoze zone: a field scale experiment in north-east Greece.

    PubMed

    Vryzas, Zisis; Papadakis, Emmanuel Nikolaos; Papadopoulou-Mourkidou, E

    2012-04-15

    An extensive four-year research program has been carried out to explore and acquire knowledge about the fundamental agricultural practices and processes affecting the mobility and bioavailability of pesticides in soils under semi-arid Mediterranean conditions. Pesticide leaching was studied under field conditions at five different depths using suction cups. Monitoring of metolachlor, alachlor, atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and bromide ions in soil water, as well as dye patterns made apparent the significant role of preferential flow to the mobility of the studied compounds. Irrespective to their adsorption capacities and degradation rates, atrazine, metolachlor and bromide ions were simultaneously detected to 160 cm depth. Following 40 mm irrigation, just after their application, both alachlor and atrazine were leached to 160 cm depth within 18 h, giving maximum concentrations of 211 and 199 μg L(-1), respectively. Metolachlor was also detected in all depth when its application was followed by a rainfall event (50 mm) two weeks after its application. The greatest concentrations of atrazine, alachlor and metolachlor in soil water were 1795, 1166 and 845 μg L(-1), respectively. The greatest concentrations of atrazine's degradation products (both DEA and DIA) appeared later in the season compared to the parent compound. Metolachlor exhibited the greatest persistence with concentrations up to 10 μg L(-1) appearing in soil water 18 months after its application. Brilliant blue application followed by 40 mm irrigation clearly depict multi-branching network of preferential flow paths allowing the fast flow of the dye down to 150 cm within 24 h. This network was created by soil cracks caused by shrinking of dry soils, earthworms and plant roots. Chromatographic flow of the stained soil solution was evident only in the upper 10-15 cm of soil. PMID:22325931

  15. Metolachlor

    Integrated Risk Information System (IRIS)

    Metolachlor ; CASRN 51218 - 45 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  16. Occurrence of alachlor and its sulfonated metabolite in rivers and reservoirs of the midwestern United States: The importance of sulfonation in the transport of chloroacetanilide herbicides

    USGS Publications Warehouse

    Thurman, E.M.; Goolsby, D.A.; Aga, D.S.; Pomes, M.L.; Meyer, M.T.

    1996-01-01

    Alachlor and its metabolite, 2-[(2',6'-diethylphenyl)- (methoxymethyl)amino]-2-oxoethanesulfonate (ESA), were identified in 76 reservoirs in the midwestern United States using immunoassay, liquid chromatography, and gas chromatography/mass spectrometry. The median concentration of ESA (0.48 ??g/L) exceeded the median concentration of alachlor (<0.05 ??g/L), with highest values in the upper Midwest. ESA also was detected in the Mississippi River from the mouth to the headwaters at concentrations of 0.2-1.5 ??g/L, exceeding the concentration of alachlor. In a field runoff study, alachlor rapidly formed ESA. It is hypothesized that a glutathione conjugate forms, which later oxidizes in soil to ESA. The removal of the chlorine atom lessens the toxicity of the parent compound and increases runoff potential. It is hypothesized further that sulfonic acid metabolites of other chloroacetanilides, including acetochlor, butachlor, metolachlor, and propachlor, also occur in surface water.

  17. Volatilization of alachlor from polymeric formulations.

    PubMed

    Dailey, Oliver D

    2004-11-01

    Pesticides may be dispersed throughout the environment by several means, including groundwater contamination, surface water contamination, and volatilization with subsequent atmospheric transport and deposition. In earlier research primarily directed at reducing the potential for groundwater contamination, a number of herbicides were microencapsulated within several different polymers. These polymeric formulations were evaluated for efficacy in the greenhouse. In the studies described in this paper, three polymeric alachlor formulations that were the most effective in the greenhouse were evaluated in laboratory volatility studies using pure alachlor and a commercial formulation (Lasso 4EC) for comparison purposes. In a given experiment, technical alachlor, Lasso 4EC, and two polymeric formulations were applied to soil and evaluated in a contained system under 53% humidity with a fixed flow rate. Evolved alachlor was collected in ethylene glycol, recovered with C18 solid phase extraction cartridges, and analyzed by reverse-phase high-performance thin-layer chromatography with densitometry. Duration of the studies ranged from 32 to 39 days. In studies in which all formulations were uniformly incorporated in the soil, total alachlor volatilization from the polymeric microcapsules was consistently lower than that from the alachlor and Lasso 4EC formulations. In studies in which the polymeric formulations were sprinkled on the surface of the soil, microcapsules prepared with the polymer cellulose acetate butyrate released the smallest quantity of volatilized alachlor.

  18. DNA adduct formation by alachlor metabolites

    SciTech Connect

    Brown, M.A.; Kimmel, E.C.; Casida, J.E.

    1988-01-01

    The extent of DNA adduct formation by alachlor (ArN(CH/sub 2/OCH/sub 3/)C(O)CH/sub 2/Cl wherein Ar is 2,6-diethylphenyl) and its metabolites is used as a guide to deduce the causal agent(s) in the carcinogenicity of this major herbicide. (/sup 14/C-phenyl)Alachlor is compared to its two metabolic cleavage products, (/sup 14/C-phenyl) 2-chloro-N-(2,6-diethylphenyl)acetamide (CDEPA) (ArNHC(O)CH/sub 2/Cl) and (/sup 14/C-phenyl)2,6-diethylaniline (DEA) (ArNH/sub 2/), and to (/sup 14/C-methoxy)alachlor in various in vitro and in vivo systems. Horseradish peroxidase and hydrogen peroxide activate DEA, but not CEDPA or alachlor, for formation of adducts with calf thymus DNA, which probably involves 2,6-diethylnitrosobenzene (ArNO) as an intermediate. Mouse liver microsomes and NADPH are both required to enhance the binding from each labeled preparation to calf thymus DNA; 4-fold higher labeling is observed from (/sup 14/C-methoxy)- than from (/sup 14/C-phenyl)alachlor. This 4-fold preferential DNA labeling from the /sup 14/C-methoxy compound is likewise found in the liver of mice treated intraperitoneally. Mouse liver protein and hemoglobin are also labeled, in vivo, with (/sup 14/C-phenyl)alachlor, -CDEPA and -DEA, and, as with the DNA, the labeling of these proteins is 1.5- to 2-fold higher with (/sup 14/C-methoxy)alachlor.

  19. Biodegradation of acetochlor by a newly isolated Pseudomonas strain.

    PubMed

    Luo, Wei; Gu, Qiuya; Chen, Wenting; Zhu, Xiangcheng; Duan, Zhibing; Yu, Xiaobin

    2015-05-01

    A novel microbial strain JD115 capable of degrading acetochlor was isolated from the sludge of acetochlor manufacture and was identified as Pseudomonas aeruginosa species. This strain was able to grow on acetochlor as the sole source of both carbon and nitrogen. The biodegradation of acetochlor by strain JD115 could be described either by the pseudo-first-order or by the second-order kinetics models, while the latter gave a better performance. The strain optimally degraded acetochlor at a pH value of 7.0 and a temperature of 37 °C. Additional nutriments could greatly enhance the degradation rate of acetochlor up to 95.4% in the presence of 50 mg acetochlor l(-1). The metabolite analyses by GC-MS presumed that catechol was an intermediate product of acetochlor, which was finally degraded for 5 days of incubation. This study highlights the potential use of this strain for the bioremediation of an acetochlor-polluted environment.

  20. Metolachlor stereoisomers: Enantioseparation, identification and chiral stability.

    PubMed

    Xie, Jingqian; Zhang, Lijuan; Zhao, Lu; Tang, Qiaozhi; Liu, Kai; Liu, Weiping

    2016-09-01

    Metolachlor is a chiral herbicide consisting of four stereoisomers, which is typically used as a racemic mixture or is enriched with the herbicidally active 1'S-isomers. Because studies on the enantioselective behavior of phyto-biochemical processes and the environmental fate of metolachlor have become significant, a practical method for analyzing and separating metolachlor stereoisomers must be developed. In the present study, the enantiomeric separation of metolachlor was achieved using OD-H, AS-H, OJ-H and AY-H chiral columns. The effects of different organic modifiers in an n-hexane-based mobile phase were investigated, and various temperatures and flow rates, which may influence metolachlor separation, were also explored. The optimal resolution was obtained using an AY-H column with n-hexane/EtOH (96/4) as the mobile phase at a rate and temperature of 0.6mLmin(-1) and 25°C, respectively. The absolute configuration of the four stereoisomers was identified as αSS, αRS, αSR, αRR using computed and experimentally measured ECD and VCD spectra. Thermal interconversion and solvent stability experiments were also performed. Pure metolachlor stereoisomers in different organic solvents and water at 4°C or 30°C were stable. These results were used to establish a sound method for analyzing, preparing, characterizing, and preserving individual metolachlor stereoisomers in most natural environments. PMID:27544750

  1. Development of controlled release formulations of alachlor in ethylcellulose.

    PubMed

    Fernandez-Urrusuno, R; Gines, J M; Morillo, E

    2000-01-01

    The herbicide alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide) is frequently implicated in groundwater contamination. Microencapsulated alachlor should have reduced potential for leaching in the soil while maintaining effective biological activity. Microspheres of alachlor were prepared using ethylcellulose, according to the solvent evaporation method. The influence of formulation variables affecting the release rate of pesticide, such as the molecular weight of ethylcellulose, the amount of emulsifying agent, the pesticide/polymer ratio and the particle size, were investigated. The results showed that microspheres retarded the release of alachlor in different degrees. Pesticide/polymer ratio and particle size were the more important factors determining the alachlor release. Ethylcellulose microspheres may prove useful for the prolonged release of alachlor.

  2. Microorganisms capable of metabolizing the herbicide metolachlor.

    PubMed Central

    Saxena, A; Zhang, R W; Bollag, J M

    1987-01-01

    We screened several strains of microorganisms and microbial populations for their ability to mineralize or transform the herbicide metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetami de] because such cultures would potentially be useful in the cleanup of contaminated sites. Although we used various inocula and enrichment culture techniques, we were not able to isolate microorganisms that could mineralize metolachlor. However, strains of Bacillus circulans, Bacillus megaterium, Fusarium sp., Mucor racemosus, and an actinomycete were found to transform metolachlor. Several metabolites could be determined with high-performance liquid chromatography. The tolerance of the strains to high concentrations of metolachlor was also evaluated for the usefulness of the strains for decontamination. Tolerance of the actinomycete to metolachlor concentrations over 200 ppm (200 micrograms/ml) was low and could not be increased by doubling the sucrose concentration in the growth medium or by using a large biomass as inoculum. However, a Fusarium sp. could grow and transform metolachlor up to a concentration of 300 ppm. PMID:3105457

  3. [The transferability of acetochlor and butachlor in soil].

    PubMed

    Zheng, H; Ye, C

    2001-09-01

    The transferability of acetochlor and butachlor in soil was studied by soil thin layer chromatography. Acetochlor and butachlor were dropped on the glass plate and spreaded soil on the glass plate was collected per 2 cm, then acetochlor and butachlor were analyzed quantitatively by HPlC. When river water was as the spread solution, Rf(relative flow) of acetochlor and butachlor in the Haidian loam were 0.116 and 0.031 respectively, Rf of acetochlor and butachlor in the Baiyangdian sandy loam were 0.147 and 0.032 respectively. When 30 mg.L-1 dodecylbenzene sulfonic acid sodium salt solution was as the spread solution, Rf of acetochlor and butachlor in the Haidian loam were 0.159 and 0.034 respectively. Acetochlor's transferability was weak and the gradation of its transferability was II grade, while butachlor's was more weak and the gradation was I grade. Anionic surfactant solution can promote pesticides to transfer. Cationic surfactant solution can impede pesticides to transfer.

  4. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... stoichiometric equivalents of acetochlor, in or on the following commodities: Commodity Parts per million Beet, sugar, dried pulp 0.50 Beet, sugar, molasses 0.80 Beet, sugar, roots 0.30 Beet, sugar, tops 0.70...

  5. Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

    PubMed

    Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

    2002-10-01

    The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

  6. Progression of alachlor-induced olfactory mucosal tumours

    PubMed Central

    Genter, Mary Beth; Burman, Dawn M; Bolon, Brad

    2002-01-01

    Alachlor is an herbicide used primarily in the production of corn (maize), peanuts, and soybeans and is associated with cancer of the nasal cavity, thyroid, and stomach in rats. Previous work from our laboratory demonstrated that the nasal cavity tumours originate from the olfactory mucosa, and that neoplasms were present following 6 months of exposure (126 mg/kg/day in the diet). The studies presented herein were conducted to determine more precisely the earliest time point at which alachlor-induced tumours were present, and to describe the histological changes that occur en route to tumour formation. We determined that dramatic histological changes, including respiratory metaplasia of the olfactory mucosa, were present following 3 months of exposure, and the earliest alachlor-induced olfactory mucosal tumours were detected following 5 months of treatment. Because alachlor is positive in short-term mutagenicity assays with olfactory mucosal activation, and because of the relatively short time-to-tumour formation observed with alachlor, we also conducted a ‘stop’ study in which rats were treated with alachlor for 1 month and then held without further treatment for an additional 5 months. This study demonstrated that abbreviated alachlor exposure did not result in subsequent tumour formation within the 6-month observation period. PMID:12657139

  7. ACETANILIDE HERBICIDE DEGRADATION PRODUCTS BY LC/MS

    EPA Science Inventory

    Acetanilide herbicides are frequently applied in the U.S. on crops (corn, soybeans, popcorn, etc.) to control broadleaf and annual weeds. The acetanilide and acetamide herbicides currently registered for use in the U.S. are alachlor, acetochlor, metolachlor, propachlor, flufen...

  8. Implications of sampling frequency to herbicide conservation effects assessment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide losses from row crop agriculture represent potential human health hazards. In particular, atrazine concentrations in drinking water must not exceed its maximum contaminant level (MCL) of 3 'g/L. Atrazine, simazine, alachlor, acetochlor, metolachlor, and glyphosate were monitored along ti...

  9. Herbicide Losses in the Saint Joseph River Watershed: Impacts of Hydrology and Land Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbicide losses from row crop agriculture represent potential human health hazards, and are a major focus of the Conservation Effects Assessment Project (CEAP). Atrazine, simazine, alachlor, acetochlor, metolachlor, and glyphosate were monitored in tile-fed drainage ditches draining to a drinking ...

  10. Isolation and characterization of a pseudomonas oleovorans degrading the chloroacetamide herbicide acetochlor.

    PubMed

    Xu, Jun; Qiu, Xinghui; Dai, Jiayin; Cao, Hong; Yang, Min; Zhang, Jing; Xu, Muqi

    2006-06-01

    To date, no pure bacterial cultures that could degrade acetochlor have been described. In this study, one strain of microorganism capable of degrading acetochlor, designated as LCa2, was isolated from acetochlor-contaminated soil. The strain LCa2 is Pseudomonas oleovorans according to the criteria of Bergey's manual of determinative bacteriology and sequence analysis of the partial 16S rRNA gene. Optimum growth temperature and pH were 35 degrees C and 8.0, respectively. The strain could degrade 98.03% of acetochlor treated at a concentration of 7.6 mg l(-1) after 7 days of incubation and could tolerate 200 mg l(-1) of acetochlor. When the acetochlor concentration became higher, the degradation cycle became longer. The acetochlor biodegradation products were identified by GC-MS based on mass spectral data and fragmentation patterns. The main plausible degradative pathways involved dechlorination, hydroxylation, N-dealkylation, C-dealkylation and dehydrogenation. PMID:16715401

  11. Acetochlor in the hydrologic system in the midwestern United States, 1994

    USGS Publications Warehouse

    Kolpin, D.W.; Nations, B.K.; Goolsby, D.A.; Thurman, E.M.

    1996-01-01

    The herbicide acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide] was given conditional registration in the United States by the U.S. Environmental Protection Agency in March 1994. This registration provided a rare opportunity to investigate the occurrence of a pesticide during its first season of extensive use in the midwestern United States. Water samples collected and analyzed by the U.S. Geological Survey during 1994 documented the distribution of acetochlor in the hydrologic system; it was detected in 29% of the rain samples from four sites in Iowa, 17% of the stream samples from 51 sites across nine states, and 0% of the groundwater samples from 38 wells across eight states. Acetochlor exhibited concentration increases in rain and streams following its application to corn in the midwestern United States, with 75% of the rainwater and 35% of the stream samples having acetochlor detected during this time period. Acetochlor concentrations in rain decreased as the growing season progressed. Based on the limited data collected for this study, it is anticipated that acetochlor concentrations will have a seasonal pattern in rain and streams similar to those of other acetanilide herbicides examined. Possible explanations for the absence of acetochlor in groundwater for this study include the rapid degradation of acetochlor in the soil zone, insufficient time for this first extensive use of acetochlor to have reached the aquifers sampled, and the possible lack of acetochlor use in the recharge areas for the wells examined.

  12. Use of acetochlor and cancer incidence in the Agricultural Health Study

    PubMed Central

    Lerro, Catherine C.; Koutros, Stella; Andreotti, Gabriella; Hines, Cynthia J.; Blair, Aaron; Lubin, Jay; Ma, Xiaomei; Zhang, Yawei; Freeman, Laura E. Beane

    2015-01-01

    Since its registration in 1994 acetochlor has become a commonly used herbicide in the US, yet no epidemiologic study has evaluated its carcinogenicity in humans. We evaluated use of acetochlor and cancer incidence among licensed pesticide applicators in the Agricultural Health Study. In telephone interviews administered 1999-2005, participants provided information on acetochlor use, use of other pesticides, and additional potential confounders. We used Poisson regression to estimate relative risks (RR) and 95% confidence intervals (95% CI) for cancers that occurred from the time of interview through 2011 in Iowa and 2010 in North Carolina. Among 33,484 men, there were 4,026 applicators who used acetochlor and 3,234 incident cancers, with 304 acetochlor-exposed cases. Increased risk of lung cancer was observed among acetochlor users (RR = 1.74; 95% CI: 1.07-2.84) compared to nonusers, and among individuals who reported using acetochlor/atrazine product mixtures (RR = 2.33; 95% CI: 1.30-4.17), compared to nonusers of acetochlor. Colorectal cancer risk was significantly elevated among the highest category of acetochlor users (RR = 1.75; 95% CI: 1.08-2.83) compared to never users. Additionally, borderline significantly increased risk of melanoma (RR = 1.61; 95% CI: 0.98-2.66) and pancreatic cancer (RR = 2.36; 95% CI: 0.98-5.65) were observed among acetochlor users. The associations between acetochlor use and lung cancer, colorectal cancer, melanoma, and pancreatic cancer are suggestive, however the lack of exposure-response trends, small number of exposed cases, and relatively short time between acetochlor use and cancer development, prohibit definitive conclusions. PMID:25559664

  13. Use of acetochlor and cancer incidence in the Agricultural Health Study.

    PubMed

    Lerro, Catherine C; Koutros, Stella; Andreotti, Gabriella; Hines, Cynthia J; Blair, Aaron; Lubin, Jay; Ma, Xiaomei; Zhang, Yawei; Beane Freeman, Laura E

    2015-09-01

    Since its registration in 1994 acetochlor has become a commonly used herbicide in the US, yet no epidemiologic study has evaluated its carcinogenicity in humans. We evaluated the use of acetochlor and cancer incidence among licensed pesticide applicators in the Agricultural Health Study. In telephone interviews administered during 1999-2005, participants provided information on acetochlor use, use of other pesticides and additional potential confounders. We used Poisson regression to estimate relative risks (RR) and 95% confidence intervals (95% CI) for cancers that occurred from the time of interview through 2011 in Iowa and 2010 in North Carolina. Among 33,484 men, there were 4,026 applicators who used acetochlor and 3,234 incident cancers, with 304 acetochlor-exposed cases. Increased risk of lung cancer was observed among acetochlor users (RR = 1.74; 95% CI: 1.07-2.84) compared to nonusers, and among individuals who reported using acetochlor/atrazine product mixtures (RR = 2.33; 95% CI: 1.30-4.17), compared to nonusers of acetochlor. Colorectal cancer risk was significantly elevated among the highest category of acetochlor users (RR = 1.75; 95% CI: 1.08-2.83) compared to never users. Additionally, borderline significantly increased risk of melanoma (RR = 1.61; 95% CI: 0.98-2.66) and pancreatic cancer (RR = 2.36; 95% CI: 0.98-5.65) were observed among acetochlor users. The associations between acetochlor use and lung cancer, colorectal cancer, melanoma and pancreatic cancer are suggestive, however the lack of exposure-response trends, small number of exposed cases and relatively short time between acetochlor use and cancer development prohibit definitive conclusions.

  14. Soil Pseudomonas community structure and its antagonism towards Rhizoctonia solani under the stress of acetochlor.

    PubMed

    Wu, Minna; Zhang, Xiaoli; Zhang, Huiwen; Zhang, Yan; Li, Xinyu; Zhou, Qixing; Zhang, Chenggang

    2009-09-01

    In a microcosm experiment, the amplified ribosomal DNA restriction analysis was adopted to investigate the Pseudomonas community structure in soils applied with different concentrations (0, 50, 150, and 250 mg/kg) of acetochlor, and an in vitro assay was made to examine the antagonistic activity of isolated Pseudomonas strains acting on soil-borne pathogen Rhizoctonia solani. The results showed that acetochlor application changed the community structure of Pseudomonas in aquic brown soil. The diversity of Pseudomonas and the amount of isolated Pseudomonas strains with antagonistic activity decreased with an increasing acetochlor concentration, and the toxic effect of acetochlor reached to a steady level at 150-250 mg/kg.

  15. Evaluation of mortality and cancer incidence among alachlor manufacturing workers.

    PubMed Central

    Acquavella, J F; Riordan, S G; Anne, M; Lynch, C F; Collins, J J; Ireland, B K; Heydens, W F

    1996-01-01

    Alachlor is the active ingredient in a family of preemergence herbicides. We assessed mortality rates from 1968 to 1993 and cancer incidence rates from 1969 to 1993 for manufacturing workers with potential alachlor exposure. For workers judged to have high alachlor exposure, mortality from all causes combined was lower than expected [23 observed, standardized mortality ratio (SMR) = 0.7, 95% CI, 0.4-1.0], cancer mortality was similar to expected (6 observed, SMR = 0.7, 95% CI, 0.3-1.6), and there were no cancer deaths among workers with 5 or more years high exposure and 15 or more years since first exposure (2.3 expected, SMR = 0, 95% CI, 0-1.6). Cancer incidence for workers with high exposure potential was similar to the state rate [18 observed, standardized incidence ratio (SIR) = 1.2, 95% CI, 0.7-2.0], especially for workers exposed for 5 or more years and with at least 15 years since first exposure (4 observed, SIR = 1.0, 95% CI, 0.3-2.7). The most common cancer for these latter workers was colorectal cancer (2 observed, SIR 3.9, 95% CI, 0.5-14.2 among workers). Despite the limitations of this study with respect to small size and exposure estimating, the findings are useful for evaluating potential alachlor-related health risks because past manufacturing exposures greatly exceeded those characteristic of agricultural operations. These findings suggest no appreciable effect of alachlor exposure on worker mortality or cancer incidence rates during the study period. PMID:8841758

  16. Organo-clay formulation of acetochlor for reduced movement in soil.

    PubMed

    El-Nahhal, Y; Nir, S; Serban, C; Rabinovitz, O; Rubin, B

    2001-11-01

    This study aimed to design ecologically acceptable formulations of acetochlor by adsorbing it on montmorillonite exchanged by a small organic cation, phenyltrimethylammonium (PTMA). Adsorption of acetochlor on the clay mineral exchanged with different organic cations and its release from these complexes were determined by GC and modeled by Langmuir equation. Interactions between acetochlor molecules and the exchanged organic cation on the clay surface were studied by Fourier transform infrared spectroscopy. Leaching of acetochlor in soil was determined by a bioassay using a column technique and Setaria viridis as a test plant. The adsorbed amounts of acetochlor on montmorillonite exchanged by PTMA at a loading of 0.5 mmol/g of clay were higher than at a loading up to the cation-exchange capacity, i.e., 0.8 mmol/g, and were higher than obtained by using a clay mineral exchanged by other organic cations. Preloading montmorillonite by PTMA at 0.5 mmol/g yielded maximal shifts of the infrared peaks of the herbicide. The above formulation of acetochlor yielded slow release in water and showed improved weed control in field and greenhouse experiments in comparison with the commercial formulation. The PTMA-clay formulation of acetochlor maintained herbicidal activity in the topsoil and yielded the most significant reduction in herbicide leaching and persistence under field conditions. The application of this formulation can minimize the risk to groundwater and can reduce the applied rates.

  17. Enantioselective toxicity of metolachlor to Scenedesmus obliquus in the presence of cyclodextrins.

    PubMed

    Liu, Hui J; Cai, Wei D; Huang, Ruo N; Xia, Hui L; Wen, Yue Z

    2012-02-01

    Cyclodextrins (CDs) possess a variety of chiral centers and are capable of recognizing enantiomeric molecules through the formation of inclusion complexes. Two types of CDs, α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), were selected to evaluate the effects of the enantioselective ecotoxicity of racemic metolachlor (Rac-metolachlor) and its S-enantiomer (S-metolachlor) on the freshwater algae Scenedesmus obliquus (S. obliquus) by acute toxicity test. The results showed that the aquatic toxicity of S-metolachlor was higher than Rac-metolachlor and that CDs enhanced the toxicity of metolachlor enantioselectively by increasing the aquatic toxicity of Rac-metolachlor rather than that of S-metolachlor to S. obliquus. The equilibrium constant for Rac-metolachlor-CD complexes was higher than that of S-metolachlor-CDs, which was responsible for the greater aquatic toxicity shift effect of Rac-metolachlor. Thermodynamic studies of CD complexes showed that inclusion for all of the complexes was primarily a spontaneous, enthalpy-driven process. These results will help to understand the preliminary mechanism of shifting aquatic toxicity of metolachlor by CDs and the CDs mediated environmental processes of metolachlor, to correctly apply CDs to chiral pesticides formulation and environmental remediation of chiral contaminants. PMID:22180313

  18. An evaluation of the feasibility of using cytogenetic damage as a biomarker for alachlor exposure.

    PubMed

    Kligerman, A D; Erexson, G L

    1999-04-26

    Alachlor is a widely used herbicide for which there is significant human exposure, principally through groundwater contamination and inhalation. Because alachlor is purported to be carcinogenic and mutagenic, we initiated studies to determine if induced cytogenetic damage could be used as a biomarker for exposure to this herbicide. Both isolated and whole blood human lymphocytes were exposed to alachlor using several protocols. The lymphocytes were cultured for analysis of sister chromatid exchange (SCE), chromosome aberrations (CAs), micronuclei (MN) in cytochalasin B-induced binucleated cells, and proliferation kinetics using the replicative index (RI). In addition, CD rats were injected with either 10 or 50 mg kg-1 of alachlor, 2-chloro-N-(2,6-diethylphenyl) acetamide (CDEPA) or 2, 6-diethylanaline (DEA). After 24 h, the peripheral blood lymphocytes were removed and cultured for SCE and RI analysis. Alachlor did induce a concentration-related increase in SCE in vitro, but neither it nor its metabolites (CDEPA or DEA) induced a significant increase in SCEs or an alteration of RI in vivo. At the highest in vitro concentration tested, alachlor induced a statistically-significant increase in MN, but no concomitant increase in CAs was seen. From analyses of our data and the literature on alachlor clastogenicity and exposure levels, we concluded that cytogenetic damage may not be an adequately sensitive marker for evaluating human exposure to alachlor.

  19. KINETICS OF ALACHLOR TRANSFORMATION AND IDENTIFICATION OF METABOLITES UNDER ANAEROBIC CONDITIONS. (R825549C037)

    EPA Science Inventory

    Alachlor is one of the two most commonly used herbicides in the United States. In the environment, little mineralization of this compound has been found to occur, and metabolites of alachlor may be formed and could accumulate. The objectives of this study were to determine the...

  20. Chiral separation of metolachlor ethane sulfonic acid as a groundwater dating tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have studied the hydrologic fate of metolachlor and its two predominant metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid, in groundwater and base flows of streams for several years. These two metabolites are excellent markers for groundwater processes related to...

  1. Using chiral identification of metolachlor ethane sulfonic acid as a groundwater dating tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have studied the hydrologic fate of metolachlor and its two predominant metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid, in groundwater and base flows of streams for several years. These two metabolites are excellent markers for groundwater processes related to...

  2. [Residual levels of acetochlor in source water and drinking water of China's major cities].

    PubMed

    Yu, Zhi-Yong; Jin, Fen; Li, Hong-Yan; An, Wei; Yang, Min

    2014-05-01

    The concentration levels of acetochlor were investigated in source water and drinking water from 36 major cities in China by solid phase extraction (SPE) combined with gas chromatography - mass spectrometry (GC-MS). Acetochlor detection rate was 66.9% in all the 145 source water samples collected with an average concentration of 33.9 ng L-1. The average removal rate of acetochlor was limited through the drinking water treatment process. The detection concentration of the northeast region was the highest. The concentrations of acetochlor detected in lake were higher than those in river and groundwater as source water. The detection rate and concentration of Liaohe river watershed and the coastal watershed were the highest.

  3. The Metolachlor Herbicide: An Exercise in Today's Stereochemistry

    ERIC Educational Resources Information Center

    Mannschreck, Albrecht; von Angerer, Erwin

    2009-01-01

    Metolachlor is one of the most widely used agents registered for the protection of many cultivated plants against weeds. Because of axial and central chirality, this molecule forms four stereoisomers, the investigation of which by [superscript 1]H NMR and chromatography is described. It is shown that the isomers do not interconvert at room…

  4. Dissipation and leaching of pyroxasulfone and s-metolachlor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pyroxasulfone dissipation and mobility in the soil was evaluated and compared to S-metolachlor in 2009 and 2010 at two field sites in northern Colorado, on a Nunn fine clay loam, and Olney fine sandy loam soil. Pyroxasulfone dissipation half-life (DT50) values varied from 47 to 134 d, and those of S...

  5. Effects of soil type upon metolachlor losses in subsurface drainage.

    PubMed

    Novak, S M; Portal, J M; Schiavon, M

    2001-01-01

    A field experiment at La Bouzule (Lorraine, France) investigated metolachlor movement to subsurface drains in two soil types, a silt loam and a heavy clay soil, under identical agricultural management practices and climatic conditions. Drainage volumes and concentrations of metolachlor in the soil plough layer and drainwater were monitored after herbicide application from May 1996 to February 1997, and from May to August 1998. Total losses in drainwater were 0.08% and 0.18% of the amount applied to the silt loam compared with 0.59% and 0.41% for the clay soil, in 1996/97 and 1998, respectively. In 1996/97, 32% of total metolachlor loss from the silt loam and 91% from the clay soil occurred during the spring/summer period following treatment. Peak concentrations were 18.5 and 171.6 microg l(-1) for the silt loam and 130.6 and 395.3 microg l(-1) for the clay soil during the spring/summer periods of 1996/97 and 1998, respectively. During the autumn/winter period, concentrations did not exceed 2.2 microg l(-1) for the silt loam and 2.6 microg l(-1) for the clay soil. The experimental results indicate that metolachlor losses in drainwater were primarily caused by preferential flow (macropore flow) which was greater in the clay soil than in the silt loam, and occurring mainly during the spring/summer periods.

  6. Biodegradation of Metolachlor by Soil Bacteria and Yeast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metolachlor (2-chloro-6’-ethyl-N-(2-methoxy-1-methylethyl) aceto-o-toluidide) is a pre-emergent chloroacetanilide herbicide used to control broadleaf and annual grassy weeds of corn, soybean, peanuts, sorghum, potatoes, cotton, and woody ornamental plants. It has been estimated that 15-24 and 20-24 ...

  7. Effects of soil type upon metolachlor losses in subsurface drainage.

    PubMed

    Novak, S M; Portal, J M; Schiavon, M

    2001-01-01

    A field experiment at La Bouzule (Lorraine, France) investigated metolachlor movement to subsurface drains in two soil types, a silt loam and a heavy clay soil, under identical agricultural management practices and climatic conditions. Drainage volumes and concentrations of metolachlor in the soil plough layer and drainwater were monitored after herbicide application from May 1996 to February 1997, and from May to August 1998. Total losses in drainwater were 0.08% and 0.18% of the amount applied to the silt loam compared with 0.59% and 0.41% for the clay soil, in 1996/97 and 1998, respectively. In 1996/97, 32% of total metolachlor loss from the silt loam and 91% from the clay soil occurred during the spring/summer period following treatment. Peak concentrations were 18.5 and 171.6 microg l(-1) for the silt loam and 130.6 and 395.3 microg l(-1) for the clay soil during the spring/summer periods of 1996/97 and 1998, respectively. During the autumn/winter period, concentrations did not exceed 2.2 microg l(-1) for the silt loam and 2.6 microg l(-1) for the clay soil. The experimental results indicate that metolachlor losses in drainwater were primarily caused by preferential flow (macropore flow) which was greater in the clay soil than in the silt loam, and occurring mainly during the spring/summer periods. PMID:11100922

  8. Nuclear Magnetic Resonance Identification of New Sulfonic Acid Metabolites of Chloroacetanilide Herbicides

    USGS Publications Warehouse

    Morton, M.D.; Walters, F.H.; Aga, D.S.; Thurman, E.M.; Larive, C.K.

    1997-01-01

    The detection of the sulfonic acid metabolites of the chloroacetanilide herbicides acetochlor, alachlor, butachlor, propachlor, and, more recently, metolachlor in surface and ground water suggests that a common mechanism for dechlorination exists via the glutathione conjugation pathway. The identification of these herbicides and their metabolites is important due to growing public awareness and concern about pesticide levels in drinking water. Although these herbicides are regulated, little is known about the fate of their metabolites in soil. The sulfonic acid metabolites were synthesized by reaction of the parent compounds with an excess of sodium sulfite. Acetochlor, alachlor, butachlor, metolachlor, and propachlor and their sulfonic acid metabolites were studied by nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry. This paper provides a direct method for the preparation and characterization of these compounds that will be useful in the analysis and study of chloracetanilide herbicides and their metabolites.

  9. Identification of a new sulfonic acid metabolite of metolachlor in soil

    USGS Publications Warehouse

    Aga, D.S.; Thurman, E.M.; Yockel, M.E.; Zimmerman, L.R.; Williams, T.D.

    1996-01-01

    An ethanesulfonic acid metabolite of metolachlor (metolachlor ESA) was identified in soil-sample extracts by negative-ion, fast-atom bombardment mass spectrometry (FAB-MS) and FAB tandem mass spectrometry (FAB-MS/MS). Production fragments from MS/MS analysis of the deprotonated molecular ion of metolachlor ESA in the soil extract can be reconciled with the structure of the synthesized standard. The elemental compositions of the (M - H)- ions of the metolachlor ESA standard and the soil-sample extracts were confirmed by high-resolution mass spectrometry. A dissipation study revealed that metolachlor ESA is formed in soil under field conditions corresponding to a decrease in the concentration of the parent herbicide, metolachlor. The identification of the sulfonated metabolite of metolachlor suggests that the glutathione conjugation pathway is a common detoxification pathway shared by chloroacetanilide herbicides.

  10. Mechanism study of alachlor biodegradation by Paecilomyces marquandii with proteomic and metabolomic methods.

    PubMed

    Szewczyk, Rafał; Soboń, Adrian; Słaba, Mirosława; Długoński, Jerzy

    2015-06-30

    Alachlor is an herbicide that is widely used worldwide to protect plant crops against broadleaf weeds and annual grasses. However, due to its endocrine-disrupting activity, its application had been banned in the European Union. As described in our earlier work, Paecilomyces marquandii is a microscopic fungus capable of alachlor removal by N-acetyl oxidation. Our current work uses proteomics and metabolomics to gain a better understanding of alachlor biodegradation by the microscopic fungus P. marquandii. The data revealed that the addition of alachlor reduced the culture growth and glucose consumption rates. Moreover, the rates of glycolysis and the tricarboxylic acids (TCA) cycle increased during the initial stage of growth, and there was a shift toward the formation of supplementary materials (UDP-glucose/galactose) and reactive oxygen species (ROS) scavengers (ascorbate). Proteomic analysis revealed that the presence of xenobiotics resulted in a strong upregulation of enzymes related to energy, sugar metabolism and ROS production. However, the unique overexpression of cyanide hydratase in alachlor-containing cultures may implicate this enzyme as the key protein involved in the alachlor biodegradation pathway. The characterization of P. marquandii-mediated alachlor removal in terms of cell structure and function provides a deeper insight into the strategies of microorganisms toward xenobiotic biodegradation. PMID:25765177

  11. Mechanism study of alachlor biodegradation by Paecilomyces marquandii with proteomic and metabolomic methods.

    PubMed

    Szewczyk, Rafał; Soboń, Adrian; Słaba, Mirosława; Długoński, Jerzy

    2015-06-30

    Alachlor is an herbicide that is widely used worldwide to protect plant crops against broadleaf weeds and annual grasses. However, due to its endocrine-disrupting activity, its application had been banned in the European Union. As described in our earlier work, Paecilomyces marquandii is a microscopic fungus capable of alachlor removal by N-acetyl oxidation. Our current work uses proteomics and metabolomics to gain a better understanding of alachlor biodegradation by the microscopic fungus P. marquandii. The data revealed that the addition of alachlor reduced the culture growth and glucose consumption rates. Moreover, the rates of glycolysis and the tricarboxylic acids (TCA) cycle increased during the initial stage of growth, and there was a shift toward the formation of supplementary materials (UDP-glucose/galactose) and reactive oxygen species (ROS) scavengers (ascorbate). Proteomic analysis revealed that the presence of xenobiotics resulted in a strong upregulation of enzymes related to energy, sugar metabolism and ROS production. However, the unique overexpression of cyanide hydratase in alachlor-containing cultures may implicate this enzyme as the key protein involved in the alachlor biodegradation pathway. The characterization of P. marquandii-mediated alachlor removal in terms of cell structure and function provides a deeper insight into the strategies of microorganisms toward xenobiotic biodegradation.

  12. The influence of alachlor, trifluralin, and diazinon on the development of endogenous mycorrhizae in soybeans.

    PubMed

    Burpee, L L; Cole, H

    1978-02-01

    Preplant incorporated treatments of 2 and 4 kg/ha of trifluralin and diazinon had no significant effect on growth, P accumulation or root colonization by mycorrhizal fungi in soybeans planted in an Andover clay loam. At 4 kg/ha, alachlor and trifluralin inhibited root development of 25 day-old plants. The 4 kg/ha alachlor treatment reduced shoot weight of 25 day old plants significantly and suppressed mycorrhizal development of 25 to 60 day old plants. At currently used commercial rates neither alachlor, trifluralin, nor diazinon affected mycorrhizal development under the conditions of the experiment.

  13. Occurrence and distribution of pesticides in streams of the Eastern Iowa Basins, 1996-98

    USGS Publications Warehouse

    Schnoebelen, Douglas J.; Kalkhoff, Stephen J.; Becher, Kent D.

    2001-01-01

    Occurrence of pesticide compounds varied by landform region. The triazine herbicides, atrazine and cyanazine and their degradates were present in significantly greater concentrations in the Southern Iowa Drift Plain (predominantly loess soils) than either the Des Moines Lobe or the Iowan Surface (predominantly till soils). Less atrazine and cyanazine are applied to till soils because of pH and organic carbon content. Alachlor, metolachlor, and acetochlor have often been used to offset triazine pesticide reductions in area with till soils.

  14. ANALYTICAL METHOD DEVELOPMENT FOR ALACHLOR ESA AND OTHER ACETANILIDE HERBICIDE DEGRADATION PRODUCTS

    EPA Science Inventory

    In 1998, USEPA published a Drinking Water Contaminant Candidate List (CCL) of 50 chemicals and 10 microorganisms. "Alachlor ESA and other acetanilide herbicide degradation products" is listed on the the 1998 CCL. Acetanilide degradation products are generally more water soluble...

  15. Degradation of alachlor using an enhanced sono-Fenton process with efficient Fenton's reagent dosages.

    PubMed

    Wang, Chikang; Liu, Zonghan

    2015-01-01

    In this study, an enhanced sono-Fenton process for the degradation of alachlor is presented. At high ultrasonic power, low pH, and in the presence of adequate Fenton's reagent dosages, alachlor degradation can reach nearly 100%. The toxicity of treated alachlor wastewater, which was measured by changes in cell viability, slightly decreased after the Fenton or ultrasound/H2O2 process and significantly decreased after the enhanced sono-Fenton process. A satisfactory relationship was observed between the total organic carbon removal and cell viability increment, indicating that alachlor mineralization is a key step in reducing the toxicity of the solution. The formation of alachlor degradation byproducts was observed during the oxidation process, in which the first step was the substitution of a chloride by a hydroxyl group. In conclusion, the enhanced sono-Fenton process was effective in the degradation and detoxification of alachlor within a short reaction time. Thus, the treated wastewater can then be passed through a biological treatment unit for further treatment.

  16. Ethylcellulose formulations for controlled release of the herbicide alachlor in a sandy soil.

    PubMed

    Sopeña, Fátima; Cabrera, Alegría; Maqueda, Celia; Morillo, Esmeralda

    2007-10-01

    The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control.

  17. Potential impacts of seasonal variation on atrazine and metolachlor persistence in andisol soil.

    PubMed

    Jaikaew, Piyanuch; Boulange, Julien; Thuyet, Dang Quoc; Malhat, Farag; Ishihara, Satoru; Watanabe, Hirozumi

    2015-12-01

    To estimate the potential effect of seasonal variation on the fate of herbicides in andisol soil, atrazine and metolachlor residues were investigated through the summer and winter seasons during 2013 and 2014 under field condition. The computed half-lives of atrazine and metolachlor in soil changed significantly through the two seasons of the trial. The half-lives were shorter in summer season with 16.0 and 23.5 days for atrazine and metolachlor, respectively. In contrast, the half-lives were longer during the winter season with 32.7 and 51.8 days for atrazine and metolachlor, respectively. The analysis of soil water balance suggested that more pesticide was lost in deeper soil layers through infiltration in summer than in winter. In addition, during the summer season, metolachlor was more likely to leach into deeper soil layer than atrazine possibly due to high water solubility of metolachlor.

  18. Herbicide concentrations in the Mississippi River Basin - The importance of chloroacetanilide herbicide degradates

    USGS Publications Warehouse

    Rebich, R.A.; Coupe, R.H.; Thurman, E.M.

    2004-01-01

    The proportion of chloroacetanilide herbicide degradates, specifically the ethane sulfonic (ESA) and oxanilic (OA) acids, averaged 70% of the total herbicide concentration in samples from the Upper Mississippi River. In samples from the Missouri River and the Ohio River, the proportion of chloroacetanilide degradates in the total herbicide concentration was much less, 24% and 41%, respectively. The amount of tile drainage throughout the Mississippi River Basin appeared to be related to the occurrence and distribution of chloroacetanilide degradates in water samples. Pesticide concentrations in streams of the Mississippi River Basin have been well characterized. However, recent research demonstrates that in order to more fully understand the fate and transport of pesticides, the major pesticide degradates need to be included in the analysis. From March 1999 through May 2001, water samples from four major junctures of the Mississippi River Basin were collected and analyzed for a suite of herbicides and their degradate compounds. Each sampling site was selected to represent a major part of the Mississippi River: upper and lower Mississippi, Missouri and Ohio Rivers. Each basin has unique landscape variables, geology, hydrology, precipitation, and land use, which is reflected in the pesticide content at the most downstream sample site near the mouth of the Mississippi River. Atrazine was the most frequently detected herbicide (detected in 97% of the samples), followed by metolachlor (60%), and acetochlor (31%). The most frequently detected degradates were metolachlor ESA (69%), followed by deethylatrazine (62%), metolachlor OA (37%), and alachlor ESA (37%). Metolachlor ESA was detected more frequently than its parent compound (69 vs. 60%), as was alachlor ESA (37 vs. 9%). After an improvement was made in the analytical method, metolachlor ESA was detected in every sample, metolachlor OA in 89% of the samples, alachlor ESA in 84%, acetochlor ESA in 71%, and acetochlor

  19. Accelerated metolachlor degradation in soil by zerovalent iron and compost amendments.

    PubMed

    Kim, Sung-Chul; Yang, Jae E; Ok, Yong Sik; Skousen, Jeff; Kim, Dong-Guk; Joo, Jin-Ho

    2010-04-01

    Soil incubation and germination tests were conducted to assess zerovalent iron (ZVI), organic compost, moisture and their combinations on metolachlor degradation in soil. The ZVI alone degraded 91% of metolachlor in soil within 40 days following bi-phasic kinetics. Organic amendment alone facilitated metolachlor degradation in soil up to 60% after 40 days depending on the amendment rate. However, the combination of ZVI with compost amendment at 30 ton ha(-1) and 30% moisture content accelerated metolachlor degradation to 90% after 3 days and 98% after 40 days. The half life (t (1/2)) of metolachlor degradation with ZVI, compost at 30 ton ha(-1), and 30% moisture was about 1 day, which was faster than ZVI treatment alone and 98% faster than controls. Germination and growth of lettuce (Lactuca sativa) and crabgrass (Digitaria sanguinalis L. Scop.) were severely inhibited in unamended metolachlor-contaminated soils but when these soils were amended with ZVI, germination and growth was comparable to controls (metolachlor free soil). Metolachlor degradation was greatest when ZVI, compost and moisture were used together, suggesting that these treatments will maximize in situ remediation of metolachlor-contaminated soils in the field.

  20. Cellular effects of metolachlor exposure on human liver (HepG2) cells.

    PubMed

    Hartnett, Sean; Musah, Sadiatu; Dhanwada, Kavita R

    2013-01-01

    Metolachlor is one of the most commonly used herbicides in the United States. Protein synthesis is inhibited when roots and shoots of susceptible plants absorb this synthetic herbicide. While quite effective in killing weeds, several studies have shown that exposure to metolachlor results in decreased cell proliferation, growth and reproductive ability of non-target organisms. However, the mode of metolachlor action in non-target organisms has not yet been elucidated. The current study assessed effects of metolachlor exposure on immortalized human liver (HepG2) cells. Results from cell proliferation assays showed that a 72-h exposure to 50 parts per billion (ppb) metolachlor significantly inhibited growth of these cells compared to untreated controls while a decrease in the cell division rate required exposure to 500 ppb metolachlor for 48 h. Flow cytometry analysis of cell cycle distribution revealed that 500 ppb metolachlor treatment resulted in fewer HepG2 cells in G2/M phase after 72 h. Real-time PCR analysis showed a significant decrease in the abundance of the cyclin A transcripts after 12h in cells exposed to 300 ppb metolachlor. These results suggest metolachlor may affect progression through the S phase of the cell cycle and entrance into the G2 phase. PMID:23084262

  1. Atrazine, alachlor, and cyanazine in a large agricultural river system

    USGS Publications Warehouse

    Schottler, S.P.; Eisenreich, Steven J.; Capel, P.D.

    1994-01-01

    Atrazine, alachlor, and cyanazine exhibited maximum concentrations of about 1000-6000 ng/L in the Minnesota River in 1990 and 1991, resulting from precipitation and runoff following the application period. Transport of these herbicides to the river occurs via overland flow or by infiltration to tile drainage networks. Suspended sediment, SO42-, and Cl- concentrations were used as indicators of transport mechanisms. The atrazine metabolite, DEA, was present in the river throughout the year. The ratio of DEA to atrazine concentration was used to calculate an apparent first-order soil conversion rate of atrazine to DEA. Half lives of 21-58 d were calculated for 1990 and 1991, respectively. The longer conversion rate in 1991 results from rapid flushing from the soil and minimum exposure to soil microorganisms. Total flux of herbicide to the river was 1-6.5 t, with over 60% of this loading occurring during the month of June. Loading to the river accounts for less than 1.5% of applied herbicide. ?? 1994 American Chemical Society.

  2. Field-scale mobility and persistence of commercial and stargh-encapusulated atrazine and alachlor

    SciTech Connect

    Gish, T.J.; Shirmohammadi, A.; Wienhold, B.J.

    1994-03-01

    Recent laboratory studies have shown that starch-encapsulation (SE) may reduce leachate losses of certain pesticides. This study compares field-scale mobility and persistence of SE-atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] and alachlor [2-chloro-N(2,6 diethylphenyl)-N-(methoxymethyl)acetamide] to that of a commerciall formulation (CF) of atrazine and alachlor. The research site consisted of four (0.25 ha) fields. Two fields were under no-tillage management (NT) and two were under conventional tillage (CT). One field in each tillage system received SE-formulated atritzine and alachlor, while the others received CF-atrazine and alachlor. Chemical movement and persistence was determined by analysis of surface samples ({approximately}3 cm) taken immediately after application and 1.1-m soil cores collected seven times over 2 yr. No significant difference in herbicide residue levels was observed between NT and CT, but there was a herbicide formulation effect. Soil residue analysis suggests that SE-atrazine was more persistent and less mobile than CF-atrazine. Starch- encapsulated-alachlor was slightly more persistent than CF-alachlor, but no differences in mobility between formulations was observed. The differential field behavior between SE-herbicides is attributed to the faster release of alachlor from the starch granules. Increased atrazine persistence was attributed to the reduction of leachate losses. The reduction in atrazine leaching is likely due to the slow release from the starch granules and subsequent diffusion into the son matrix where it is less subject to preferential flow processes. 20 refs., 6 figs., 1 tab.

  3. Comparative metabolism of chloroacetamide herbicides and selected metabolites in human and rat liver microsomes.

    PubMed Central

    Coleman, S; Linderman, R; Hodgson, E; Rose, R L

    2000-01-01

    Acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methyl-phenyl)-acetamide], alachlor [N-(methoxymethyl)-2-chloro-N-(2, 6-diethyl-phenyl)acetamide], butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-diethyl-phenyl)acetamide], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] are pre-emergent herbicides used in the production of agricultural crops. These herbicides are carcinogenic in rats: acetochlor and alachlor cause tumors in the nasal turbinates, butachlor causes stomach tumors, and metolachlor causes liver tumors. It has been suggested that the carcinogenicity of these compounds involves a complex metabolic activation pathway leading to a DNA-reactive dialkylbenzoquinone imine. Important intermediates in this pathway are 2-chloro-N-(2,6-diethylphenyl)acetamide (CDEPA) produced from alachlor and butachlor and 2-chloro-N-(2-methyl-6-ethylphenyl)acetamide (CMEPA) produced from acetochlor and metolachlor. Subsequent metabolism of CDEPA and CMEPA produces 2,6-diethylaniline (DEA) and 2-methyl-6-ethylaniline (MEA), which are bioactivated through para-hydroxylation and subsequent oxidation to the proposed carcinogenic product dialkylbenzoquinone imine. The current study extends our earlier studies with alachlor and demonstrates that rat liver microsomes metabolize acetochlor and metolachlor to CMEPA (0.065 nmol/min/mg and 0.0133 nmol/min/mg, respectively), whereas human liver microsomes can metabolize only acetochlor to CMEPA (0.023 nmol/min/mg). Butachlor is metabolized to CDEPA to a much greater extent by rat liver microsomes (0.045 nmol/min/mg) than by human liver microsomes (< 0.001 nmol/min/mg). We have determined that both rat and human livers metabolize both CMEPA to MEA (0.308 nmol/min/mg and 0.541 nmol/min/mg, respectively) and CDEPA to DEA (0.350 nmol/min/mg and 0.841 nmol/min/mg, respectively). We have shown that both rat and human liver microsomes metabolize MEA (0.035 nmol/min/mg and 0.069 nmol/min/mg, respectively

  4. Trends in acetochlor concentrations in surface waters of the White River Basin, Indiana, 1994-96

    USGS Publications Warehouse

    Crawford, Charles G.

    1997-01-01

    Corn herbicides are used extensively in the White River Basin and account for about 70 percent of the total agricultural pesticide use in the basin. Acetochlor, a corn herbicide registered for use in 1994, is expected to reduce the total amount of corn herbicides used because of its broad-spectrum weed control and low use rates. Acetochlor is considered to be a probable human carcinogen, and its continued registration is contingent on concentrations in surface and ground water not exceeding target levels. During 1994, acetochlor was detected in only trace concentrations near the mouth of the White River and not at all in a small stream (93-square-mile drainage) in the northern part of the basin. By 1996, peak concentrations were about 2 and 3 micrograms per liter near the mouth of the White River and in the small stream, respectively. The estimated annual average concentration of acetochlor near the mouth of the White River in 1996 was 0.15 micrograms per liter, well below the 2 micrograms per liter criterion for surface-water supplied community-water systems.

  5. Henry's law constants measurements of alachlor and dichlorvos between 283 and 298 K

    NASA Astrophysics Data System (ADS)

    Gautier, Céline; Le Calvé, Stéphane; Mirabel, Philippe

    In this work, a dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube was used to determine experimentally the Henry's law constants (HLC) of two pesticides: alachlor and dichlorvos. The measurements were conducted over the range 283-298 K. At 298 K, HLC were found to be equal to HLC=(14±2)×10 3 and HLC=(4.0±0.6)×10 3 (in units of M atm -1) for alachlor and dichlorvos, respectively. The obtained data were use to derive the following Arrhenius expressions: HLC=(8.0±3.4)×10 -10 exp((9200±1600)/ T) for alachlor and HLC=(2.8±0.4)×10 -13 exp((11 100±1500)/ T) for dichlorvos. At a cumulus temperature of 283 K, the fraction of alachlor and dichlorvos in the atmospheric aqueous phase is about 45% and 22%, respectively. Assuming that annual rainfall rate is 1 m/year, the wet deposition lifetimes were then estimated to be of the order of 2.8 days for alachlor and 5.6 days for dichlorvos. These latter are used to compare the relative importance of wet removal towards the lifetime in the gas phase.

  6. Removal of alachlor from water by catalyzed ozonation on Cu/Al2O3 honeycomb

    PubMed Central

    2013-01-01

    Background The herbicide alachlor (2-chloro-2′6′-diethyl-N-methoxymethylacetanilide) has been known as a probable human carcinogen, and the MCL (minimum contamination level) for drinking water has been set at 2 μg L-1. Therefore, the advanced methods for effectively removing it from water are a matter of interest. Catalyzed ozonation is a promising method for refractory organics degradation. Cu/Al2O3 catalyzed ozonation for degrading an endocrine disruptor (alachlor) in water was investigated. Results Experimental results showed that the ozonation of alachlor can be effectively catalyzed and enhanced by Cu/Al2O3-honeycomb. The main intermediate products formed (aliphatic carboxylic acids) were mineralized to a large extent in the catalytic process. Conclusions This study has shown that Cu/Al2O3-honeycomb is a feasible and efficient catalyst in the ozonation of alachlor in water. Less intermediate oxidation product was produced in the catalytic process than in the uncatalytic one. Furthermore, the mineralization of alachlor could be enhanced by increasing the pH of the reaction solution. PMID:23977841

  7. Infiltration of acetochlor and two of its metabolites in two contrasting soils.

    PubMed

    Baran, Nicole; Mouvet, Christophe; Dagnac, Thierry; Jeannot, Roger

    2004-01-01

    To obtain data concerning the risk of leaching of acetochlor (2-chloro-2'-methyl-6'-ethyl-N-ethoxymethyl-acetanilide) and its major metabolites, ethanesulfonic acid (ESA) and oxanilic acid (OA), to ground water, we studied the fate of these products in two different soil types (luvisol and calcisol) under the same weather conditions. The metabolites were detected in the soils as early as 7 d after application, indicating a rapid onset of acetochlor degradation. Ethanesulfonic acid was predominant over OA in the calcisol, regardless of time or depth, whereas the ESA to OA ratio varied with both time and depth in the luvisol. The maximum depths at which they were detected were 60 to 70 and 10 to 20 cm for ESA and OA, respectively, in the luvisol, and 60 to 70 cm (maximum depth sampled) and 30 to 40 cm for ESA and OA, respectively, in the calcisol. Acetochlor was still detected in the surface layer of the two soils 344 d after its application, although the molecule was partially leached. The maximum depths at which acetochlor was detected (60-70 cm in the luvisol and 50-60 cm [maximum depth sampled] in the calcisol) were recorded during the first sampling 7 d after application. Acetochlor was not detected on later dates below the 30- to 40-cm layer in the calcisol or the 5- to 10-cm layer in the luvisol. The greater preferential flow in the luvisol, which would have favored leaching, might partially explain why the mass balances done 7 d after application were lower in the luvisol (approximately 26%) than in the calcisol (approximately 45%).

  8. Analysis of metolachlor ethane sulfonic acid chirality in groundwater: A tool for dating groundwater movement in agricultural settings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical chirality of pesticides can be a useful tool for studying environmental processes. The chiral forms of metolachlor ethane sulfonic acid (MESA), an abundant metabolite of metolachlor, and metolachlor were examined over a 6 year period in groundwater and a groundwater-fed stream in a riparia...

  9. Alachlor transformation patterns in aquatic field mesocosms under variable oxygen and nutrient conditions

    USGS Publications Warehouse

    Graham, D.W.; Miley, M.K.; Denoyelles, F.; Smith, V.H.; Thurman, E.M.; Carter, R.

    2000-01-01

    Alachlor is one of the most commonly used herbicides in both Europe and North America. Because of its toxic properties, its fate and attenuation in natural waters is practically important. This paper assesses factors that affect alachlor decay rate in aquatic systems using field-scale experimental units. In particular, we used field mesocosms (11.3 m3 outdoor fiberglass tanks) to examine the affect of oxygen level and other factors on decay rate in water columns. This is one of the first studies ever performed where diverse water column conditions have been successfully simulated using common mesocosm-scale facilities. Four treatments were assessed, including aerobic systems (aerobic); low nutrient, oxygen-stratified systems (stratified-LN); moderate nutrient, oxygen-stratified systems (stratified-HN); and anaerobic systems (anaerobic). The lowest half-lives were observed in the anaerobic units (9.7 days) followed by the aerobic (21 days), stratified-HN (22 days), and stratified-LN (46 days) units. Our results indicate that alachlor is transformed most rapidly under anaerobic conditions, although the ambient phosphorus level also appears to influence decay rate. In this study, two common alachlor breakdown products, ethane sulfonic acid (ESA) and oxanilic acid, were also monitored. Oxanilic acid was produced in greater quantities than ESA under all treatments with the highest levels being produced in the stratified-HN units. In general, our results suggest that previous laboratory data, which indicated that high rates of alachlor decay can occur under oxygen-free methanogenic conditions, is translatable to field-scale applications. Copyright (C) 2000 Elsevier Science Ltd.Alachlor is one of the most commonly used herbicides in both Europe and North America. Because of its toxic properties, its fate and attenuation in natural waters is practically important. This paper assesses factors that affect alachlor decay rate in aquatic systems using field-scale experimental

  10. Cytogenetic effects of alachlor and/or atrazine in vivo and in vitro

    SciTech Connect

    Meisner, L.F.; Roloff, B.D. ); Belluck, D.A. )

    1992-01-01

    The purpose of this study was to assess the cytogenetic effects of two commonly used herbicides, alachlor and atrazine, which are often found together in groundwater. Chromosome damage was examined in bone marrow cells of mice drinking water containing 20 ppm alachlor and/or 20 ppm atrazine, with an immunosuppressive dose of cyclophosphamide used as a positive control. Chromosome damage was also quantified in human lymphocytes. The in vitro study demonstrated dose related cytogenetic damage not associated with mitotic inhibition or cell death, with damage due to the alachlor-atrazine combination suggesting an additive model. The fact that the elevated mitotic index was associated with immune suppresion in the cyclophosphamide group suggests that death of cells with accumulated chromosomal aberrations resulted in increased bone marrow proliferation, so a higher fraction of cells examined were newer with less damage.

  11. Using compound-specific isotope analysis to assess the degradation of chloroacetanilide herbicides in lab-scale wetlands.

    PubMed

    Elsayed, O F; Maillard, E; Vuilleumier, S; Nijenhuis, I; Richnow, H H; Imfeld, G

    2014-03-01

    Compound-specific isotope analysis (CSIA) is a promising tool to study the environmental fate of a wide range of contaminants including pesticides. In this study, a novel CSIA method was developed to analyse the stable carbon isotope signatures of widely used chloroacetanilide herbicides. The developed method was applied in combination with herbicide concentration and hydrochemical analyses to investigate in situ biodegradation of metolachlor, acetochlor and alachlor during their transport in lab-scale wetlands. Two distinct redox zones were identified in the wetlands. Oxic conditions prevailed close to the inlet of the four wetlands (oxygen concentration of 212±24μM), and anoxic conditions (oxygen concentrations of 28±41μM) prevailed towards the outlet, where dissipation of herbicides mainly occurred. Removal of acetochlor and alachlor from inlet to outlet of wetlands was 56% and 51%, whereas metolachlor was more persistent (23% of load dissipation). CSIA of chloroacetanilides at the inlet and outlet of the wetlands revealed carbon isotope fractionation of alachlor (εbulk=-2.0±0.3‰) and acetochlor (εbulk=-3.4±0.5‰), indicating that biodegradation contributes to the dissipation of both herbicides. This study is a first step towards the application of CSIA to evaluate the transport and degradation of chloroacetanilide herbicides in the environment.

  12. Occurrence and load of selected herbicides and metabolites in the lower Mississippi River

    USGS Publications Warehouse

    Clark, G.M.; Goolsby, D.A.

    2000-01-01

    Analyses of water samples collected from the Mississippi River at Baton Rouge, Louisiana, during 1991-1997 indicate that hundreds of metric tons of herbicides and herbicide metabolites are being discharged annually to the Gulf of Mexico. Atrazine, metolachlor, and the ethane-sulfonic acid metabolite of alachlor (alachlor ESA) were the most frequently detected herbicides and, in general, were present in the largest concentrations. Almost 80% of the annual herbicide load to the Gulf of Mexico occurred during the growing season from May to August. The concentrations and loads of alachlor in the Mississippi River decreased dramatically after 1993 in response to decreased use in the basin. In contrast, the concentrations and loads of acetochlor increased after 1994, reflecting its role as a replacement for alachlor. The peak annual herbicide load occurred in 1993, when approximately 640 metric tons (t) of atrazine, 320 t of cyanazine, 215 t of metolachlor, 53 t of simazine, and 50 t of alachlor were discharged to the Gulf of Mexico. The annual loads of atrazine and cyanazine were generally 1-2% of the amount annually applied in the Mississippi River drainage basin; the annual loads of acetochlor, alachlor, and metolachlor were generally less than 1%. Despite a reduction in atrazine use, historical data do not indicate a long-term downward trend in the atrazine load to the Gulf of Mexico. Although a relation (r2=0.62) exists between the atrazine load and stream discharge during May to August, variations in herbicide use and rainfall patterns within subbasins can have a large effect on herbicide loads in the Mississippi River Basin and probably explain a large part of the annual variation in atrazine load to the Gulf of Mexico. Copyright (C) 2000 Elsevier Science B.V.

  13. Degradation of alachlor and pyrimethanil by combined photo-Fenton and biological oxidation.

    PubMed

    Ballesteros Martín, M M; Sánchez Pérez, J A; García Sánchez, J L; Montes de Oca, L; Casas López, J L; Oller, I; Malato Rodríguez, S

    2008-06-30

    Biodegradability of aqueous solutions of the herbicide alachlor and the fungicide pyrimethanil, partly treated by photo-Fenton, and the effect of photoreaction intermediates on growth and DOC removal kinetics of the bacteria Pseudomonas putida CECT 324 are demonstrated. Toxicity of 30-120 mg L(-1) alachlor and pyrimethanil has been assayed in P. putida. The biodegradability of photocatalytic intermediates found at different photo-treatment times was evaluated for each pesticide. At a selected time during batch-mode phototreatment, larger-scale biodegradation kinetics were analysed in a 12 L bubble column bioreactor. Both alachlor and pyrimethanil are non-toxic for P. putida CECT 324 at the test concentrations, but they are not biodegradable. A approximately 100 min photo-Fenton pre-treatment was enough to enhance biodegradability, the biological oxidation response being dependent on the pesticide tested. The different alachlor and pyrimethanil respiration and carbon uptake rates in pre-treated solutions are related to change in the growth kinetics of P. putida. Reproducible results have shown that P. putida could be a suitable microorganism for determining photo-Fenton pre-treatment time. PMID:18162295

  14. Erythema multiforme major due to occupational exposure to the herbicides alachlor and butachlor.

    PubMed

    Kim, Hoon; Min, JinHong; Park, JungSoo; Lee, SukWoo; Lee, JiYeonn

    2011-02-01

    Alachlor and butachlor are commonly used chloroacetanilide herbicides. They are cytotoxic, but there have been rare reported cases of alachlor or butachlor induced erythema multiforme major. We report the case of a 38-year-old farmer with erythema multiforme major due to the occupational exposure to alachlor/butachlor. The patient presented to the ED because of itching. Confluent erythematous to violaceous maculopatches with bullae and erosions were seen on the trunk, both upper extremities and both lower extremities. He had no relevant past or family history of a similar skin disease. He had used alachlor/butachlor for 3 days before he developed the itch. We performed a skin incisional biopsy and found diffuse hydropic degeneration with many necrotic keratinocytes in the epidermis and mild to moderate superficial perivascular lymphocytic infiltrate admixed with neutrophils and eosinophils in the upper dermis. These results confirmed the diagnosis of erythema multiforme major. The patient was admitted and received systemic and topical steroids. After 18 days, most lesions had healed, and he was discharged.

  15. Environmentally friendly formulations of alachlor and atrazine: preparation, characterization, and reduced leaching.

    PubMed

    Sánchez-Verdejo, Trinidad; Undabeytia, Tomás; Nir, Shlomo; Villaverde, Jaime; Maqueda, Celia; Morillo, Esmeralda

    2008-11-12

    Atrazine and alachlor formulations were designed by encapsulating the herbicide molecules into phosphatidylcholine (PC) vesicles, which subsequently were adsorbed on montmorillonite. PC and montmorillonite are classified as substances of minimal toxicological risk by the U.S. EPA. PC enhanced alachlor and atrazine solubilities by 15- and 18-fold, respectively. A 6 mM PC:5 g/L clay ratio was found as optimal for PC adsorption on the clay. Active ingredient contents of the PC-clay formulations ranged up to 8.6% for atrazine and 39.5% for alachlor. Infrared spectroscopy showed hydrophobic interactions of herbicide molecules with the alkyl chains of PC, in addition to hydrophilic interactions with the PC headgroup. Release experiments in a sandy soil showed a slower rate from the PC-clay formulations than the commercial ones. Soil column experiments under moderate irrigation and bioactivity experiments indicate that a reduction in the recommended dose of alachlor and atrazine can be accomplished by using PC-clay formulations.

  16. Haplo-diploid gene expression and pollen selection for tolerance to acetochlor in maize.

    PubMed

    Frascaroli, E; Galletti, S; Landi, P

    1994-08-01

    The objectives of this research were to determine if genes controlling the reaction to the herbicide acetochlor in maize (Zea mays L.) are active during both the haploid and the diploid phases of the life cycle and if pollen selection can be utilized for improving sporophytic resistance. Pollen of eight inbred lines, previously characterized through sporophytic analysis for the level of tolerance to acetochlor, showed a differential reaction to the herbicide forin vitro tube length; moreover, such pollen reactions proved to be significantly correlated (r =0.786(*),df=6) with those of the sporophytes producing the pollen. Pollen analysis of two inbred lines (i.e. Mo17, tolerant, and B79, susceptible) and their single cross showed that thein vitro pollen-tube length reaction of the hybrid was intermediate between those of two parents. An experiment on pollen selection was then performed by growing tassels of Mo17xB79 in the presence of the herbicide. Pollen obtained from treated tassels showed a greater tolerance to acetochlor, assessed asin vitro tube length reaction, than pollen obtained from control tassels. Moreover, the backcross [B79 (Mo17xB79)] sporophytic population obtained using pollen from the treated tassels was more tolerant (as indicated by the fresh weight of plants grown in the presence of the herbicide) than was the control backcross population. The two populations did not differ when grown without the herbicide. These findings indicate that genes controlling the reaction to acetochlor in maize have haplodiploid expression; consequently, pollen selection can be applied for improving plant tolerance. PMID:24186178

  17. Influence of degradation and sorption processes on the persistence and movement of alachlor and dicamba in soils

    SciTech Connect

    Yen, P.Y.

    1992-01-01

    The impact of herbicide usage in agriculture on ground water quality is controlled by the interaction of herbicide degradation, sorption, and transport processes as the herbicide moves through the soil to ground water. The objectives of this thesis were to determine the influence of degradation and sorption processes on the fate of a non-ionic (alachlor) and a weak acid (dicamba) herbicide in four soils (Kim loam, Port Byron silt loam, Webster silty clay loam, and Estherville sandy loam) as a function of soil depth. Alachlor dissipated rapidly under field conditions in Kim soil. Although laboratory studied underestimated the rate of alachlor degradation compared to field conditions, they showed that microbial degradation rather than leaching below sampling depth was the major dissipation pathway of alachlor in soil. Laboratory studies are showed that soils obtained from lower depths had capacities to degrade alachlor, however, at slower rates than surface soils. Sorption of alachlor to soils was moderate (Freundlich sorption coefficient, K[sub f] = 0.7 to 7.3). Movement of alachlor in Kim soil under field conditions was overestimated by leachability indices calculated based on laboratory degradation and sorption studies. Leachability indices would classify alachlor as a [open quotes]leacher[close quotes] in Kim, Port Byron and Estherville soils. In the case of Webster soil, alachlor would be classified as transitional between a [open quotes]leacher[close quotes] and [open quotes]nonleacher[close quotes]. Field dissipation experiments are currently being conducted to evaluate potential leachability of dicamba in the three Minnesota soils. Laboratory studies showed that degradation of dicamba in the four soils was slow (50% dissipation time, DT[sub 50] > 70 days) due to a long lag phase. Soils below 15 cm depth demonstrated slower dicamba degradation capacities than the surface soils. Sorption of dicamba to these soils was minimal (K[sub f] = 0.004 to 0.50).

  18. [Effects of metolachlor on biological activities in celery rhizophere and non-rhizosphere soil].

    PubMed

    Chen, Bo; Xu, Dongmei; Liu, Guangshen; Liu, Weiping

    2006-05-01

    The study with rhizobag showed that in celery rhizophere and non-rhizosphere soil, metolachlor had a certain inhibitory effect on catalase activity, but stimulated dehydrogenase activity. Generally, the enzyme activities in rhizosphere soil were higher than those in non-rhizosphere soil. After 45 days of metolachlor treatment, the numbers of bacteria and fungi in rhizosphere soil were higher than those in non-rhizosphere soil, and the R/S was 1.76 to approximately 2. 51. The numbers of actinomycetes were relatively stable, and the rhizosphere effect was not significant. The degradation rate of metolachlor in rhizosphere and nonrhizosphere soil was 0. 0217 and 0.0176, and the corresponding half-live was 31.9 and 39.4 days, respectively. The degradation of metolachlor was enhanced greatly in rhizosphere soil.

  19. Sorption and dissipation of aged metolachlor residues in eroded and rehabilitated soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accurately determine availability for offsite transport, sorption and dissipation of aged metolachlor were characterized in rehabilitated and eroded prairie soils using sequential batch slurry and accelerated solvent extraction (ASE). In the eroded upper slope, soil-landscape rehabilitation more ...

  20. Cancer incidence and metolachlor use in the Agricultural Health Study: An update.

    PubMed

    Silver, Sharon R; Bertke, Steven J; Hines, Cynthia J; Alavanja, Michael C R; Hoppin, Jane A; Lubin, Jay H; Rusiecki, Jennifer A; Sandler, Dale P; Beane Freeman, Laura E

    2015-12-01

    Metolachlor, a widely used herbicide, is classified as a Group C carcinogen by the U.S. Environmental Protection Agency based on increased liver neoplasms in female rats. Epidemiologic studies of the health effects of metolachlor have been limited. The Agricultural Health Study (AHS) is a prospective cohort study including licensed private and commercial pesticide applicators in Iowa and North Carolina enrolled 1993-1997. We evaluated cancer incidence through 2010/2011 (NC/IA) for 49,616 applicators, 53% of whom reported ever using metolachlor. We used Poisson regression to evaluate relations between two metrics of metolachlor use (lifetime days, intensity-weighted lifetime days) and cancer incidence. We saw no association between metolachlor use and incidence of all cancers combined (n = 5,701 with a 5-year lag) or most site-specific cancers. For liver cancer, in analyses restricted to exposed workers, elevations observed at higher categories of use were not statistically significant. However, trends for both lifetime and intensity-weighted lifetime days of metolachor use were positive and statistically significant with an unexposed reference group. A similar pattern was observed for follicular cell lymphoma, but no other lymphoma subtypes. An earlier suggestion of increased lung cancer risk at high levels of metolachlor use in this cohort was not confirmed in this update. This suggestion of an association between metolachlor and liver cancer among pesticide applicators is a novel finding and echoes observation of increased liver neoplasms in some animal studies. However, our findings for both liver cancer and follicular cell lymphoma warrant follow-up to better differentiate effects of metolachlor use from other factors. PMID:26033014

  1. Cancer incidence and metolachlor use in the Agricultural Health Study: An update

    PubMed Central

    Silver, Sharon R.; Bertke, Steven J.; Hines, Cynthia J.; Alavanja, Michael C.R.; Hoppin, Jane A.; Lubin, Jay H.; Rusiecki, Jennifer A.; Sandler, Dale P.; Beane Freeman, Laura E.

    2015-01-01

    Metolachlor, a widely used herbicide, is classified as a Group C carcinogen by the U.S. Environmental Protection Agency based on increased liver neoplasms in female rats. Epidemiologic studies of the health effects of metolachlor have been limited. The Agricultural Health Study (AHS) is a prospective cohort study including licensed private and commercial pesticide applicators in Iowa and North Carolina enrolled 1993–1997. We evaluated cancer incidence through 2010/2011 (NC/IA) for 49,616 applicators, 53% of whom reported ever using metolachlor. We used Poisson regression to evaluate relations between two metrics of metolachlor use (lifetime days, intensity-weighted lifetime days) and cancer incidence. We saw no association between metolachlor use and incidence of all cancers combined (n = 5,701 with a 5-year lag) or most site-specific cancers. For liver cancer, in analyses restricted to exposed workers, elevations observed at higher categories of use were not statistically significant. However, trends for both lifetime and intensity-weighted lifetime days of metolachor use were positive and statistically significant with an unexposed reference group. A similar pattern was observed for follicular cell lymphoma, but no other lymphoma subtypes. An earlier suggestion of increased lung cancer risk at high levels of metolachlor use in this cohort was not confirmed in this update. This suggestion of an association between metolachlor and liver cancer among pesticide applicators is a novel finding and echoes observation of increased liver neoplasms in some animal studies. However, our findings for both liver cancer and follicular cell lymphoma warrant follow-up to better differentiate effects of metolachlor use from other factors. PMID:26033014

  2. Eleven-year trend in acetanilide pesticide degradates in the Iowa River, Iowa

    USGS Publications Warehouse

    Kalkhoff, Stephen J.; Vecchia, Aldo V.; Capel, Paul D.; Meyer, Michael T.

    2012-01-01

    Trends in concentration and loads of acetochlor, alachlor, and metolachlor and their ethanasulfonic (ESA) and oxanilic (OXA) acid degradates were studied from 1996 through 2006 in the main stem of the Iowa River, Iowa and in the South Fork Iowa River, a small tributary near the headwaters of the Iowa River. Concentration trends were determined using the parametric regression model SEAWAVE-Q, which accounts for seasonal and flow-related variability. Daily estimated concentrations generated from the model were used with daily streamflow to calculate daily and yearly loads. Acetochlor, alachlor, metolachlor, and their ESA and OXA degradates were generally present in >50% of the samples collected from both sites throughout the study. Their concentrations generally decreased from 1996 through 2006, although the rate of decrease was slower after 2001. Concentrations of the ESA and OXA degradates decreased from 3 to about 23% yr-1. The concentration trend was related to the decreasing use of these compounds during the study period. Decreasing concentrations and constant runoff resulted in an average reduction of 10 to >3000 kg per year of alachlor and metolachlor ESA and OXA degradates being transported out of the Iowa River watershed. Transport of acetochlor and metolachlor parent compounds and their degradates from the Iowa River watershed ranged from <1% to about 6% of the annual application. These trends were related to the decreasing use of these compounds during the study period, but the year-to-year variability cannot explain changes in loads based on herbicide use alone. The trends were also affected by the timing and amount of precipitation. As expected, increased amounts of water moving through the watershed moved a greater percentage of the applied herbicides, especially the relatively soluble degradates, from the soils into the rivers through surface runoff, shallow groundwater inflow, and subsurface drainage.

  3. Eleven-year trend in acetanilide pesticide degradates in the Iowa River, Iowa.

    PubMed

    Kalkhoff, Stephen J; Vecchia, Aldo V; Capel, Paul D; Meyer, Michael T

    2012-01-01

    Trends in concentration and loads of acetochlor, alachlor, and metolachlor and their ethanasulfonic (ESA) and oxanilic (OXA) acid degradates were studied from 1996 through 2006 in the main stem of the Iowa River, Iowa and in the South Fork Iowa River, a small tributary near the headwaters of the Iowa River. Concentration trends were determined using the parametric regression model SEAWAVE-Q, which accounts for seasonal and flow-related variability. Daily estimated concentrations generated from the model were used with daily streamflow to calculate daily and yearly loads. Acetochlor, alachlor, metolachlor, and their ESA and OXA degradates were generally present in >50% of the samples collected from both sites throughout the study. Their concentrations generally decreased from 1996 through 2006, although the rate of decrease was slower after 2001. Concentrations of the ESA and OXA degradates decreased from 3 to about 23% yr. The concentration trend was related to the decreasing use of these compounds during the study period. Decreasing concentrations and constant runoff resulted in an average reduction of 10 to >3000 kg per year of alachlor and metolachlor ESA and OXA degradates being transported out of the Iowa River watershed. Transport of acetochlor and metolachlor parent compounds and their degradates from the Iowa River watershed ranged from <1% to about 6% of the annual application. These trends were related to the decreasing use of these compounds during the study period, but the year-to-year variability cannot explain changes in loads based on herbicide use alone. The trends were also affected by the timing and amount of precipitation. As expected, increased amounts of water moving through the watershed moved a greater percentage of the applied herbicides, especially the relatively soluble degradates, from the soils into the rivers through surface runoff, shallow groundwater inflow, and subsurface drainage. PMID:23099949

  4. Metolachlor and atrazine fate in surface water systems

    SciTech Connect

    Rice, P.J.; Anderson, T.A.; Coats, J.R.

    1995-12-31

    The detection of pesticides in surface water and ground water provokes concern involving human health risks associated with pesticide exposure. Monitoring studies of surface waters have detected concentrations of herbicides that exceed the U.S. Environmental Protection Agency proposed maximum contamination level (MCL) for drinking water. Conventional water treatment processes do not remove many herbicides. Tap water drawn from surface-water sources has been reported to contain levels of herbicides above the regulatory limits. There is current interest in the use of artificial wetlands and macrophyte-cultured ponds in waste-water-treatment systems. Aquatic plant-based water treatment systems improve waste water effluent by solid filtration and nutrient assimilation. Various aquatic plants have been shown to accumulate metals, absorb inorganic ions, and accelerate the biodegradation of complex organics. Our research evaluates the fate of metolachlor and atrazine in surface water, surface water/sediment, and surface water/aquatic plant incubation systems to study the influence of sediment and aquatic plants in the removal and biotransformation of herbicides from contaminated waters. Aquatic macrophyte systems may prove to be useful in the remediation of herbicide contaminated surface waters in water treatment facilities or in the reduction of herbicide concentrations from tile drain effluents prior to entering watersheds.

  5. Toxicity assessment of the herbicide metolachlor comparative effects on bacterial and mitochondrial model systems.

    PubMed

    Pereira, Susana P; Fernandes, Maria A S; Martins, João D; Santos, Maria S; Moreno, António J M; Vicente, Joaquim A F; Videira, Romeu A; Jurado, Amália S

    2009-12-01

    Metolachlor is one of the most intensively used chloroacetamide herbicides. However, its effects on the environment and on non-target animals and humans as well as its interference at a cell/molecular level have not yet been fully elucidated. The aim of this study was: firstly, to evaluate the potential toxicity of metolachlor at a cell/subcellular level by using two in vitro biological model systems (a strain of Bacillus stearothermophilus and rat liver mitochondria); secondly, to evaluate the relative sensibility of these models to xenobiotics to reinforce their suitability for pollutant toxicity assessment. Our results show that metolachlor inhibits growth and impairs the respiratory activity of B.stearothermophilus at concentrations two to three orders of magnitude higher than those at which bacterial cells are affected by other pesticides. Also at concentrations significantly higher than those of other pesticides, metolachlor depressed the respiratory control ratio, membrane potential and respiration of rat liver mitochondria when malate/glutamate or succinate were used as respiratory substrates. Moreover, metolachlor impaired the respiratory activity of rat liver mitochondria in the same concentration range at which it inhibited bacterial respiratory system (0.4-5.0 micromol/mg of protein). In conclusion, the high concentration range at which metolachlor induces toxicity in vitro suggests that this compound is safer than other pesticides previously studied in our laboratory, using the same model systems. The good parallelism between metolachlor effects on both models and the toxicity data described in the literature, together with results obtained in our laboratory with other compounds, indicate the suitability of these systems to assess toxicity in vitro. PMID:19607910

  6. Reduction in metolachlor and degradate concentrations in shallow groundwater through cover crop use.

    PubMed

    White, Paul M; Potter, Thomas L; Bosch, David D; Joo, Hyun; Schaffer, Bruce; Muñoz-Carpena, Rafael

    2009-10-28

    Pesticide use during crop production has the potential to adversely impact groundwater quality. In southern Florida, climatic and hydrogeologic conditions and agronomic practices indicate that contamination risks are high. In the current study, dissipation of the widely used herbicide, metolachlor, and levels of the compound and selected degradates in shallow groundwater beneath six 0.15-ha plots in sweet corn (Zea mays) production were evaluated over a two-year period. During fallow periods (May to October), plots were either left bare or cover cropped with sunn hemp (Crotalaria juncea L.). Metolachlor was broadcast applied at label recommended rates prior to planting sweet corn each year. Groundwater monitoring wells hydraulically upgradient and downgradient, and within each plot were sampled biweekly. Results showed that metolachlor dissipation was rapid, as evidenced by the detection of relatively high levels of the metolachlor ethane sulfonic degradate (MESA) in groundwater beneath plots and a rapid metolachlor DT(50) (9-14 days) in a companion laboratory soil incubation. Other degradates detected included hydroxymetolachlor in soil and in groundwater metolachlor oxanilic acid (MOA) and a product tentatively identified as 2-chloro-N-(2-acetyl-6-methylphenyl-N-(2-methoxy-1-methylethyl) acetamide, a photo-oxidation product. Metolachlor and MESA levels, up to 16 and 2.4 times higher in groundwater beneath the noncover cropped plots when compared to those of the cover cropped plots, indicate that cover cropping results in more rapid dissipation and/or reduced leaching. The study demonstrated that integration of cover crops into agronomic systems in the region may yield water quality benefits by reducing herbicide inputs to groundwater.

  7. Mortality and cancer incidence among alachlor manufacturing workers 1968–99

    PubMed Central

    Acquavella, J; Delzell, E; Cheng, H; Lynch, C; Johnson, G

    2004-01-01

    Background: Alachlor is the active ingredient in pre-emergent herbicide formulations that have been used widely on corn, soybeans, and other crops. It has been found to cause nasal, stomach, and thyroid tumours in rodent feeding studies at levels that are much higher than likely human exposures. Aims: To evaluate mortality rates from 1968 to 1999 and cancer incidence rates from 1969 to 1999 for alachlor manufacturing workers at a plant in Muscatine, Iowa. Methods: Worker mortality and cancer incidence rates were compared to corresponding rates for the Iowa state general population. Analyses addressed potential intensity and duration of exposure. Results: For workers with any period of high alachlor exposure, mortality from all causes combined was lower than expected (42 observed deaths, SMR 64, 95% CI 46 to 86) and cancer mortality was slightly lower than expected (13 observed deaths, SMR 79, 95% CI 42 to 136). Cancer incidence for workers with potential high exposure was similar to that for Iowa residents, both overall (29 observed cases, SIR 123, 95% CI 82 to 177) and for workers exposed for five or more years and with at least 15 years since first exposure (eight observed cases, SIR 113, 95% CI 49 to 224). There were no cases of nasal, stomach, or thyroid cancer. Conclusions: There were no cancers of the types found in toxicology studies and no discernible relation between cancer incidence for any site and years of alachlor exposure or time since first exposure. Despite the small size of this population, the findings are important because these workers had chronic exposure potential during extended manufacturing campaigns, while use in agriculture is typically limited to a few days or weeks each year. PMID:15258274

  8. Cometabolism of low concentrations of propachlor, alachlor, and cycloate in sewage and lake water.

    PubMed Central

    Novick, N J; Alexander, M

    1985-01-01

    Low concentrations of propachlor (2-chloro-N-isopropylacetanilide) and alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide] were not mineralized, cycloate (S-ethyl-N-ethylthiocyclohexanecarbamate) was slowly or not mineralized, and aniline and cyclohexylamine were readily mineralized in sewage and lake water. Propachlor, alachlor, and cycloate were extensively metabolized, but the products were organic. Little conversion of propachlor and alachlor was evident in sterilized sewage or lake water. The cometabolism of propachlor was essentially linear with time in lake water and was well fit by zero-order kinetics in short periods and by first-order kinetics in longer periods in sewage. The rate of cometabolism in sewage was directly proportional to propachlor concentration at levels from 63 pg/ml to more than 100 ng/ml. Glucose but not aniline increased the yield of products formed during propachlor cometabolism in sewage. No microorganism able to use propachlor as a sole source of carbon and energy was isolated, but bacteria isolated from sewage and lake water metabolized this chemical. During the metabolism of this herbicide by two of the bacteria, none of the carbon was assimilated. Our data indicate that cometabolism of these pesticides takes place at concentrations of synthetic compounds that commonly occur in natural waters. PMID:4004208

  9. Degradation mechanism of alachlor during direct ozonation and O(3)/H(2)O(2) advanced oxidation process.

    PubMed

    Qiang, Zhimin; Liu, Chao; Dong, Bingzhi; Zhang, Yalei

    2010-01-01

    The degradation of alachlor by direct ozonation and advanced oxidation process O(3)/H(2)O(2) was investigated in this study with focus on identification of degradation byproducts. The second-order reaction rate constant between ozone and alachlor was determined to be 2.5+/-0.1M(-1)s(-1) at pH 7.0 and 20 degrees C. Twelve and eight high-molecular-weight byproducts (with the benzene ring intact) from alachlor degradation were identified during direct ozonation and O(3)/H(2)O(2), respectively. The common degradation byproducts included N-(2,6-diethylphenyl)-methyleneamine, 8-ethyl-3,4-dihydro-quinoline, 8-ethyl-quinoline, 1-chloroacetyl-2-hydro-3-ketone-7-acetyl-indole, 2-chloro-2',6'-diacetyl-N-(methoxymethyl)acetanilide, 2-chloro-2'-acetyl-6'-ethyl-N-(methoxymethyl)-acetanilide, and two hydroxylated alachlor isomers. In direct ozonation, four more byproducts were also identified including 1-chloroacetyl-2,3-dihydro-7-ethyl-indole, 2-chloro-2',6'-ethyl-acetanilide, 2-chloro-2',6'-acetyl-acetanilide and 2-chloro-2'-ethyl-6'-acetyl-N-(methoxymethyl)-acetanilide. Degradation of alachlor by O(3) and O(3)/H(2)O(2) also led to the formation of low-molecular-weight byproducts including formic, acetic, propionic, monochloroacetic and oxalic acids as well as chloride ion (only detected in O(3)/H(2)O(2)). Nitrite and nitrate formation was negligible. Alachlor degradation occurred via oxidation of the arylethyl group, N-dealkylation, cyclization and cleavage of benzene ring. After O(3) or O(3)/H(2)O(2) treatment, the toxicity of alachlor solution examined by the Daphnia magna bioassay was slightly reduced. PMID:20022076

  10. Relative mobilities of atrazine, atrazine degradates, metolachlor, and simazine in five soils from Iowa

    SciTech Connect

    Coats, J.R.; Kruger, E.L.; Beilei Zhu

    1995-12-31

    The relative mobilities of atrazine, deethylatrazine, deisopropylatrazine, didealkylatrazine, hydroxyatrazine, ammeline, metolachlor and simazine were determined in soils from five locations in Iowa by soil thin-layer chromatography (TLC). Surface (0 to 30 cm) and subsurface (65 to 90 cm) soils taken from Ames, Treynor, Fruitland, Nashua, and Chariton were used to make soil TLC plates. Uniformly ring-labeled {sup 14}C chemicals were spotted on plates which were then developed by ascending chromatography using water as the solvent. Preliminary results from Ames, Treynor, and Fruitland soils indicate four groups based on relative mobilities. Deethylatrazine was the most mobile compound studied. The intermediate mobility group included atrazine, didealkylatrazine, and deisopropylatrazine. The less mobile group included metolachlor and simazine, however, metolachlor was, in some soils, in the intermediate mobility group. The immobile group included ammeline and hydroxyatrazine. Additional results from Nashua and Chariton soils, as well as correlations of mobility with soil characteristics will also be presented.

  11. Metolachlor dissipation following fall and spring application to eroded and rehabilitated landscapes of the US Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the effects of landscape position and soil properties on the rate of metolachlor dissipation and weed control efficacy of fall- and spring-applied metolachlor in eroded and rehabilitated landforms in the midwestern United States. Soil-landscape rehabilitation result...

  12. Green rust and iron oxide formation influences metolachlor dechlorination during zerovalent iron treatment.

    PubMed

    Satapanajaru, Tunlawit; Shea, Patrick J; Comfort, Steve D; Roh, Yul

    2003-11-15

    Electron transfer from zerovalent iron (Fe0) to targeted contaminants is affected by initial Fe0 composition, the oxides formed during corrosion, and surrounding electrolytes. We previously observed enhanced metolachlor destruction by Fe0 when iron or aluminum salts were present in the aqueous matrix and Eh/pH conditions favored formation of green rusts. To understand these enhanced destruction rates, we characterized changes in Fe0 composition during treatment of metolachlor with and without iron and aluminum salts. Raman microspectroscopy and X-ray diffraction (XRD) indicated that the iron source was initially coated with a thin layer of magnetite (Fe3O4), maghemite (gamma-Fe2O3), and wüstite (FeO). Time-resolved analysis indicated that akaganeite (beta-FeOOH) was the dominant oxide formed during Fe0 treatment of metolachlor. Goethite (alpha-FeOOH) and some lepidocrocite (gamma-FeOOH) formed when Al2(SO4)3 was present, while goethite and magnetite (Fe3O4) were identified in Fe0 treatments containing FeSO4. Although conditions favoring formation of sulfate green rust (GR(II); Fe6(OH)12SO4) facilitated Fe0-mediated dechlorination of metolachlor, only adsorption was observed when GR(II) was synthesized (without Fe0) in the presence of metolachlor and Eh/pH changed to favor Fe(III)oxyhydroxide or magnetite formation. In contrast, dechlorination occurred when magnetite or natural goethite was amended with Fe(II) (as FeSO4) at pH 8 and continued as long as additional Fe(II) was provided. While metolachlor was not dechlorinated by GR(II) itself during a 48-h incubation, the GR(II) provided a source of Fe(II) and produced magnetite (and other oxide surfaces) that coordinated Fe(II), which then facilitated dechlorination.

  13. Experimental design approach to the optimization of ultrasonic degradation of alachlor and enhancement of treated water biodegradability.

    PubMed

    Torres, Ricardo A; Mosteo, Rosa; Pétrier, Christian; Pulgarin, Cesar

    2009-03-01

    This work presents the application of experimental design for the ultrasonic degradation of alachlor which is pesticide classified as priority substance by the European Commission within the scope of the Water Framework Directive. The effect of electrical power (20-80W), pH (3-10) and substrate concentration (10-50mgL(-1)) was evaluated. For a confidential level of 90%, pH showed a low effect on the initial degradation rate of alachlor; whereas electrical power, pollutant concentration and the interaction of these two parameters were significant. A reduced model taking into account the significant variables and interactions between variables has shown a good correlation with the experimental results. Additional experiments conducted in natural and deionised water indicated that the alachlor degradation by ultrasound is practically unaffected by the presence of potential *OH radical scavengers: bicarbonate, sulphate, chloride and oxalic acid. In both cases, alachlor was readily eliminated ( approximately 75min). However, after 4h of treatment only 20% of the initial TOC was removed, showing that alachlor by-products are recalcitrant to the ultrasonic action. Biodegradability test (BOD5/COD) carried out during the course of the treatment indicated that the ultrasonic system noticeably increases the biodegradability of the initial solution. PMID:18930694

  14. Changes in herbicide concentrations in Midwestern streams in relation to changes in use, 1989-1998

    USGS Publications Warehouse

    Scribner, E.A.; Battaglin, W.A.; Goolsby, D.A.; Thurman, E.M.

    2000-01-01

    Water samples were collected from Midwestern streams in 1994-1995 and 1998 as part of a study to help determine if changes in herbicide use resulted in changes in herbicide concentrations since a previous reconnaissance study in 1989-1990. Sites were sampled during the first significant runoff period after the application of pre-emergent herbicides in 1989-1990, 1994-1995, and 1998. Samples were analyzed for selected herbicides, two atrazine metabolites, three cyanazine metabolites, and one alachlor metabolite. In the Midwestern USA, alachlor use was much greater in 1989 than in 1995, whereas acetochlor was not used in 1989 but was commonly used in 1995. The use of atrazine, cyanazine, and metolachlor was approximately the same in 1989 and 1995. The median concentrations of atrazine, alachlor, cyanazine, and metolachlor were substantially higher in 1989-1990 than in 1994-1995 or 1998. The median acetochlor concentration was higher in 1998 than in 1994 or 1995. Copyright (C) 2000 Elsevier Science B.V.

  15. Degradation of chloroacetanilide herbicides and bacterial community composition in lab-scale wetlands.

    PubMed

    Elsayed, Omniea Fawzy; Maillard, Elodie; Vuilleumier, Stéphane; Millet, Maurice; Imfeld, Gwenaël

    2015-07-01

    Degradation of chloroacetanilide herbicides rac-metolachlor, acetochlor, and alachlor, as well as associated bacterial populations, were evaluated in vertical upflow wetland columns using a combination of hydrochemical and herbicide analyses, and DNA-based approaches. Mass dissipation of chloroacetanilides, continuously supplied at 1.8-1.9 μM for 112 days, mainly occurred in the rhizosphere zone under nitrate and sulphate-reducing conditions, and averaged 61±14%, 52±12% and 29±19% for acetochlor, alachlor and rac-metolachlor, respectively. Metolachlor enantiomer fractions of 0.494±0.009 in the oxic zone and 0.480±0.005 in the rhizosphere zone indicated preferential biodegradation of the S-enantiomer. Chloroacetanilide ethane sulfonic acid and oxanilic acid degradates were detected at low concentrations only (0.5 nM), suggesting extensive degradation and the operation of yet unknown pathways for chloroacetanilide degradation. Hydrochemical parameters and oxygen concentration were major drivers of bacterial composition, whereas exposure to chloroacetanilides had no detectable impact. Taken together, the results underline the importance of anaerobic degradation of chloroacetanilides in wetlands, and highlight the potential of complementary chemical and biological approaches to characterise processes involved in the environmental dissipation of chloroacetanilides.

  16. Effects of the organic matter from swine wastewater on the adsorption and desorption of alachlor in soil.

    PubMed

    Dal Bosco, Tatiane C; Sampaio, Silvio C; Coelho, Silvia R M; Cosmann, Natássia J; Smanhotto, Adriana

    2012-01-01

    The application of swine wastewater to the soil for agricultural purposes results in the addition of total and dissolved organic matter to the soil, which may interfere with the dynamics of pesticides in the soil. The objective of this study was to evaluate the effects of the application of total and dissolved organic matter from a biodigester and a treatment lagoon of swine wastewater in the adsorption and desorption of alachlor [2-chloro-2,6-diethyl-N(methoxymethyl acetamide)]. The assay was performed by the batch equilibrium method, and the results were fitted to the Freundlich model. The curve comparison test revealed a greater adsorption of alachlor in the soil treated with swine wastewater from the biodigester. The adsorption and desorption of alachlor increased in the soils where swine wastewater was added, and hysteresis was observed in all of the treatments. PMID:22494371

  17. Effects of the organic matter from swine wastewater on the adsorption and desorption of alachlor in soil.

    PubMed

    Dal Bosco, Tatiane C; Sampaio, Silvio C; Coelho, Silvia R M; Cosmann, Natássia J; Smanhotto, Adriana

    2012-01-01

    The application of swine wastewater to the soil for agricultural purposes results in the addition of total and dissolved organic matter to the soil, which may interfere with the dynamics of pesticides in the soil. The objective of this study was to evaluate the effects of the application of total and dissolved organic matter from a biodigester and a treatment lagoon of swine wastewater in the adsorption and desorption of alachlor [2-chloro-2,6-diethyl-N(methoxymethyl acetamide)]. The assay was performed by the batch equilibrium method, and the results were fitted to the Freundlich model. The curve comparison test revealed a greater adsorption of alachlor in the soil treated with swine wastewater from the biodigester. The adsorption and desorption of alachlor increased in the soils where swine wastewater was added, and hysteresis was observed in all of the treatments.

  18. Transport of Alachlor, Atrazine, Dicamba, and Bromide through Silt and Loam Soils

    NASA Astrophysics Data System (ADS)

    Tindall, J. A.

    2015-12-01

    The herbicides alachlor, atrazine, and dicamba, as well as bromide were applied to soils overlying the High Plains aquifer in Nebraska, to both macropore and non-macropore sites. Three of 6 study areas (exhibiting a high percentage of macropores) were used for analysis of chemical transport. Twelve intact soil cores (30 cm diameter; 40 cm height), were excavated (two each from 0-40 cm and 40-80 cm depths). The first three study areas and soil cores were used to study preferential flow characteristics using dye staining and to determine hydraulic properties; the remaining cores were treated the same as field macropore sites. Two undisturbed experimental field plots, each with a 1 m2 surface area, were established in each of the three macropore study areas. Each preferential plot was instrumented with suction lysimeters, tensiometers, and neutron access tubes - 10 cm increments to 80 cm - and planted in corn. Three study areas that did not exhibit macropores had alachlor, atrazine, and dicamba and bromide disked into the top 15 cm of soil; concentrations were tracked for 120 days - samples were collected on a grid, distributed within 3 plots measuring 50 m x 50 m each. Core samples were collected prior to and immediately after application, and then at 30, 60, and 120 days after application. Each lab core sample was in 15-cm lengths from 0-15 cm, 15-30 cm, 45-60 cm, and 75-90 cm. For areas exhibiting macropores, herbicides had begun to move between 10-15 days after application with concentrations peaking at various depths after heavy rainfall events. Field lysimeter samples showed increases in concentrations of herbicides at depths where laboratory data indicated greater percentages of preferential flowpaths. Concentrations of atrazine, alachlor and dicamba exceeding 0.30, 0.30, and 0.05 μg m1-1 respectively were observed with depth (10-30 cm and 50-70 cm) after two months following heavy rainfall events indicating that preferential flowpaths were a significant

  19. Impact of redox conditions on metolachlor and metribuzin degradation in Mississippi flood plain soils.

    PubMed

    Mulbach, C K; Porthouse, J D; Jugsujinda, A; DeLaune, R D; Johnson, A B

    2000-11-01

    The effect of soil redox conditions on the degradation of metolachlor and metribuzin in two Mississippi soils (Forrestdale silty clay loam and Loring silt loam) were examined in the laboratory. Herbicides were added to soil in microcosms and incubated either under oxidized (aerobic) or reduced (anaerobic) conditions. Metolachlor and metribuzin degradation under aerobic condition in the Forrestdale soil proceeded at rates of 8.83 ngd(-1) and 25 ngd(-1), respectively. Anaerobic degradation rates for the two herbicides in the Forestdale soil were 8.44 ngd(-1) and 32.5 ngd(-1), respectively. Degradation rates for the Loring soil under aerobic condition were 24.8 ngd(-1) and 12.0 ngd(-1) for metolachlor and metribuzin, respectively. Metolachlor and metribuzin degradation rates under anaerobic conditions in the Loring soil were 20.9 ngd(-1) and 5.35 ngd(-1). Metribuzin degraded faster (12.0 ngd(-1)) in the Loring soil under aerobic conditions as compared to anaerobic conditions (5.35 ngd(-1)).

  20. Simulated fate and transport of metolachlor in the unsaturated zone, Maryland, USA

    USGS Publications Warehouse

    Bayless, E.R.; Capel, P.D.; Barbash, J.E.; Webb, R.M.T.; Hancock, T.L.C.; Lampe, D.C.

    2008-01-01

    An unsaturated-zone transport model was used to examine the transport and fate of metolachlor applied to an agricultural site in Maryland, USA. The study site was instrumented to collect data on soil-water content, soil-water potential, ground water levels, major ions, pesticides, and nutrients from the unsaturated zone during 2002-2004. The data set was enhanced with site-specific information describing weather, soils, and agricultural practices. The Root Zone Water Quality Model was used to simulate physical, chemical, and biological processes occurring in the unsaturated zone. Model calibration to bromide tracer concentrations indicated flow occurred through the soil matix. Simulated recharge rates were within the measured range of values. The pesticide transport model was calibrated to the intensive data collection period (2002-2004), and the calibrated model was then used to simulate the period 1984 through 2004 to examine the impact of sustained agricultural management practices on the concentrations of metolachlor and its degradates at the study site. Simulation results indicated that metolachlor degrades rapidly in the root zone but that the degradates are transported to depth in measurable quantities. Simulations indicated that degradate transport is strongly related to the duration of sustained use of metolachlor and the extent of biodegradation. 

  1. Enantiomeric separation of metolachlor and its metabolites using LC-MS and CZE

    USGS Publications Warehouse

    Klein, C. John; Schneider, R.J.; Meyer, M.T.; Aga, D.S.

    2006-01-01

    The stereoisomers of metolachlor and its two polar metabolites [ethane sulfonic acid (ESA) and oxanilic acid (OXA)] were separated using liquid chromatography-mass spectrometry (LC-MS) and capillary zone electrophoresis (CZE), respectively. The separation of metolachlor enantiomers was achieved using a LC-MS equipped with a chiral stationary phase based on cellulose tris(3,5-dimethylphenyl carbamate) and an atmospheric pressure chemical ionization source operated under positive ion mode. The enantiomers of ESA and OXA were separated using CZE with gamma-cyclodextrin (??-CD) as chiral selector. Various CZE conditions were investigated to achieve the best resolution of the ESA and OXA enantiomers. The optimum background CZE electrolyte was found to consist of borate buffer (pH = 9) containing 20% methanol (v/v) and 2.5% ??-CD (w/v). Maximum resolution of ESA and OXA enantiomers was achieved using a capillary temperature of 15??C and applied voltage of 30 kV. The applicability of the LC-MS and CZE methods was demonstrated successfully on the enantiomeric analysis of metolachlor and its metabolites in samples from a soil and water degradation study that was set up to probe the stereoselectivity of metolachlor biodegradation. These techniques allow the enantiomeric ratios of the target analytes to be followed over time during the degradation process and thus will prove useful in determining the role of chirality in pesticide degradation and metabolite formation. ?? 2005 Elsevier Ltd. All rights reserved.

  2. Weed management in transplanted lettuce with Pendimethalin and S-metolachlor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few herbicides are available for use in lettuce and hand weeding is required for commercially acceptable weed control. More effective herbicides are needed. Here we report field evaluations of pendimethalin and S-metolachlor for weed control in transplanted lettuce. Pendimethalin was evaluated PRE a...

  3. Effect of meteorology and soil condition on metolachlor and atrazine volatilization over a 10 year period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 10-year study was conducted to focus on the impact of soil and climatic factors governing herbicide volatilization from an agricultural field. For the first 5 years, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] and atrazine [6-chloro-N-ethyl-N’-(1-methyl...

  4. Occurrence of metolachlor and trifluralin losses in the Save river agricultural catchment during floods.

    PubMed

    Boithias, Laurie; Sauvage, Sabine; Taghavi, Lobat; Merlina, Georges; Probst, Jean-Luc; Pérez, José Miguel Sánchez

    2011-11-30

    Rising pesticide levels in streams draining intensively managed agricultural land have a detrimental effect on aquatic ecosystems and render water unfit for human consumption. The Soil and Water Assessment Tool (SWAT) was applied to simulate daily pesticide transfer at the outlet from an agriculturally intensive catchment of 1110 km(2) (Save river, south-western France). SWAT reliably simulated both dissolved and sorbed metolachlor and trifluralin loads and concentrations at the catchment outlet from 1998 to 2009. On average, 17 kg of metolachlor and 1 kg of trifluralin were exported at outlet each year, with annual rainfall variations considered. Surface runoff was identified as the preferred pathway for pesticide transfer, related to the good correlation between suspended sediment exportation and pesticide, in both soluble and sorbed phases. Pesticide exportation rates at catchment outlet were less than 0.1% of the applied amount. At outlet, SWAT hindcasted that (i) 61% of metolachlor and 52% of trifluralin were exported during high flows and (ii) metolachlor and trifluralin concentrations exceeded European drinking water standards of 0.1 μg L(-1) for individual pesticides during 149 (3.6%) and 17 (0.4%) days of the 1998-2009 period respectively. SWAT was shown to be a promising tool for assessing large catchment river network pesticide contamination in the event of floods but further useful developments of pesticide transfers and partition coefficient processes would need to be investigated.

  5. Enantiomeric separation of metolachlor and its metabolites using LC-MS and CZE.

    PubMed

    Klein, Christine; Schneider, Rudolf J; Meyer, Michael T; Aga, Diana S

    2006-03-01

    The stereoisomers of metolachlor and its two polar metabolites [ethane sulfonic acid (ESA) and oxanilic acid (OXA)] were separated using liquid chromatography-mass spectrometry (LC-MS) and capillary zone electrophoresis (CZE), respectively. The separation of metolachlor enantiomers was achieved using a LC-MS equipped with a chiral stationary phase based on cellulose tris(3,5-dimethylphenyl carbamate) and an atmospheric pressure chemical ionization source operated under positive ion mode. The enantiomers of ESA and OXA were separated using CZE with gamma-cyclodextrin (gamma-CD) as chiral selector. Various CZE conditions were investigated to achieve the best resolution of the ESA and OXA enantiomers. The optimum background CZE electrolyte was found to consist of borate buffer (pH=9) containing 20% methanol (v/v) and 2.5% gamma-CD (w/v). Maximum resolution of ESA and OXA enantiomers was achieved using a capillary temperature of 15 degrees C and applied voltage of 30 kV. The applicability of the LC-MS and CZE methods was demonstrated successfully on the enantiomeric analysis of metolachlor and its metabolites in samples from a soil and water degradation study that was set up to probe the stereoselectivity of metolachlor biodegradation. These techniques allow the enantiomeric ratios of the target analytes to be followed over time during the degradation process and thus will prove useful in determining the role of chirality in pesticide degradation and metabolite formation.

  6. Solar radiation, relative humidity, and soil water effects on metolachlor volatilization.

    PubMed

    Prueger, John H; Gish, Timothy J; McConnell, Laura L; Mckee, Lynn G; Hatfield, Jerry L; Kustas, William P

    2005-07-15

    Pesticide volatilization is a significant loss pathway that may have unintended consequences in nontarget environments. Field-scale pesticide volatilization involves the interaction of a number of complex variables. There is a need to acquire pesticide volatilization fluxes from a location where several of these variables can be held constant. Accordingly, soil properties, tillage practices, surface residue management, and pesticide formulations were held constant while fundamental information regarding metolachlor volatilization (a pre-emergent pesticide) was monitored over a five-year period as influenced by meteorological variables and soil water content. Metolachlor vapor concentrations were measured continuously for 120 h after each application using polyurethane foam plugs in a logarithmic profile above the soil surface. A flux gradient technique was used to compute volatilization fluxes from metolachlor concentration profiles and turbulent fluxes of heat and water vapor (as determined from eddy covariance measurements). Differences in meteorological conditions and surface soil water contents resulted in variability of the volatilization losses over the years studied. The peak volatilization losses for each year occurred during the first 24 h after application with a maximum flux rate in 2001 (1500 ng m(-2) s(-1)) associated with wet surface soil conditions combined with warm temperatures. The cumulative volatilization losses for the 120-hour period following metolachlor application varied over the years from 5 to 25% of the applied active ingredient, with approximately 87% of the losses occurring during the first 72 h. In all of the years studied, volatilization occurred diurnally and accounted for between 43 and 86% during the day and 14 and 57% during the night of the total measured loss. The results suggest that metolachlor volatilization is influenced by multiple factors involving meteorological, surface soil, and chemical factors.

  7. Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor.

    PubMed

    Elsayed, O F; Maillard, E; Vuilleumier, S; Imfeld, G

    2014-11-15

    Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold(®) contaminated water (960 g L(-1) of the herbicide S-metolachlor, >80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was >40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93-97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p=0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems.

  8. Effects of atrazine and metolachlor on the survivorship and infectivity of Echinostoma trivolvis trematode cercariae.

    PubMed

    Griggs, Jennifer L; Belden, Lisa K

    2008-02-01

    Parasites play important roles in ecosystems and can be impacted by chemical inputs. In a series of experiments, we examined the impact of two common herbicides, metolachlor and atrazine, on a host-parasite system consisting of the trematode, Echinostoma trivolvis and its two intermediate hosts, the snail Planorbella trivolvis and larval Rana spp. tadpoles. Metolachlor and atrazine are two widely used agricultural herbicides that inhibit the growth of pre-emergent vegetation. Residues of these pesticides are commonly found in water bodies near agricultural areas. In our first experiment in the laboratory, we examined changes in survivorship when free-living trematode cercariae were exposed to a low concentration (10 ppb: 15 ppb) and high concentration (85 ppb: 100 ppb) mixture of metolachlor and atrazine, respectively. These exposure levels were chosen to represent the higher end of levels that have been documented in aquatic systems. There was a significant decline in cercarial survivorship in the high concentration treatment at 14 hours. In our second experiment, we exposed the parasites, the second intermediate host tadpoles, or both the parasites and the tadpoles, to the pesticide mixtures for a maximum of 10 hours prior to infection and examined subsequent tadpole infection levels. The atrazine and metolachlor mixtures had no significant effects on parasite load, although newly shed cercariae were more likely than 10-hour-old cercariae to infect tadpoles. In our final experiment, we utilized outdoor mesocosms to expose parasites, infected snail hosts, and Rana sylvatica tadpoles to the pesticide mixtures for two weeks and examined differences in tadpole parasite loads. The pesticides had no significant effect on tadpole parasite loads in the mesocosms. Overall, our findings suggest that atrazine and metolachlor mixtures at the doses we examined do not significantly alter the short-term dynamics of Echinostoma trivolvis infection in aquatic systems.

  9. The decreasing of corn root biomembrane penetration for acetochlor with vermicompost amendment

    NASA Astrophysics Data System (ADS)

    Sytnyk, Svitlana; Wiche, Oliver

    2016-04-01

    One of the topical environmental security issues is management and control of anthropogenic (artificially synthesized) chemical agents usage and utilization. Protection systems development against toxic effects of herbicides should be based on studies of biological indication mechanisms for identification of stressors effect in organisms. Lipid degradation is non-specific reaction to exogenous chemical agents effects. Therefore it is important to study responses of lipid components depending on the stressor type. We studied physiological and biochemical characteristics of lipid metabolism under action of herbicides of chloracetamide group. Corn at different stages of ontogenesis was used as testing object during model laboratory and microfield experiments. Cattle manure treated with earth worms Essenia Foetida was used as compost fertilizer to add to chain: chernozem (black soil) -corn system. It was found several acetochlor actions as following: -decreasing of sterols, phospholipids, phosphatidylcholines and phosphatidylethanolamines content; -increasing pool of available fatty acids and phosphatidic acids associated with intensification of hydrolysis processes; -lypase activity stimulation under effect of stressor in low concentrations; -lypase activity inhibition under effect of high stressor level; -decreasing of polyenoic free fatty acids indicating biomembrane degradation; -accumulation of phospholipids degradation products (phosphatidic acids); -decreasing of high-molecular compounds (phosphatidylcholin and phosphatidylinositol) concentrations; -change in the index of unsaturated and saturated free fatty acids ratio in biomembranes structure; It was established that incorporation of vermicompost in dose 0.4 kg/m2 in black soil lead to corn roots biomembrane restoration. It was fixed the decreasing roots biomembrane penetration for acetochlor in trial with vermicompost. Second compost substances antidote effect is the soil microorganism's activation

  10. RESPONSES OF MOLECULAR INDICATORS OF EXPOSURE IN MESOCOSMS: COMMON CARP (CYPRINUS CARPIO) EXPOSED TO THE HERBICIDES ALACHLOR AND ATRAZINE

    EPA Science Inventory

    Common carp (Cyprinus carpio) were treated in aquatic mesocosms with a single pulse of the herbicides atrazine or alachlor to study the bioavailability and biological activity of these herbicides using molecular indicators: Liver vitellogenin gene expression in male fish for estr...

  11. Determination of alachlor and its sulfonic acid metabolite in water by solid-phase extraction and enzyme-linked immunosorbent assay

    USGS Publications Warehouse

    Aga, D.S.; Thurman, E.M.; Pomes, M.L.

    1994-01-01

    Solid-phase extraction (SPE) and enzyme-linked immunosorbent assay (ELISA) were combined for the trace analysis of the herbicide alachlor and its major soil metabolite, ethanesulfonic acid (ESA). The anti-alachlor antibody cross-reacted with ESA, which produced false-positive detections of alachlor in water samples by immunoassay screens. Alachlor and ESA were isolated from water by SPE on a C18 resin and eluted sequentially with ethyl acetate and methanol. Alachlor is soluble in ethyl acetate while the anionic ESA is not. Thus ESA remained adsorbed on the C18 resin and was eluted later with methanol. The combination of SPE with ELISA effectivety separated and quantified both alachlor and ESA using the same antibody for two ELISA methods. The general method may have applicability for the separation of other herbicides and their ionic metabolites. The SPE-ELISA method has a, detection limit of 0.01 ??g/L for alachlor and 0.05 ??g/L for ESA, with a precision of ?? 10%. Analyses of surface and ground water samples were confirmed by gas chromatography/mass spectrometry and high-performance liquid chromatography with photodiode-array detection. Results showed widespread occurrence of ESA in surface and ground water of the midwestern United States, with concentrations ranging from 10 ??g/L.

  12. Spectroscopic investigations of the chiral interactions of metolachlor and its (S)-isomer with lipase and phosphatase.

    PubMed

    Wen, Yue Z; Yuan, Yu L; Chen, Hui; Wang, He L; Liu, Hui J; Kang, Xiao D; Fu, Liu S

    2010-04-01

    Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] is a chiral acetanilide herbicide. We investigated its enantioselective interactions, and that of its (S)-isomer, with Penicillium expansum alkaline lipase and phosphatase. UV differential spectroscopy and fluorescence spectrophotometry studies were conducted in phosphate buffered solution at pH 7. Chiral differences in the UV absorption and fluorescence spectra of lipase and phosphatase with metolachlor and its (S)-isomer were detected. The results showed that the interactions of metolachlor and its (S)-isomer with lipase and phosphatase occur statically through complex formation, and enantioselectivity was clearly observed. In addition, both UV absorption and fluorescence spectrophotometry showed that the (S)-isomer interacted more strongly with lipase and phosphatase than metolachlor. PMID:20390958

  13. Spectroscopic investigations of the chiral interactions of metolachlor and its (S)-isomer with lipase and phosphatase.

    PubMed

    Wen, Yue Z; Yuan, Yu L; Chen, Hui; Wang, He L; Liu, Hui J; Kang, Xiao D; Fu, Liu S

    2010-04-01

    Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] is a chiral acetanilide herbicide. We investigated its enantioselective interactions, and that of its (S)-isomer, with Penicillium expansum alkaline lipase and phosphatase. UV differential spectroscopy and fluorescence spectrophotometry studies were conducted in phosphate buffered solution at pH 7. Chiral differences in the UV absorption and fluorescence spectra of lipase and phosphatase with metolachlor and its (S)-isomer were detected. The results showed that the interactions of metolachlor and its (S)-isomer with lipase and phosphatase occur statically through complex formation, and enantioselectivity was clearly observed. In addition, both UV absorption and fluorescence spectrophotometry showed that the (S)-isomer interacted more strongly with lipase and phosphatase than metolachlor.

  14. Exposure to the herbicide acetochlor alters thyroid hormone-dependent gene expression and metamorphosis in Xenopus Laevis.

    PubMed Central

    Crump, Doug; Werry, Kate; Veldhoen, Nik; Van Aggelen, Graham; Helbing, Caren C

    2002-01-01

    A growing number of substances released into the environment disrupt normal endocrine mechanisms in a wide range of vertebrates. Little is known about the effects and identities of endocrine-disrupting chemicals (EDCs) that target thyroid hormone (TH) action, particularly at the cellular level. Frog tadpole metamorphosis depends completely on TH, which has led to the suggestion of a metamorphosis-based assay for screening potential EDCs. A major mechanism of TH action is the alteration of gene expression via hormone-bound nuclear receptors. To assess the gene expression profiles in the frog model, we designed a novel multispecies frog cDNA microarray. Recently, the preemergent herbicide acetochlor was shown to accelerate 3,5,3 -triiodothyronine (T3)-induced forelimb emergence and increase mRNA expression of thyroid hormone ss receptors in ranid tadpoles. Here we show that T3-induced metamorphosis of Xenopus laevis, a species commonly used in the laboratory, is accelerated upon acute exposure to an environmentally relevant level of acetochlor. The morphologic changes observed are preceded by alterations in gene expression profiles detected in the tadpole tail, and the nature of these profiles suggest a novel mechanism of action for acetochlor. PMID:12460798

  15. S-metolachlor pulse exposure on the alga Scenedesmus vacuolatus: effects during exposure and the subsequent recovery.

    PubMed

    Vallotton, Nathalie; Moser, Daya; Eggen, Rik I L; Junghans, Marion; Chèvre, Nathalie

    2008-09-01

    In streams and creeks, the aquatic flora is exposed to fluctuating concentrations of herbicides during and following their application. Peak concentrations of herbicides, like the chloroacetanilide S-metolachlor, are usually detected following rain events. In this study, we assessed the effect of S-metolachlor pulse exposure on the algae Scenedesmus vacuolatus. We measured the time-dependency of effects during exposure on algae population and identified the algae development stage most sensitive to S-metolachlor. Furthermore, we assessed the time-to-recovery of the algae following exposure. A 6h pulse exposure at 598microgl(-1) was sufficient to inhibit cell reproduction by 50%. However, the exposure period had to coincide with the cell development stage specifically inhibited by S-metolachlor, which is the end of the cell growth phase. In algae populations composed of cells at all development stages, we initially observed an increase in the size of some algal cells, ultimately leading to an inhibition of the growth rate. In these experimental conditions, effects were observed after 18h of exposure and greatly increased with time. The recovery of algae following exposure to strongly inhibiting S-metolachlor concentrations was delayed and only occurred after 29h. These findings suggest that peak exposure to S-metolachlor may affect the growth of sensitive alga in surface waters, considering that the effects extend beyond the period of exposure. PMID:18602658

  16. Involvement of the Cytochrome P450 System EthBAD in the N-Deethoxymethylation of Acetochlor by Rhodococcus sp. Strain T3-1

    PubMed Central

    Wang, Fei; Zhou, Jie; Li, Zhoukun; Dong, Weiliang; Hou, Ying; Huang, Yan

    2015-01-01

    Acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] is a widely applied herbicide with potential carcinogenic properties. N-Deethoxymethylation is the key step in acetochlor biodegradation. N-Deethoxymethylase is a multicomponent enzyme that catalyzes the conversion of acetochlor to 2′-methyl-6′-ethyl-2-chloroacetanilide (CMEPA). Fast detection of CMEPA by a two-enzyme (N-deethoxymethylase–amide hydrolase) system was established in this research. Based on the fast detection method, a three-component enzyme was purified from Rhodococcus sp. strain T3-1 using ammonium sulfate precipitation and hydrophobic interaction chromatography. The molecular masses of the components of the purified enzyme were estimated to be 45, 43, and 11 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Based on the results of peptide mass fingerprint analysis, acetochlor N-deethoxymethylase was identified as a cytochrome P450 system, composed of a cytochrome P450 oxygenase (43-kDa component; EthB), a ferredoxin (45 kDa; EthA), and a reductase (11 kDa; EthD), that is involved in the degradation of methyl tert-butyl ether. The gene cluster ethABCD was cloned by PCR amplification and expressed in Escherichia coli BL21(DE3). Resting cells of a recombinant E. coli strain showed deethoxymethylation activity against acetochlor. Subcloning of ethABCD showed that ethABD expressed in E. coli BL21(DE3) has the activity of acetochlor N-deethoxymethylase and is capable of converting acetochlor to CMEPA. PMID:25595756

  17. Effect of fly ash amendment on metolachlor and atrazine degradation and microbial activity in two soils.

    PubMed

    Ghosh, Rakesh Kumar; Singh, Neera; Singh, Shashi Bala

    2016-08-01

    The study reports the effect of Inderprastha (IP) and Badarpur (BP) fly ashes on degradation of metolachlor and atrazine in Inceptisol and Alfisol soils. Metolachlor dissipated at faster rate in Alfisol (t1/2 8.2-8.6 days) than in Inceptisol (t1/2 13.2-14.3 days). The fly ashes enhanced the persistence of metolachlor in both the soils; however, the extent of effect was more in Inceptisol (t1/2 16.6-33.8 days) than Alfisol (t1/2 8.4-12 days) and effect increased with fly ash dose. 2-Ethyl-6-methylacetanilide was detected as the only metabolite of metolachlor. Atrazine was more persistent in flooded soils (t1/2 10.8-20.3 days) than nonflooded soils (t1/2 3.7-12.6 days) and fly ash increased its persistence, but effect was more pronounced in the flooded Inceptisol (t1/2 23.7-31 days) and nonflooded Alfisol (t1/2 6.3-10.1 days). Increased herbicide sorption in the fly ash-amended soils might have contributed to the increased pesticide persistence. The IP fly ash inhibited microbial biomass carbon at 5 % amendment levels in both the soils, while BP fly ash slightly increased microbial biomass carbon (MBC) content. Dehydrogenase activity was inhibited by both fly ashes in both the soils with maximum inhibition observed in the IP fly ash-amended Alfisol. No significant effect of fly ash amendment was observed on the fluorescein diacetate activity. PMID:27456695

  18. Aqueous-phase disappearance of atrazine, metolachlor, and chlorpyrifos in laboratory aquaria and outdoor macrocosms

    USGS Publications Warehouse

    Mazanti, L.; Rice, C.; Bialek, K.; Sparling, D.; Stevenson, C.; Johnson, W.E.; Kangas, P.; Rheinstein, J.

    2003-01-01

    Dissipation processes are described for a combination of commonly used pesticides--atrazine (6-chloro-4--ethylamino-6-isopropylamino-s-triazine), metolachlor (2-chloro-N-[2-ethyl-6-methyl-phenyl]-N-[2-methoxy-l-methylethyl] acetamide), and chlorpyrifos (O-O diethyl O-[3,5,6-trichloro-2-pyridinyl] phosphorothioate)--in a laboratory and outdoor pond systems. Dosing rates and timing were designed to duplicate those common in the mid-Atlantic Coastal Plain, USA. Treatment ranged from 2 and 2.5 mg/L to 0.2 and 0.25 mg/L respectively for atrazine and metolachlor, and chlorpyrifos was added at 1.0 and 0.1 mg/L in the aquaria and at 0.1 mg/L in the outdoor macrocosms. Chlorpyrifos disappearance was rapid in all of the systems and followed a two-phase sequence. Initial half-lives varied from 0.16 da), to 0.38 day and showed similar rates in the aquaria and the outdoor systems. The second phase of the chlorpyrifos loss pattern was slower (18-20 days) in all the treatments except for the low herbicide treatment in the outdoor test, where it was 3.4 days. Compared to the outdoor system, herbicide losses were much slower in the aquaria, e.g., 150 days for atrazine and 55 days for metolachlor, and no appreciable loss of herbicide was apparent in the high-treated aquaria. In the outdoor systems, the half-lives for the low herbicide treatment were 27 days and 12 days, respectively, for atrazine and metolachlor, and 48 and 20 days, respectively for the high herbicide-treated pond. Very low levels of CIAT (6-amino-2-chloro-4-iso-propylamino-s-triazine) and CEAT (2-chloro-4-ethylamino-6-ethylamino-s-triazine), degradation products of atrazine, were observed in the outdoor studies.

  19. Adsorption-desorption of metolachlor and atrazine in Indian soils: effect of fly ash amendment.

    PubMed

    Ghosh, Rakesh K; Singh, Neera

    2013-02-01

    The effect of two fly ashes as soil amendment on the adsorption-desorption of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylphenyl)] and atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) was studied in alluvial and laterite soils. The adsorption data for both the herbicides fitted well the Freundlich equation, and Freundlich adsorption coefficient (K (f)) increased with an increase of fly ash amount. Both the fly ashes differed in their extent to increase herbicide sorption, and the effect was different in different soils. Atrazine was sorbed more in the soils/soils + fly ash mixtures than the metolachlor. The K (f) values showed significant correlation with the amount of fly ash amendment (correlation coefficient, R > 0.982). The desorption isotherms also fitted the Freundlich equation, and desorption showed hysteresis which increased with an increase in the content of fly ash amendment. The free energy change (ΔG) indicated that the sorption process is exothermic, spontaneous, and physical in nature. The study has shown that fly ash as soil amendment significantly increased the sorption of metolachlor and atrazine, but the effect is soil- and fly ash-specific. PMID:22572800

  20. Adsorption-desorption of metolachlor and atrazine in Indian soils: effect of fly ash amendment.

    PubMed

    Ghosh, Rakesh K; Singh, Neera

    2013-02-01

    The effect of two fly ashes as soil amendment on the adsorption-desorption of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylphenyl)] and atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) was studied in alluvial and laterite soils. The adsorption data for both the herbicides fitted well the Freundlich equation, and Freundlich adsorption coefficient (K (f)) increased with an increase of fly ash amount. Both the fly ashes differed in their extent to increase herbicide sorption, and the effect was different in different soils. Atrazine was sorbed more in the soils/soils + fly ash mixtures than the metolachlor. The K (f) values showed significant correlation with the amount of fly ash amendment (correlation coefficient, R > 0.982). The desorption isotherms also fitted the Freundlich equation, and desorption showed hysteresis which increased with an increase in the content of fly ash amendment. The free energy change (ΔG) indicated that the sorption process is exothermic, spontaneous, and physical in nature. The study has shown that fly ash as soil amendment significantly increased the sorption of metolachlor and atrazine, but the effect is soil- and fly ash-specific.

  1. Effect of acetochlor on transcription of genes associated with oxidative stress, apoptosis, immunotoxicity and endocrine disruption in the early life stage of zebrafish.

    PubMed

    Jiang, Jinhua; Wu, Shenggan; Liu, Xinju; Wang, Yanhua; An, Xuehua; Cai, Leiming; Zhao, Xueping

    2015-09-01

    The study presented here aimed to characterize the effects of acetochlor on expression of genes related to endocrine disruption, oxidative stress, apoptosis and immune system in zebrafish during its embryo development. Different trends in gene expression were observed after exposure to 50, 100, 200μg/L acetochlor for 96h. Results demonstrated that the transcription patterns of many key genes involved in the hypothalamic-pituitary-gonadal/thyroid (HPG/HPT) axis (e.g., VTG1, ERβ1, CYP19a and TRα), cell apoptosis pathway (e.g., Bcl2, Bax, P53 and Cas8), as well as innate immunity (e.g., CXCL-C1C, IL-1β and TNFα) were affected in newly hatched zebrafish after exposure to acetochlor. In addition, the up-regulation of CAT, GPX, GPX1a, Cu/Zn-SOD and Ogg1 suggested acetochlor might trigger oxidative stress in zebrafish. These finding indicated that acetochlor could simultaneously induce multiple responses during zebrafish embryonic development, and bidirectional interactions among oxidative stress, apoptosis pathway, immune and endocrine systems might be present.

  2. Effect of acetochlor on transcription of genes associated with oxidative stress, apoptosis, immunotoxicity and endocrine disruption in the early life stage of zebrafish.

    PubMed

    Jiang, Jinhua; Wu, Shenggan; Liu, Xinju; Wang, Yanhua; An, Xuehua; Cai, Leiming; Zhao, Xueping

    2015-09-01

    The study presented here aimed to characterize the effects of acetochlor on expression of genes related to endocrine disruption, oxidative stress, apoptosis and immune system in zebrafish during its embryo development. Different trends in gene expression were observed after exposure to 50, 100, 200μg/L acetochlor for 96h. Results demonstrated that the transcription patterns of many key genes involved in the hypothalamic-pituitary-gonadal/thyroid (HPG/HPT) axis (e.g., VTG1, ERβ1, CYP19a and TRα), cell apoptosis pathway (e.g., Bcl2, Bax, P53 and Cas8), as well as innate immunity (e.g., CXCL-C1C, IL-1β and TNFα) were affected in newly hatched zebrafish after exposure to acetochlor. In addition, the up-regulation of CAT, GPX, GPX1a, Cu/Zn-SOD and Ogg1 suggested acetochlor might trigger oxidative stress in zebrafish. These finding indicated that acetochlor could simultaneously induce multiple responses during zebrafish embryonic development, and bidirectional interactions among oxidative stress, apoptosis pathway, immune and endocrine systems might be present. PMID:26318563

  3. Atrazine and metolachlor occurrence in shallow ground water of the United States, 1993 to 1995: Relations to explanatory factors

    USGS Publications Warehouse

    Kolpin, D.W.; Barbash, J.E.; Gilliom, R.J.

    2002-01-01

    Since 1991, the U.S. Geological Survey has been conducting the National Water Quality Assessment (NAWQA) Program to determine the quality of the Nation's water resources. In an effort to obtain a better understanding of why pesticides are found in shallow ground water on a national scale, a set of factors likely to affect the fate and transport of two herbicides in the subsurface were examined. Atrazine and metolachlor were selected for this discussion because they were among the most frequently detected pesticides in ground water during the first phase of the NAWQA Program (1993 to 1995), and each was the most frequently detected compound in its chemical class (triazines and acetanilides, respectively). The factors that most strongly correlated with the frequencies of atrazine detection in shallow ground-water networks were those that provided either: (1) an indication of the potential susceptibility of ground water to atrazine contamination, or (2) an indication of relative ground-water age. The factors most closely related to the frequencies of metolachlor detection in ground water, however, were those that estimated or indicated the intensity of the agricultural use of metolachlor. This difference is probably the result of detailed use estimates for these compounds being available only for agricultural settings. While atrazine use is relatively extensive in nonagricultural settings, in addition to its widespread agricultural use, metolachlor is used almost exclusively for agricultural purposes. As a result, estimates of agricultural applications provide a less reliable indication of total chemical use for atrazine than for metolachlor. A multivariate analysis demonstrated that the factors of interest explained about 50 percent of the variance in atrazine and metolachlor detection frequencies among the NAWQA land-use studies examined. The inclusion of other factors related to pesticide fate and transport in ground water, or improvements in the quality and

  4. Responses of molecular indicators of exposure in mesocosms: common carp (Cyprinus carpio) exposed to the herbicides alachlor and atrazine.

    PubMed

    Chang, Lina W; Toth, Gregory P; Gordon, Denise A; Graham, David W; Meier, John R; Knapp, Charles W; deNoyelles, F Jerry; Campbell, Scott; Lattier, David L

    2005-01-01

    Common carp (Cyprinus carpio) were treated in aquatic mesocosms with a single pulse of the herbicides atrazine or alachlor to study the bioavailability and biological activity of these herbicides using molecular indicators: Liver vitellogenin gene expression in male fish for estrogenic activity, liver cytochrome P4501A1 gene expression, and DNA damage in blood cells using the single-cell gel electrophoresis method. Both alachlor and atrazine showed dose-related increases in DNA strand breaks at environmentally relevant concentrations (<100 ppb). Gene expression indicators showed that neither herbicide had estrogenic activity in the carp, whereas atrazine at concentrations as low as 7 ppb induced cytochrome P4501A1. These results support the study of molecular indicators for exposure in surrogate ecosystems to gauge relevant environmental changes following herbicide treatments.

  5. Determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: alachlor ethanesulfonic acid (ESA); alachlor oxanilic acid; acetochlor ESA; acetochlor oxanilic acid; metolachlor ESA; and metolachlor oxanilic acid. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The average HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.5 and 2.0 ??g/l ranged from 84 to 112%, with relative standard deviations of 18% or less. The average HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.2 and 2.0 ??g/l ranged from 81 to 118%, with relative standard deviations of 20% or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 ??g/l, whereas the LOQ using the HPLC/MS method was at 0.05 ??g/l. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water. Copyright (C) 2000 Elsevier Science B.V.

  6. Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group; determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Zimmerman, L.R.; Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The mean HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.50, and 2.0 mg/L (micrograms per liter) ranged from 84 to 112 percent, with relative standard deviations of 18 percent or less. The mean HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.20, and 2.0 mg/L ranged from 81 to 125 percent, with relative standard deviations of 20 percent or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 mg/L, whereas the LOQ using the HPLC/MS method was 0.05 mg/L. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water.

  7. Degradation of chloroacetanilide herbicides: The prevalence of sulfonic and oxanilic acid metabolites in Iowa groundwaters and surface waters

    USGS Publications Warehouse

    Kalkhoff, S.J.; Kolpin, D.W.; Thurman, E.M.; Ferrer, I.; Barcelo, D.

    1998-01-01

    Water samples were collected from 88 municipal wells throughout Iowa during the summer and were collected monthly at 12 stream sites in eastern Iowa from March to December 1996 to study the occurrence of the sulfonic and oxanilic metabolites of acetochlor, alachlor, and metolachlor. The sulfonic and oxanilic metabolites were present in almost 75% of the groundwater samples and were generally present from 3 to 45 times more frequently than their parent compounds. In groundwater, the median value of the summed concentrations of acetochlor, alachlor, and metolachlor was less than 0.05 μg/L, and the median value of the summed concentrations of the six metabolites was 1.2 μg/L. All surface water samples contained at least one detectable metabolite compound. Individual metabolites were detected from 2 to over 100 times more frequently than the parent compounds. In surface water, the median value of the summed concentrations of the three parent compounds was 0.13 μg/L, and the median value of the summed concentrations of the six metabolites was 6.4 μg/L. These data demonstrate the importance of analyzing both parent compounds and metabolites to more fully understand the environmental fate and transport of herbicides in the hydrologic system.

  8. A urinary metabonomics analysis of long-term effect of acetochlor exposure on rats by ultra-performance liquid chromatography/mass spectrometry.

    PubMed

    Li, Longxue; Wang, Maoqing; Chen, Shuhong; Zhao, Wei; Zhao, Yue; Wang, Xu; Zhang, Yang

    2016-03-01

    The study was to assess the long-term toxic effects of acetochlor on rats. Two different doses (42.96 and 107.4 mg/kg body weight/day) of acetochlor were administered to Wistar rats through their food for over 24 weeks. Rat urine samples were collected at two time-points for the measurements of the metabonomics profiles with ultra-performance liquid chromatography-mass spectrometry (UPLC-MSMS). The results of clinical chemistry and histopathology suggested that long-term use of acetochlor in rats caused liver and kidney damage, and dysfunction of antioxidant system. The urinary metabonomics analysis indicated that the high and low-dose exposure of acetochlor could cause alterations of these metabonomics in urine in the rat. Significant changes of the levels of hippuric acid (0.403-fold decrease), citric acid (0.430-fold decrease), pantothenic acid (0.486-fold decrease), uracil (0.419-fold decrease), β-Alanine (0.325-fold decrease), nonanedioic acid (0.445-fold decrease), L-tyrosine (0.410-fold decrease), D-glucuronic acid (8.389-fold increase) and 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide in urine were observed. In addition, it may interfere with the fatty acid synthesis, the pyrimidine degradation and pantothenate biosynthesis. The level of 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide is detected in all treated groups which is not found in the control groups, indicating which can be used as an early, sensitive marker of acetochlor exposure in rat. This study illustrates the important utility of metabonomics approaches to understand the toxicity of long-term exposure of acetochlor.

  9. A urinary metabonomics analysis of long-term effect of acetochlor exposure on rats by ultra-performance liquid chromatography/mass spectrometry.

    PubMed

    Li, Longxue; Wang, Maoqing; Chen, Shuhong; Zhao, Wei; Zhao, Yue; Wang, Xu; Zhang, Yang

    2016-03-01

    The study was to assess the long-term toxic effects of acetochlor on rats. Two different doses (42.96 and 107.4 mg/kg body weight/day) of acetochlor were administered to Wistar rats through their food for over 24 weeks. Rat urine samples were collected at two time-points for the measurements of the metabonomics profiles with ultra-performance liquid chromatography-mass spectrometry (UPLC-MSMS). The results of clinical chemistry and histopathology suggested that long-term use of acetochlor in rats caused liver and kidney damage, and dysfunction of antioxidant system. The urinary metabonomics analysis indicated that the high and low-dose exposure of acetochlor could cause alterations of these metabonomics in urine in the rat. Significant changes of the levels of hippuric acid (0.403-fold decrease), citric acid (0.430-fold decrease), pantothenic acid (0.486-fold decrease), uracil (0.419-fold decrease), β-Alanine (0.325-fold decrease), nonanedioic acid (0.445-fold decrease), L-tyrosine (0.410-fold decrease), D-glucuronic acid (8.389-fold increase) and 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide in urine were observed. In addition, it may interfere with the fatty acid synthesis, the pyrimidine degradation and pantothenate biosynthesis. The level of 2-ethyl-6-methyl-N-methyl-2-chloro-acetanilide is detected in all treated groups which is not found in the control groups, indicating which can be used as an early, sensitive marker of acetochlor exposure in rat. This study illustrates the important utility of metabonomics approaches to understand the toxicity of long-term exposure of acetochlor. PMID:26969444

  10. Comparative study of photocatalytic and photoelectrocatalytic properties of alachlor using different morphology TiO2/Ti photoelectrodes.

    PubMed

    Xin, Yanjun; Liu, Huiling; Han, Lei; Zhou, Yabin

    2011-09-15

    Wormhole-shaped TiO(2)/Ti (WT) and nanotube-shaped TiO(2)/Ti (TNT) photoelectrodes were prepared by anodic oxidation method. The morphology and structure were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was found that both crystal types of WT and TNT photoelectrodes were composed of anatase and rutile TiO(2) phases; however TNT photoelectrodes had highly ordered nanostructure. The photoelectrochemical (PECH) and photoelectrocatalytic (PEC) properties of WT and TNT photoelectrodes were investigated by photocurrent transient, open-circuit potential and degradation rate of alachlor under the artificial solar light illumination. All results showed that TNT photoelectrodes prepared in NaF-Na(2)SO(4) solution have more excellent photoelectron properties than WT photoelectrodes prepared in H(2)SO(4) solution. The photocatalytic (PC) and PEC experiments of alachlor showed that PC and PEC activities of TNT photoelectrodes were superior to WT photoelectrodes. At applied bias potentials the degradation rate of alachlor at TNT photoelectrodes increased significantly to 94.5%. The higher PC and PEC performance of TNT photoelectrodes were ascribed to the long-range ordered structure and short-orientation diffusion distance of photogenerated carries.

  11. Dechlorinating chloroacetanilide herbicides by dithionite-treated aquifer sediment and surface soil.

    PubMed

    Boparai, Hardiljeet K; Shea, Patrick J; Comfort, Steve D; Snow, Daniel D

    2006-05-01

    The prevalent use of chloroacetanilide herbicides has resulted in nonpoint contamination of some groundwater and surface water. We determined the efficacy of dithionite-treated sediment and soils to transform chloroacetanilides. When used alone, dithionite rapidly dechlorinates chloroacetanilides in water, with the following order of reactivity: propachlor > alachlor > acetochlor > metolachlor. Stoichiometric release of chloride occurs during reaction with dithionite, and thiosulfate herbicide derivatives are produced. Treating aquifer sediment with dithionite reduces native Fe(lII), creating a redox barrier of Fe(ll)-bearing minerals and surface-bound Fe(ll). Washing the reduced sediment (buffered with citrate-bicarbonate) with oxygen-free water removed Fe(ll) and excess dithionite and no alachlor transformation was observed. In contrast, a dithionite-treated surface soil, rich in clay and iron, effectively dechlorinated alachlor after washing. Exposing alachlor to aquifer sediment treated with dithionite in potassium carbonate buffer (pH 8.5-9.0) produced dechlorinated alachlor as the major degradation product. Our results provide proof-of-concept that dechlorination of chloroacetanilide herbicides by dithionite and dithionite-treated aquifer sediment and soil is a remediation option in natural environments where iron-bearing minerals are abundant.

  12. Metolachlor Sorption and Degradation in Soil Amended with Fresh and Aged Biochars.

    PubMed

    Trigo, Carmen; Spokas, Kurt A; Hall, Kathleen E; Cox, Lucia; Koskinen, William C

    2016-04-27

    Addition of organic amendments such as biochar to soils can influence pesticide sorption-desorption processes and, in turn, the amount of pesticide readily availability for transport and biodegradation. Sorption-desorption processes are affected by both the physical and chemical properties of soils and pesticides, as well as soil-pesticide contact time, or aging. Changes in sorption-desorption of metolachlor with aging in soil amended with three macadamia nut shell biochars aged 0 (BCmac-fr), 1 year (BCmac-1yr), and 2 years (BCmac-2yr) and two wood biochars aged 0 (BCwood-fr) and 5 years (BCwood-5yr) were determined. Apparent sorption coefficient (Kd-app) values increased with incubation time to a greater extent in amended soil as compared to unamended soils; Kd-app increased by 1.2-fold for the unamended soil, 2.0-fold for BCwood-fr, 1.4-fold for BCwood-5yr, 2.4-fold for BCmac-fr, 2.5-fold for BCmac-1yr, and 1.9-fold for BCmac-4yr. The increase in calculated Kd-app value was the result of a 15% decrease in the metolachlor solution concentration extractable with CaCl2 solution with incubation time in soil as compared to a 50% decrease in amended soil with very little change in the sorbed concentration. Differences could possibly be due to diffusion to less accessible or stronger binding sites with time, a faster rate of degradation (in solution and on labile sites) than desorption, or a combination of the two in the amended soils. These data show that transport models would overpredict the depth of movement of metolachlor in soil if effects of aging or biochar amendments are not considered.

  13. Metolachlor Sorption and Degradation in Soil Amended with Fresh and Aged Biochars.

    PubMed

    Trigo, Carmen; Spokas, Kurt A; Hall, Kathleen E; Cox, Lucia; Koskinen, William C

    2016-04-27

    Addition of organic amendments such as biochar to soils can influence pesticide sorption-desorption processes and, in turn, the amount of pesticide readily availability for transport and biodegradation. Sorption-desorption processes are affected by both the physical and chemical properties of soils and pesticides, as well as soil-pesticide contact time, or aging. Changes in sorption-desorption of metolachlor with aging in soil amended with three macadamia nut shell biochars aged 0 (BCmac-fr), 1 year (BCmac-1yr), and 2 years (BCmac-2yr) and two wood biochars aged 0 (BCwood-fr) and 5 years (BCwood-5yr) were determined. Apparent sorption coefficient (Kd-app) values increased with incubation time to a greater extent in amended soil as compared to unamended soils; Kd-app increased by 1.2-fold for the unamended soil, 2.0-fold for BCwood-fr, 1.4-fold for BCwood-5yr, 2.4-fold for BCmac-fr, 2.5-fold for BCmac-1yr, and 1.9-fold for BCmac-4yr. The increase in calculated Kd-app value was the result of a 15% decrease in the metolachlor solution concentration extractable with CaCl2 solution with incubation time in soil as compared to a 50% decrease in amended soil with very little change in the sorbed concentration. Differences could possibly be due to diffusion to less accessible or stronger binding sites with time, a faster rate of degradation (in solution and on labile sites) than desorption, or a combination of the two in the amended soils. These data show that transport models would overpredict the depth of movement of metolachlor in soil if effects of aging or biochar amendments are not considered. PMID:27050383

  14. Single-step uncalcined N-TiO2 synthesis, characterizations and its applications on alachlor photocatalytic degradations

    NASA Astrophysics Data System (ADS)

    Suwannaruang, Totsaporn; Wantala, Kitirote

    2016-09-01

    The aims of this research were to synthesize nitrogen doped TiO2 (N-TiO2) photocatalysts produced by hydrothermal technique and to test the degradation performance of alachlor by photocatalytic process under UV irradiations in the effect of aging temperature and time in the preparation process. The characterizations of synthesized TiO2 such as specific surface area, particle size, phase structure and elements were analyzed by using the Brunauer-Emmett-Teller (BET) technique, Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD) and Energy Dispersive X-ray spectrometer (EDX), respectively. The Central Composite Design (CCD) was used to design the experiment to determine the optimal condition, main effects and their interactions by using specific surface area, percent alachlor removal and observed first-order rate constant as responses. The kinetic reactions of alachlor degradation were explained by using Langmuir-Hinshelwood expression to confirm the reaction took place on the surface of photocatalyst. The results showed that the effect of aging temperatures was significant on surface area, whereas aging time was insignificant. Additionally, the square term of aging temperature and interaction term were shown significant on the specific surface area as well. The highest specific surface area from response surface at aging temperature between 150-175 °C and aging time between 6-13 h was found in a range of 100-106 m2/g. The average particle size of TiO2 was similar to crystallite size. Therefore, it can be concluded that one particle has only one crystal. The element analysis has shown 10% of nitrogen in TiO2 structure that the energy band-gap about 2.95 eV was found. Although, the effects of aging temperature and time on percent alachlor removal and observed first-order rate constants were insignificant, both terms were significant in term of the square for alachlor photocatalytic degradation. The optimal condition of both responses was achieved at an

  15. Environmentally friendly slow release formulations of alachlor based on clay-phosphatidylcholine.

    PubMed

    Sánchez-Verdejo, Trinidad; Undabeytia, Tomas; Nir, Shlomo; Maqueda, Celia; Morillo, Esmeralda

    2008-08-01

    A new clay-liposome complex was developed for reducing leaching of herbicides and contamination of groundwater. The liposomes were composed of the neutral and Environmental Protection Agency approved phospholipid phosphatidylcholine (PC). Adsorption of PC liposomes on the clay mineral montmorillonite could exceed the cation exchange capacity of the clay, and was well simulated by the Langmuir equation. X-ray diffraction results for 6 mM PC and 1.6 g/L clay (3 day incubation) yielded a basal spacing of 7.49 nm, which was interpreted as the formation of a supported planar bilayer on montmorillonite platelets. Fluorescence methods demonstrated structural changes which reflected adsorption of PC followed by loss of vesicle integrity as measured by the penetration of dithionite into the internal monolayer of fluorescently labeled liposomes, resulting in a decrease in fluorescence intensity to 18% of initial after 4 h. Energy transfer was demonstrated after 1 h from labeled liposomes to montmorillonite labeled by an acceptor. The neutral herbicide alachlor adsorbed on the liposome-clay complex, yielding a formulation of up to 40% active ingredient, and 1.6-fold reduction in herbicide release in comparison to the commercial formulation. Hence, the PC-montmorillonite complex can form a basis for environmentally friendly formulations of herbicides, which would yield reduced leaching.

  16. Reconnaissance data for glyphosate, other selected herbicides, their degradation products, and antibiotics in 51 streams in nine midwestern states, 2002

    USGS Publications Warehouse

    Scribner, Elisabeth A.; Battaglin, William A.; Dietze, Julie E.; Thurman, E.M.

    2003-01-01

    Since 1989, the U.S. Geological Survey has conducted periodic reconnaissance studies of streams in the Midwestern United States to determine the geographic and seasonal distribution of herbicide compounds. These studies have documented that large amounts of acetochlor, alachlor, atrazine, cyanazine, metolachlor, and their degradation products are flushed into streams during post-application runoff. Additional studies show that peak herbicide concentrations tend to occur during the first runoff after herbicide application and that herbicide flushes can occur during runoff for several weeks to months following application. Since the first stream study conducted in 1989, several significant changes in herbicide use have occurred. The most substantial change is the tripling in the use of glyphosate during the past 5 years. Over this same time period (1997-2001), usage of acetochlor and atrazine increased slightly, whereas alachlor, cyanazine, and metolachlor usage decreased. During 2002, 154 samples were collected from 51 streams in nine Midwestern States during three periods of runoff. This report provides a compilation of the analytical results of five laboratory methods. Results show that glyphosate was detected in 55 (36 percent) of the samples, and aminomethylphosphonic acid (a degradation product of glyphosate) was detected in 107 (69 percent) of the samples. Atrazine, the most frequently detected herbicide, was found in 93 percent of the samples, followed by metolachlor, found in 73 percent of the samples; metolachlor ethanesulfonic acid (ESA) and oxanilic acid (OXA) were the most frequently detected herbicide degradation products, both being found in more than 95 percent of the samples. The data presented here are valuable for comparison with results from the earlier reconnaissance studies.

  17. Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group?Determination of acetamide herbicides and their degradation products in water using online solid-phase extraction and liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Lee, E.A.; Strahan, A.P.

    2003-01-01

    An analytical method for the determination of 6 acetamide herbicides (acetochlor, alachlor, dimethenamid, flufenacet, metolachlor, and propachlor) and 16 of their degradation products in natural water samples using solid-phase extraction and liquid chromatography/mass spectrometry is described in this report. Special consideration was given during the development of the method to prevent the formation of degradation products during the analysis. Filtered water samples were analyzed using octadecylsilane as the solid-phase extraction media on online automated equipment followed by liquid chromatography/mass spectrometry. The method uses only 10 milliliters of sample per injection. Three different water-sample matrices, a reagent-water, a ground-water, and a surface-water sample spiked at 0.10 and 1.0 microgram per liter, were analyzed to determine method performance. Method detection limits ranged from 0.004 to 0.051 microgram per liter for the parent acetamide herbicides and their degradation products. Mean recoveries for the acetamide compounds in the ground- and surface-water samples ranged from 62.3 to 117.4 percent. The secondary amide of acetochlor/metolachlor ethanesulfonic acid (ESA) was recovered at an average rate of 43.5 percent. The mean recoveries for propachlor and propachlor oxanilic acid (OXA) were next lowest, ranging from 62.3 to 95.5 percent. Mean recoveries from reagent-water samples ranged from 90.3 to 118.3 percent for all compounds. Overall the mean of the mean recoveries of all compounds in the three matrices spiked at 0.10 and 1.0 microgram per liter ranged from 89.9 to 100.7 percent, including the secondary amide of acetochlor/metolachlor ESA and the propachlor compounds. The acetamide herbicides and their degradation products are reported in concentrations ranging from 0.05 to 2.0 micrograms per liter. The upper concentration limit is 2.0 micrograms per liter for all compounds without dilution. With the exception of the secondary amide of

  18. Uptake, translocation, and metabolism of oxabetrinil and CGA-133205 in grain sorghum (Sorghum bicolor) and their influence on metolachlor metabolism

    SciTech Connect

    Yenne, S.P.; Hatzios, K.K.; Meredith, S.A. )

    1990-10-01

    The uptake, translocation, and metabolism of the oxime ether safeners oxabetrinil and CGA-133205 in grain sorghum (Sorghum bicolor (L.) Moench, var. Funk G-522-DR) were investigated. Following application of ({sup 14}C)oxabetrinil and ({sup 14}C)CGA-133205 to imbibed seeds, it appears that the safeners are conferring protection to grain sorghum by increasing the rate of metolachlor metabolism.

  19. Hydrothermal Synthesis of FeS2 as a High-Efficiency Fenton Reagent to Degrade Alachlor via Superoxide-Mediated Fe(II)/Fe(III) Cycle.

    PubMed

    Liu, Wei; Wang, Yueyao; Ai, Zhihui; Zhang, Lizhi

    2015-12-30

    In this study, we demonstrate that hydrothermally synthesized FeS2 (syn-FeS2) is highly efficient at catalyzing the H2O2 decomposition for alachlor degradation at a wide range of initial pH (3.2-9.2). The alachlor degradation rate of syn-FeS2 heterogeneous Fenton system was almost 55 times that of its commercial pyrite (com-FeS2) counterpart at an initial pH of 6.2. Experimental results revealed that the alachlor oxidation enhancement in the syn-FeS2 Fenton system was attributed to the molecular oxygen activation induced by more surface-bound ferrous ions on syn-FeS2. The molecular oxygen activation process could generate superoxide anions to accelerate the Fe(II)/Fe(III) cycle on the syn-FeS2 surface, which favored the H2O2 decomposition to generate more hydroxyl radicals for the alachlor oxidation. It was found that the hydroxyl radicals generation rate constant of syn-FeS2 Fenton system was 71 times that of its com-FeS2 counterpart, and even 1-3 orders of magnitude larger than those of commonly used Fe-bearing heterogeneous catalysts. We detected the alachlor degradation intermediates with gas chromatography-mass spectrometry to propose tentatively a possible alachlor degradation pathway. These interesting findings could provide some new insights on the molecular oxygen activation induced by FeS2 minerals and the subsequent heterogeneous Fenton degradation of organic pollutants in the environment. PMID:26646468

  20. Determination of diphenamide, napropamide and metolachlor in tobacco by gel permeation chromatographic clean-up and high performance liquid chromatography.

    PubMed

    Liu, Hongxia; Dang, Yuanlin; Zhang, Shusheng; Liu, Huimin; Qu, Lingbo; Liao, Xincheng; Zhao, Yufen; Wu, Yangjie

    2005-05-01

    Diphenamide, napropamide and metolachlor (FIG. 1) are selective, pre-emergence arylamide herbicides used to control the growth of annual grasses and broadleaf weeds in a variety of fields, e.g. fruit trees, nuts, corns, green crops, etc. They possess high activity and moderate toxicity. For food and environment safety, the detailed investigations on their residues and metabolism are very important. Diphenamide, napropamide and metolachlor in the pesticide products, serum, urine, soil, environmental water, fruits and wine have been widely analyzed by ELISA, fluorescence, phosphorescence, capillary electrophoresis, high performance liquid chromatography (HPLC), gas chromatography(GC) and GC mass spectrometry (GC-MS). However, to our knowledge, simultaneous residue analysis of diphenamide, napropamide and metolachlor in tobacco samples has not been extensively documented. Tobacco is greatly consumed by smokers throughout the world. The pesticide residue in tobaccos might be potentially harmful to smokers' health. With this in mind the residue determination and control of diphenamide, napropamide and metolachlor in the tobacco leaves are very important for tobacco products and consumers. For these three herbicides, the tolerable maximum residue limits (MRLs) have been limited ranging from 0.05 (for tobacco products) to 5 mg/kg (for tobacco leaves) in different European countries. For the complex tobacco samples, the GC and HPLC with UV detection suffer from matrix interference making quantification and identification of these herbicides difficult. In such cases the removal of the matrix effects and identification of the target compounds are of great importance. The present work reports the extraction and clean up procedures, as well as, the chromatographic conditions developed for the simultaneous determination of diphenamide, napropamide and metolachlor residues in the fluecured tobacco leaves, from the different sources using HPLC-UV method. PMID:16477944

  1. Comparison of enzyme-linked immunosorbent assay and gas chromatography procedures for the detection of cyanazine and metolachlor in surface water samples

    USGS Publications Warehouse

    Schraer, S.M.; Shaw, D.R.; Boyette, M.; Coupe, R.H.; Thurman, E.M.

    2000-01-01

    Enzyme-linked immunosorbent assay (ELISA) data from surface water reconnaissance were compared to data from samples analyzed by gas chromatography for the pesticide residues cyanazine (2-[[4-chloro-6-(ethylamino)-l,3,5-triazin-2-yl]amino]-2-methylpropanenitrile ) and metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide). When ELISA analyses were duplicated, cyanazine and metolachlor detection was found to have highly reproducible results; adjusted R2s were 0.97 and 0.94, respectively. When ELISA results for cyanazine were regressed against gas chromatography results, the models effectively predicted cyanazine concentrations from ELISA analyses (adjusted R2s ranging from 0.76 to 0.81). The intercepts and slopes for these models were not different from 0 and 1, respectively. This indicates that cyanazine analysis by ELISA is expected to give the same results as analysis by gas chromatography. However, regressing ELISA analyses for metolachlor against gas chromatography data provided more variable results (adjusted R2s ranged from 0.67 to 0.94). Regression models for metolachlor analyses had two of three intercepts that were not different from 0. Slopes for all metolachlor regression models were significantly different from 1. This indicates that as metolachlor concentrations increase, ELISA will over- or under-estimate metolachlor concentration, depending on the method of comparison. ELISA can be effectively used to detect cyanazine and metolachlor in surface water samples. However, when detections of metolachlor have significant consequences or implications it may be necessary to use other analytical methods.

  2. Are shifts in herbicide use reflected in concentration changes in Midwestern rivers?

    USGS Publications Warehouse

    Battaglin, W.A.; Goolsby, D.A.

    1999-01-01

    In many Midwestern rivers, elevated concentrations of herbicides occur during runoff events for 1-3 months following application. The highest or 'peak' herbicide concentration often occurs during one of these runoff events. Herbicide concentrations in rivers are affected by a number of factors, including herbicide use patterns within the associated basin. Changing agricultural practices, reductions in recommended and permitted herbicide applications, shifts to new herbicides, and greater environmental awareness in the agricultural community have resulted in changes to herbicide use patterns. In the Midwestern United States, alachlor use was much larger in 1989 than in 1995, while acetochlor was not used in 1989, and commonly used in 1995. Use of atrazine, cyanazine, and metolachlor was about the same in 1989 and 1995. Herbicide concentrations were measured in samples from 53 Midwestern rivers during the first major runoff event that occurred after herbicide application (postapplication) in 1989, 1990, 1994, and 1995. The median concentrations of atrazine, alachlor, cyanazine, metribuzin, metolachlor, propazine, and simazine all were significantly higher in 1989/90 than in 1994/95. The median acetochlor concentration was higher in 1995 than in 1994. Estimated daily yields for all herbicides and degradation products measured, with the exception of acetochlor, were higher in 1989/90 than in 1994/95. The differences in concentration and yield do not always parallel changes in herbicide use, suggesting that other changes in herbicide or crop management are affecting concentrations in Midwestern rivers during runoff events.In many Midwestern rivers, elevated concentrations of herbicides occur during runoff events for 1-3 months following application. The highest or `peak' herbicide concentration often occurs during one of these runoff events. Herbicide concentrations in rivers are affected by a number of factors, including herbicide use patterns within the associated

  3. Relation of Landscape Position and Irrigation to Concentrations of Alachlor, Atrazine, and Selected Degradates in Regolith in Northeastern Nebraska

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Lewis, D.T.; McCallister, D.L.; Parkhurst, A.; Thurman, E.M.

    1996-01-01

    Concentrations of alachlor, its ethanesulfonic acid degradate, atrazine and its degradates, deethylatrazine and deisopropylatrazine, in the upper regolith and associated shallow aquifers were determined in relation to landscape position (floodplains, terraces, and uplands) and irrigation (nonirrigated and irrigated corn cropland) in 1992. Irrigated and nonirrigated sites were located on each landscape position. Samples were collected from three depths. Canonical discriminant and multivariate analyses were used to interpret data. Herbicides and their degradation products tended to be present in soils with high percent organic matter, low pH, and low sand content. Atrazine was present more frequently on the floodplain at all depths than the other compounds. Atrazine (maximum 17.5 ??g/kg) and ethanesulfonic acid (maximum 10 ??g/kg) were associated with landscape position, but not with irrigation. Alachlor (maximum 24 ??g/kg), deethylatrazine (maximum 1.5 ??g/kg), and deisopropylatrazine (maximum 3.5 ??g/kg) were not significantly associated with either landscape position or irrigation. Ground-water analytical results suggested that concentrations of these herbicides and degradates in ground water did not differ among landscape position or between irrigated and nonirrigated corn cropland.

  4. Runoff and leaching of metolachlor from Mississippi River alluvial soil during seasons of average and below-average rainfall.

    PubMed

    Southwick, Lloyd M; Appelboom, Timothy W; Fouss, James L

    2009-02-25

    The movement of the herbicide metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] via runoff and leaching from 0.21 ha plots planted to corn on Mississippi River alluvial soil (Commerce silt loam) was measured for a 6-year period, 1995-2000. The first three years received normal rainfall (30 year average); the second three years experienced reduced rainfall. The 4-month periods prior to application plus the following 4 months after application were characterized by 1039 +/- 148 mm of rainfall for 1995-1997 and by 674 +/- 108 mm for 1998-2000. During the normal rainfall years 216 +/- 150 mm of runoff occurred during the study seasons (4 months following herbicide application), accompanied by 76.9 +/- 38.9 mm of leachate. For the low-rainfall years these amounts were 16.2 +/- 18.2 mm of runoff (92% less than the normal years) and 45.1 +/- 25.5 mm of leachate (41% less than the normal seasons). Runoff of metolachlor during the normal-rainfall seasons was 4.5-6.1% of application, whereas leaching was 0.10-0.18%. For the below-normal periods, these losses were 0.07-0.37% of application in runoff and 0.22-0.27% in leachate. When averages over the three normal and the three less-than-normal seasons were taken, a 35% reduction in rainfall was characterized by a 97% reduction in runoff loss and a 71% increase in leachate loss of metolachlor on a percent of application basis. The data indicate an increase in preferential flow in the leaching movement of metolachlor from the surface soil layer during the reduced rainfall periods. Even with increased preferential flow through the soil during the below-average rainfall seasons, leachate loss (percent of application) of the herbicide remained below 0.3%. Compared to the average rainfall seasons of 1995-1997, the below-normal seasons of 1998-2000 were characterized by a 79% reduction in total runoff and leachate flow and by a 93% reduction in corresponding metolachlor movement via these routes

  5. Pesticide and transformation product detections and age-dating relations from till and sand deposits

    USGS Publications Warehouse

    Warner, K.L.; Morrow, W.S.

    2007-01-01

    Pesticide and transformation product concentrations and frequencies in ground water from areas of similar crop and pesticide applications may vary substantially with differing lithologies. Pesticide analysis data for atrazine, metolachlor, alachlor, acetochlor, and cyanazine and their pesticide transformation products were collected at 69 monitoring wells in Illinois and northern Indiana to document occurrence of pesticides and their transformation products in two agricultural areas of differing lithologies, till, and sand. The till is primarily tile drained and has preferential fractured flow, whereas the sand primarily has surface water drainage and primary porosity flow. Transformation products represent most of the agricultural pesticides in ground water regardless of aquifer material - till or sand. Transformation products were detected more frequently than parent pesticides in both the till and sand, with metolachlor ethane sulfonic acid being most frequently detected. Estimated ground-water recharge dates for the sand were based on chlorofluorocarbon analyses. These age-dating data indicate that ground water recharged prior to 1990 is more likely to have a detection of a pesticide or pesticide transformation product. Detections were twice as frequent in ground water recharged prior to 1990 (82%) than in ground water recharged on or after 1990 (33%). The highest concentrations of atrazine, alachlor, metolachlor, and their transformation products, also were detected in samples from ground water recharged prior to 1990. These age/pesticide detection relations are opposite of what would normally be expected, and may be the result of preferential flow and/or ground-water mixing between aquifers and aquitards as evident by the detection of acetochlor transformation products in samples with estimated ground-water ages predating initial pesticide application. ?? 2007 American Water Resources Association.

  6. Determination of alachlor and its metabolite 2,6-diethylaniline in microbial culture medium using online microdialysis enriched-sampling coupled to high-performance liquid chromatography.

    PubMed

    Chen, Chi-Zen; Yan, Cheing-Tong; Kumar, Ponnusamy Vinoth; Huang, Jenn-Wen; Jen, Jen-Fon

    2011-08-10

    In this study, a simple and novel microdialysis sampling technique incorporating hollow fiber liquid phase microextraction (HF-LPME) coupled online to high-performance liquid chromatography (HPLC) for the one-step sample pretreatment and direct determination of alachlor (2-chloro-2',6'-diethyl-N -(methoxymethyl)acetanilide) and its metabolite 2,6-diethylaniline (2,6-DEA) in microbial culture medium has been developed. A reversed-phase C-18 column was utilized to separate alachlor and 2,6-DEA from other species using an acetonitrile/water mixture (1:1) containing 0.1 M phosphate buffer solution at pH 7.0 as the mobile phase. Detection was carried out with a UV detector operated at 210 nm. Parameters that influenced the enrichment efficiency of online HF-LPME sampling, including the length of the hollow fiber, the perfusion solvent and its flow rate, the pH, and the salt added in sample solution, as well as chromatographic conditions were thoroughly optimized. Under optimal conditions, excellent enrichment efficiency was achieved by the microdialysis of a sample solution (pH 7.0) using hexane as perfusate at the flow rate of 4 μL/min. Detection limits were 72 and 14 ng/mL for alachlor and 2,6-DEA, respectively. The enrichment factors were 403 and 386 (RSD < 5%) for alachlor and 2,6-DEA, respectively, when extraction was performed by using a 40 cm regenerated cellulose hollow fiber and hexane as perfusion solvent at the flow rate of 0.1 μL/min. The proposed method provides a sensitive, flexible, fast, and eco-friendly procedure to enrich and determine alachlor and its metabolite (2,6-DEA) in microbial culture medium. PMID:21707080

  7. Pesticide fate and transport throughout unsaturated zones in five agricultural settings, USA

    USGS Publications Warehouse

    Hancock, T.C.; Sandstrom, M.W.; Vogel, J.R.; Webb, R.M.T.; Bayless, E.R.; Barbash, J.E.

    2008-01-01

    Pesticide transport through the unsaturated zone is a function of chemical and soil characteristics, application, and water recharge rate. The fate and transport of 82 pesticides and degradates were investigated at five different agricultural sites. Atrazine and metolachlor, as well as several of the degradates of atrazine, metolachlor, acetochlor, and alachlor, were frequently detected in soil water during the 2004 growing season, and degradates were generally more abundant than parent compounds. Metolachlor and atrazine were applied at a Nebraska site the same year as sampling, and focused recharge coupled with the short time since application resulted in their movement in the unsaturated zone 9 m below the surface. At other sites where the herbicides were applied 1 to 2 yr before sampling, only degradates were found in soil water. Transformations of herbicides were evident with depth and during the 4-mo sampling time and reflected the faster degradation of metolachlor oxanilic acid and persistence of metolachor ethanesulfonic acid. The fraction of metolachlor ethanesulfonic acid relative to metolachlor and metolachlor oxanilic acid increased from 0.3 to > 0.9 at a site in Maryland where the unsaturated zone was 5 m deep and from 0.3 to 0.5 at the shallowest depth. The flux of pesticide degradates from the deepest sites to the shallow ground water was greatest (3.0–4.9 μmol m−2 yr−1) where upland recharge or focused flow moved the most water through the unsaturated zone. Flux estimates based on estimated recharge rates and measured concentrations were in agreement with fluxes estimated using an unsaturated-zone computer model (LEACHM).

  8. GC-MS(n) and LC-MS/MS couplings for the identification of degradation products resulting from the ozonation treatment of Acetochlor.

    PubMed

    Bouchonnet, Stéphane; Bourcier, Sophie; Souissi, Yasmine; Genty, Christophe; Sablier, Michel; Roche, Pascal; Boireau, Véronique; Ingrand, Valérie

    2012-04-01

    The degradation of the chloracetamide herbicide acetochlor has been studied under simulated ozonation treatment plant conditions. The degradation of acetochlor included the formation of several degradation products that were identified using GC/ion-trap mass spectrometry with EI and CI and HPLC/electrospray-QqTOF mass spectrometry. Thirteen ozonation products of acetochlor have been identified. Ozonation of the deuterated herbicide combined to MS(n) and high-resolution mass measurement allowed effective characterization of the degradation products. At the exception of one of them, the product B (2-chloro-2', ethyl-6', methyl-acetanilide), none of the identified degradation products has been already reported in the literature. Post-ozonation kinetics studies revealed that the concentrations of most degradation products evolved noticeably with time, particularly during the first hours following the ozonation treatment. This raises concerns about the fate of degradation products in the effluents of treatment plants and suggests the need for a better control on these products if their toxicity was demonstrated. PMID:22689619

  9. Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

    PubMed

    Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

    2016-02-01

    Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation.

  10. Degradation and leaching of the herbicides metolachlor and diuron: a case study in an area of Northern Italy.

    PubMed

    Barra Caracciolo, A; Giuliano, G; Grenni, P; Guzzella, L; Pozzoni, F; Bottoni, P; Fava, L; Crobe, A; Orrù, M; Funari, E

    2005-04-01

    In this work the degradation of the herbicides metolachlor, diuron, monuron and of the metabolites 2-ethyl-6-methylaniline (EMA), and 3,4-dichloroaniline (DCA) was assessed in laboratory experiments on microbiologically active and sterilized soils. Their leaching potentials were calculated, using Gustafson's equation, by determining their mobility (as Koc) and persistence (expressed as DT50). Lysimeter experiments were also conducted to assess the actual leaching of the studied herbicides in a cereal crop tillage area vulnerable to groundwater contamination. The data obtained from the field were compared to the laboratory results. Moreover, some compounds of particular concern were searched for in the groundwater located near the experimental area in order to evaluate actual contamination and to test the reliability of the leaching potential. The GUS index, computed on data from microbiologically active soil, shows monuron as a leacher compound, EMA and DCA as non-leachers, metolachlor and diuron as transient ones. The presence of metolachlor in the groundwater monitored, even at concentrations up to 0.1 mug/l, confirms the possibility that transient compounds can be leached if microbial activity has not completely occurred in active surface soil.

  11. Ground-water quality in northeastern St. Joseph County, Indiana

    USGS Publications Warehouse

    Fenelon, J.M.; Bayless, E. Randall; Watson, Lee R.

    1995-01-01

    No industrial organic compounds were detected in the water samples. Four pesticides - alachlor, carbofuran, metolachlor, and triazines - were detected in water samples; the highest pesticide concentration in a water sample was 1.0 microgram per liter of alachlor.

  12. Experimental and modeling of the unsaturated transports of S-metolachlor and its metabolites in glaciofluvial vadose zone solids

    NASA Astrophysics Data System (ADS)

    Sidoli, Pauline; Lassabatere, Laurent; Angulo-Jaramillo, Rafael; Baran, Nicole

    2016-07-01

    The transport of pesticides to groundwater is assumed to be impacted by flow processes and geochemical interactions occurring in the vadose zone. In this study, the transport of S-metolachlor (SMOC) and its two metabolites ESA-metolachlor (MESA) and OXA-metolachlor (MOXA) in vadose zone materials of a glaciofluvial aquifer is studied at laboratory scale. Column experiments are used to study the leaching of a conservative tracer (bromide) and SMOC, MESA and MOXA under unsaturated conditions in two lithofacies, a bimodal gravel (Gcm,b) and a sand (S-x). Tracer experiments showed water fractionation into mobile and immobile compartments more pronounced in bimodal gravel columns. In both lithofacies columns, SMOC outflow is delayed (retardation factor > 2) and mass balance reveals depletion (mass balance of 0.59 and 0.77 in bimodal gravel and sand, respectively). However, complete mass elution associated with retardation factors close to unity shows that there is no adsorption of MESA and MOXA in either lithofacies. SMOC transport is characterized by non-equilibrium sorption and sink term in both bimodal gravel and sand columns. Batch experiments carried out using agitation times consistent with column water residence times confirmed a time-dependence of SMOC sorption and high adsorption rates (> 80%) of applied concentrations. Desorption experiments confirm the irreversibility of a major part of the SMOC adsorption onto particles, corresponding to the sink term in columns. In the bimodal gravel column, SMOC adsorption occurs mainly on reactive particles in contact with mobile water because of flow regionalization whereas in the sand column, there is pesticide diffusion to the immobile water. Such results clearly show that sorption mechanisms in the vadose zone solids below the soil are both solute and contact-time-dependent and are impacted by hydrodynamic conditions. The more rapid transport of MESA and MOXA to the aquifer would be controlled mainly by water flow

  13. Herbicide-induced anthocyanin accumulation in transgenic rice by expression of rice OSB2 under the control of rice CYP72A21 promoter.

    PubMed

    Hirose, Sakiko; Kawahigashi, Hiroyuki; Tagiri, Akemi; Ohkawa, Yasunobu

    2008-02-27

    CYP72A21, a rice cytochrome P450 gene, is induced by chloroacetamide herbicides. OSB2, a rice myc-type transcription factor, induces anthocyanin accumulation in rice leaves. To produce plants for biomonitoring by color change, we combined the CYP72A21 promoter and the OSB2 gene and introduced them into the rice isogenic line Taichung-65 CB A (T65), which contains loci CB and A from the rice cultivar Murasakiine. Leaves of the transgenic plants turned red upon treatment with the chloroacetamide herbicides acetochlor, alachlor, and metolachlor. Seedling shoots reddened upon treatment with alachlor or metolachlor at 10 microM, a concentration slightly higher than that used in the field. Anthocyanin content was increased approximately 200% by the treatment. The color changes were consistent with increased shoot expression of OSB2 and the anthocyanidin synthase gene (ANS). This system promises easy detection of rice plant gene expression. Transgenic plants could be used in the future to biomonitor accumulated herbicides.

  14. Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation.

    PubMed

    Abdel-Rahman, A R; Wauchope, R D; Truman, C C; Dowler, C C

    1999-05-01

    Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler-irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47-mm rain falling in a 2-hour event 24 hours after application of alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide) and atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2, 4-diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its' solubility were observed. When the herbicides were applied in 64,000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally-treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater

  15. Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation.

    PubMed

    Abdel-Rahman, A R; Wauchope, R D; Truman, C C; Dowler, C C

    1999-05-01

    Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler-irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47-mm rain falling in a 2-hour event 24 hours after application of alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide) and atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2, 4-diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its' solubility were observed. When the herbicides were applied in 64,000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally-treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater

  16. Evaluating the Influence of Drainage, Application, and Tillage Practices on the Dissipation of Chloroacetanilide Herbicides in Minnesota Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetochlor and metolachlor are herbicides used in Minnesota and the United States for the control of broadleaf and annual weeds in corn, soybean and other crops. Water monitoring studies have reported the occurrences of acetochlor, metolachlor and their breakdown products in both ground and surface ...

  17. Comparison of Metolachlor Leaching Predicted by Upscaled One-dimensional Point Models With That Predicted by a Semi-distributed Watershed Model

    NASA Astrophysics Data System (ADS)

    Webb, R. M.; Wieczorek, M. E.; Linard, J. I.

    2006-12-01

    Understanding how metolachlor, commonly applied to corn fields prior to planting, and other pesticides may leach to shallow ground water under agricultural fields is a primary goal of the U.S. Geological Survey's National Water Quality Assessment Program (NAWQA). Two modeling approaches were used to predict leaching of metolachlor and its degradates in the 33-km2 Morgan Creek watershed on the Delmarva Peninsula. In particular, the overall patterns and timing of leaching predicted with an ensemble of one-dimensional Leaching Estimation and Chemistry models (LEACHM) are compared with those predicted by the Water, Energy, and Biogeochemical MODel (WEBMOD), a semi- distributed TOPMODEL-based watershed model. Both modeling approaches predict that leaching will be inversely proportional to the residence time of the herbicides in the unsaturated zone. Degradation of metolachlor is increased and leaching is reduced where the unsaturated zone is thicker, recharge rates are slower, or evapotranspiration rates are higher. Over a period of 10 years, fields subject to corn-soy crop rotations would receive five applications of metolachor at a rate of 1.36 kg/ha. Upscaled results of the one-dimensional LEACHM point models predict approximately 0.5 percent of the 15 metric tons of applied metolachlor to leach to shallow ground water, the majority in the form of its degradates metolachlor oxynilic acid and metolachlor ethanesulfonic acid. The semi-distributed watershed model, WEBMOD, predicts a greater percentage of the applied parent product to leach to shallow ground water because its coarse discretization of soil horizons results in a much greater effective dispersivity.

  18. Whole Genome Sequence Analysis of an Alachlor and Endosulfan Degrading Micrococcus sp. strain 2385 Isolated from Ochlockonee River, Florida.

    PubMed

    Pathak, Ashish; Chauhan, Ashvini; Ewida, Ayman Y I; Stothard, Paul

    2016-01-01

    We recently isolated Micrococcus sp. strain 2385 from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides- alachlor [(2-chloro-2`,6`-diethylphenyl-N (methoxymethyl)acetanilide)] and endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain 2385, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of Micrococcus sp. strain 2385 consisted of 1,460,461,440 bases which assembled into 175 contigs with an N50 contig length of 50,109 bases and a coverage of 600x. The genome size of this strain was estimated at 2,431,226 base pairs with a G+C content of 72.8 and a total number of 2,268 putative genes. RAST annotated a total of 340 subsystems in the genome of strain 2385 along with the presence of 2,177 coding sequences. A genome wide survey indicated that that strain 2385 harbors a plethora of genes to degrade other pollutants including caprolactam, PAHs (such as naphthalene), styrene, toluene and several chloroaromatic compounds.

  19. Whole Genome Sequence Analysis of an Alachlor and Endosulfan Degrading Micrococcus sp. strain 2385 Isolated from Ochlockonee River, Florida.

    PubMed

    Pathak, Ashish; Chauhan, Ashvini; Ewida, Ayman Y I; Stothard, Paul

    2016-01-01

    We recently isolated Micrococcus sp. strain 2385 from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides- alachlor [(2-chloro-2`,6`-diethylphenyl-N (methoxymethyl)acetanilide)] and endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain 2385, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of Micrococcus sp. strain 2385 consisted of 1,460,461,440 bases which assembled into 175 contigs with an N50 contig length of 50,109 bases and a coverage of 600x. The genome size of this strain was estimated at 2,431,226 base pairs with a G+C content of 72.8 and a total number of 2,268 putative genes. RAST annotated a total of 340 subsystems in the genome of strain 2385 along with the presence of 2,177 coding sequences. A genome wide survey indicated that that strain 2385 harbors a plethora of genes to degrade other pollutants including caprolactam, PAHs (such as naphthalene), styrene, toluene and several chloroaromatic compounds. PMID:27672405

  20. Whole Genome Sequence Analysis of an Alachlor and Endosulfan Degrading Micrococcus sp. strain 2385 Isolated from Ochlockonee River, Florida

    PubMed Central

    Pathak, Ashish; Chauhan, Ashvini; Ewida, Ayman Y.I.; Stothard, Paul

    2016-01-01

    We recently isolated Micrococcus sp. strain 2385 from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides- alachlor [(2-chloro-2`,6`-diethylphenyl-N (methoxymethyl)acetanilide)] and endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain 2385, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of Micrococcus sp. strain 2385 consisted of 1,460,461,440 bases which assembled into 175 contigs with an N50 contig length of 50,109 bases and a coverage of 600x. The genome size of this strain was estimated at 2,431,226 base pairs with a G+C content of 72.8 and a total number of 2,268 putative genes. RAST annotated a total of 340 subsystems in the genome of strain 2385 along with the presence of 2,177 coding sequences. A genome wide survey indicated that that strain 2385 harbors a plethora of genes to degrade other pollutants including caprolactam, PAHs (such as naphthalene), styrene, toluene and several chloroaromatic compounds.

  1. Whole Genome Sequence Analysis of an Alachlor and Endosulfan Degrading Micrococcus sp. strain 2385 Isolated from Ochlockonee River, Florida

    PubMed Central

    Pathak, Ashish; Chauhan, Ashvini; Ewida, Ayman Y.I.; Stothard, Paul

    2016-01-01

    We recently isolated Micrococcus sp. strain 2385 from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides- alachlor [(2-chloro-2`,6`-diethylphenyl-N (methoxymethyl)acetanilide)] and endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain 2385, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of Micrococcus sp. strain 2385 consisted of 1,460,461,440 bases which assembled into 175 contigs with an N50 contig length of 50,109 bases and a coverage of 600x. The genome size of this strain was estimated at 2,431,226 base pairs with a G+C content of 72.8 and a total number of 2,268 putative genes. RAST annotated a total of 340 subsystems in the genome of strain 2385 along with the presence of 2,177 coding sequences. A genome wide survey indicated that that strain 2385 harbors a plethora of genes to degrade other pollutants including caprolactam, PAHs (such as naphthalene), styrene, toluene and several chloroaromatic compounds. PMID:27672405

  2. Tests of the pesticide root zone model and the aggregate model for transport and transformation of aldicarb, metolachlor, and bromide

    SciTech Connect

    Parrish, R.S.; Smith, C.N.; Fong, F.K.

    1992-01-01

    Mathematical models are widely used to predict leaching of pesticides and nutrients in agricultural systems. The work was conducted to investigate the predictive capability of the Pesticide Root Zone Model (PRZM) and the Aggregate Model (AGGR) for the pesticides aldicarb (2-methyl-2-(methylthio)propionaldehyde-O-(methyl-carbamoyl)oxime), metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide) and for a bromide tracer. Model predictions were compared with data collected from 1984 to 1987 in the Dougherty Plain area of southwestern Georgia. Field data were used to estimate mean concentrations of pesticide and bromide residues in the soil profile on various dates after application in each of four growing seasons. Both models tended to predict rates of movement of bromide tracer compounds in excess of that observed. For metolachlor, a pesticide with a soprption-partition coefficient that is higher than for other compounds in the study, both models provided reasonably accurate predictions within the upper 30-cm zone. For the pesticide aldicarb, results were more variable.

  3. Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group-Update and Additions to the Determination of Chloroacetanilide Herbicide Degradation Compounds in Water Using High-Performance Liquid Chromatography/Mass Spectrometry

    USGS Publications Warehouse

    Lee, E.A.; Kish, J.L.; Zimmerman, L.R.; Thurman, E.

    2001-01-01

    An analytical method using high-performance liquid chromatography/mass spectrometry (HPLC/MS) was developed by the U.S. Geological Survey in 1999 for the analysis of selected chloroacetanilide herbicide degradation compounds in water. These compounds were acetochlor ethane sulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. The HPLC/MS method was updated in 2000, and the method detection limits were modified accordingly. Four other degradation compounds also were added to the list of compounds that can be analyzed using HPLC/MS; these compounds were dimethenamid ESA, dimethenamid OXA, flufenacet ESA, and flufenacet OXA. Except for flufenacet OXA, good precision and accuracy were demonstrated for the updated HPLC/MS method in buffered reagent water, surface water, and ground water. The mean HPLC/MS recoveries of the degradation compounds from water samples spiked at 0.20 and 1.0 ?g/L (microgram per liter) ranged from 75 to 114 percent, with relative standard deviations of 15.8 percent or less for all compounds except flufenacet OXA, which had relative standard deviations ranging from 11.3 to 48.9 percent. Method detection levels (MDL's) using the updated HPLC/MS method varied from 0.009 to 0.045 ?g/L, with the flufenacet OXA MDL at 0.072 ?g/L. The updated HPLC/MS method is valuable for acquiring information about the fate and transport of the parent chloroacetanilide herbicides in water.

  4. Trends in concentrations and use of agricultural herbicides for Corn Belt rivers, 1996-2006

    USGS Publications Warehouse

    Vecchia, A.V.; Gilliom, R.J.; Sullivan, D.J.; Lorenz, D.L.; Martin, J.D.

    2009-01-01

    Trends in the concentrations and agricultural use of four herbicides (atrazine, acetochlor, metolachlor, and alachlor) were evaluated for major rivers of the Corn Belt for two partially overlapping time periods: 1996-2002 and 2000-2006. Trends were analyzed for 11 sites on the mainstems and selected tributaries in the Ohio, Upper Mississippi, and Missouri River Basins. Concentration trends were determined using a parametric regression model designed for analyzing seasonal variability, flow-related variability, and trends in pesticide concentrations(SEAWAVE-Q).TheSEAWAVE-Qmodel accounts for the effect of changing flow conditions in order to separate changes caused by hydrologic conditions from changes caused by other factors, such as pesticide use. Most of the trends in atrazine and acetochlor concentrations for both time periods were relatively small and nonsignificant, but metolachlor and alachlor were dominated by varying magnitudes of concentration downtrends. Overall, with trends expressed as a percent change per year, trends in herbicide concentrations were consistent with trends in agricultural use; 84 of 88 comparisons for different sites, herbicides, and time periods showed no significant difference between concentration trends and agricultural use trends. Results indicate that decreasing use appears to have been the primary cause for the concentration downtrends during 1996-2006 and that, while there is some evidence that nonuse management factors may have reduced concentrations in some rivers, reliably evaluating the influence of these factors on pesticides in large streams and rivers will require improved, basin-specific information on both management practices and use over time. ?? 2009 American Chemical Society.

  5. Leaching of atrazine, metolachlor and diuron in the field in relation to their injection depth into a silt loam soil.

    PubMed

    Delphin, J E; Chapot, J Y

    2006-09-01

    A field experiment was conducted on a Calcaric Cambisol soil to study the consequences of the penetration depth and properties of pesticides on the risk of subsequent leaching. Three pesticides with different mobility characteristics and bromide were injected at 30 cm (where soil organic matter (OM) was 2%) and 80 cm (soil OM 0.5%) on irrigated plots without a crop. The migration of injected solutes was assessed for two years by sampling the soil solution using six porous cups installed at 50 and 150 cm depth and by relating solute contents to drainage water flux estimated by the STICS model (Simulateur mulTIdisciplinaire pour les Cultures Standard). Pesticides injected at 30 cm were strongly retained so that no metolachlor or diuron was detected at 50 and 150 cm. The ratio of atrazine peak concentration in the soil solution to concentration in the injected solution (C/C(0)) was 1 x 10(-3) and 0.2 x 10(-3), respectively, at 50 and 150 cm. When injected at 80 cm, (C/C(0)) of atrazine, metolachlor and diuron were 10 x 10(-3), 1 x 10(-3) and 0.3 x 10(-3) at 150 cm, respectively; 1/(C/C(0)) was correlated with K(oc) values reported from databases. The ratio of drainage volume to the amount of water at field capacity in the soil layer between the injection point at 30 cm and the water sampling level (V/V(0)) at 50 and 150 cm was 0.6 and 0.9, respectively, for bromide and 1.6 and 1.0 for atrazine. V/V(0) of the injected solutes at 80 cm was for bromide, atrazine, metolachlor and diuron 0.6, 0.9, 1.2 and 1.7, respectively; pesticide V/V(0) was correlated with K(oc). The retardation factor was a good indicator of migration risk, but tended to overestimate retardation of molecules with high K(oc). Atrazine desorption represented an additional leaching risk as a source of prolonged low contamination. The large variability in soil solution of bromide and pesticide concentrations in the horizontal plane was attributed to flow paths and clods in the tilled soil layer. This

  6. Experimental and modeling of the unsaturated transports of S-metolachlor and its metabolites in glaciofluvial vadose zone solids.

    PubMed

    Sidoli, Pauline; Lassabatere, Laurent; Angulo-Jaramillo, Rafael; Baran, Nicole

    2016-07-01

    The transport of pesticides to groundwater is assumed to be impacted by flow processes and geochemical interactions occurring in the vadose zone. In this study, the transport of S-metolachlor (SMOC) and its two metabolites ESA-metolachlor (MESA) and OXA-metolachlor (MOXA) in vadose zone materials of a glaciofluvial aquifer is studied at laboratory scale. Column experiments are used to study the leaching of a conservative tracer (bromide) and SMOC, MESA and MOXA under unsaturated conditions in two lithofacies, a bimodal gravel (Gcm,b) and a sand (S-x). Tracer experiments showed water fractionation into mobile and immobile compartments more pronounced in bimodal gravel columns. In both lithofacies columns, SMOC outflow is delayed (retardation factor>2) and mass balance reveals depletion (mass balance of 0.59 and 0.77 in bimodal gravel and sand, respectively). However, complete mass elution associated with retardation factors close to unity shows that there is no adsorption of MESA and MOXA in either lithofacies. SMOC transport is characterized by non-equilibrium sorption and sink term in both bimodal gravel and sand columns. Batch experiments carried out using agitation times consistent with column water residence times confirmed a time-dependence of SMOC sorption and high adsorption rates (>80%) of applied concentrations. Desorption experiments confirm the irreversibility of a major part of the SMOC adsorption onto particles, corresponding to the sink term in columns. In the bimodal gravel column, SMOC adsorption occurs mainly on reactive particles in contact with mobile water because of flow regionalization whereas in the sand column, there is pesticide diffusion to the immobile water. Such results clearly show that sorption mechanisms in the vadose zone solids below the soil are both solute and contact-time-dependent and are impacted by hydrodynamic conditions. The more rapid transport of MESA and MOXA to the aquifer would be controlled mainly by water flow

  7. Comparative study of cytotoxic and genotoxic effects induced by herbicide S-metolachlor and its commercial formulation Twin Pack Gold® in human hepatoma (HepG2) cells.

    PubMed

    Nikoloff, Noelia; Escobar, Luciana; Soloneski, Sonia; Larramendy, Marcelo L

    2013-12-01

    The in vitro effects of S-metolachlor and its formulation Twin Pack Gold(®) (96% a.i.) were evaluated in human hepatoma (HepG2) cells. Cytokinesis-blocked micronucleus cytome (CBMN-cyt) and MTT assays as well as Neutral Red uptake were employed for genotoxicity and cytotoxicity evaluation. Activities were tested within the concentration range of 0.25-15 μg/ml S-metolachlor for 24h of exposure. Both compounds rendered a minor reduction in the NDI although not reaching statistical significance. Results demonstrated that the S-metolachlor was not able to induce MNs. On the other hand, 0.5-6 μg/ml Twin Pack Gold(®) increased the frequency of MNs. When cytotoxicity was estimated, S-metolachlor was not able to induce either a reduction of lysosomal or mitochondrial activity. Contrarily, whereas 1-15 μg/ml Twin Pack Gold(®) induced a significant reduction of mitochondrial activity, all tested concentrations of the formulated product induced a significant decrease of lysosomal performance as a function of the concentration of the S-metolachlor-based formulation titrated into cultures. Genotoxicity and cytotoxicity differences obtained with pure S-metolachlor and the commercial S-metolachlor-based formulation indicate that the latter may contain additional unsafe xenobiotics and support the concept of the importance of evaluating not only the active principle but also the commercial formulation when estimating the real hazard from agrochemicals.

  8. Modelling the effect of exposing algae to pulses of S-metolachlor: How to include a delay to the onset of the effect and in the recovery.

    PubMed

    Copin, Pierre-Jean; Perronet, Léa; Chèvre, Nathalie

    2016-01-15

    In agriculture, herbicides are applied to improve crop productivity. During and after rain event, herbicides can be transported by surface runoff in streams and rivers. As a result, the exposure pattern in creeks is time-varying, i.e., a repeated pollution of aquatic system. In previous studies, we developed a model to assess the effects of pulse exposure patterns on algae. This model was validated for triazines and phenylureas, which are substances that induce effects directly after exposure with no delay in recovery. However, other herbicides display a mode of action characterized by a time-dependency effect and a delay in recovery. In this study, we therefore investigate whether this previous model could be used to assess the effects of pulse exposure by herbicides with time delay in effect and recovery. The current study focuses on the herbicide S-metolachlor. We showed that the effect of the herbicide begins only after 20 h of exposure for the alga Scenedesmus vacuolatus based on both the optical density and algal cells size measurements. Furthermore, the duration of delay of the recovery for algae previously exposed to S-metolachlor was 20 h and did not depend on the pulse exposure duration or the height of the peak concentration. By accounting for these specific effects, the measured and predicted effects were similar when pulse exposure of S-metolachlor is tested on the alga S. vacuolatus. However, the sensitivity of the alga is greatly modified after being previously exposed to a pulse of S-metolachlor. In the case of scenarios composed of several pulses, this sensitivity should be considered in the modelling. Therefore, modelling the effects of any pulse scenario of S-metolachlor on an alga is feasible but requires the determination of the effect trigger, the delay in recovery and the possible change in the sensitivity of the alga to the substance. PMID:26410701

  9. Major herbicides in ground water: Results from the National Water-Quality Assessment

    USGS Publications Warehouse

    Barbash, J.E.; Thelin, G.P.; Kolpin, D.W.; Gilliom, R.J.

    2001-01-01

    To improve understanding of the factors affecting pesticide occurrence in ground water, patterns of detection were examined for selected herbicides, based primarily on results from the National Water-Quality Assessment (NAWQA) program. The NAWQA data were derived from 2227 sites (wells and springs) sampled in 20 major hydrologic basins across the USA from 1993 to 1995. Results are presented for six high-use herbicides - atrazine (2-chloro-4-ethylamino-6-iso-propylamino-s-triazine), cyanazine (2-[4-chloro-6-ethylamino-l,3,5-triazin-2-yl]amino]-2-methylpropionitrile), simazine (2-chloro-4,6-bis[ethylamino]-s-triazine), alachlor (2-chloro-N-[2,6-diethylphenyl]-N-[methoxymethyl]acetamide), acetochlor (2-chloro-N-[ethoxymethyl]. N-[2-ethyl-6-methylphenyl]acetamide), and metolachlor (2-chloro-N-[2-ethyl-6-methylphenyl]-N-[2-methoxy-l- methylethyl]acetamide) - as well as for prometon (2,4-bis[isopropylamino]-6-methoxy-s-triazine), a nonagricultural herbicide detected frequently during the study. Concentrations were <1 ??g L-1 at 98% of the sites with detections, but exceeded drinking-water criteria (for atrazine) at two sites. In urban areas, frequencies of detection (at or above 0.01 ??g L-1) of atrazine, cyanazine, simazine, alachlor, and metolachlor in shallow ground water were positively correlated with their nonagricultural use nationwide (P < 0.05). Among different agricultural areas, frequencies of detection were positively correlated with nearby agricultural use for atrazine, cyanazine, alachlor, and metolachlor, but not simazine. Multivariate analysis demonstrated that for these five herbicides, frequencies of detection beneath agricultural areas were positively correlated with their agricultural use and persistence in aerobic soil. Acetochlor, an agricultural herbicide first registered in 1994 for use in the USA, was detected in shallow ground water by 1995, consistent with previous field-scale studies indicating that some pesticides may be detected in ground

  10. Determination of Low Concentrations of Acetochlor in Water by Automated Solid-Phase Extraction and Gas Chromatography with Mass-Selective Detection

    USGS Publications Warehouse

    Lindley, C.E.; Stewart, J.T.; Sandstrom, M.W.

    1996-01-01

    A sensitive and reliable gas chromatographic/mass spectrometric (GC/MS) method for determining acetochlor in environmental water samples was developed. The method involves automated extraction of the herbicide from a filtered 1 L water sample through a C18 solid-phase extraction column, elution from the column with hexane-isopropyl alcohol (3 + 1), and concentration of the extract with nitrogen gas. The herbicide is quantitated by capillary/column GC/MS with selected-ion monitoring of 3 characteristic ions. The single-operator method detection limit for reagent water samples is 0.0015 ??g/L. Mean recoveries ranged from about 92 to 115% for 3 water matrixes fortified at 0.05 and 0.5 ??g/L. Average single-operator precision, over the course of 1 week, was better than 5%.

  11. Effects of realistic doses of atrazine, metolachlor, and glyphosate on lipid peroxidation and diet-derived antioxidants in caged honey bees (Apis mellifera).

    PubMed

    Helmer, Stephanie Hedrei; Kerbaol, Anahi; Aras, Philippe; Jumarie, Catherine; Boily, Monique

    2015-06-01

    The decline in the population of pollinators is a worrying phenomenon worldwide. In North America, the extensive use of herbicides in maize and soya crops may affect the health of nontarget organisms like the honey bee. In this study, caged honey bees were exposed to realistic doses of atrazine, metolachlor, and glyphosate for 10 days via contaminated syrup. Peroxidation of lipids was evaluated using the thiobarbituric acid reactive substance (TBARS) test, and diet-derived antioxidants-carotenoids, all-trans-retinol (at-ROH) and α-tocopherol-were detected and quantified using reversed-phase HPLC techniques. Significant increases in syrup consumption were observed in honey bees exposed to metolachlor, and a lower TBARS value was recorded for the highest dose. No relationship was observed between the peroxidation of lipids and the levels of antioxidants. However, β-carotene, which was found to be the most abundant carotenoid, and at-ROH (derived from β-carotene) both decreased with increasing doses of atrazine and glyphosate. In contrast, metolachlor increased levels of at-ROH without any effects on β-carotene. These results show that the honey bee carotenoid-retinoid system may be altered by sublethal field-realistic doses of herbicides.

  12. Phytoremediation of the herbicides atrazine and metolachlor by transgenic rice plants expressing human CYP1A1, CYP2B6, and CYP2C19.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2006-04-19

    This study evaluated the expression of human cytochrome P450 genes CYP1A1, CYP2B6, and CYP2C19 in rice plants (Oryza sativa cv. Nipponbare) introduced using the plasmid pIKBACH. The transgenic rice plants (pIKBACH rice plants) became more tolerant toward various herbicides than nontransgenic Nipponbare rice plants. Rice plants expressing pIKBACH grown in soil showed tolerance to the herbicides atrazine, metolachlor, and norflurazon and to a mixture of the three herbicides. The degradation of atrazine and metolachlor by pIKBACH rice plants was evaluated to confirm the metabolic activity of the introduced P450s. Although both pIKBACH and nontransgenic Nipponbare rice plants could decrease the amounts of the herbicides in plant tissue and culture medium, pIKBACH rice plants removed greater amounts in greenhouse experiments. The ability of pIKBACH rice plants to remove atrazine and metolachlor from soil was confirmed in large-scale experiments. The metabolism of herbicides by pIKBACH rice plants was enhanced by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, pIKBACH rice plants may become useful tools for the breeding of herbicide-tolerant crops and for phytoremediation of environmental pollution by organic chemicals. PMID:16608219

  13. Effects of realistic doses of atrazine, metolachlor, and glyphosate on lipid peroxidation and diet-derived antioxidants in caged honey bees (Apis mellifera).

    PubMed

    Helmer, Stephanie Hedrei; Kerbaol, Anahi; Aras, Philippe; Jumarie, Catherine; Boily, Monique

    2015-06-01

    The decline in the population of pollinators is a worrying phenomenon worldwide. In North America, the extensive use of herbicides in maize and soya crops may affect the health of nontarget organisms like the honey bee. In this study, caged honey bees were exposed to realistic doses of atrazine, metolachlor, and glyphosate for 10 days via contaminated syrup. Peroxidation of lipids was evaluated using the thiobarbituric acid reactive substance (TBARS) test, and diet-derived antioxidants-carotenoids, all-trans-retinol (at-ROH) and α-tocopherol-were detected and quantified using reversed-phase HPLC techniques. Significant increases in syrup consumption were observed in honey bees exposed to metolachlor, and a lower TBARS value was recorded for the highest dose. No relationship was observed between the peroxidation of lipids and the levels of antioxidants. However, β-carotene, which was found to be the most abundant carotenoid, and at-ROH (derived from β-carotene) both decreased with increasing doses of atrazine and glyphosate. In contrast, metolachlor increased levels of at-ROH without any effects on β-carotene. These results show that the honey bee carotenoid-retinoid system may be altered by sublethal field-realistic doses of herbicides. PMID:24728576

  14. Screening for the Pesticides Atrazine, Chlorpyrifos, Diazinon, Metolachlor, and Simazine in Selected Michigan Streams, March-November 2005

    USGS Publications Warehouse

    Fogarty, Lisa R.; Duris, Joseph W.

    2007-01-01

    From March through November 2005, the U.S. Geological Survey, in cooperation with the Michigan Department of Environmental Quality (MDEQ), did a statewide screening to aid in understanding the occurrence and distribution of selected pesticides in Michigan streams. Stream-water samples were collected from 23 sites throughout Michigan. In all, 320 water samples were analyzed by use of rapid immunoassay methods for the herbicides atrazine, metolachlor, and simazine and the insecticides chlorpyrifos and diazinon. On one occasion (June, 2005), atrazine concentrations exceeded the Michigan water-quality value (7.3 micrograms per liter) at the Black River in St. Clair County. Neither chlorpyrifos nor diazinon was detected during April through September. MDEQ detected chlorpyrifos in streams throughout the state in November. Herbicide concentrations were highest in samples influenced by intensive agriculture; however, median herbicide concentrations were similar among agricultural and urban sites. Concentrations of herbicides were very low to undetected in undeveloped areas. Seasonal patterns were also evident during the sampling period. Increased concentrations generally occurred in late spring to early summer. At 11 sites, daily sampling was done every day for 5 days following a rainfall after herbicide application in the area. Substantial changes in concentrations of herbicides - greater than tenfold from the previous day - were observed during the daily sampling. No consistent relation was found between concentration and streamflow. Results of this study may be used to aid in the development of a more comprehensive pesticide monitoring study for the State of Michigan.

  15. A High-Performance Liquid Chromatography-Based Screening Method for the Analysis of Atrazine, Alachlor, and Ten of Their Transformation Products

    USGS Publications Warehouse

    Schroyer, B.R.; Capel, P.D.

    1996-01-01

    A high-performance liquid Chromatography (HPLC) method is presented for the for the fast, quantitative analysis of the target analytes in water and in low organic-carbon, sandy soils that are known to be contaminated with the parent herbicides. Speed and ease of sample preparation was prioritized above minimizing detection limits. Soil samples were extracted using 80:20 methanol:water (volume:volume). Water samples (50 ??L) were injected directly into the HPLC without prior preparation. Method quantification limits for soil samples (10 g dry weight) and water samples ranged from 20 to 110 ng/g and from 20 to 110 ??g/L for atrazine and its transformation products and from 80 to 320 ng/g and from 80 to 320 ??g/L for alachlor and its transformation products, respectively.

  16. Trends in Pesticide Concentrations in Corn-Belt Streams, 1996-2006

    USGS Publications Warehouse

    Sullivan, Daniel J.; Vecchia, Aldo V.; Lorenz, David L.; Gilliom, Robert J.; Martin, Jeffrey D.

    2009-01-01

    Trends in the concentrations of commonly occurring pesticides in the Corn Belt of the United States were assessed, and the performance and application of several statistical methods for trend analysis were evaluated. Trends in the concentrations of 11 pesticides with sufficient data for trend assessment were assessed at up to 31 stream sites for two time periods: 1996-2002 and 2000-2006. Pesticides included in the trend analyses were atrazine, acetochlor, metolachlor, alachlor, cyanazine, EPTC, simazine, metribuzin, prometon, chlorpyrifos, and diazinon. The statistical methods applied and compared were (1) a modified version of the nonparametric seasonal Kendall test (SEAKEN), (2) a modified version of the Regional Kendall test, (3) a parametric regression model with seasonal wave (SEAWAVE), and (4) a version of SEAWAVE with adjustment for streamflow (SEAWAVE-Q). The SEAKEN test is a statistical hypothesis test for detecting monotonic trends in seasonal time-series data such as pesticide concentrations at a particular site. Trends across a region, represented by multiple sites, were evaluated using the regional seasonal Kendall test, which computes a test for an overall trend within a region by computing a score for each season at each site and adding the scores to compute the total for the region. The SEAWAVE model is a parametric regression model specifically designed for analyzing seasonal variability and trends in pesticide concentrations. The SEAWAVE-Q model accounts for the effect of changing flow conditions in order to separate changes caused by hydrologic trends from changes caused by other factors, such as pesticide use. There was broad, general agreement between unadjusted trends (no adjustment for streamflow effects) identified by the SEAKEN and SEAWAVE methods, including the regional seasonal Kendall test. Only about 10 percent of the paired comparisons between SEAKEN and SEAWAVE indicated a difference in the direction of trend, and none of these had

  17. Simulated ground-water flow and water quality of the Mississippi River alluvium near Burlington, Iowa, 1999

    USGS Publications Warehouse

    Boyd, Robert A.

    2001-01-01

    Water samples collected from the alluvium indicated ground water can be classified as a calcium-magnesium-bicarbonate type. Reducing conditions likely occur in some localized areas of the alluvium, as suggested by relatively large concentrations of dissolved iron (4,390 micrograms per liter) and manganese (2, 430 micrograms per liter) in some ground-water samples. Nitrite plus nitrate was detected at concentrations greater than or equal to 8 milligrams per liter in three samples collected from observation wells completed in close proximity to cropland; the nitrite plus nitrate concentration in one groundwater sample exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level for nitrate in drinking water (10 milligrams per liter as N). Triazine herbicides (atrazine, cyanazine, propazine, simazine, and selected degradation products) and chloroacetanilide herbicides (acetochlor, alachlor, and metolachlor) were detected in some water samples. A greater number of herbicide compounds were detected in surface-water samples than in ground-water samples. Herbicide concentrations typically were at least an order of magnitude greater in surfacewater samples than in ground-water samples. The Maximum Contaminant Level for alachlor (2 micrograms per liter) was exceeded in a sample from Dry Branch Creek at Tama Road and for atrazine (3 micrograms per liter) was exceeded in samples collected from Dry Branch Creek at Tama Road and the county drainage ditch at Tama Road.

  18. Does S-metolachlor affect the performance of Pseudomonas sp. strain ADP as bioaugmentation bacterium for atrazine-contaminated soils?

    PubMed

    Viegas, Cristina A; Costa, Catarina; André, Sandra; Viana, Paula; Ribeiro, Rui; Moreira-Santos, Matilde

    2012-01-01

    Atrazine (ATZ) and S-metolachlor (S-MET) are two herbicides widely used, often as mixtures. The present work examined whether the presence of S-MET affects the ATZ-biodegradation activity of the bioaugmentation bacterium Pseudomonas sp. strain ADP in a crop soil. S-MET concentrations were selected for their relevance in worst-case scenarios of soil contamination by a commercial formulation containing both herbicides. At concentrations representative of application of high doses of the formulation (up to 50 µg g(-1) of soil, corresponding to a dose approximately 50× higher than the recommended field dose (RD)), the presence of pure S-MET significantly affected neither bacteria survival (~10(7) initial viable cells g(-1) of soil) nor its ATZ-mineralization activity. Consistently, biodegradation experiments, in larger soil microcosms spiked with 20× or 50 × RD of the double formulation and inoculated with the bacterium, revealed ATZ to be rapidly (in up to 5 days) and extensively (>96%) removed from the soil. During the 5 days, concentration of S-MET decreased moderately to about 60% of the initial, both in inoculated and non-inoculated microcosms. Concomitantly, an accumulation of the two metabolites S-MET ethanesulfonic acid and S-MET oxanilic acid was found. Despite the dissipation of almost all the ATZ from the treated soils, the respective eluates were still highly toxic to an aquatic microalgae species, being as toxic as those from the untreated soil. We suggest that this high toxicity may be due to the S-MET and/or its metabolites remaining in the soil.

  19. Extracellular signal-regulated kinase pathway play distinct role in acetochlor-mediated toxicity and intrinsic apoptosis in A549 cells.

    PubMed

    Zerin, Tamanna; Song, Ho-Yeon; Kim, Yong-Sik

    2015-02-01

    Acetochlor (ACETO), a member of the chloroacetanilide family of herbicides, is widely used globally and is very frequently detected in watersheds of agricultural lands and fresh water streams. The human health consequences of environmental exposure to ACETO are unknown. This study was designed to elucidate the effect and molecular mechanisms of ACETO on human alveolar A549 cells. Established assays of cell viability and cytotoxicity were performed to detect the potential effects of ACETO on A549 cells. ACETO generated reactive oxygen species, which may have been crucial to apoptosis-mediated cytotoxicity. ACETO-treatment showed a concentration dependent up-regulation of pro-apoptotic proteins including Bax, Bak, BID and Bad, but a differential level of expression of anti-apoptotic proteins were observed, leading to the release of cytochrome c from mitochondria to the cytoplasm as well as activation of caspase-3, and cleavage of caspase-9 and PARP. ACETO also induced activation of extracellular signal-regulated kinase (ERK). Inhibition of the expression of ERK by PD98059 partially reversed ACETO-induced cytotoxicity, apoptosis and the expression of caspase-3, -9 and PARP in A549 cells. Comparative evaluation of the results indicates that the principal mechanism underlying ACETO-mediated cytotoxicity is likely to be through ERK-mediated intrinsic pathway of apoptosis. PMID:25291404

  20. Sorption and mineralization of S-metolachlor and its ionic metabolites in soils and vadose zone solids: consequences on groundwater quality in an alluvial aquifer (Ain Plain, France).

    PubMed

    Baran, Nicole; Gourcy, Laurence

    2013-11-01

    This study characterizes the transfer of S-metolachlor (SMOC) and its metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA) to the alluvial aquifer. Sorption and mineralization of SMOC and its two ionic metabolites were characterized for cultivated soils and solids from the vadose (unsaturated) zone in the Ain Plain (France). Under sterile soil conditions, the absence of mineralization confirms the importance of biotic processes in SMOC degradation. There is some adsorption and mineralization of the parent molecule and its metabolites in the unsaturated zone, though less than in soils. For soils, the MESA adsorption constant is statistically higher than that of MOXA and the sorption constants of the two metabolites are significantly lower than that of SMOC. After 246 days, for soils, maximums of 26% of the SMOC, 30% of the MESA and 38% of the MOXA were mineralized. This partly explains the presence of these metabolites in the groundwater at concentrations generally higher than those of the parent molecule for MESA, although there is no statistical difference in the mineralization of the 3 molecules. The laboratory results make it possible to explain the field observations made during 27 months of groundwater quality monitoring (monthly sampling frequency). The evolution of both metabolite concentrations in the groundwater is directly related to recharge dynamics; there is a positive correlation between concentrations and the groundwater level. The observed lag of several months between the signals of the parent molecule and those of the metabolites is probably due to greater sorption of the parent molecule than of its metabolites and/or to degradation kinetics.

  1. Sorption and mineralization of S-metolachlor and its ionic metabolites in soils and vadose zone solids: Consequences on groundwater quality in an alluvial aquifer (Ain Plain, France)

    NASA Astrophysics Data System (ADS)

    Baran, Nicole; Gourcy, Laurence

    2013-11-01

    This study characterizes the transfer of S-metolachlor (SMOC) and its metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA) to the alluvial aquifer. Sorption and mineralization of SMOC and its two ionic metabolites were characterized for cultivated soils and solids from the vadose (unsaturated) zone in the Ain Plain (France). Under sterile soil conditions, the absence of mineralization confirms the importance of biotic processes in SMOC degradation. There is some adsorption and mineralization of the parent molecule and its metabolites in the unsaturated zone, though less than in soils. For soils, the MESA adsorption constant is statistically higher than that of MOXA and the sorption constants of the two metabolites are significantly lower than that of SMOC. After 246 days, for soils, maximums of 26% of the SMOC, 30% of the MESA and 38% of the MOXA were mineralized. This partly explains the presence of these metabolites in the groundwater at concentrations generally higher than those of the parent molecule for MESA, although there is no statistical difference in the mineralization of the 3 molecules. The laboratory results make it possible to explain the field observations made during 27 months of groundwater quality monitoring (monthly sampling frequency). The evolution of both metabolite concentrations in the groundwater is directly related to recharge dynamics; there is a positive correlation between concentrations and the groundwater level. The observed lag of several months between the signals of the parent molecule and those of the metabolites is probably due to greater sorption of the parent molecule than of its metabolites and/or to degradation kinetics.

  2. Whole genome sequence analysis of an Alachlor and Endosulfan degrading Pseudomonas strain W15Feb9B isolated from Ochlockonee River, Florida.

    PubMed

    Chauhan, Ashvini; Pathak, Ashish; Ewida, Ayman Y I; Griffiths, Zabrenna; Stothard, Paul

    2016-06-01

    We recently isolated a Pseudomonas sp. strain W15Feb9B from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides - Alachlor [(2-chloro-2',6'-diethylphenyl-N (methoxymethyl)acetanilide)] and Endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain W15Feb9B, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of strain 2385 has been deposited in GenBank under accession number JTKF00000000; BioSample number SAMN03151543. The sequences obtained from strain 2385 assembled into 192 contigs with a genome size of 6,031,588, G + C content of 60.34, and 5512 total number of putative genes. RAST annotated a total of 542 subsystems in the genome of strain W15Feb9B along with the presence of 5360 coding sequences. A genome wide survey of strain W15Feb9B indicated that it has the potential to degrade several other pollutants including atrazine, caprolactam, dioxin, PAHs (such as naphthalene) and several chloroaromatic compounds.

  3. Consensus diagnoses and mode of action for the formation of gastric tumors in rats treated with the chloroacetanilide herbicides alachlor and butachlor.

    PubMed

    Furukawa, Satoshi; Harada, Takanori; Thake, Daryl; Iatropoulos, Michael J; Sherman, James H

    2014-01-01

    A panel of pathologists (Panel) was formed to evaluate the pathogenesis and human relevance of tumors that developed in the fundic region of rat stomachs in carcinogenicity and mechanistic studies with alachlor and butachlor. The Panel evaluated stomach sections stained with hematoxylin and eosin, neuron-specific enolase, and chromogranin A to determine the presence and relative proportion of enterochromaffin-like (ECL) cells in the tumors and concluded all tumors were derived from ECL cells. Biochemical and pathological data demonstrated the tumor formation involved a nongenotoxic threshold mode of action (MOA) initially characterized by profound atrophy of the glandular fundic mucosa that affected gastric glands, but not surface epithelium. This resulted in a substantial loss of parietal cells and a compensatory mucosal cell proliferation. The loss of parietal cells caused a marked increase in gastric pH (hypochlorhydria), leading to sustained and profound hypergastrinemia. The mucosal atrophy, together with the increased gastrin, stimulated cell growth in one or more ECL cell populations, resulting in neoplasia. ECL cell autocrine and paracrine effects led to dedifferentiation of ECL cell tumors. The Panel concluded the tumors develop via a threshold-dependent nongenotoxic MOA, under conditions not relevant to humans.

  4. Whole genome sequence analysis of an Alachlor and Endosulfan degrading Pseudomonas strain W15Feb9B isolated from Ochlockonee River, Florida.

    PubMed

    Chauhan, Ashvini; Pathak, Ashish; Ewida, Ayman Y I; Griffiths, Zabrenna; Stothard, Paul

    2016-06-01

    We recently isolated a Pseudomonas sp. strain W15Feb9B from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides - Alachlor [(2-chloro-2',6'-diethylphenyl-N (methoxymethyl)acetanilide)] and Endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain W15Feb9B, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of strain 2385 has been deposited in GenBank under accession number JTKF00000000; BioSample number SAMN03151543. The sequences obtained from strain 2385 assembled into 192 contigs with a genome size of 6,031,588, G + C content of 60.34, and 5512 total number of putative genes. RAST annotated a total of 542 subsystems in the genome of strain W15Feb9B along with the presence of 5360 coding sequences. A genome wide survey of strain W15Feb9B indicated that it has the potential to degrade several other pollutants including atrazine, caprolactam, dioxin, PAHs (such as naphthalene) and several chloroaromatic compounds. PMID:27330991

  5. Effects of the herbicides prosulfuron and metolachlor on fluxes of CO2, N2O, and CH4 in a fertilized Colorado grassland soil

    USGS Publications Warehouse

    Kinney, C.A.; Mosier, A.R.; Ferrer, I.; Furlong, E.T.; Mandernack, K.W.

    2004-01-01

    The effect that pesticides have on trace gas production and consumption in agricultural soils is often overlooked. Independent field and laboratory experiments were used to measure the effects that the commonly used herbicides prosulfuron and metolachlor have on trace gas fluxes (CO2, N2O, and CH4) from fertilized soil of the Colorado shortgrass steppe. Separate sample plots (1 m2) on tilled and no-till soil at the sites included the following treatments: 1) a control without fertilizer or herbicide, 2) a fertilized (NH4NO3 equivalent to 244 kg ha-1) control without herbicide, 3) and fertilized plots amended with an herbicide (prosulfuron equivalent to 0.46 kg ha-1 57% by weight active ingredient or metolachlor equivalent to 5.7 L ha-1, 82.4% by weight active ingredient). During an initial study of one year duration, measurement of gas exchange revealed that prosulfuron-amendment stimulated N2O emissions and CH4 consumption by as much as 1600% and 1300% during a single measurement, respectively. During a second set of flux measurements beginning in August 2001, more frequent weekly measurements were made during a twelve week period. From this second study an increased N2O efflux and CH4 uptake occurred after a 7-week lag period that persisted for about 5 weeks. These changes in gas flux amounted to an overall increase of 41% and 30% for N2O emission and CH4 consumption, respectively. The co-occurrence of stimulated N2O and CH4 fluxes suggests a similar cause that is related to prosulfuron degradation. Evidence suggested that prosulfuron degradation stimulated microbial activity responsible for trace gas flux. Ultimately, prosulfuron-amendment led to an ???50% reduction in the global warming potential from N2O and CH4 fluxes at this field site, which is equivalent to a reduction of the global warming potential of 0.18 mols CO2 m-2 d-1 from these gases. Metolachlor application did not significantly affect the trace gas fluxes measured. These results demonstrate the

  6. Quantification of toxic effects of the herbicide metolachlor on marine microalgae Ditylum brightwellii (Bacillariophyceae), Prorocentrum minimum (Dinophyceae), and Tetraselmis suecica (Chlorophyceae).

    PubMed

    Ebenezer, Vinitha; Ki, Jang-Seu

    2013-02-01

    Toxic effects of the herbicide metolachlor (MC) were evaluated for three marine microalgae, Tetraselmis suecica (chlorophyte), Ditylum brightwellii (diatom), and Prorocentrum minimum (dinoflagellate). MC showed a significant reduction in cell counts and chlorophyll a levels. Median effective concentration (EC50) was calculated based on chlorophyll a levels after a 72-h MC exposure. EC50 values for T. suecica, D. brightwellii, and P. minimum were 21.3, 0.423, and 0.07 mg/L, respectively. These values showed that the dinoflagellate was most sensitive when exposed to the herbicide, at a concentration comparable to freshwater algae, suggesting its potential as an appropriate model organism for ecotoxicity assessments in marine environments. PMID:23456723

  7. Ferric complexes as catalysts for {open_quotes}Fenton{close_quotes} degradation of 2,4-D and metolachlor in soil

    SciTech Connect

    Pignatello, J.J.; Baehr, K.

    1994-03-01

    Fenton-type reactions of hydrogen peroxide with Fe compounds generate bydroxyl radical (OH{center_dot}) or other reactive species and are potentially useful for degrading organic contaminants in soil. The use of simple Fe salts is limited, however. This study investigated certain pH 6-soluble Fe(III) complexes (Fe-L, where L is an organic tigand) as catalysts for degradation of herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and metolachlor (2-chloro-N-[2-ethyl 6-methylphenyl]-N-[2-methoxy-l-methylethyl]acetamide). Reactions were carried out in 1:1 aqueous suspensions of a topsoil (15.7 g kg{sup -1} organic C) at the natural pH of 5.7 with herbicides at concentrations representative of a spill (2-3 g kg{sup -1} about 0.01 mol kg{sup -1}). The two herbicides had contrasting sorption behavior in that 2,4-D was mostly in solution, whereas metotachlor was mostly sorbed. The best results were obtained using Fe-nitrilotriscetate (NTA) or Fe-hydroxyethyleniminodiacetate (HEIDA) at 0.01 mol kg-{sup -1} and [H{sub 2}O{sub 2}]{ge} 0.5 mol kg{sup -1}. The gallic acid complex was less effective. In 3 h,{sup 14}C-labeled 2,4-D was quantitatively dechlorinated and partially (15-30%) converted to {sup 14}CO{sub 2}: metolachlor was 93% transformed and 29% dechlorinated. Controls using free ligand plus peroxide or peroxide alone gave little or no reaction. Fe-L + H{sub 2}O{sub 2} was superior to the Fenton reagent itself (Fe{sup 2+} + H{sub 2}O{sub 2}). The results of this study demonstrate that relatively mild chemical oxidation can be effective for remediation of certain contaminants in soil 23 refs., 2 figs., 6 tabs.

  8. Atmospheric Transport and Deposition of Agricultural Chemicals

    NASA Astrophysics Data System (ADS)

    Majewski, M. S.; Vogel, J. R.; Capel, P. D.

    2006-05-01

    Concentrations of more than 80 pesticides and select transformation products were measured in atmospheric deposition during two growing seasons in five agricultural areas across the United States. Rainfall samples were collected at study areas in California, Indiana, Maryland, and Nebraska. In the arid Yakima Valley of Washington, dry deposition for the same compounds was estimated using air concentration measurements and depositional models. In the predominantly corn, soybean, and alfalfa growing region of Nebraska, Indiana, and Maryland, the herbicides acetochlor, alachlor, atrazine, and metolachlor where the predominant pesticides detected, and the highest concentrations ranged from 0.64 microgram per liter (ug/L) for metolachlor in a small, predominantly dairy use dominated watershed in Maryland to 6.6 ug/L and 19 ug/L for atrazine in Indiana and Nebraska, respectively. California showed a different seasonal occurrence pattern and suite of detected pesticides because the rainy season occurs during the winter months and a wide variety of crops are grown throughout the year. With the exception of metolachlor (0.23 ug/L, max.), the corn and soybean herbicides were not used to any great extent in the California study area and were not detected. The insecticides diazinon (1.21 ug/L, max.) and chlorpyrifos (0.12 ug/L, max.) were detected in nearly every sample taken in California. The Washington study area was similar to California in terms of the variety of crops grown and the pesticides use, but it receives very little rainfall. Dry deposition was estimated at this site from air concentrations and particle settling velocities. The results of these studies show the importance of the atmosphere as an additional source of pesticide loading to agricultural watersheds.

  9. Fate and movement of atrazine, cyanazine, metolachlor and selected degradation products in water resources of the deep Loess Hills of Southwestern Iowa, USA.

    PubMed

    Steinheimer, T R; Scoggin, K D

    2001-02-01

    The environmental fate and movement of herbicides widely used for weed control in corn are assessed for a deep loess soil in southwestern Iowa. Beginning in the early 1980s, the herbicide-based weed control program emphasized the application of atrazine (ATR) or cyanazine (CYN) and metolachlor (MET) for both broadleaf and grass control. Between 1992 and 1995, concentrations of ATR, desethylatrazine (DEA), desisopropylatrazine (DIA), CYN and MET were measured in rainwater, both shallow and deep vadose zone water, and well water. Results show that the frequency of herbicide detections and the range and distribution of occurrences are dependent upon both landscape position and temporal inputs of recharge water from rainfall. Generally, DIA was observed more frequently and in higher mean concentration in well water than DEA, while DEA was observed more frequently than DIA in vadose zone groundwater. A chromatographic analogy is suggested to explain the occurrence patterns observed for both parent herbicide and degradation products within the unsaturated zone water. Analysis of rainwater samples collected during this time also revealed low concentrations of ATR, CYN and MET, with the timing of the detections indicative of non-local transport. Results show that the deep loess soil conducts both water and agricultural chemicals relatively rapidly and as such represents a production system which is vulnerable to contamination of shallow groundwater by herbicide-derived chemicals. Results also illustrate the importance of including major herbicide degradation products in water resource impact assessment studies.

  10. Direct aqueous injection LC-ESI/MS/MS analysis of water for 11 chloro- and thiomethyltriazines and metolachlor and its ethanesulfonic and oxanilic acid degradates.

    PubMed

    Huang, Sung-Ben; Mayer, Thomas J; Yokley, Robert A

    2008-04-23

    A multianalyte method is reported for the determination of atrazine, simazine, propazine, and their respective dealkylated chlorotriazine metabolites; ametryn and prometryn and their respective dealkylated thiomethyltriazine metabolites; and S-metolachlor and its ethanesulfonic and oxanilic acid degradates in deionized, ground, surface, and finished drinking water. Water samples are analyzed using direct aqueous injection (DAI) liquid chromatography-electrospray ionization/mass spectrometry/mass spectrometry (LC-ESI/MS/MS). No preanalysis sample manipulation is required other than transfer of a small portion of sample to an injection vial. The lower limit of the method validation is 0.050 microg/L (ppb) for all analytes except 2,4-diamino-6-chloro- s-triazine (didealkylatrazine, DDA, or G-28273). For this compound the LLMV is 0.50 microg/L (ppb). The overall mean procedural recoveries (and percent relative standard deviations) for all water types for all analytes ranged from 95 to 101% (4.5-11%). The method validation was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160.

  11. A silica coated paper substrate: development and its application in paper spray mass spectrometry for rapid analysis of pesticides in milk.

    PubMed

    Wang, Qian; Zheng, Yajun; Zhang, Xiaoling; Han, Xiaoxiao; Wang, Teng; Zhang, Zhiping

    2015-12-01

    A novel silica coated paper substrate is developed through a facile vacuum filtration method by using the commercially available silica particles as the coating material and corn starch as the adhesive agent. Unlike the commercial silica coated paper (namely grade SG81 paper), the resulting paper substrate was covered by a layer of silica particles on the top side of the paper, and no cellulosic fibers were exposed at its surface. After loading a solution sample on its surface, the coated silica particles allowed the target analytes to remain at the top side rather than penetration through the substrate. Owing to this effect and the special interactions with analytes, the as-prepared silica coated paper demonstrated superior performance in the analysis of different pesticides in milk using paper spray mass spectrometry to the uncoated filter paper and grade SG81 paper. Compared to the other two papers, paper spray analysis using the as-prepared paper improved the estimated lower limit of quantitation of seven pesticides (alachlor, acetochlor, pretilachlor, butachlor, metolachlor, napropamid and benzeneacetamide) in milk by a factor of 2 to 19-fold depending on the pesticide. This study offers a novel paper substrate for paper spray in high sensitivity analysis of target analytes in a complex foodstuff matrix without any pretreatment.

  12. Identification of ionic chloroacetanilide-herbicide metabolites in surface water and groundwater by HPLC/MS using negative ion spray

    USGS Publications Warehouse

    Ferrer, I.; Thurman, E.M.; Barcelo, D.

    1997-01-01

    Solid-phase extraction (SPE) was combined with high-performance liquid chromatography/high-flow pneumatically assisted electrospray mass spectrometry (HPLC/ESP/MS) for the trace analysis of oxanilic and sulfonic acids of acetochlor, alachlor, and metolachlor. The isolation procedure separated the chloroacetanilide metabolites from the parent herbicides during the elution from C18 cartridges using ethyl acetate for parent compounds, followed by methanol for the anionic metabolites. The metabolites were separated chromatographically using reversed-phase HPLC and analyzed by negative-ion MS using electrospray ionization in selected ion mode. Quantitation limits were 0.01 ??g/L for both the oxanilic and sulfonic acids based on a 100-mL water sample. This combination of methods represents an important advance in environmental analysis of chloroacetanilide-herbicide metabolites in surface water and groundwater for two reasons. First, anionic chloroacetanilide metabolites are a major class of degradation products that are readily leached to groundwater in agricultural areas. Second, anionic metabolites, which are not able to be analyzed by conventional methods such as liquid extraction and gas chromatography/mass spectrometry, are effectively analyzed by SPE and high-flow pneumatically assisted electrospray mass spectrometry. This paper reports the first HPLC/MS identification of these metabolites in surface water and groundwater.

  13. Acetamide herbicides and their degradation products in ground water and surface water of the United States, 1993-2003

    USGS Publications Warehouse

    Scribner, Elisabeth A.; Dietze, Julie E.; Thurman, Michael

    2004-01-01

    During 1993 through 2003, the U.S. Geological Survey conducted a number of studies to investigate and document the occurrence, fate, and transport of acetamide herbicides and their degradation products in ground and surface water. As part of these studies, approximately 5,100 water samples were collected and analyzed for the acetamide parent herbicides acetochlor, alachlor, dimethenamid, flufenacet, and metolachlor and their degradation products ethanesulfonic acid, oxanilic acid, and sulfinyl acetic acid. During this period, various analytical methods were developed to detect and measure concentrations of acetamide herbicides and their degradation products in ground water and surface water. Results showed that the degradation products of acetamide herbicides in ground water were detected more frequently and occurred at higher concentrations than their parent compounds. Further study showed that the acetamide herbicides and their degradation products were detected more frequently in surface water than in ground water. In general, the parent compounds were detected at similar or greater frequencies than the degradation products in surface water. The developed methods and data were valuable for acquiring information about the occurrence, fate, and transport of the herbicides and their degradation products and the importance of analyzing for both parent compounds and their degradate products in water-quality studies.

  14. Herbicide and degradate flux in the Yazoo River Basin

    USGS Publications Warehouse

    Coupe, R.H.; Welch, H.L.; Pell, A.B.; Thurman, E.M.

    2005-01-01

    During 1996-1997, water samples were collected from five sites in the Yazoo River Basin and analysed for 14 herbicides and nine degradates. These included acetochlor, alachlor, atrazine, cyanazine, fluometuron, metolachlor, metribuzin, molinate, norflurazon, prometryn, propanil, propazine, simazine, trifluralin, three degradates of fluometuron, two degradates of atrazine, one degradate of cyanazine, norflurazon, prometryn, and propanil. Fluxes generally were higher in 1997 than in 1996 due to a greater rainfall in 1997 than 1996. Fluxes were much larger from streams in the alluvial plain (an area of very productive farmland) than from the Skuna River in the bluff hills (an area of small farms, pasture, and forest). Adding the flux of the atrazine degradates to the atrazine flux increased the total atrazine flux by an average of 14.5%. The fluometuron degradates added about 10% to the total fluometuron flux, and adding the norflurazon degradate flux to the norflurazon flux increased the flux by 82% in 1996 and by 171% in 1997. ?? 2005 Taylor & Francis.

  15. Pesticide monitoring in surface water and groundwater using passive samplers

    NASA Astrophysics Data System (ADS)

    Kodes, V.; Grabic, R.

    2009-04-01

    Passive samplers as screening devices have been used within a czech national water quality monitoring network since 2002 (SPMD and DGT samplers for non polar substances and metals). The passive sampler monitoring of surface water was extended to polar substances, in 2005. Pesticide and pharmaceutical POCIS samplers have been exposed in surface water at 21 locations and analysed for polar pesticides, perfluorinated compounds, personal care products and pharmaceuticals. Pesticide POCIS samplers in groundwater were exposed at 5 locations and analysed for polar pesticides. The following active substances of plant protection products were analyzed in surface water and groundwater using LC/MS/MS: 2,4,5-T, 2,4-D, Acetochlor, Alachlor, Atrazine, Atrazine_desethyl, Azoxystrobin, Bentazone, Bromacil, Bromoxynil, Carbofuran, Clopyralid, Cyanazin, Desmetryn, Diazinon, Dicamba, Dichlobenil, Dichlorprop, Dimethoat, Diuron, Ethofumesate, Fenarimol, Fenhexamid, Fipronil, Fluazifop-p-butyl, Hexazinone, Chlorbromuron, Chlorotoluron, Imazethapyr, Isoproturon, Kresoxim-methyl, Linuron, MCPA, MCPP, Metalaxyl, Metamitron, Methabenzthiazuron, Methamidophos, Methidathion, Metobromuron, Metolachlor, Metoxuron, Metribuzin, Monolinuron, Nicosulfuron, Phorate, Phosalone, Phosphamidon, Prometryn, Propiconazole, Propyzamide, Pyridate, Rimsulfuron, Simazine, Tebuconazole, Terbuthylazine, Terbutryn, Thifensulfuron-methyl, Thiophanate-methyl and Tri-allate. The POCIS samplers performed very well being able to provide better picture than grab samples. The results show that polar pesticides and also perfluorinated compounds, personal care products and pharmaceuticals as well occur in hydrosphere of the Czech republic. Acknowledgment: Authors acknowledge the financial support of grant No. 2B06095 by the Ministry of Education, Youth and Sports.

  16. Semen quality in relation to biomarkers of pesticide exposure.

    PubMed Central

    Swan, Shanna H; Kruse, Robin L; Liu, Fan; Barr, Dana B; Drobnis, Erma Z; Redmon, J Bruce; Wang, Christina; Brazil, Charlene; Overstreet, James W

    2003-01-01

    We previously reported reduced sperm concentration and motility in fertile men in a U.S. agrarian area (Columbia, MO) relative to men from U.S. urban centers (Minneapolis, MN; Los Angeles, CA; New York, NY). In the present study we address the hypothesis that pesticides currently used in agriculture in the Midwest contributed to these differences in semen quality. We selected men in whom all semen parameters (concentration, percentage sperm with normal morphology, and percentage motile sperm) were low (cases) and men in whom all semen parameters were within normal limits (controls) within Missouri and Minnesota (sample sizes of 50 and 36, respectively) and measured metabolites of eight current-use pesticides in urine samples provided at the time of semen collection. All pesticide analyses were conducted blind with respect to center and case-control status. Pesticide metabolite levels were elevated in Missouri cases, compared with controls, for the herbicides alachlor and atrazine and for the insecticide diazinon [2-isopropoxy-4-methyl-pyrimidinol (IMPY)]; for Wilcoxon rank test, p = 0.0007, 0.012, and 0.0004 for alachlor, atrazine, and IMPY, respectively. Men from Missouri with high levels of alachlor or IMPY were significantly more likely to be cases than were men with low levels [odds ratios (ORs) = 30.0 and 16.7 for alachlor and IMPY, respectively], as were men with atrazine levels higher than the limit of detection (OR = 11.3). The herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and metolachlor were also associated with poor semen quality in some analyses, whereas acetochlor levels were lower in cases than in controls (p = 0.04). No significant associations were seen for any pesticides within Minnesota, where levels of agricultural pesticides were low, or for the insect repellent DEET (N,N-diethyl-m-toluamide) or the malathion metabolite malathion dicarboxylic acid. These associations between current-use pesticides and reduced semen quality suggest that

  17. Assessing the environmental fate of S-metolachlor, its commercial product Mercantor Gold® and their photoproducts using a water-sediment test and in silico methods.

    PubMed

    Gutowski, Lukasz; Baginska, Ewelina; Olsson, Oliver; Leder, Christoph; Kümmerer, Klaus

    2015-11-01

    Pesticides enter surface and groundwater by several routes in which partition to sediment contributes to their fate by abiotic (e.g. photolysis, hydrolysis) and biotic processes. Yet, little is known about S-metolachlor (SM) transformation in water-sediment systems. Therefore, a newly developed screening water-sediment test (WST) was applied to compare biodegradation and sorption processes between pure SM and Mercantor Gold® (MG), a commercial formulation of SM. Photolysis in water was performed by Xe lamp irradiation. Subsequently, the biodegradability of SM and MG photolysis mixtures was examined in WST. The primary elimination of SM from water phase was monitored and structures of its TPs resulting from biotransformation (bio-TPs) were elucidated by LC-MS/MS. SM was extracted from sediment in order to estimate the role of sorption in WST for its elimination. A set of in silico prediction software tools was applied for toxicity assessment of SM and its bio-TPs. Obtained results suggest that the MG adjuvants do not significantly affect biodegradation, but do influence diffusion of SM into sediment. 50% of SM could not be re-extracted from sediment with 0.01 M CaCl2 aqueous solution recommended in OECD test guideline for adsorption. Neither the parent compound nor the photo-TPs were biodegraded. However, new bio-TPs have been generated from SM and MG photo-TPs due to bacterial activity in the water-sediment interphase. Moreover, according to in silico assessment of the bio-TPs the biotransformation might lead to an increased toxicity to the water organisms compared with the SM. This might raise concerns of bio-TPs presence in the environment. PMID:26299980

  18. Assessing the environmental fate of S-metolachlor, its commercial product Mercantor Gold® and their photoproducts using a water-sediment test and in silico methods.

    PubMed

    Gutowski, Lukasz; Baginska, Ewelina; Olsson, Oliver; Leder, Christoph; Kümmerer, Klaus

    2015-11-01

    Pesticides enter surface and groundwater by several routes in which partition to sediment contributes to their fate by abiotic (e.g. photolysis, hydrolysis) and biotic processes. Yet, little is known about S-metolachlor (SM) transformation in water-sediment systems. Therefore, a newly developed screening water-sediment test (WST) was applied to compare biodegradation and sorption processes between pure SM and Mercantor Gold® (MG), a commercial formulation of SM. Photolysis in water was performed by Xe lamp irradiation. Subsequently, the biodegradability of SM and MG photolysis mixtures was examined in WST. The primary elimination of SM from water phase was monitored and structures of its TPs resulting from biotransformation (bio-TPs) were elucidated by LC-MS/MS. SM was extracted from sediment in order to estimate the role of sorption in WST for its elimination. A set of in silico prediction software tools was applied for toxicity assessment of SM and its bio-TPs. Obtained results suggest that the MG adjuvants do not significantly affect biodegradation, but do influence diffusion of SM into sediment. 50% of SM could not be re-extracted from sediment with 0.01 M CaCl2 aqueous solution recommended in OECD test guideline for adsorption. Neither the parent compound nor the photo-TPs were biodegraded. However, new bio-TPs have been generated from SM and MG photo-TPs due to bacterial activity in the water-sediment interphase. Moreover, according to in silico assessment of the bio-TPs the biotransformation might lead to an increased toxicity to the water organisms compared with the SM. This might raise concerns of bio-TPs presence in the environment.

  19. Surface water-ground water interaction: Herbicide transport into municipal collector wells

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Carr, J.D.; Steele, G.V.; Thurman, E.M.; Bastian, K.C.; Dormedy, D.F.

    1999-01-01

    During spring runoff events, herbicides in the Platte River are transported through an alluvial aquifer into collector wells located on an island in the river in 6 to 7 d. During two spring runoff events in 1995 and 1996, atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] concentrations in water from these wells reached approximately 7 ??g/L, 70 times more than the background concentration in ground water. Concentrations of herbicides and metabolites in the collector wells generally were one-half to one-fifth the concentrations of herbicides in the river for atrazine, alachlor [2-chloro-2'-6'-diethyl-N-(methoxymethyl)-acetanilide], alachlor ethane-sulfonic acid (ESA) [2-((2,6-diethylphenyl) (methoxymethyl)amino)-2- oxoethane-sulfonic acid], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N- (2-methoxy-1-methylethyl)acetamide], cyanazine [2-((4-chloro-6-(ethyl-amino)- 1,3,5 triazin-2-yl)-amino)-2-methylpropionitrile], and acetochlor [2-chloro- N-(ethoxymethyl)-N-(2-ethyl-6methyl-phenyl) acetamide], suggesting that 20 to 50% river water could be present in the water from the collector wells, assuming no degradation. The effect of the river on the quality of water from the collector wells can be reduced through selective management of horizontal laterals of the collector wells. The quality of the water from the collector wells is dependent on the (i) selection of the collector well used, (ii) number and selection of laterals used, (iii) chemical characteristics of the contaminant, and (iv) relative mixing of the Platte River and a major upstream tributary.

  20. Pesticides in ground water in selected agricultural land-use areas and hydrogeologic settings in Pennsylvania, 2003-07

    USGS Publications Warehouse

    Loper, Connie A.; Breen, Kevin J.; Zimmerman, Tammy M.; Clune, John W.

    2009-01-01

    absence of bacteria only for the 10 wells representing the Blue Ridge crystalline and Triassic Lowland siliciclastic setting. Results of Spearman’s rank test showed strong positive correlations in the Devonian-Silurian carbonate setting between 1) the number of pesticides above the MRLs and nitrate concentration, and 2) concentrations of atrazine and nitrate. Atrazine concentration and nitrate concentration also showed a statistically significant positive correlation in the Great Valley siliciclastic setting. An additional component of baseline monitoring was to evaluate changes in pesticide concentration in water from wells representing hydrogeologic settings most vulnerable to contamination from pesticides. In 2003, 16 wells originally sampled in the 1990s were resampled—4 each in the Appalachian Mountain carbonate, Triassic Lowland siliciclastic, Great Valley carbonate, and Piedmont carbonate settings. Nine of these wells, where pesticide concentrations from 1993 and 2003 were analyzed at the NWQL, were chosen for a paired-sample analysis using concentrations of atrazine and metolachlor. A statistically significant decrease in atrazine concentration was identified using the Wilcoxon signed-rank test (p = 0.004); significant temporal changes in metolachlor concentrations were not observed (p = 0.625). Monitoring in three areas of special ground-water protection, where selected pesticide concentrations in well water were at or above the PPGWS action levels, was done at wells BE 1370 (Berks County, Oley Township), BA 437 (Blair County, North Woodbury Township), and LN 1842 (Lancaster County, Earl Township). Co-occurrence of pesticide-degradation products with parent compounds was documented for the first time in ground-water samples collected from these three wells. Degradation products of atrazine, cyanazine, acetochlor, alachlor, and metolachlor were commonly at larger concentrations than the parent compound in the same water sample. Pesticide occurrence in water

  1. Influence of surfactants on the sorption of two chloroacetanilide in an Romanian chernozem soil.

    PubMed

    Coroi, I G; De Wilde, T; Cara, M S; Jitareanu, G; Steurbaut, W

    2011-01-01

    Pesticides have been extensively used in modern agriculture. Due to the prevalent use, there have been serious problems generated by pesticides wastes which could eventually endanger water resources and human health. The development of technologies for the decontamination of soils and waters polluted by hydrophobic organic compounds has encouraged research into the use of non-ionic surfactants as potential agents for the enhanced solubilization and removal of contaminants from soils and sediments. Sorption of two chloroacetanilide herbicides, acetochlor and metolachlor was studied on a representative chernozem soil of the Main Agricultural Research Station Ezareni belonging to the "Ion Ionescu de la Brad" University of Agriculture and Veterinary Medicine lasi, Romania, in the presence and absence of surfactants. Three different non-ionic surfactants were selected: Tween-20, Synperonic 91/5 and Silwet L-77, to verify the influence of their presence on herbicide sorption at different concentrations. Our results showed that the sorption of the studied herbicides within the soil-water-non-ionic surfactant system was influenced by the presence of non-ionic surfactants. The n values obtained were lower than 1 for all pesticide-surfactant combinations, which indicates that the amount of acetochor and metolachlor sorbed decreased with an increase in pesticide concentration. The sorption of acetochlor increased in the following order: Acetochlor+Synperonic 91/5 < Acetochlor < Acetochlor+Tween-20 < Acetochlor+Silwet L-77. In the case of metolachlor+Synperonic and metolachlor+Silwet L-77, the Kf values were significantly higher than the Kf value of metolachlor+Tween-20 on soil, where a lower Kf value could be observed with however a higher n value which indicate a higher sorption capacity at higher concentrations.

  2. 78 FR 13264 - Acetochlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ... July 25, 2012 (77 FR 43562) (FRL-9353- 6), EPA issued a document pursuant to FFDCA section 408(d)(3... FR 47445) (FRL-8434-1). C. Exposure Assessment 1. Dietary exposure from food and feed uses. In... Review'' (58 FR 51735, October 4, 1993). Because this final rule has been exempted from review...

  3. Pesticides in rain in four agricultural watersheds in the United States

    USGS Publications Warehouse

    Vogel, J.R.; Majewski, M.S.; Capel, P.D.

    2008-01-01

    Rainfall samples were collected during the 2003 and 2004 growing seasons at four agricultural locales across the USA in Maryland, Indiana, Nebraska, and California. The samples were analyzed for 21 insecticides, 18 herbicides, three fungicides, and 40 pesticide degradates. Data from all sites combined show that 7 of the 10 most frequently detected pesticides were herbicides, with atrazine (70%) and metolachlor (83%) detected at every site. Dacthal, acetochlor, simazine, alachlor, and pendimethalin were detected in more than 50% of the samples. Chlorpyrifos, carbaryl, and diazinon were the only insecticides among the 10 most frequently detected compounds. Of the remaining pesticide parent compounds, 18 were detected in fewer than 30% of the samples, and 13 were not detected. The most frequently detected degradates were deethylatrazine; the oxygen analogs (OAs) of the organophosphorus insecticides chlorpyrifos, diazinon, and malathion; and 1-napthol (degradate of carbaryl). Deethylatrazine was detected in nearly 70% of the samples collected in Maryland, Indiana, and Nebraska but was detected only once in California. The OAs of chlorpyrifos and diazinon were detected primarily in California. Degradates of the acetanilide herbicides were rarely detected in rain, indicating that they are not formed in the atmosphere or readily volatilized from soils. Herbicides accounted for 91 to 98% of the total pesticide mass deposited by rain except in California, where insecticides accounted for 61% in 2004. The mass of pesticides deposited by rainfall was estimated to be less than 2% of the total applied in these agricultural areas. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  4. Occurrence of sulfonylurea, sulfonamide, imidazolinone, and other herbicides in rivers, reservoirs and ground water in the Midwestern United States, 1998

    USGS Publications Warehouse

    Battaglin, W.A.; Furlong, E.T.; Burkhardt, M.R.; Peter, C.J.

    2000-01-01

    Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are relatively new classes of chemical compounds that function by inhibiting the action of a plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but plants demonstrate a wide range in sensitivity to SUs, SAs, and IMIs with over a 10000-fold difference in observed toxicity levels for some compounds. SUs, SAs, and IMIs are applied either pre- or post-emergence to crops commonly at 1/50th or less of the rate of other herbicides. Little is known about their occurrence, fate, or transport in surface water or ground water in the USA. To obtain information on the occurrence of SU, SA, and IMI herbicides in the Midwestern United States, 212 water samples were collected from 75 surface-water and 25 ground-water sites in 1998. These samples were analyzed for 16 SU, SA and IMI herbicides by USGS Methods Research and Development Program staff using high-performance liquid chromatography/mass spectrometry. Samples were also analyzed for 47 pesticides or pesticide degradation products. At least one of the 16 SUs, SAs or IMIs was detected above the method reporting limit (MRL) of 0.01 ??g/l in 83% of 130 stream samples. Imazethapyr was detected most frequently (71% of samples) followed by flumetsulam (63% of samples) and nicosulfuron (52% of samples). The sum of SU, SA and IMI concentrations exceeded 0.5 ??g/l in less than 10% of stream samples. Acetochlor, alachlor, atrazine, cyanazine and metolachlor were all detected in 90% or more of 129 stream samples. The sum of the concentration of these five herbicides exceeded 50 ??g/l in approximately 10% of stream samples. At least one SU, SA, or IMI herbicide was detected above the MRL in 24% of 25 ground-water samples and 86% of seven reservoir samples. Copyright (C) 2000 Elsevier Science B.V.

  5. Transport and attenuation of chloroacetanilides in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Lefrancq, Marie; Imfeld, Gwenaël; Millet, Maurice; Payraudeau, Sylvain

    2015-04-01

    Chloroacetanilides (e.g., S-metolachlor and acetochlor) are pre-emergent herbicides used on corn and sugar beet and are applied to bare soil, which is prone to runoff and erosion. Some of these herbicides are chiral and the commercial products can be isomerically enriched in the enantiomer-S compared to the enantiomer-R as an example S-metolachlor 80/20% S to R . Determination of the transport of these herbicides in the dissolved and particulate phases of runoff water and degradation in agricultural catchments is currently lacking. The objectives of this study were i) to quantify over an corn growing season the export of chloroacetanilides and their main degradation products (ethane sulfonic (ESA) and oxanilic acid (OXA) degradates of metolachlor (MESA and MOXA) and acetochlor (AcESA and AcOXA)) in an 47 ha agricultural head-catchment in the dissolved and particulate phases, and ii) to evaluate S-metolachlor biodegradation from its application on the field to its export from the catchment using enantiomer analysis. Runoff, erosion, hydrochemistry and chloroacetanilide transport were evaluated at both the plot and catchment scales. Our results showed that an important amount of the pesticide load is missed when only the dissolved concentration of the parent compound is analysed. The total export coefficients for S-metolachlor and acetochlor and their degradation products were 11.4 and 11.8%, respectively, which includes both the dissolved and particulate loads. The partitioning of S-metolachlor and acetochlor between the dissolved and particulate phases varied widely over time and was linked to the suspended solid concentrations. Detection of S-metolachlor degradation products in runoff water was more frequent compared to that of acetochlor degradation products. Enrichment up to 37% of R-metolachlor was observed during the corn growing season, supporting enantioselective degradation of S-metolachlor. Our field study indicates the potential of enantiomer analyses for

  6. Herbicide interchange between a stream and the adjacent alluvial aquifer

    USGS Publications Warehouse

    Wang, W.; Squillace, P.

    1994-01-01

    Herbicide interchange between a stream and the adjacent alluvial aquifer and quantification of herbicide bank storage during high streamflow were investigated at a research site on the Cedar River flood plain, 10 km southeast of Cedar Rapids, Iowa. During high streamflow in March 1990, alachlor, atrazine, and metolachlor were detected at concentrations above background in water from wells as distant as 20, 50, and 10 m from the river's edge, respectively. During high streamflow in May 1990, alachlor, atrazine, cyanazine, and metolachlor were detected at concentrations above background as distant as 20, 50, 10, and 20 m from the river's edge, respectively. Herbicide bank storage took place during high streamflow when hydraulic gradients were from the river to the alluvial aquifer and the laterally infiltrating river water contained herbicide concentrations larger than background concentrations in the aquifer. The herbicide bank storage can be quantified by multiplying herbicide concentration by the "effective area" that a well represented and an assumed porosity of 0.25. During March 1990, herbicide bank storage values were calculated to be 1.7,79, and 4.0 mg/m for alachlor, atrazine, and metolachlor, respectively. During May 1990, values were 7.1, 54, 11, and 19 mg/m for alachlor, atrazine, cyanazine, and metolachlor, respectively. ?? 1994 American Chemical Society.

  7. Metolachlor dissipation in eroded and restored landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In hilly landforms subject to long-term cultivation, erosion has denuded upper slope positions of topsoil and accumulated topsoil in lower slope positions. Landscape restoration is one approach to remediate these eroded landforms by moving soil from areas of topsoil accumulation to areas of topsoil ...

  8. Pesticides in surface water in the lower Illinois River basin, 1996-98

    USGS Publications Warehouse

    King, Robin B.

    2003-01-01

    the Sangamon River at Monticello. The maximum atrazine concentration in the lower Illinois River was 20 mg/L, measured at Valley City, although most of the relatively elevated concentrations in the Illinois River sites were in the range from 5 to 8 mg/L. The concentrations of the herbicide cyanazine exceeded the health advisory guideline of 1 mg/L in about 19 percent (15 of 80) of the May to June samples. The pesticides chlorpyrifos, diazinon, metolachlor, and 2,4-D exceeded aquatic health guidelines at various times from May to August. Three dominant factors that affect the presence of pesticides in streams are identified: the pesticide usage, the time-of-year (or season), and the flow condition. The pesticides with the highest usage--atrazine, metolachlor, cyanazine, and acetochlor--generally were the pesticides detected most frequently and at the highest concentrations. Notable exceptions to this general observation are alachlor and simazine, which did not have high usage but were detected frequently. The elevated pesticide concentrations were most affected by seasonality--most of these elevated concentrations were observed across all flow conditions during May to June. Flow conditions also affect pesticide concentrations, but not as much as seasonality. The maximum pesticide loads were observed between March and July on the Illinois River. The net contribution of pesticides applied in the study area to net increases in load indicates that only about 1-2 percent of the pesticides applied exit the basin through the Illinois River at Valley City. The chloroacetanilide-class transformation products observed in samples collected in summer 1998 persistently contained elevated concentrations relative to the associated parent pesticide compound at all locations and for all streamflow conditions. The concentration of the transformation product metolachlor ethane sulfonic acid (ESA) usually was about 10 times higher than the parent compound in the mainstem of the lower

  9. Pesticides and pesticide degradates in the East Fork Little Miami River and William H. Harsha Lake, southwestern Ohio, 1999-2000

    USGS Publications Warehouse

    Funk, Jason M.; Reutter, David C.; Rowe, Gary L.

    2003-01-01

    In 1999 and 2000, the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program conducted a national pilot study of pesticides and degradates in drinking-water supplies, in cooperation with the U.S. Environmental Protection Agency (USEPA). William H. Harsha Lake, which provides drinking water for several thousand people in southwestern Ohio, was selected as one of the drinking-water supplies for this study. East Fork Little Miami River is the main source of water to Harsha Lake and drains a predominantly agricultural basin. Samples were collected from the East Fork Little Miami River upstream from Harsha Lake, at the drinking-water intake at Harsha Lake, at the outfall just below Harsha Lake, and from treated water at the Bob McEwen Treatment Plant. These samples were analyzed using standardized methods developed for the NAWQA Program. In all, 42 pesticide compounds (24 herbicides, 4 insecticides, 1 fungicide, and 13 degradates) were detected at least once in samples collected during this study. No compound in the treated water samples exceeded any drinking-water standard, although atrazine concentrations in untreated water exceeded the USEPA Maximum Contaminant Level (MCL) for drinking water (3 ?g/L) on four occasions. At least eight compounds were detected with greater than 60 percent frequency at each sampling location. Herbicides, such as atrazine, alachlor, acetochlor, cyanazine, metolachlor, and simazine, were detected most frequently. Rainfall affected the pesticide concentrations in surface waters of the East Fork Little Miami River Basin. Drought conditions from May through November 1999 led to lower streamflow and pesticide concentrations throughout southwestern Ohio. More normal climate conditions during 2000 resulted in higher streamflows and seasonally higher concentrations in the East Fork Little Miami River and Harsha Lake for some pesticides Comparison of pesticide concentrations in untreated lake water and treated drinking water

  10. Risk assessment of herbicides and booster biocides along estuarine continuums in the Bay of Vilaine area (Brittany, France).

    PubMed

    Caquet, Th; Roucaute, M; Mazzella, N; Delmas, F; Madigou, C; Farcy, E; Burgeot, Th; Allenou, J-P; Gabellec, R

    2013-02-01

    A 2-year study was implemented to characterize the contamination of estuarine continuums in the Bay of Vilaine area (NW Atlantic Coast, Southern Brittany, France) by 30 pesticide and biocide active substances and metabolites. Among these, 11 triazines (ametryn, atrazine, desethylatrazine, desethylterbuthylazine, desisopropyl atrazine, Irgarol 1051, prometryn, propazine, simazine, terbuthylazine, and terbutryn), 10 phenylureas (chlortoluron, diuron, 1-(3,4-dichlorophenyl)-3-methylurea, fenuron, isoproturon, 1-(4-isopropylphenyl)-3-methylurea, 1-(4-isopropylphenyl)-urea, linuron, metoxuron, and monuron), and 4 chloroacetanilides (acetochlor, alachlor, metolachlor, and metazachlor) were detected at least once. The objectives were to assess the corresponding risk for aquatic primary producers and to provide exposure information for connected studies on the responses of biological parameters in invertebrate sentinel species. The risk associated with contaminants was assessed using risk quotients based on the comparison of measured concentrations with original species sensitivity distribution-derived hazardous concentration values. For EU Water Framework Directive priority substances, results of monitoring were also compared with regulatory Environmental Quality Standards. The highest residue concentrations and risks for primary producers were recorded for diuron and Irgarol 1051 in Arzal reservoir, close to a marina. Diuron was present during almost the all survey periods, whereas Irgarol 1051 exhibited a clear seasonal pattern, with highest concentrations recorded in June and July. These results suggest that the use of antifouling biocides is responsible for a major part of the contamination of the lower part of the Vilaine River course for Irgarol 1051. For diuron, agricultural sources may also be involved. The presence of isoproturon and chloroacetanilide herbicides on some dates indicated a significant contribution of the use of plant protection products in

  11. Herbicide Transport and Transformations in the Unsaturated Zone of Three Small Agricultural Basins with Corn and Soybean Row Crops

    NASA Astrophysics Data System (ADS)

    Hancock, T. C.; Vogel, J. R.; Sandstrom, M. W.; Capel, P. D.; Bayless, R. E.; Webb, R. M.

    2006-05-01

    locations this fraction increased over time. At the Maple Creek sites, atrazine, metalochlor, acetochlor, and alachlor were detected, typically at concentrations higher than their metabolites. The Maple Creek site is influenced by focused recharge, macropore flow, and variable soil-moisture retention properties in soils that transition from loess to sand.

  12. Stability and recovery of triazine and chloroacetamide herbicides from pH adjusted water samples by using empore solid-phase extraction disks and gas chromatography with ion trap mass spectrometry.

    PubMed

    Mueller, T C; Senseman, S A; Carson, K H; Sciumbato, A S

    2001-01-01

    Empore disks were used to successfully extract herbicide residues from a difficult-to-analyze surface water source and deionized water. Herbicide recoveries were lower in surface water at 7,14, or 21 days after fortification and storage at 4 degrees C, presumably due to chemical sorption onto precipitated organic particulates. The addition of acid to the samples, as recommended in EPA Method 525.2, did not affect recoveries of alachlor and metolachlor, but reduced recoveries of atrazine, simazine, and cyanazine. Treatment of water samples with sodium hypochlorite did not affect alachlor or metolachlor recoveries, but greatly reduced the recovery of all triazine herbicides. This indicates that addition of acid or sodium hypochlorite to water samples may be detrimental to triazine analysis.

  13. A reconnaissance study of herbicides and their metabolites in surface water of the midwestern united states using immunoassay and gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Michael, Thurman E.; Goolsby, D.A.; Meyer, M.T.; Mills, M.S.; Pomes, M.L.

    1992-01-01

    Preemergent herbicides and their metabolites, particularly atrazine, deethylatrazine, and metolachlor, persisted from 1989 to 1990 in the majority of rivers and streams in the midwestern United States. In spring, after the application of herbicides, the concentrations of atrazine, alachlor, and simazine were frequently 3-10 times greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL). The concentration of herbicides exceeded the MCLs both singly and in combination. Two major degradation products of atrazine (deisopropylatrazine and deethylatrazine) also were found in many of the streams. The order of persistence of the herbicides and their metabolites in surface water was atrazine > deethylatrazine > metolachlor > alachlor > deisopropylatrazine > cyanazine. Storm runoff collected at several sites exceeded the MCL multiple times during the summer months as a function of stream discharge, with increased concentrations during times of increased streamflow. It is proposed that metabolites of atrazine may be used as indicators of surface-water movement into adjacent alluvial aquifers.

  14. Herbicides and nitrates in the Iowa River alluvial aquifer prior to changing land use, Iowa County, Iowa, 1996

    USGS Publications Warehouse

    Savoca, Mark E.; Tobias, Jennifer L.; Sadorf, Eric M.; Birkenholtz, Trevor L.

    1997-01-01

    Four herbicides (alachlor, atrazine, cyanazine, and metolachlor) and one nutrient (nitrate) were selected for study on the basis of frequent usage in Iowa and high detection rates in ground water (Detroy and Kuzniar, 1988). Alachlor was not detected at concentrations greater than the method detection limit (MDL). Atrazine was detected at concentrations greater than the MDL in samples from 48 percent of the 23 wells, cyanazine from 13 percent, metolachlor from 26 percent, and nitrate from 91 percent. None of the four herbicides were detected at concentrations greater than the respective U.S. Environmental Protection Agency's (USEPA) Maximum Contaminant Level (MCL) for drinking water. Thirteen percent of the samples had nitrate concentrations above the USEPA's MCL of 10 mg/L (milligrams per liter). Relations between constituent concentration and well depth were observed for specific constituents at individual well nests.

  15. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet..., rice, and wheat, grain 0.05 Pea and bean, dried shelled, except soybean, subgroup 6C 0.05 Potato...

  16. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet..., rice, and wheat, grain 0.05 Pea and bean, dried shelled, except soybean, subgroup 6C 0.05 Potato...

  17. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., stover 2.5 Corn, sweet, forage 1.5 Corn, sweet, kernels plus cob with husks removed 0.05 Corn, sweet... wheat, grain 0.05 Pea and bean, dried shelled, except soybean, subgroup 6C 0.05 Potato 0.05...

  18. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., stover 1.0 Cotton, gin byproducts 4.0 Cotton, undelinted seed 0.6 Sorghum, grain, forage 1.6 Sorghum, grain, grain 0.05 Sorghum, grain, stover 1.7 Soybean, meal 1.2 Soybean, seed 1.0 (b) Section 18... corn, grain sorghum, rice and wheat, forage 0.5 Grain, cereal, forage, fodder and straw, group...

  19. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., meat 0.02 Hog, fat 0.02 Hog meat byproducts 0.02 Hog, meat 0.02 Horse, fat 0.02 Horse, meat byproducts 0.02 Horse, meat 0.02 Milk 0.02 Peanut 0.5 Poultry, fat 0.02 Poultry, meat byproducts 0.02 Poultry..., dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  20. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., meat 0.02 Hog, fat 0.02 Hog meat byproducts 0.02 Hog, meat 0.02 Horse, fat 0.02 Horse, meat byproducts 0.02 Horse, meat 0.02 Milk 0.02 Peanut 0.5 Poultry, fat 0.02 Poultry, meat byproducts 0.02 Poultry..., dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  1. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., meat 0.02 Hog, fat 0.02 Hog meat byproducts 0.02 Hog, meat 0.02 Horse, fat 0.02 Horse, meat byproducts 0.02 Horse, meat 0.02 Milk 0.02 Peanut 0.5 Poultry, fat 0.02 Poultry, meat byproducts 0.02 Poultry..., dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  2. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., meat 0.02 Hog, fat 0.02 Hog meat byproducts 0.02 Hog, meat 0.02 Horse, fat 0.02 Horse, meat byproducts 0.02 Horse, meat 0.02 Milk 0.02 Peanut 0.5 Poultry, fat 0.02 Poultry, meat byproducts 0.02 Poultry..., dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  3. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., meat 0.02 Hog, fat 0.02 Hog meat byproducts 0.02 Hog, meat 0.02 Horse, fat 0.02 Horse, meat byproducts 0.02 Horse, meat 0.02 Milk 0.02 Peanut 0.5 Poultry, fat 0.02 Poultry, meat byproducts 0.02 Poultry..., dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  4. Characterization of Ground-Water Quality, Upper Republican Natural Resources District, Nebraska, 1998-2001

    USGS Publications Warehouse

    Frankforter, Jill D.; Chafin, Daniele T.

    2004-01-01

    south-central Dundy, and south-central Perkins Counties. Generally, these concentrations were detected in samples from wells located in upland areas with permeable soils and a high percentage of cropland. In 1999, 31 of the ground-water samples collected from irrigation wells were analyzed for pesticides, and 14 samples (45 percent) had detectable concentrations of at least one pesticide compound. In 2000, all of the 23 irrigation-well samples analyzed had one or more pesticides present at detectable concentrations. In 2001, 12 of 26 domestic-well samples (46 percent) had detectable concentrations. Although the analytical method used during the study was changed to increase the number of pesticides included in the analyses, the pesticides detected in the ground-water samples from domestic and irrigation wells were limited to the commonly used herbicide compounds acetochlor, alachlor, atrazine, metolachlor, prometon, propachlor, propazine, trifluralin, and the atrazine degradation product deethylatrazine. Of the compounds detected, only atrazine (3.0 micrograms per liter) and alachlor (2.0 micrograms per liter) have MCLs established by the U.S. Environmental Protection Agency. None of the ground-water samples from the URNRD study area had concentrations that exceeded either MCL. Tritium age-dating analyses indicate water from about one-third of the sites entered the ground-water system prior to 1952. Because the increase in agricultural practices occurred during the 1950s and 1960s, it can be assumed that this water was not influenced by agricultural practices. Nitrogen-isotope speciation analyses for samples from three irrigation wells indicated that the source of nitrates in the ground water probably is synthetic fertilizer; however, the source at most irrigation wells probably is either naturally occurring or a mixture of water from various anthropogenic sources (such as synthetic fertilizer and animal waste).

  5. Herbicides and their metabolites in rainfall: Origin, transport, and deposition patterns across the midwestern and northeastern United States, 1990-1991

    USGS Publications Warehouse

    Goolsby, D.A.; Thurman, E.M.; Pomes, M.L.; Meyer, M.T.; Battaglin, W.A.

    1997-01-01

    Herbicides were detected in rainfall throughout the midwestern and northeastern United States during late spring and summer of 1990 and 1991. Herbicide concentrations exhibited distinct geographic and seasonal patterns. The highest concentrations occurred in midwestern cornbelt states following herbicide application to cropland. Volume-weighted concentrations of 0.2- 0.4??g/L for atrazine and alachlor were typical in this area during mid- April through mid-July, and weighted concentrations as large as 0.6-0.9 ??g/L occurred at several sites. Concentrations of 1-3 ??g/L were measured in a few individual samples. Atrazine was detected most often followed by alachlor, deethylatrazine, metolachlor, cyanazine, and deisopropyl-atrazine. The high ratio (~0.5) of deethylatrazine to atrazine in rainfall suggests atmospheric degradation of atrazine. Mass deposition of herbicides was greatest in areas where herbicide use was high and decreased with distance from the cornbelt. Estimated deposition rates for both atrazine and alachlor ranged from more than 240 ??g m-2 yr-1 for some areas in the midwestern states to less than 10 ??g m-2 yr-1 for the New England states. The estimated annual deposition of atrazine on the Great Lakes ranged from about 12 to 63 ??g m-2 yr-1. The total amounts of atrazine and alachlor deposited annually in rainfall in the study area represent about 0.6% of the atrazine and 0.4% of the alachlor applied annually to crops in the study area.

  6. Pesticide fate in tropical wetlands of Brazil: an aquatic microcosm study under semi-field conditions.

    PubMed

    Laabs, V; Wehrhan, A; Pinto, A; Dores, E; Amelung, W

    2007-03-01

    A contamination of off-site aquatic environments with pesticides has been observed in the tropics, yet only sparse information exists about pesticide fate in such ecosystems. The objective of our semi-field study was to elucidate the fate of alachlor, atrazine, chlorpyrifos, endosulfan, metolachlor, profenofos, simazine, and trifluralin in the aqueous environment of the Pantanal wetland (MT, Brazil). To this aim, water and water/sediment microcosms of two sizes (0.78 and 202 l) were installed in the outskirts of this freshwater lagoon environment and pesticide dissipation was monitored for up to 50 d after application. The physical-chemical water conditions that developed in the microcosms were reproducible among field replicates for both system sizes. Pesticide dissipation was substantially enhanced for most pesticides in small microcosms relative to the large ones (reduced DT(50) by a factor of up to 5.3). The presence of sediment in microcosms led to increased persistence of chlorpyrifos, endosulfan, and trifluralin in the test systems, while for polar pesticides (alachlor, atrazine, metolachlor, profenofos, and simazine) a lesser persistence was observed. Atrazine, simazine, metolachlor, and alachlor were identified as the most persistent pesticides in large water microcosms (DT(50) > or = 47 d); in large water/sediment systems endosulfan beta, atrazine, metolachlor, and simazine showed the slowest dissipation (DT(50) > or = 44 d). A medium-term accumulation in the sediment of tropical ecosystems can be expected for chlorpyrifos and endosulfan isomers (11-35% of applied amount still extractable at 50 d after application). We conclude that the persistence of the studied pesticides in aquatic ecosystems of the tropics is not substantially lower than during summer in temperate regions. PMID:17166548

  7. 75 FR 56897 - S-metolachlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-17

    ...-5805. II. Summary of Petitioned-For Tolerance In the Federal Register of January 6, 2010 (75 FR 864... types of actions from review under Executive Order 12866, entitled Regulatory Planning and Review (58 FR... That Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355, May 22, 2001) or...

  8. 77 FR 48902 - S-Metolachlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... FR 55329) (FRL- 8886-7), EPA issued a notice pursuant to FFDCA section 408(d)(3), 21 U.S.C. 346a(d)(3..., 2010 (75 FR 56899) (FRL-8842-3). C. Exposure Assessment 1. Dietary exposure from food and feed uses. In... Executive Order 12866, entitled ``Regulatory Planning and Review'' (58 FR 51735, October 4, 1993)....

  9. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....20 Poultry, fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Safflower, seed 0.10 Sheep, fat..., fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Pumpkin 0.10 Safflower, seed 0.10...

  10. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Poultry, meat byproducts 0.05 Safflower, seed 0.10 Sheep, fat 0.02 Sheep, kidney 0.20 Sheep, liver 0.05..., meal 0.40 Poultry, fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Pumpkin 0.10...

  11. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....20 Poultry, fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Safflower, seed 0.10 Sheep, fat..., fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Pumpkin 0.10 Safflower, seed 0.10...

  12. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Poultry, meat byproducts 0.05 Safflower, seed 0.10 Sheep, fat 0.02 Sheep, kidney 0.20 Sheep, liver 0.05..., fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Pumpkin 0.10 Safflower, seed 0.10...

  13. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Poultry, meat byproducts 0.05 Safflower, seed 0.10 Sheep, fat 0.02 Sheep, kidney 0.20 Sheep, liver 0.05..., fat 0.02 Poultry, meat 0.02 Poultry, meat byproducts 0.05 Pumpkin 0.10 Safflower, seed 0.10...

  14. Use of enzyme immunoassay for large water-quality surveys of major herbicides

    SciTech Connect

    Thurman, E.M.; Aga, D.S.; Zimmerman, L.R.; Goolsby, D.A.

    1996-10-01

    Commercially available enzyme-linked immunosorbent assay (ELISA) was used for the determination of major herbicides in several large water-quality surveys of surface water, rainwater, and ground water throughout the United States. The ELISA results were compared with gas chromatography/mass spectrometry (GC/MS) for accuracy and cross reactivity. In total, five compounds were analyzed: alachlor, atrazine, cyanazine, metolachlor, and (2,4-dichlorophenoxy) acetic acid (2,4-D). Results indicated that the ELISA and GC/MS results were comparable for cyanazine and metolachlor. The atrazine ELISA correlated well with GC/MS for surface- and ground-water samples from the central United States but did not correlate with samples from Texas where the cotton triazine, prometryn, is used. Results using the alachlor ELISA were poor because of cross reactivity with the metabolite, alachlor ethane-sulfonic acid. The ELISA for (2,4-dichlorophenoxy) acetic acid was insensitive at concentrations that occur in most surface water.

  15. Organo/layered double hydroxide nanohybrids used to remove non ionic pesticides.

    PubMed

    Chaara, D; Bruna, F; Ulibarri, M A; Draoui, K; Barriga, C; Pavlovic, I

    2011-11-30

    The preparation and characterization of organo/layered double hydroxide nanohybrids with dodecylsulfate and sebacate as interlayer anion were studied in detail. The aim of the modification of the layered double hydroxides (LDHs) was to change the hydrophilic character of the interlayer to hydrophobic to improve the ability of the nanohybrids to adsorb non-ionic pesticides such as alachlor and metolachlor from water. Adsorption tests were conducted on organo/LDHs using variable pH values, contact times and initial pesticide concentrations (adsorption isotherms) in order to identify the optimum conditions for the intended purpose. Adsorbents and adsorption products were characterized several physicochemical techniques. The adsorption test showed that a noticeable increase of the adsorption of the non-ionic herbicides was produced. Based on the results, the organo/LDHs could be good adsorbents to remove alachlor and metolachlor from water. Different organo/LDHs complexes were prepared by a mechanical mixture and by adsorption. The results show that HTSEB-based complex displays controlled release properties that reduce metolachlor leaching in soil columns compared to a technical product and the other formulations. The release was dependent on the nature of the adsorbent used to prepare the complexes. Thus, it can be concluded that organo/LDHs might act as suitable supports for the design of pesticide slow release formulations with the aim of reducing the adverse effects derived from rapid transport losses of the chemical once applied to soils. PMID:21978582

  16. Organo/layered double hydroxide nanohybrids used to remove non ionic pesticides.

    PubMed

    Chaara, D; Bruna, F; Ulibarri, M A; Draoui, K; Barriga, C; Pavlovic, I

    2011-11-30

    The preparation and characterization of organo/layered double hydroxide nanohybrids with dodecylsulfate and sebacate as interlayer anion were studied in detail. The aim of the modification of the layered double hydroxides (LDHs) was to change the hydrophilic character of the interlayer to hydrophobic to improve the ability of the nanohybrids to adsorb non-ionic pesticides such as alachlor and metolachlor from water. Adsorption tests were conducted on organo/LDHs using variable pH values, contact times and initial pesticide concentrations (adsorption isotherms) in order to identify the optimum conditions for the intended purpose. Adsorbents and adsorption products were characterized several physicochemical techniques. The adsorption test showed that a noticeable increase of the adsorption of the non-ionic herbicides was produced. Based on the results, the organo/LDHs could be good adsorbents to remove alachlor and metolachlor from water. Different organo/LDHs complexes were prepared by a mechanical mixture and by adsorption. The results show that HTSEB-based complex displays controlled release properties that reduce metolachlor leaching in soil columns compared to a technical product and the other formulations. The release was dependent on the nature of the adsorbent used to prepare the complexes. Thus, it can be concluded that organo/LDHs might act as suitable supports for the design of pesticide slow release formulations with the aim of reducing the adverse effects derived from rapid transport losses of the chemical once applied to soils.

  17. Pesticides and their metabolites in wells of Suffolk County, New York, 1998

    USGS Publications Warehouse

    Phillips, Patrick J.; Eckhardt, D.A.; Terracciano, S.A.; Rosenmann, Larry

    1999-01-01

    Five insecticide residues and 20 herbicide residues were detected in water samples collected from 50 shallow wells screened in the surficial sand and gravel aquifer in Suffolk County, Long Island in areas with known or suspected residues. Laboratory analytical methods with extremely low detection limits - from 0.001 to 0.2 ?g/L (micrograms per liter) - were used to analyze the samples for 60 pesticide residues. Forty-four of the samples contained at least one pesticide residue, and some samples contained as many as 11 different pesticides or pesticide metabolites. Only four water- quality standards were exceeded in the samples collected in this study. Dieldrin exceeded the New York State Class GA standard (0.004 ?g/L) in samples from eight wells. The Federal and New York State Maximum Contaminant Level for simazine (4 ?g/L) was exceeded in samples from two wells, and the State Class GA standard for simazine (0.5 ?g/L) was exceeded in samples from six wells. Federal water-quality standards have not been established for many of the compounds detected in this study, including herbicide metabolites. Maximum concentrations of four herbicide metabolites -metolachlor ESA (ethanesulfonic acid), metolachlor OA (oxanilic acid), and the alachlor metabolites alachlor ESA and alachlor OA -exceeded 20 ?g/L. The maximum concentration of one herbicide (tebuthiuron) exceeded 10 ?g/L, and the maximum concentration of three herbicides (simazine, metolachlor, and atrazine) and one herbicide metabolite (deisopropylatrazine) ranged from 1 to 10 ?g/L. The herbicide metolachlor, which is used on potato fields in Suffolk County, and its metabolites (metolachlor ESA and metolachlor OA) were most frequently detected in samples from agricultural areas. The herbicides simazine and tebuthiuron, which were used in utility rights-of-way, and the simazine metabolite deisopropylatrazine were detected at concentrations greater than 0.05 ?g/L most frequently in samples from residential and mixed land

  18. Selection and analysis of sites highly vulnerable to groundwater contamination in southwestern Michigan. Final technical report, 1 April 1991-31 March 1992

    SciTech Connect

    Ervin, J.L.; Lusch, D.P.

    1992-04-01

    An ongoing study in central Cass County has demonstrated extensive nitrate contamination of the glacial drift aquifer in the Donnell Lake watershed. In addition, about 20% of 121 wells sampled showed detectable herbicides (atrazine, alachlor/metolachlor, and/or alachlor soil metabolite). Monthly monitoring of these wells in 1991 demonstrated stable water quality in the deeper wells, with some shallow wells showing from 30 to 300% increases in nitrate concentration over the summer. One well showed an 80% decrease in nitrate concentration. Herbicide concentrations were quite stable and consistent with previous findings. Generally the deeper wells (over 50 feet) demonstrated less contamination, but one 80 foot deep well demonstrated substantial nitrate and herbicide concentrations.

  19. Assessing the transfer of pesticides to the atmosphere during and after application. Development of a multiresidue method using adsorption on Tenax and thermal desorption-GC/MS.

    PubMed

    Briand, Olivier; Millet, Maurice; Bertrand, Florence; Clément, Michel; Seux, René

    2002-11-01

    An air sampling and analytical method based on adsorption on porous polymer (Tenax TA) followed by automatic thermal desorption (ATD) and GC/MS analysis was developed for ten pesticides commonly used on major crops in Britanny and some of their metabolites in air (from spray drift and volatilisation transfer processes): alachlor, atrazine (and two major degradation products: deethylatrazine and deisopropylatrazine), carbofuran, cyprodinil, epoxyconazole, iprodione (and 3,5-dichloroaniline), lindane (and -HCH, its isomer), metolachlor, terbuconazole and trifluralin. This method was established with special consideration for optimal thermal desorption conditions, linear ranges, limits of detection and quantification. Moreover, collection efficiencies of Tenax TA at room temperature were examined. This method was then applied to the determination of ambient pesticide levels during the spraying season at a rural area. The method was also applied to determine the vertical gradient of alachlor concentrations on a treated maize parcel to evaluate volatilisation fluxes.

  20. The occurrence and transport of agricultural pesticides in the Tuttle Creek lake-stream system, Kansas and Nebraska

    USGS Publications Warehouse

    Bevans, Hugh E.; Fromm, Carla Hyde; Watkins, Sharon A.

    1995-01-01

    Median monthly atrazine concentrations detected in surface-water samples from the Big Blue River basin (1977-86) exceeded the U.S. Environmental Protection Agency health-advisory level (3.0 micrograms per liter) during May through September. Herbicide loads transported from the basin in 1986, expressed in tons and in percentage of amount applied, were alachlor (1.2 tons, 0.23 percent), atrazine (19 tons, 2.2 percent), and metolachlor (2.2 tons, 2.7 percent).

  1. Synthetic organic agrochemicals in the lower Mississippi River and its major tributaries: Distribution, transport and fate

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Leiker, T.J.; ,

    1992-01-01

    The Mississippi River and its major tributaries transport herbicides and their degradation products from agricultural areas in the mid-western U.S.A. These compounds include atrazine and its degradation products (desethyl- and desisopropylatrazine), simazine, cyanazine, metolachlor, and alachlor and its degradation products (2-chloro-2',6'-diethylacetanilide, 2-hydroxy-2',6'-diethylacetanilide and 2,6-diethylaniline). These compounds were identified and confirmed by gas chromatography-ion trap mass spectrometry. Loads of these compounds were determined during five sampling trips in 1987-1989. Stream loads of these compounds indicated that atrazine and metolachlor were relatively conservative in downstream transport. Alachlor and its degradation products were generated from point and non-point sources. Seasonal variations and hydrologic conditions controlled the loads of these compounds in the Mississippi River. Cross-channel mixing was slow downstream from major river confluences, possibly requiring several hundred kilometers of downriver transit for completion. The annual transport of these compounds into the Gulf of Mexico was estimated to be < 2% of the annual application of each herbicide in the Midwest.The Mississippi River and its major tributaries transport herbicides and their degradation products from agricultural areas in the mid-western U.S.A. These compounds include atrazine and its degradation products (desethyl- and desisopropylatrazine), simazine, cyanazine, metolachlor, and alachlor and its degradation products (2-chloro-2???,6???-diethylacetanilide, 2-hydroxy-2???,6???-diethylacetanilide and 2,6-diethylaniline). These compounds were identified and confirmed by gas chromatography-ion trap mass spectrometry. Loads of these compounds were determined during five sampling trips in 1987-1989. Stream loads of these compounds indicated that atrazine and metolachlor were relatively conservative in downstream transport. Alachlor and its degradation products

  2. Laboratory and quality assurance protocols for the analysis of herbicides in ground water from the Management Systems Evaluation Area, Princeton, Minnesota

    USGS Publications Warehouse

    Larson, S.J.; Capel, P.D.; VanderLoop, A.G.

    1996-01-01

    Laboratory and quality assurance procedures for the analysis of ground-water samples for herbicides at the Management Systems Evaluation Area near Princeton, Minnesota are described. The target herbicides include atrazine, de-ethylatrazine, de-isopropylatrazine, metribuzin, alachlor, 2,6-diethylaniline, and metolachlor. The analytical techniques used are solid-phase extraction, and analysis by gas chromatography with mass-selective detection. Descriptions of cleaning procedures, preparation of standard solutions, isolation of analytes from water, sample transfer methods, instrumental analysis, and data analysis are included.

  3. Natural attenuation of chloroacetinilide herbicides in aquatic systems

    USGS Publications Warehouse

    Graham, D.W.; Graham, W.H.; DeNoyelles, F.; Smith, V.H.; ,

    1999-01-01

    A 4-yr research program that studied the transformation of alachlor and metolachlor in aquatic systems using field microcosms is presented. The field microcosms provided an accurate simulation of natural ecosystems while also permitting the controlled creation of numerous contamination scenarios and sufficient replication to allow statistical evaluation of the results. Different treatments were assessed including conditions as diverse as anaerobic, eutrophic waters typical of nutrient-rich wetland to aerobic, oligotrophic waters typical of the epilimnion of Canadian glacial lake. Herbicide transformation rate was most strongly affected by water temperature, oxygen conditions, nutrient levels within the system, and the specific herbicide assessed.

  4. Effects of urbanization on water quality in the Kansas River, Shunganunga Creek Basin, and Soldier Creek, Topeka, Kansas, October 1993 through September 1995

    USGS Publications Warehouse

    Pope, L.M.; Putnam, J.E.

    1997-01-01

    , respectively, before treatment-plant discharge to a calculated 4,900 and 4,700 colonies per 100 milliliters of water, respectively, after discharge. Median concentrations of dissolved solids were not significantly different between three sampling sites in the Shunganunga Creek Basin. Median concentrations of dissolved nitrate as nitrogen, total phosphorus, and dissolved orthophosphate were significantly larger in water from the upstream- most Shunganunga Creek sampling site than in water from either of the other sampling sites in the Shunganunga Creek Basin probably because of the site's proximity to a wastewater-treatment plant.Median concentrations of dissolved nitrate as nitrogen and total phosphorus during 1993-95 at upstream sampling sites were either significantlylarger than during 1979-81 in response to increase of wastewater-treatment plant discharge or smaller because of the elimination of wastewater-treatment plant discharge. Median concentrations of dissolved ammonia as nitrogen were significantly less during 1993-95 than during 1979-81. Median concentrations of total aluminum, iron, maganese, and molybdenum were significantly larger in water from the downstream-mostShunganunga Creek sampling site than in water from the upstream-most sampling site. This probably reflects their widespread use in the urbanenvironment between the upstream and downstream Shunganunga Creek sampling sites. Little water-quality effect from the urbanization was indicated by results from the Soldier Creek sampling site. Median concentrations of most water-quality constituents in water from this sampling site were the smallest in water from any sampling site in the study area. Herbicides were detected in water from all sampling sites. Some of the more frequently detected herbicides included acetochlor, alachlor,atrazine, cyanazine, EPTC, metolachlor, prometon, simazine, and tebuthiuron. Detected insecticides including chlordane,

  5. Anthropogenic Organic Compounds in Source Water of Selected Community Water Systems that Use Groundwater, 2002-05

    USGS Publications Warehouse

    Hopple, Jessica A.; Delzer, Gregory C.; Kingsbury, James A.

    2009-01-01

    Source water, defined as groundwater collected from a community water system well prior to water treatment, was sampled from 221 wells during October 2002 to July 2005 and analyzed for 258 anthropogenic organic compounds. Most of these compounds are unregulated in drinking water and include pesticides and pesticide degradates, gasoline hydrocarbons, personal-care and domestic-use products, and solvents. The laboratory analytical methods used in the study have detection levels that commonly are 100 to 1,000 times lower than State and Federal standards and guidelines for protecting water quality. Detections of anthropogenic organic compounds do not necessarily indicate a concern to human health but rather help to identify emerging issues and track changes in occurrence and concentrations over time. Less than one-half (120) of the 258 compounds were detected in at least one source-water sample. Chloroform, in 36 percent of samples, was the most commonly detected of the 12 compounds that were in about 10 percent or more of source-water samples. The herbicides atrazine, metolachlor, prometon, and simazine also were among the commonly detected compounds. The commonly detected degradates of atrazine - deethylatrazine and deisopropylatrazine - as well as degradates of acetochlor and alachlor, generally were detected at concentrations similar to or greater than concentrations of the parent herbicide. The compounds perchloroethene, trichloroethene, 1,1,1-trichloroethane, methyl tert-butyl ether, and cis-1,2-dichloroethene also were detected commonly. The most commonly detected compounds in source-water samples generally were among those detected commonly across the country and reported in previous studies by the U.S. Geological Survey's National Water-Quality Assessment Program. Relatively few compounds were detected at concentrations greater than human-health benchmarks, and 84 percent of the concentrations were two or more orders of magnitude less than benchmarks. Five

  6. Environmental and human risk hierarchy of pesticides: A prioritization method, based on monitoring, hazard assessment and environmental fate.

    PubMed

    Tsaboula, Aggeliki; Papadakis, Emmanouil-Nikolaos; Vryzas, Zisis; Kotopoulou, Athina; Kintzikoglou, Katerina; Papadopoulou-Mourkidou, Euphemia

    2016-05-01

    A pesticide prioritization approach was developed and implemented in the Pinios River Basin of Central Greece. It takes under consideration the Level of Environmental Risk containing information on the frequency of occurrence of pesticides above environmental thresholds, the intensity of this occurrence and the spatial distribution as well as information about the fate and behavior of pesticides in the environment and the potential to have adverse impact on humans' health. Original 3-year monitoring data from 102 Stationary Sampling Sites located on rivers and their tributaries, reservoirs, streams and irrigation/drainage canals giving rise to a collection of 2382 water samples resulting in 7088 data sets, were included in this integrated prioritization study. Among 302 monitored active ingredients, 119 were detected at least once and the concentrations found in the aquatic systems for 41% of compounds were higher than the respective lowest Predicted Non-Effect Concentration (PNEC) values. Sixteen and 5 pesticides were found with risk ratios (MECmax/PNEC) above 10 (high concern) and 100 (very high concern), respectively. However, pesticides with maximum Measured Environmental Concentration (MECmax) values exceeding by 1000 times the respective lowest PNEC values were also found which were considered of extremely high concern; in the latter group were included prometryn, chlorpyrifos, diazinon, λ-cyhalothrin, cypermethrin, α-cypermethrin deltamethrin, ethalfluralin and phosmet. The sensitivity of the analytical methods used in the monitoring study was considered inadequate to meet the toxicological endpoints for 32 pesticides. The widest distribution of occurrence in the Stationary Sampling Sites of the monitoring program was found for the pesticides, prometryn, fluometuron, terbuthylazine, S-metolachlor, chlorpyrifos, diphenylamine, acetochlor, alachlor, 2,4-D, etridiazole, imidacloprid and lindane (γ-ΗCH). Among the 27 priority pesticides included in the

  7. Occurrence of Agricultural Chemicals in Shallow Ground Water and the Unsaturated Zone, Northeast Nebraska Glacial Till, 2002-04

    USGS Publications Warehouse

    Stanton, Jennifer S.; Steele, Gregory V.; Vogel, Jason R.

    2007-01-01

    included parent or degradate compounds of acetochlor, alachlor, atrazine, and metolachlor. Overall, pesticide concentrations in ground-water samples collected in 2003 and 2004 were small and did not exceed public drinking-water standards where established. On average, more pesticides were detected in the flow-path wells than in the glacial-till network wells. The presence of a perennial stream within 1,640 feet of a well was correlated to smaller nitrate-N concentrations in the well water, and the presence of a road ditch within 164 feet of the well was correlated to the presence of detectable pesticides in the well water. All other variables tested showed no significant correlations to nitrate-N concentrations or pesticide detections. Unsaturated zone soil cores collected in 2002 from well boreholes indicated that nitrogen in the forms of nitrate-N and ammonia as nitrogen (ammonia-N) was available in the unsaturated zone for transport to ground water. Concentrations of nitrate-N and ammonia-N in these soil cores were inversely correlated to depth, and nitrate-N concentrations were correlated to chloride concentrations.

  8. Environmental and human risk hierarchy of pesticides: A prioritization method, based on monitoring, hazard assessment and environmental fate.

    PubMed

    Tsaboula, Aggeliki; Papadakis, Emmanouil-Nikolaos; Vryzas, Zisis; Kotopoulou, Athina; Kintzikoglou, Katerina; Papadopoulou-Mourkidou, Euphemia

    2016-05-01

    A pesticide prioritization approach was developed and implemented in the Pinios River Basin of Central Greece. It takes under consideration the Level of Environmental Risk containing information on the frequency of occurrence of pesticides above environmental thresholds, the intensity of this occurrence and the spatial distribution as well as information about the fate and behavior of pesticides in the environment and the potential to have adverse impact on humans' health. Original 3-year monitoring data from 102 Stationary Sampling Sites located on rivers and their tributaries, reservoirs, streams and irrigation/drainage canals giving rise to a collection of 2382 water samples resulting in 7088 data sets, were included in this integrated prioritization study. Among 302 monitored active ingredients, 119 were detected at least once and the concentrations found in the aquatic systems for 41% of compounds were higher than the respective lowest Predicted Non-Effect Concentration (PNEC) values. Sixteen and 5 pesticides were found with risk ratios (MECmax/PNEC) above 10 (high concern) and 100 (very high concern), respectively. However, pesticides with maximum Measured Environmental Concentration (MECmax) values exceeding by 1000 times the respective lowest PNEC values were also found which were considered of extremely high concern; in the latter group were included prometryn, chlorpyrifos, diazinon, λ-cyhalothrin, cypermethrin, α-cypermethrin deltamethrin, ethalfluralin and phosmet. The sensitivity of the analytical methods used in the monitoring study was considered inadequate to meet the toxicological endpoints for 32 pesticides. The widest distribution of occurrence in the Stationary Sampling Sites of the monitoring program was found for the pesticides, prometryn, fluometuron, terbuthylazine, S-metolachlor, chlorpyrifos, diphenylamine, acetochlor, alachlor, 2,4-D, etridiazole, imidacloprid and lindane (γ-ΗCH). Among the 27 priority pesticides included in the

  9. Source, extent, and degradation of herbicides in a shallow aquifer near Hesston, Kansas

    USGS Publications Warehouse

    Perry, C.A.

    1990-01-01

    Atrazine, alachlor, cyanazine, metolachlor, and metribuzin were detected in water from a domestic well completed in a shallow aquifer underlying the Harvey County Experiment Field near Hesston, Kansas. The study described in this report investigated the source, extent, and degradation of these five herbicides. Hydrogeologic analysis of the site enabled estimation of the degradation half-lives of the herbicides in the saturated zone. The most probable source of the contamination was back- siphonage or spillage of herbicides from a sprayer tank into a trench backfilled with sand. The herbicides moved downgradient to the domestic well and then moved into the aquifer via the annular space in the well. Once in the aquifer, the contaminants remained nearly stationary with very little lateral movement away from the point of injection. Decreases in herbicide concentrations were caused mainly by degradation of the parent compounds and to a lesser degree, by extensive pumping of the well. Estimated herbicide degradation half-lives in the saturated environment were 1,000 days for atrazine, 400 days for alachlor, 250 days for cyanazine, 350 days for metolachlor, and 350 days for metribuzin. The herbicides will likely be eliminated from the soil and groundwater at the experiment field by continued natural degradation at the land surface and by degradation in and continued pumping of water from the aquifer. Pumping will remove any degradation products as well as the remaining parent compounds. (USGS)

  10. Nonpoint source contamination of the Mississippi river and its tributaries by herbicides

    USGS Publications Warehouse

    Pereira, W.E.; Hostettler, F.D.

    1993-01-01

    A study of the Mississippi River and its tributaries during July-August 1991, October-November 1991, and April-May 1992 has indicated that the entire navigable reach of the river is contaminated with a complex mixture of agrochemicals and their transformation products derived from nonpoint sources. Twenty-three compounds were identified, including triazine, chloroacetanilide, thiocarbamate, phenylurea, pyridazine, and organophosphorus pesticides. The upper and middle Mississippi River Basin farm lands are major sources of herbicides applied to corn, soybeans, and sorghum. Farm lands in the lower Mississippi River Basin are a major source of rice and cotton herbicides. Inputs of the five major herbicides atrazine, cyanazine, metolachlor, alachlor, and simazine to the Mississippi River are mainly from the Minnesota, Des Moines, Missouri, and Ohio Rivers. Ratios of desethylatrazine/atrazine potentially are useful indicators of groundwater and surface water interactions in the Mississippi River. These ratios suggested that during baseflow conditions, there is a significant groundwater contribution to the river. The Mississippi River thus serves as a drainage channel for pesticide-contaminated surface and groundwater from the midwestern United States. Conservative estimates of annual mass transport indicated that about 160 t of atrazine, 71 t of cyanazine, 56 t of metolachlor, and 18 t of alachlor were discharged into the Gulf of Mexico in 1991.

  11. Agricultural chemicals in ground and surface water in a small watershed in Clayton County, Iowa, 1988-91

    USGS Publications Warehouse

    Kalkhoff, S.J.; Schaap, B.D.

    1995-01-01

    Nitrogen was present in all water samples from Deer Creek. Nitrate concentrations ranged from 0.70 to 17 mg/L. Alachlor was detected in 11 percent of the samples, atrazine in 69 percent, cyanazine in 19 percent, and metolachlor in 33 percent. Alachlor concentrations ranged from less than 0.10 to 0.53 ug/L, atrazine ranged from less than 0.10 to 55 ug/L, cyanazine ranged from less than 0.10 to 12 ug/L, and metolachlor ranged from less than 0.10 to 69 ug/L. Herbicide detections occurred most frequently in late spring and early summer during or just following chemical application. Overland flow is an important source of nitrogen and herbicides to Deer Creek. Substantial amounts of agricultural chemicals are transported from the watershed. As much as 4,700 pounds, or 6.7 pounds per acre, of nitrogen were estimated to be transported from the watershed in 1 year. Nitrogen loads transported from the Deer Creek watershed were less during dry years than during years with average or greater than average rainfall.

  12. Occurrence of herbicides, nitrite plus nitrate, and selected trace elements in ground water from northwestern and northeastern Missouri, July 1991 and 1992

    USGS Publications Warehouse

    Wilkison, Donald H.; Maley, Randall D.

    1994-01-01

    The U.S. Geological Survey and the Missouri Department of Health collected water samples for analysis of nitrite plus nitrate and herbicides from rural domestic wells in northwestern and northeastern Missouri in 1991 and 1992. In July 1991, samples were collected from 130 wells in Caldwell, Clinton, Daviess, Gentry, and Nodaway Counties in northwestern Missouri. Nitrite plus nitrate concentrations as nitrogen ranged from less than 0.05 to 63 milligrams per liter. Nitrite plus nitrate concentrations exceeded the State drinking-water standard of 10 milligrams per liter in water samples from 28 wells. One or more of the herbicides--alachlor, atrazine, cyanazine; metribuzin, metolachlor, and trifluralin--were detected at concentrations greater than or equal to 0.05 micrograms per liter in 19 samples. Atrazine was detected in water samples from 16 wells. In July 1992, water samples were collected from 147 wells in Audrain, Clark, Lewis, Monroe, Scotland, and Shelby Counties in northeastern Missouri. Nitrite plus nitrate as nitrogen concentrations in samples ranged from less than 0.05 to 60 milligrams per liter and exceeded 10 milligrams per liter in samples from 28 wells. One or more of the herbicides-alachlor, atrazine, cyanazine, metribuzin, and metolachlor-were detected at concentrations greater than 0.10 microgram per liter in water samples from 19 of the wells sampled. Atrazine was detected in water from 18 wells.

  13. Estimating contributions of nitrate and herbicides from groundwater to headwater streams, northern Atlantic Coastal Plain, USA

    USGS Publications Warehouse

    Ator, Scott; Denver, Judith M.

    2012-01-01

    Groundwater transport often complicates understanding of surface-water contamination. We estimated the regional flux of nitrate and selected herbicides from groundwater to nontidal headwater streams of the Atlantic Coastal Plain (New Jersey through North Carolina) based on late-winter or spring base-flow samples from 174 streams. Sampled streams were selected randomly, and flux estimates are based on resulting population estimates rather than on empirical models, which have been used previously for similar estimates. Base-flow flux in the estimated 8,834 headwater streams of the study area are an estimated 21,200 kg/day of nitrate (as N) and 5.83, 0.565, and 20.7 kg/day of alachlor, atrazine, and metolachlor (and selected degradates), respectively. Base-flow flux of alachlor and metolachlor is <3% of the total base-flow flux of those compounds plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications is typically highest in well-drained areas and lowest in areas with abundant poor drainage and anoxic conditions. In Coastal Plain watersheds of Albemarle and Pamlico Sounds, <2% of applied nitrogen reaches headwater streams as base flow. On the Delmarva Peninsula part of the Chesapeake Bay watershed, however, more than 10% of such applications are transported through groundwater to streams, and base-flow nitrate flux represents 70% of total nitrogen flux in headwater streams.

  14. HPLC-NMR INVESTIGATION OF THE ISOMERIZATION OF ALACHLOR-ETHANE SULFONIC ACID. (R829008)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. Novel Three-Component Rieske Non-Heme Iron Oxygenase System Catalyzing the N-Dealkylation of Chloroacetanilide Herbicides in Sphingomonads DC-6 and DC-2

    PubMed Central

    Chen, Qing; Wang, Cheng-Hong; Deng, Shi-Kai; Wu, Ya-Dong; Li, Yi; Yao, Li; Jiang, Jian-Dong; Yan, Xin; Li, Shun-Peng

    2014-01-01

    Sphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor via N-dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing the N-dealkylation of these herbicides. The oxygenase component gene cndA is located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyze N- or O-demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity of cndA. The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicamba O-demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO. cndA, the four ferredoxin genes, and the two reductases genes were expressed in Escherichia coli, and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showed N-dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His6 was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). The N-dealkylase utilizes NADH, but not NADPH, as the electron donor. PMID:24928877

  16. Quality of water in alluvial aquifers in eastern Iowa

    USGS Publications Warehouse

    Savoca, Mark E.; Sadorf, Eric M.; Linhart, S. Michael; Barnes, Kimberlee K.

    2001-01-01

    Pesticides were detected in 84 percent of samples from agricultural areas and 70 percent from urban areas. Atrazine and metolachlor were the most frequently detected pesticides in samples from agricultural areas; atrazine and prometon were the most frequently detected pesticides in samples from urban areas. None of the pesticide concentrations exceeded U.S. Environmental Protection Agency maximum contaminant levels or lifetime health advisories for drinking water. Pesticide degradates were detected in 94 percent of samples from agricultural areas and 53 percent from urban areas. Metolachlor ethane sulfonic acid and deethylatrazine were the most frequently detected metabolites in samples from agricultural areas; metolachlor ethane sulfonic acid and alachlor ethane sulfonic acid were the most frequently detected degradates in samples from urban areas. Total degradate concentrations were significantly higher in samples from agricultural areas than in samples from urban areas. Total pesticide concentrations (parent compounds) tended to be higher in samples from agricultural areas; however, this difference was not statistically significant. Degradates constituted the major portion of the total residue concentration

  17. Contribution of subsoil and aquifer microorganisms to ground-water quality. Technical report, 1 July 1988-30 June 1989. (Final)

    SciTech Connect

    Turco, R.F.; Konopka, A.E.

    1989-06-01

    Little information about the microbiology of the subsurface environment is available. The study was conducted to better understand the microbiology and microbial processes that occur in the subsurface under a typical midwestern agricultural soil. A 26-meter bore was installed in November of 1988. Sterile collections of soils were made at 17 different depths. A physical as well as biological investigation of the subsurface materials was conducted. Among the measured parameters were particle-size analysis, carbon, carbonates, nitrogen, phosphorus, potassium, and water-holding capacity. The level of three pesticides, atrazine, metolachlor, and alachlor, was determined. Microbial biomass was assessed using direct counts, phospholipid content, and plate counts. The ability of microbial populations resident in the strata to use glucose, phenol, aniline, (14)C-ring labeled 2-methyl-6-ethyl-aniline, (14)C-ring labeled metolachlor, (14)C-carbonyl labeled metolachlor, and atrazine was assessed. Physical analysis indicated that the site contained up to 17 different strata. The site materials were primarily glacial tills with high carbonate content. Microbial numbers and activity in the tills was much lower than either in the surface materials or the aquifer located at 25 m.

  18. Particle size distributions of currently used pesticides in a rural atmosphere of France

    NASA Astrophysics Data System (ADS)

    Coscollà, Clara; Yahyaoui, Abderrazak; Colin, Patrice; Robin, Corine; Martinon, Laurent; Val, Stéphanie; Baeza-Squiban, Armelle; Mellouki, Abdelwahid; Yusà, Vicent

    2013-12-01

    This work presents first data on the particle size distributions of current-used pesticides in the atmosphere. Ambient air samples were collected using a cascade impactor distributed into four size fractions in a rural site of Centre Region (France). Most pesticides were accumulated in the fine (0.1-1 μm) particle size fraction such as cyprodinil, pendimethalin, fenpropidin, fenpropimorph and spiroxamine. Other pesticides such as acetochlor and metolachlor presented a bimodal distribution with maximum concentrations in the ultrafine (0.03-0.1 μm)-coarse (1-10 μm) and in the ultrafine-fine size ranges, respectively. No pesticides were detected in the size fraction >10 μm.

  19. Occurrence of pesticides in groundwater and sediments and mineralogy of sediments and grain coatings underlying the Rutgers Agricultural Research and Extension Center, Upper Deerfield, New Jersey, 2007

    USGS Publications Warehouse

    Reilly, Timothy J.; Smalling, Kelly L.; Meyer, Michael T.; Sandstrom, Mark W.; Hladik, Michelle L.; Boehlke, Adam R.; Fishman, Neil S.; Battaglin, William A.; Kuivila, Kathryn M.

    2014-01-01

    Water and sediment samples were collected from June through October 2007 from seven plots at the Rutgers Agricultural Research and Extension Center in Upper Deerfield, New Jersey, and analyzed for a suite of pesticides (including fungicides) and other physical and chemical parameters (including sediment mineralogy) by the U.S. Geological Survey. Plots were selected for inclusion in this study on the basis of the crops grown and the pesticides used. Forty-one pesticides were detected in 14 water samples; these include 5 fungicides, 13 herbicides, 1 insecticide, and 22 pesticide degradates. The following pesticides and pesticide degradates were detected in 50 percent or more of the groundwater samples: 1-amide-4-hydroxy-chorothalonil, alachlor sulfonic acid, metolachlor oxanilic acid, metolachlor sulfonic acid, metalaxyl, and simazine. Dissolved-pesticide concentrations ranged from below their instrumental limit of detection to 36 micrograms per liter (for metolachlor sulfonic acid, a degradate of the herbicide metolachlor). The total number of pesticides found in groundwater samples ranged from 0 to 29. Fourteen pesticides were detected in sediment samples from continuous cores collected within each of the seven sampled plots; these include 4 fungicides, 2 herbicides, and 7 pesticide degradates. Pesticide concentrations in sediment samples ranged from below their instrumental limit of detection to 34.2 nanograms per gram (for azoxystrobin). The total number of pesticides found in sediment samples ranged from 0 to 8. Quantitative whole-rock and grain-coating mineralogy of sediment samples were determined by x-ray diffraction. Whole-rock analysis indicated that sediments were predominantly composed of quartz. The materials coating the quartz grains were removed to allow quantification of the trace mineral phases present.

  20. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen from agricultural activities contributes to the hypoxic zones and severe declines in water quality in the Gulf of Mexico and the Chesapeake Bay. The Federal Clean Water Act requires nitrogen load reductions to restore the integrity of these important waterways. Tools are needed to track t...

  1. Comparison of fate and transport of isoxaflutole to atrazine and metolachlor in 10 Iowa rivers

    USGS Publications Warehouse

    Meyer, M.T.; Scribner, E.A.; Kalkhoff, S.J.

    2007-01-01

    Isoxaflutole (IXF), a newer low application rate herbicide, was introduced for weed control in corn (Zea mays) to use as an alternative to widely applied herbicides such as atrazine. The transport of IXF in streamwater has not been well-studied. The fate and transport of IXF and two of its degradation products was studied in 10 Iowa rivers during 2004. IXF rapidly degrades to the herbicidally active diketonitrile (DKN), which degrades to a biologically inactive benzoic acid (BA) analogue. IXF was detected in only four, DKN in 56, and BA in 43 of 75 samples. The concentrations of DKN and BA were approximately 2 orders of magnitude less than those of the commonly detected triazine and acetamide herbicides and their degradation products. Concentrations of IXF, DKN, and BA were highest during the May through June postplanting period. The concentration ratio of BA/DKN was similar to the deethylatrazine/atrazine ratio with smaller ratios occurring during May and June. The relative temporal variation of DKN and BA was similar to that observed for atrazine and deethylatrazine. This study shows that low application rate herbicides can have similar temporal transport patterns in streamwater as compared to more widely applied herbicides but at lower concentrations.

  2. Metolachlor sorption and degradation in soil amended with fresh and aged biochar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Addition of organic amendments such as biochar to soils can influence pesticide sorption-desorption processes, and in turn, pesticide availability and biodegradation. Availability is affected by both the physical and chemical properties of soils and pesticides, as well as soil-pesticide contact time...

  3. ALUMINUM AND IRON SALT-CATALYZED DESTRUCTION OF METOLACHLOR BY ZEROVALENT IRON. (R829422E03)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. Effect of meteorology and soil condition on metolachlor and atrazine volatilization over a 10 year period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatilization of pesticides can detrimentally affect the environment by contaminating soil and surface waters far away from where the pesticides were applied. A 10-year study was conducted to focus on the impact of soil and climatic factors governing herbicide volatilization from an agricultural f...

  5. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed

    USGS Publications Warehouse

    McCarty, Gregory W.; Hapeman, Cathleen J.; Rice, Clifford P.; Hively, W. Dean; McConnell, Laura L.; Sadeghi, Ali M.; Lang, Megan W.; Whitall, David R.; Bialek, Krystyna; Downey, Peter

    2014-01-01

    Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R2 = 0.65, p 2 ≤ 0.99) for all eight sampling dates except one where R2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such as cover crops which sequester the residual N should be strongly encouraged. In poorly drained areas where denitrification can occur, wetland restoration and controlled drained structures that minimize ditch flow should be used to maximize denitrification.

  6. Characterization of ‘Aged’ Metolachlor Sorption in Soil Using an Accelerated Solvent Extraction (ASE) Technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorption interactions of pesticides with soil determine pesticide availability for transport and degradation in soil. Thus, knowing and understanding pesticide sorption, particularly in aged soils, is important in determining pesticide fate in soils. Sorption of pesticides is traditionally character...

  7. How do laboratory assessments of S-metolachlor sorption and dissipation agree with field behavior?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research has suggested that existing bonds become stronger with aging time, decreasing the extractability and bioavailability of some pesticides in soil. We found that using high-energy extraction conditions (elevated temperature and pressure in ASE) removed a higher proportion of sorbed S-metolachl...

  8. Mitigation of atrazine, S-metolachlor, and diazinon using common aquatic emergent vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Based on current population rates, by the year 2050, the population of the United States will reach over 418 million, while the global population will reach 9.6 billion. To continue providing safe food and fiber for this population increase, agriculture must balance the mixture of natural resources...

  9. Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed.

    PubMed

    McCarty, Gregory W; Hapeman, Cathleen J; Rice, Clifford P; Hively, W Dean; McConnell, Laura L; Sadeghi, Ali M; Lang, Megan W; Whitall, David R; Bialek, Krystyna; Downey, Peter

    2014-03-01

    Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R(2)=0.65, p<0.001) takes into consideration not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N concentrations within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R(2) ≤ 0.99) for all eight sampling dates except one where R(2)=0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such as cover crops which sequester the residual N should be strongly encouraged. In poorly drained areas where denitrification can occur, wetland restoration and controlled drained structures that minimize ditch flow should be used to maximize denitrification.

  10. Herbicide concentrations in and loads transported by the Conestoga River and Pequea Creek, Lancaster County, Pennsylvania, 1992-95

    USGS Publications Warehouse

    Reed, Lloyd A.; Koerkle, Edward H.; Takita, Charles S.

    1997-01-01

    Water samples were collected from four streams in Lancaster County from 1992 through 1995 and analyzed for selected herbicides. Samples were collected from the Little Conestoga Creek near Churchtown, Mill Creek (a tributary to the Conestoga River) at Elshelman Mill Road near Lyndon, the Conestoga River at Conestoga, and Pequea Creek at Martic Forge. Most samples were collected from stormflow that occurred during the growing season. Samples were analyzed for alachlor, aldrin, atrazine, chlordane, cyanazine, dieldrin, malathion, metolachlor, propazine, simazine, and toxaphene. Most samples had detectable concentrations of alachlor, atrazine, metolachlor, and simazine, and the loads of these constituents that were transported during each of the 4 years were computed. Of the samples collected from each of the streams?Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek?10, 12, 15, and 18 percent, respectively, had atrazine concentrations greater than 3.0 micrograms per liter, the U.S. Environmental Protection Agency maximum contaminant level. Loads of atrazine, metolochlor, and simazine were greater than loads of any other herbicides. The largest loads were transported during 1994. Loads of atrazine transported by the four streams during periods of storm- flow from May to September 1994 totaled 3.46, 28.3, 263, and 46.8 pounds, respectively. The total loads of atrazine transported by the four streams?Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek?during calendar year 1994 were 6.48, 54.1, 498, and 102 pounds, respectively. A little less than half the atrazine load transported by each stream?45, 39, 42, and 42 percent, respectively?was transported during storms that occurred from May through September. Average annual yields of atrazine for the period 1992-95 were 0.59, 0.64, 0.68, and 0.51 pounds per square mile from the Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek, respectively. Average annual yields of

  11. Cross sectional concentration data for selected organic contaminants in river waters near the confluence of the Mississippi River and the Illinois, Missouri, and Ohio Rivers, June 1989 and May-June 1990

    USGS Publications Warehouse

    Rostad, Colleen E.; Bishop, LaDonna M.; Pereira, Wilfred E.; Leiker, Thomas J.

    2004-01-01

    Water samples were collected upstream and downstream from the confluence of the Ohio River and Mississippi River to study mixing of the river waters. Samples collected in June 1989 on the Mississippi River were analyzed for alachlor, atrazine, 2-chloro-2',6'-diethylacetanilide, cyanazine, desethyl-atrazine, desisopropylatrazine, 2,6-diethylaniline, 2-hydroxy-2',6'-diethylacetanilide, metolachlor, simazine, trimethyltriazinetrione, tris(2-chloroethyl) phosphate, and tris(chloroisopropyl) phosphate. Samples collected upstream and downstream from the confluence of the Ohio River and Mississippi River in May-June 1990 were analyzed for trimethyltriazinetrione, tris(2-chloroethyl) phosphate, and tris(chloroisopropyl) phosphate. Concentration data for six to fifteen locations across the rivers are presented in tabular form for two sites in 1989 and six sites in 1990.

  12. Trends in pesticide concentrations and use for major rivers of the United States

    USGS Publications Warehouse

    Ryberg, Karen R.; Gilliom, Robert J.

    2015-01-01

    Pesticides strongly dominated by agricultural use (cyanazine, alachlor, atrazine and its degradate deethylatrazine, metolachlor, and carbofuran) had widespread agreement between concentration trends and use trends. Pesticides with substantial use in both agricultural and nonagricultural applications (simazine, chlorpyrifos, malathion, diazinon, and carbaryl) had concentration trends that were mostly explained by a combination of agricultural-use trends, regulatory changes, and urban use changes inferred from concentration trends in urban streams. When there were differences, concentration trends usually were greater than use trends (increased more or decreased less). These differences may occur because of such factors as unaccounted pesticide uses, delayed transport to the river through groundwater, greater uncertainty in the use data, or unquantified land use and management practice changes.

  13. Study of the effects of environmental parameters on the gas/particle partitioning of current-use pesticides in urban air

    NASA Astrophysics Data System (ADS)

    Sauret, Nathalie; Wortham, Henri; Putaud, Jean-Philippe; Mirabel, Philippe

    A filter-XAD-2 resin plug high-volume air sampler was used to collect particulate (P) and gaseous (G) phases of seven pesticides (atrazine, terbuthylazine, alachlor, metolachlor, cymoxanil, diflufenicanil, and fenoxaprop- p-ethyl) and two metabolites (de-ethylatrazine (DEA) and de-ethylterbuthylazine (DET)) in downtown Strasbourg (France). Most of the molecules listed above were found to be associated only with particulate aerosols and only four of them were detected regularly in both atmospheric phases (particulate and gaseous). The results presented in this work showed that models developed previously to describe the gas/particle (G/P) partitioning did not work for currently used pesticides. A new partition equation ( Korg, m 3 ng -1) was defined for the pesticides under study using environmental parameters such as temperature, relative humidity, and organic carbon content of atmospheric aerosols.

  14. Distribution of major herbicides in ground water of the United States

    USGS Publications Warehouse

    Barbash, Jack E.; Thelin, Gail P.; Kolpin, Dana W.; Gilliom, Robert J.

    1999-01-01

    Frequencies of detection at or above 0.01 microgram per liter in shallow ground water beneath agricultural areas during the NAWQA study were significantly correlated with agricultural use in those areas for atrazine, cyanazine, alachlor, and metolachlor (P<0.05; Spearman rank correlations), but not for simazine (P>0.05). In urban areas, overall frequencies of detection of these five herbicides in shallow ground water were positively correlated with their total nonagricultural use nationwide (P=0.026; simple linear correlation). Multivariate statistical analysis indicated that frequencies of detection in shallow ground water beneath agricultural areas were positively correlated with half-lives for transformation in aerobic soil and agricultural use of the comp

  15. Occurrence of pesticides in ground water in the White River Basin, Indiana, 1994-95

    USGS Publications Warehouse

    Fenelon, Joseph M.; Moore, Rhett C.

    1996-01-01

    Pesticides (herbicides and insecticides) are used extensively in the White River Basin. Application of herbicides to corn and soybeans accounts for most of the use. The U.S. Geological Survey collected samples from four networks of monitoring wells in the White River Basin during 1994-95. The most frequently detected compounds in ground water were desethyl atrazine (a breakdown product of atrazine) and the commonly used herbicides, atrazine and metolachlor. Insecticides commonly used in urban and agricultural areas were not found. The highest concentration of any pesticide detected was alachlor at 0.19 micrograms per liter. Most detections of atrazine and desethyl atrazine were in agricultural areas overlying fluvial deposits, which are vulnerable to pesticide contamination, but the concentrations were small (less than 0.1 microgram per liter).

  16. Field calibration of surface: a model of agricultural chemicals in surface waters.

    PubMed

    Gustafson, D I

    1990-10-01

    Agricultural chemicals sporadically occur at detectable levels in the surface waters of intensively farmed watersheds. HSPF, a previously released model of agricultural chemicals in surface water, had been used to predict concentrations which were much higher (10 X) than those actually observed during monitoring studies. A new model, SURFACE, is described here which is much simpler than HSPF and gives better predictions of surface water concentrations. SURFACE uses PRZM, an EPA model, to calculate edge-of-field runoff losses and simple hydraulic routing algorithms to determine concentrations at the bottom of large river basins. In water systems sampled during 1985 and 1986, SURFACE predictions of annualized mean concentrations for alachlor, atrazine, cyanazine and metolachlor were within 0.09 ppb half of the time.

  17. Treating Soil Solution Samplers To Prevent Microbial Removal of Analytes

    PubMed Central

    Lewis, David L.; Simons, Alex P.; Moore, W. Bruce; Gattie, David K.

    1992-01-01

    Soil microorganisms colonizing soil water sampling devices (lysimeters) reduced concentrations of biodegradable organic chemicals, including 2,4-dichlorophenoxyacetic acid methyl ester, alachlor, methyl m-chlorobenzoate, and metolachlor as water entered through porous ceramic cups. In some cases, losses exceeded 99%. Additions of either a biocide (sodium hypochlorite) or a bacteriostat (copper salt) prevented microbial activity so that concentrations of test chemicals inside lysimeters equaled those outside. Field studies further indicated that treating lysimeters with a copper salt effectively prevented microbial activity. Thus, chemically treating soil water samplers could improve the accuracy of soil water data for a wide variety of analytes, including environmentally important organics, such as pesticides and industrial wastes, and inorganics, such as ammonia and nitrate. Images PMID:16348616

  18. Photocatalytic oxidation of pesticides by solar-irradiated TiO[sub 2] systems

    SciTech Connect

    Sullivan, J.M.; Grinstead, J.H. Jr.

    1992-01-01

    Research at the Tennessee Valley Authority's National Fertilizer and Environmental Research Center has been directed toward the development of passive basin type solar evaporators as a simple means of reducing the volume of fertilizer and pesticide contaminated rinsewater generated at fertilizer and agrichemical dealerships. In conjunction with this work, investigations are also devoted to TiO[sub 2] catalyzed solar photooxidation as a potential procedure for destroying pesticides in dilute aqueous systems. Initial tests in which dilute samples of the herbicides; Bicep (atrazine and metolachlor), Lasso (alachlor), and Sencor (metribuzin); were recirculated continuously over TiO[sub 2] impregnated fiberglass gauze, under solar irradiation, gave promising results. In the case of metribuzin, solar irradiation induced oxidation appeared effective at concentrations as high as 600 ppM. Catalytic efficiency did not appear greatly affected by using tap water rather than distilled water to dilute the pesticides. Two solar reactor designs will be discussed.

  19. Photocatalytic oxidation of pesticides by solar-irradiated TiO{sub 2} systems

    SciTech Connect

    Sullivan, J.M.; Grinstead, J.H. Jr.

    1992-12-01

    Research at the Tennessee Valley Authority`s National Fertilizer and Environmental Research Center has been directed toward the development of passive basin type solar evaporators as a simple means of reducing the volume of fertilizer and pesticide contaminated rinsewater generated at fertilizer and agrichemical dealerships. In conjunction with this work, investigations are also devoted to TiO{sub 2} catalyzed solar photooxidation as a potential procedure for destroying pesticides in dilute aqueous systems. Initial tests in which dilute samples of the herbicides; Bicep (atrazine and metolachlor), Lasso (alachlor), and Sencor (metribuzin); were recirculated continuously over TiO{sub 2} impregnated fiberglass gauze, under solar irradiation, gave promising results. In the case of metribuzin, solar irradiation induced oxidation appeared effective at concentrations as high as 600 ppM. Catalytic efficiency did not appear greatly affected by using tap water rather than distilled water to dilute the pesticides. Two solar reactor designs will be discussed.

  20. Occurrence of active and inactive herbicide ingredients at selected sites in Iowa

    USGS Publications Warehouse

    Wang, W.; Liszewski, M.; Buchmiller, R.; Cherryholmes, K.

    1995-01-01

    Herbicides were detected in 50% of water samples, ranging from 78% of water samples from the Ames site to 25% from the Walnut Creek site. Among herbicides detected, listed in decreasing order of frequency, were atrazine > alachlor > cyanazine > metolachlor > metribuzin. Volatile organic compounds were detected in 11% of water samples. Among the compounds detected, listed in decreasing order of frequency, were xylene > toluene > acetone. One sample contained a detectable amount of aliphatic compound(s), with the empirical formula of C8H18. Results from the Deer Creek site showed that herbicides were detected primarily in the top layer (1.2 m), whereas xylene and other alkylbenzenes were detected at 2.1 m or deeper. Apparently, physico-chemical and other factors are separating herbicides and volatile organic compounds in the shallow unsaturated zone.

  1. Assessment of the effects of farming and conservation programs on pesticide deposition in high plains wetlands.

    PubMed

    Belden, Jason B; Hanson, Brittany Rae; McMurry, Scott T; Smith, Loren M; Haukos, David A

    2012-03-20

    We examined pesticide contamination in sediments from depressional playa wetlands embedded in the three dominant land-use types in the western High Plains and Rainwater Basin of the United States including cropland, perennial grassland enrolled in conservation programs (e.g., Conservation Reserve Program [CRP]), and native grassland or reference condition. Two hundred and sixty four playas, selected from the three land-use types, were sampled from Nebraska and Colorado in the north to Texas and New Mexico in the south. Sediments were examined for most of the commonly used agricultural pesticides. Atrazine, acetochlor, metolachlor, and trifluralin were the most commonly detected pesticides in the northern High Plains and Rainwater Basin. Atrazine, metolachlor, trifluralin, and pendimethalin were the most commonly detected pesticides in the southern High Plains. The top 5-10% of playas contained herbicide concentrations that are high enough to pose a hazard for plants. However, insecticides and fungicides were rarely detected. Pesticide occurrence and concentrations were higher in wetlands surrounded by cropland as compared to native grassland and CRP perennial grasses. The CRP, which is the largest conservation program in the U.S., was protective and had lower pesticide concentrations compared to cropland.

  2. Assessment of the effects of farming and conservation programs on pesticide deposition in high plains wetlands.

    PubMed

    Belden, Jason B; Hanson, Brittany Rae; McMurry, Scott T; Smith, Loren M; Haukos, David A

    2012-03-20

    We examined pesticide contamination in sediments from depressional playa wetlands embedded in the three dominant land-use types in the western High Plains and Rainwater Basin of the United States including cropland, perennial grassland enrolled in conservation programs (e.g., Conservation Reserve Program [CRP]), and native grassland or reference condition. Two hundred and sixty four playas, selected from the three land-use types, were sampled from Nebraska and Colorado in the north to Texas and New Mexico in the south. Sediments were examined for most of the commonly used agricultural pesticides. Atrazine, acetochlor, metolachlor, and trifluralin were the most commonly detected pesticides in the northern High Plains and Rainwater Basin. Atrazine, metolachlor, trifluralin, and pendimethalin were the most commonly detected pesticides in the southern High Plains. The top 5-10% of playas contained herbicide concentrations that are high enough to pose a hazard for plants. However, insecticides and fungicides were rarely detected. Pesticide occurrence and concentrations were higher in wetlands surrounded by cropland as compared to native grassland and CRP perennial grasses. The CRP, which is the largest conservation program in the U.S., was protective and had lower pesticide concentrations compared to cropland. PMID:22356096

  3. Linking ground-water age and chemistry data along flow paths: Implications for trends and transformations of nitrate and pesticides

    USGS Publications Warehouse

    Tesoriero, A.J.; Saad, D.A.; Burow, K.R.; Frick, E.A.; Puckett, L.J.; Barbash, J.E.

    2007-01-01

    Tracer-based ground-water ages, along with the concentrations of pesticides, nitrogen species, and other redox-active constituents, were used to evaluate the trends and transformations of agricultural chemicals along flow paths in diverse hydrogeologic settings. A range of conditions affecting the transformation of nitrate and pesticides (e.g., thickness of unsaturated zone, redox conditions) was examined at study sites in Georgia, North Carolina, Wisconsin, and California. Deethylatrazine (DEA), a transformation product of atrazine, was typically present at concentrations higher than those of atrazine at study sites with thick unsaturated zones but not at sites with thin unsaturated zones. Furthermore, the fraction of atrazine plus DEA that was present as DEA did not increase as a function of ground-water age. These findings suggest that atrazine degradation occurs primarily in the unsaturated zone with little or no degradation in the saturated zone. Similar observations were also made for metolachlor and alachlor. The fraction of the initial nitrate concentration found as excess N2 (N2 derived from denitrification) increased with ground-water age only at the North Carolina site, where oxic conditions were generally limited to the top 5??m of saturated thickness. Historical trends in fluxes to ground water were evaluated by relating the times of recharge of ground-water samples, estimated using chlorofluorocarbon concentrations, with concentrations of the parent compound at the time of recharge, estimated by summing the molar concentrations of the parent compound and its transformation products in the age-dated sample. Using this approach, nitrate concentrations were estimated to have increased markedly from 1960 to the present at all study sites. Trends in concentrations of atrazine, metolachlor, alachlor, and their degradates were related to the timing of introduction and use of these compounds. Degradates, and to a lesser extent parent compounds, were detected

  4. A Review of Pesticide Exposure and Cancer Incidence in the Agricultural Health Study Cohort

    PubMed Central

    Weichenthal, Scott; Moase, Connie; Chan, Peter

    2010-01-01

    Objective We reviewed epidemiologic evidence related to occupational pesticide exposures and cancer incidence in the Agricultural Health Study (AHS) cohort. Data sources Studies were identified from the AHS publication list available at http://aghealth.nci.nih.gov as well as through a Medline/PubMed database search in March 2009. We also examined citation lists. Findings related to lifetime-days and/or intensity-weighted lifetime-days of pesticide use are the primary focus of this review, because these measures allow for the evaluation of potential exposure–response relationships. Data synthesis We reviewed 28 studies; most of the 32 pesticides examined were not strongly associated with cancer incidence in pesticide applicators. Increased rate ratios (or odds ratios) and positive exposure–response patterns were reported for 12 pesticides currently registered in Canada and/or the United States (alachlor, aldicarb, carbaryl, chlorpyrifos, diazinon, dicamba, S-ethyl-N,N-dipropylthiocarbamate, imazethapyr, metolachlor, pendimethalin, permethrin, trifluralin). However, estimates of association for specific cancers were often imprecise because of small numbers of exposed cases, and clear monotonic exposure–response patterns were not always apparent. Exposure misclassification is also a concern in the AHS and may limit the analysis of exposure–response patterns. Epidemiologic evidence outside the AHS remains limited with respect to most of the observed associations, but animal toxicity data support the biological plausibility of relationships observed for alachlor, carbaryl, metolachlor, pendimethalin, permethrin, and trifluralin. Conclusions Continued follow-up is needed to clarify associations reported to date. In particular, further evaluation of registered pesticides is warranted. PMID:20444670

  5. Comparative sensitivity of Selenastrum capricornutum and Lemna minor to sixteen herbicides

    USGS Publications Warehouse

    Fairchild, J.F.; Ruessler, D.S.; Haverland, P.S.; Carlson, A.R.

    1997-01-01

    Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the specific intent to compare the relative sensitivity of various aquatic plant species to contaminants. We compared the relative sensitivity of the algae Selenestrum capricornutum and the floating vascular plant Lemna minor to 16 herbicides (atrazine, metribuzin, simazine, cyanazine, alachlor, metolachlor, chlorsulfuron, metsulfuron, triallate, EPTC, trifluralin, diquat, paraquat, dicamba, bromoxynil, and 2,4-D). The herbicides studied represented nine chemical classes and several modes of action and were chosen to represent major current uses in the United States. Both plant species were generally sensitive to the triazines (atrazine, metribuzin, simazine, and cyanazine), sulfonureas (metsulfuron and chlorsulfuron), pyridines (diquat and paraquat), dinitroaniline (trifluralin), and acetanilide (alachlor and metolachlor) herbicides. Neither plant species was uniformly more sensitive than the other across the broad range of herbicides tested. Lemna was more sensitive to the sulfonureas (metsulfuron and chlorsulfuron) and the pyridines (diquat and parequat) than Selenastrum. However Selenastrum was more sensitive than Lemna to one of two thiocarbamates (triallate) and one of the triazines (cyanazine). Neither species was sensitive to selective broadleaf herbicides including bromoxynil, EPTC, dicamba, or 2,4-D. Results were not always predictable in spite of obvious differences in herbicide modes of action and plant phylogeny. Major departures in sensitivity of Selenastrum occurred between chemicals within individual classes of the triazine, acetanilide, and thiocarbamate herbicides. Results indicate that neither

  6. Compilation of atrazine and selected herbicide data from previous surface-water-quality investigations within the Big Blue River basin, Nebraska, 1983-92

    USGS Publications Warehouse

    Frankforter, J.D.

    1994-01-01

    Atrazine has been detected in the surface water of the Big Blue River Basin during every month of the year. Recent data (1983-92) documenting the occurrence of atrazine and related herbicides in the surface water of the basin are compiled in this report. In samples analyzed during these studies, atrazine was the herbicide detected most frequently within the basin. Of the 385 samples analyzed, 369 contained atrazine in detectable concentrations with detection levels varying from 0 to 0.1 micrograms per liter. The concentrations of atrazine within the samples varied from 0.5 to 166 micrograms per liter, with a median concentration of 2.7 micrograms per liter. Other herbicides frequently detected in the Big Blue River Basin were alachlor, cyanazine, metolachlor, and simazine, and two metabolites of atrazine, desethylatrazine and deisopropylatrazine. In the 226 samples which alachlor was detected, the concentrations of the herbicide ranged from 0.05 to 56 micrograms per liter, and the median concen- tration was 1.1 micrograms per liter. Cyanazine was detected in 210 of 365 samples collected with con- centrations that ranged from 0.05 to 8.6 micrograms per liter with a median concentration of 0.4 microgram per liter. The maximum concentrations of metolachlor and simazine were 26 and 35 micrograms per liter, respectively. The median concentrations of these herbicides were 1.0 and 0.1 micrograms per liter, respectively. The maximum concentration of desethylatrazine, was 3.7 micrograms per liter, with a median concentration of 1.0 microgram per liter. Deisopropylatrazine, was detected in 152 samples with maximum and median concentrations of 2.6 and 0.6 micrograms per liter, respectively.

  7. Estimating the Regional Flux of Nitrate and Agricultural Herbicide Compounds from Groundwater to Headwater Streams of the Northern Atlantic Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Ator, S.; Denver, J. M.

    2011-12-01

    Agriculture is common in the Northern Atlantic Coastal Plain (NACP, including New Jersey through North Carolina), and groundwater discharge provides nitrogen (primarily in the form of nitrate) and herbicide compounds from agricultural sources along with the majority of flow to NACP streams. Poor water quality has contributed to ecological degradation of tidal streams and estuaries along much of the adjacent mid-Atlantic coast. Although statistical models have provided estimates of total instream nutrient flux in the Coastal Plain, the regional flux of nitrogen and herbicides during base flow is less well understood. We estimated the regional flux of nitrate and selected commonly used herbicide compounds from groundwater to non-tidal headwater streams of the NACP on the basis of late-winter or spring base-flow samples from 174 such streams. Sampled streams were selected using an unequal-probability random approach, and flux estimates are based on resulting population estimates rather than empirical models, which are commonly used for such estimates. Base-flow flux in the estimated 8,834 NACP non-tidal headwater streams are an estimated 21,200 kilograms per day of nitrate (as N) and 5.83, 0.565, and 20.7 kilograms per day of alachlor, atrazine, and metolachlor (including selected degradates), respectively. Base-flow flux of alachlor and metolachlor is dominated by degradates; flux of parent compounds is less than 3 percent of the total flux of parent plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications generally varies predictably with regional variations in hydrogeology. Abundant nonpoint (primarily agricultural) sources and hydrogeologic conditions, for example, contribute to particularly large base-flow flux from the Delmarva Peninsula to Chesapeake Bay. In the Delmarva Peninsula part of the Chesapeake Watershed, more than 10 percent of total nonpoint nitrogen applications is transported through groundwater to stream base flow

  8. Linking ground-water age and chemistry data along flow paths: Implications for trends and transformations of nitrate and pesticides

    NASA Astrophysics Data System (ADS)

    Tesoriero, Anthony J.; Saad, David A.; Burow, Karen R.; Frick, Elizabeth A.; Puckett, Larry J.; Barbash, Jack E.

    2007-10-01

    Tracer-based ground-water ages, along with the concentrations of pesticides, nitrogen species, and other redox-active constituents, were used to evaluate the trends and transformations of agricultural chemicals along flow paths in diverse hydrogeologic settings. A range of conditions affecting the transformation of nitrate and pesticides (e.g., thickness of unsaturated zone, redox conditions) was examined at study sites in Georgia, North Carolina, Wisconsin, and California. Deethylatrazine (DEA), a transformation product of atrazine, was typically present at concentrations higher than those of atrazine at study sites with thick unsaturated zones but not at sites with thin unsaturated zones. Furthermore, the fraction of atrazine plus DEA that was present as DEA did not increase as a function of ground-water age. These findings suggest that atrazine degradation occurs primarily in the unsaturated zone with little or no degradation in the saturated zone. Similar observations were also made for metolachlor and alachlor. The fraction of the initial nitrate concentration found as excess N 2 (N 2 derived from denitrification) increased with ground-water age only at the North Carolina site, where oxic conditions were generally limited to the top 5 m of saturated thickness. Historical trends in fluxes to ground water were evaluated by relating the times of recharge of ground-water samples, estimated using chlorofluorocarbon concentrations, with concentrations of the parent compound at the time of recharge, estimated by summing the molar concentrations of the parent compound and its transformation products in the age-dated sample. Using this approach, nitrate concentrations were estimated to have increased markedly from 1960 to the present at all study sites. Trends in concentrations of atrazine, metolachlor, alachlor, and their degradates were related to the timing of introduction and use of these compounds. Degradates, and to a lesser extent parent compounds, were detected

  9. Hydrologic data for the Big Spring basin, Clayton County, Iowa, water year 1991

    USGS Publications Warehouse

    Kalkhoff, S.J.; Kuzniar, R.L.

    1994-01-01

    Stream discharge, specific conductance, pH, and water temperature were monitored continuously, and monthly water-quality samples were collected at a site on Roberts Creek and at Big Spring. Nitrite plus nitrate as nitrogen concentrations in 27 samples from Roberts Creek at the point where it leaves the study area ranged from 1.8 to 22 mg/L. Herbicide concentrations in 26 samples from the Roberts Creek site ranged from less than 0.10 μg/L (micrograms per liter) to 43 μg/L. Alachlor was detected in 42 percent of the samples; atrazine in 92 percent; and cyanazine and metolachlor in 35 percent of the samples. The total suspended-sediment load discharged in Roberts Creek was about 160,000 tons. At Big Spring, the ground-water discharge point, the daily mean specific conductance ranged from 414 to 788 microsiemens per centimeter at 25 degrees Celsius, the daily median pH ranged from 6.7 to 7.1, and the daily mean water temperature ranged from 8.5 to 13.0 degrees Celsius. Concentrations of nitrite plus nitrate as nitrogen in 23 samples ranged from 4.2 to 17 mg/L. The total measured suspended-sediment discharged from Big Spring was about 17,000 tons. Alachlor was detected in 26 percent; atrazine in 100 percent; cyanazine in 26 percent, and metolachlor in 9 percent of the samples. The maximum atrazine concentration was 16 μg/L.

  10. Water supply implications of herbicide sampling: Hydrologic conditions may affect concentrations of organonitrogen herbicides and may be important considerations in complying with drinking water regulations

    USGS Publications Warehouse

    Stamer, J.K.

    1996-01-01

    The temporal distribution of the herbicides alachlor, atrazine, cyanazine, and metolachlor was documented from September 1991 through August 1992 in the Platte River at Louisville, Neb., the drainage of the Central Nebraska Basins. Lincoln, Ornaha, and other municipalities withdraw groundwater for public supplies from the adjacent alluvium, which is hydraulically connected to the Platte River. Data were collected, in part, to provide information to managers, planners, and public utilities on the likelihood of water supplies being adversely affected by these herbicides. Three computational procedures - monthly means, monthly subsampling, and quarterly subsampling - were used to calculate annual mean herbicide concentrations. When the sampling was conducted quarterly rather than monthly, alachlor and atrazine concentrations were more likely to exceed their respective maximum contaminant levels (MCLs) of 2.0 ??g/L and 3.0 ??g/L, and cyanazine concentrations were more likely to exceed the health advisory level of 1.0 ??g/L. The US Environmental Protection Agency has established a tentative MCL of 1.0 ??g/L for cyanazine; data indicate that cyanazine is likely to exceed this level under most hydrologic conditions.

  11. Pesticides in streams in the Tar-Pamlico drainage basin, North Carolina, 1992-94

    USGS Publications Warehouse

    Woodside, Michael D.; Ruhl, Kelly E.

    2001-01-01

    From 1992 to 1994, 147 water samples were collected at 5 sites in the Tar-Pamlico drainage basin in North Carolina and analyzed for 46 herbicides, insecticides, and pesticide metabolites as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Based on a common adjusted detection limit of 0.01 microgram per liter, the most frequently detected herbicides were metolachlor (84 percent), atrazine (78 percent), alachlor (72 percent), and prometon (57 percent). The insecticides detected most frequently were carbaryl (12 percent), carbofuran (7 percent), and diazinon (4 percent). Although the pesticides with the highest estimated uses generally were the compounds detected most frequently, there was not a strong correlation between estimated use and detection frequency. The development of statistical correlations between pesticide use and detection frequency was limited by the lack of information on pesticides commonly applied in urban and agricultural areas, such as prometon, chlorpyrifos, and diazinon, and the small number of basins included in this study. For example, prometon had the fourth highest detection frequency, but use information was not available. Nevertheless, the high detection frequency of prometon indicates that nonagricultural uses also contribute to pesticide levels in streams in the Tar-Pamlico drainage basin. Concentrations of the herbicides atrazine, alachlor, and trifluralin varied seasonally, with elevated concentrations generally occurring in the spring, during and immediately following application periods, and in the summer. Seasonal concentration patterns were less evident for prometon, diazinon, and chlorpyrifos. Alachlor is the only pesticide detected in concentrations that exceeded current (2000) drinking-water standards.

  12. Occurrence, distributions, and transport of herbicides and their degradation products in the lower Mississippi river and its tributaries

    USGS Publications Warehouse

    Pereira, W.E.

    1990-01-01

    The Mississippi River and its tributaries drain extensive agricultural regions of the midcontinental United States, where large amounts of herbicides are applied as weed control agents on crops such as corn and soybeans. Studies being conducted by the U.S. Geological Survey along the lower Mississippi River and its major tributaries, representing a 1930-km river reach, have confirmed that several triazine and chloroacetanilide herbicides and their degradation products are present in this riverine system. These herbicides include atrazine, and its degradation products, desethyl- and desisopropylatrazine; cyanazine; simazine; metolachlor; and alachlor and its degradation products, 2-chloro-2???,6???-diethylacetanilide, and 2-hydroxy-2???,6???-diethylacetanilide. Loads of these compounds were determined at 17 different sampling stations under various seasonal and hydrologic conditions, during five sampling trips from July 1987 to June 1989. Stream loads of herbicides were relatively small during the drought of 1987 and 1988. Stream loads were much greater during the relatively wet year of 1989. Trace levels of atrazine, cyanazine, and metolachlor also were associated with suspended sediments. Distribution coefficients (Koc) of these compounds varied considerably between sites and were much larger than Koc values reported in the literature. The annual transport of atrazine into the Gulf of Mexico was estimated to be less than 2% of the amount of atrazine applied each year in the midwest.

  13. Water quality survey of Mississippi's Upper Pearl River.

    PubMed

    Tagert, Mary Love M; Massey, Joseph H; Shaw, David R

    2014-05-15

    Surface water samples were collected from May 2002 through May 2003 at seven locations within the Upper Pearl River Basin (UPRB) in east-central Mississippi to assess levels of pesticide impairment in the watershed. Depth-integrated samples were collected at three sites from September 2001 through January 2003 for total dissolved solid (TDS) analysis. Samples were extracted via Solid Phase Extraction (SPE) and analyzed for fifteen pesticides: triclopyr, 2,4-D, tebuthiuron, simazine, atrazine, metribuzin, alachlor, metolachlor, cyanazine, norflurazon, hexazinone, pendimethalin, diuron, fluometuron, and the dichlorodiphenyltrichloroethane (DDT) degradation product p,p'-DDE. Of the analyzed compounds, hexazinone was detected in 94% of the samples, followed by metolachlor (76%), tebuthiuron (48%), and atrazine (47%). Metribuzin was detected in 6% of the samples and was the least detected compound of those analyzed. Sediment concentrations ranged from 20.64 mg/L at Burnside to 42.20mg/L at Carthage, which also had the highest cumulative total sediment concentration at 4,009 mg/L.

  14. Agricultural pesticides in six drainage basins used for public water supply in New Jersey, 1990

    USGS Publications Warehouse

    Ivahnenko, Tamara; Buxton, D.E.

    1994-01-01

    A reconnaissance study of six drainage basins in New Jersey was conducted to evaluate the presence of pesticides from agricultural runoff in surface water. In the first phase of the study, surface-water public-supply drainage basins throughout New Jersey that could be affected by pesticide applications were identified by use of a Geographic Information System. Six basins--Lower Mine Hill Reservoir, South Branch of the Raritan River, Main Branch of the Raritan River, Millstone River, Manasquan River, and Matchaponix Brook--were selected as those most likely to be affected by pesticides on the basis of calculated pesticide-application rates and percentage of agricultural land. The second phase of the project was a short-term water-quality reconnaissance of the six drainage basins to determine whether pesticides were present in the surface waters. Twenty-eight surface-water samples (22 water-quality samples, 3 sequentially collected samples, and 3 trip blanks), and 6 samples from water-treatment facilities were collected. Excluding trip blanks, samples from water-treatment facilities, and sequentially collected samples, the pesticides detected in the samples and the percentage of samples in which they were detected, were as follows: atrazine and metolachlor, 86 percent; alachlor, 55 percent; simazine, 45 percent; diazinon, 27 percent; cyanazine and carbaryl, 23 percent; linuron and isophenfos, 9 percent; and chlorpyrifos, 5 percent.Diazinon, detected in one stormflow sample collected from Matchaponix Brook on August 6, 1990, was the only compound to exceed the U.S. Environmental Protection Agency's recommended Lifetime Health Advisory Limit. Correlation between ranked metolachlor concentrations and ranked flow rates was high, and 25 percent of the variance in metolachlor concentrations can be attributed to variations in flow rate. Pesticide residues were detected in samples of pretreated and treated water from water-treatment facilities. Concentrations of all

  15. Pesticide compounds in streamwater in the Delaware River Basin, December 1998-August 2001

    USGS Publications Warehouse

    Hickman, R. Edward

    2004-01-01

    During 1998-2001, 533 samples of streamwater at 94 sites were collected in the Delaware River Basin in Pennsylvania, New Jersey, New York, and Delaware as part of the U.S. Geological Survey National Water-Quality Assessment Program. Of these samples, 531 samples were analyzed for dissolved concentrations of 47 pesticide compounds (43 pesticides and 4 pesticide degradation products); 70 samples were analyzed for an additional 6 pesticide degradation products. Of the 47 pesticide compounds analyzed for in 531 samples, 30 were detected. The most often detected compounds were atrazine (90.2 percent of samples), metolachlor (86.1 percent), deethylatrazine (82.5 percent), and simazine (78.9 percent). Atrazine, metolachlor, and simazine are pesticides; deethylatrazine is a degradation product of atrazine. Relations between concentrations of pesticides in samples from selected streamwater sites and characteristics of the subbasins draining to these sites were evaluated to determine whether agricultural uses or nonagricultural uses appeared to be the more important sources. Concentrations of atrazine, metolachlor, and pendimethalin appear to be attributable more to agricultural uses than to nonagricultural uses; concentrations of prometon, diazinon, chlorpyrifos, tebuthiuron, trifluralin, and carbaryl appear to be attributable more to nonagricultural uses. In general, pesticide concentrations during the growing season (April-October) were greater than those during the nongrowing season (November-March). For atrazine, metolachlor, and acetochlor, the greatest concentrations generally occurred during May, June, and July. Concentrations of pesticide compounds rarely (in only 7 out of 531 samples) exceeded drinking-water standards or guidelines, indicating that, when considered individually, these compounds present little hazard to the health of the public through consumption of the streamwater. The combined effects of more than one pesticide compound in streamwater were not

  16. GREEN RUST AND IRON OXIDE FORMATION INFLUENCES METOLACHLOR DECHLORINATION DURING ZEROVALENT IRON TREATMENT. (R829422E03)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  17. Water-quality characteristics and contaminants in the rural karst-dominated Spring Mill Lake watershed, southern Indiana

    USGS Publications Warehouse

    Hasenmueller, N.R.; Buehler, M.A.; Krothe, N.C.; Comer, J.B.; Branam, T.D.; Ennis, M.V.; Smith, R.T.; Zamani, D.D.; Hahn, L.; Rybarczyk, J.P.

    2006-01-01

    , acetochlor, and simazine were detected during the spring of 2001. Atrazine, metolachlor, acetochlor, and simazine are used to suppress weeds during corn and soybean production. Additional sources of atrazine and simazine may result from application to right-of-ways, orchards, and managed forest areas. ?? 2006 Geological Society of America.

  18. Sources and transport of contaminants of emerging concern: A two-year study of occurrence and spatiotemporal variation in a mixed land use watershed.

    PubMed

    Fairbairn, David J; Karpuzcu, M Ekrem; Arnold, William A; Barber, Brian L; Kaufenberg, Elizabeth F; Koskinen, William C; Novak, Paige J; Rice, Pamela J; Swackhamer, Deborah L

    2016-05-01

    The occurrence and spatiotemporal variation of 26 contaminants of emerging concern (CECs) were evaluated in 68 water samples in 2011-2012 in the Zumbro River watershed, Minnesota, U.S.A. Samples were collected across a range of seasonal/hydrological conditions from four stream sites that varied in associated land use and presence of an upstream wastewater treatment plant (WWTP). Selected CECs included human/veterinary pharmaceuticals, personal care products, pesticides, phytoestrogens, and commercial/industrial compounds. Detection frequencies and concentrations varied, with atrazine, metolachlor, acetaminophen, caffeine, DEET, and trimethoprim detected in more than 70% of samples, acetochlor, mecoprop, carbamazepine, and daidzein detected in 30%-50% of samples, and 4-nonylphenol, cotinine, sulfamethoxazole, erythromycin, tylosin, and carbaryl detected in 10%-30% of samples. The remaining target CECs were not detected in water samples. Three land use-associated trends were observed for the detected CECs. Carbamazepine, 4-nonylphenol, erythromycin, sulfamethoxazole, tylosin, and carbaryl profiles were WWTP-dominated, as demonstrated by more consistent loading and significantly greater concentrations downstream of the WWTP and during low-flow seasons. In contrast, acetaminophen, trimethoprim, DEET, caffeine, cotinine, and mecoprop patterns demonstrated both seasonally-variable non-WWTP-associated and continual WWTP-associated influences. Surface water studies of CECs often target areas near WWTPs. This study suggests that several CECs often characterized as effluent-associated have additional important sources such as septic systems or land-applied biosolids. Finally, agricultural herbicide (atrazine, acetochlor, and metolachlor) profiles were strongly influenced by agricultural land use and seasonal application-runoff, evident by significantly greater concentrations and loadings at upstream sites and in early summer when application and precipitation rates are

  19. Relations of water-quality constituent concentrations to surrogate measurements in the lower Platte River corridor, Nebraska, 2007 through 2011

    USGS Publications Warehouse

    Schaepe, Nathaniel J.; Soenksen, Philip J.; Rus, David L.

    2014-01-01

    , orthophosphate, chloride, atrazine, acetochlor, suspended sediment, and E. coli. Models developed for Salt Creek included nitrate plus nitrite, total Kjeldahl nitrogen, suspended sediment, and E. coli. Lastly, models developed for the Platte River site included total Kjeldahl nitrogen, total phosphorus, sodium, metolachlor, atrazine, acetochlor, suspended sediment, and E. coli.

  20. Biodegradation of butachlor by Rhodococcus sp. strain B1 and purification of its hydrolase (ChlH) responsible for N-dealkylation of chloroacetamide herbicides.

    PubMed

    Liu, Hong-Ming; Cao, Li; Lu, Peng; Ni, Haiyan; Li, Yun-Xiang; Yan, Xin; Hong, Qing; Li, Shun-Peng

    2012-12-19

    Rhodococcus sp. strain B1 could degrade 100 mg/L butachlor within 5 days. Butachlor was first hydrolyzed by strain B1 through N-dealkylation, which resulted in the production of butoxymethanol and 2-chloro-N-(2,6-dimethylphenyl)acetamide. Butoxymethanol could be further degraded and utilized as the carbon source for the growth of strain B1, whereas 2-chloro-N-(2,6-dimethylphenyl)acetamide could not be degraded further. The hydrolase designated ChlH, responsible for the N-dealkylation of the side chain of butachlor, was purified 185.1-fold to homogeneity with 16.1% recovery. The optimal pH and temperature of ChlH were observed to be 7.0-7.5 and 30 °C, respectively. This enzyme was also able to catalyze the N-dealkylation of other chloroacetamide herbicides; the catalytic efficiency followed the order alachlor > acetochlor >butachlor > pretilachlor, which indicated that the alkyl chain length influenced the N-dealkylation of the chloroacetamide herbicides. This is the first report on the biodegradation of chloroacetamide herbicides at the enzyme level.

  1. Characterization of a Novel Butachlor Biodegradation Pathway and Cloning of the Debutoxylase (Dbo) Gene Responsible for Debutoxylation of Butachlor in Bacillus sp. hys-1.

    PubMed

    Gao, Yang; Jin, Lei; Shi, Hui; Chu, Zhangjie

    2015-09-30

    Bacillus sp. strain hys-1, which was isolated from active sludge, could degrade >90% butachlor at a concentration of 100 mg/L within 7 days. The present work revealed that strain hys-1 could mineralize butachlor via the following pathway: butachlor was initially metabolized to 2-chloro-N-(2,6-diethylphenyl)-N-methylacetamide by debutoxylation and then transformed to form 2-chloro-N-(2,6-diethylphenyl)acetamide by N-demethylation. Subsequently, it was converted to 2,6-diethylaniline and further mineralized into CO2 and H2O. In addition, the catalytic efficiency of crude cell extracts descended as follows: alachlor > acetochlor > butachlor. Furthermore, a novel 744 bp gene responsible for transforming butachlor into 2-chloro-N-(2,6-diethylphenyl)-N-methylacetamide was cloned from strain hys-1 and the encoding debutoxylase was designated Dbo. Then Dbo was expressed in Escherichia coli BL21 (DE3) and purified using Ni-nitrilotriacetic acid affinity chromatography. Dbo displayed the highest activity against butachlor at pH 6.5 and 30 °C. Metal ions played an important role in Dbo activity. To the best of the authors' knowledge, this is the first report that strain hys-1 can mineralize butachlor by a novel metabolic mechanism and the first identification of a gene encoding butachlor debutoxylase.

  2. Effect of herbicide combinations on Bt-maize rhizobacterial diversity.

    PubMed

    Valverde, José R; Marín, Silvia; Mellado, Rafael P

    2014-11-28

    Reports of herbicide resistance events are proliferating worldwide, leading to new cultivation strategies using combinations of pre-emergence and post-emergence herbicides. We analyzed the impact during a one-year cultivation cycle of several herbicide combinations on the rhizobacterial community of glyphosate-tolerant Bt-maize and compared them to those of the untreated or glyphosate-treated soils. Samples were analyzed using pyrosequencing of the V6 hypervariable region of the 16S rRNA gene. The sequences obtained were subjected to taxonomic, taxonomy-independent, and phylogeny-based diversity studies, followed by a statistical analysis using principal components analysis and hierarchical clustering with jackknife statistical validation. The resilience of the microbial communities was analyzed by comparing their relative composition at the end of the cultivation cycle. The bacterial communites from soil subjected to a combined treatment with mesotrione plus s-metolachlor followed by glyphosate were not statistically different from those treated with glyphosate or the untreated ones. The use of acetochlor plus terbuthylazine followed by glyphosate, and the use of aclonifen plus isoxaflutole followed by mesotrione clearly affected the resilience of their corresponding bacterial communities. The treatment with pethoxamid followed by glyphosate resulted in an intermediate effect. The use of glyphosate alone seems to be the less aggressive one for bacterial communities. Should a combined treatment be needed, the combination of mesotrione and s-metolachlor shows the next best final resilience. Our results show the relevance of comparative rhizobacterial community studies when novel combined herbicide treatments are deemed necessary to control weed growth.. PMID:25394507

  3. Pesticides analysed in rainwater in Alsace region (Eastern France): Comparison between urban and rural sites

    NASA Astrophysics Data System (ADS)

    Scheyer, Anne; Morville, Stéphane; Mirabel, Philippe; Millet, Maurice

    Current-used pesticides commonly applied in Alsace region (Eastern France) on diverse crops (maize, vineyard, vegetables, etc.) were analysed, together with Lindane, in rainwater between January 2002 and June 2003 simultaneously on two sites situated in a typical rural (Erstein, France) and urban area (Strasbourg, France). Rainwater samples were collected on a weekly basis by using two automatic wet only collectors associated with an open collector for the measurement of rainwater height. Pesticides were analysed by GC-MSMS and extracted from rainwater by SPME. Two runs were performed. The first one was performed by using a PDMS (100 μm) fibre for pesticides where direct injection into GC is possible (alachlor, atrazine, azinphos-ethyl, azinphos-methyl, captan, chlorfenvinphos, dichlorvos, diflufenican, α- and β-endosulfan, iprodione, lindane, metolachlor, mevinphos, parathion-methyl, phosalone, phosmet, tebuconazole, triadimefon and trifluralin). The second run was performed by using PDMS/DVB fibre and this run concerns pesticides where a preliminary derivatisation step with pentafluorobenzylbromide (PFBBr) is required for very low volatiles (bromoxynil,2,4-MCPA, MCPP and 2,4-D) or thermo labiles (chlorotoluron, diuron and isoproturon) pesticides. Results showed that the more concentrated pesticides detected were those used as herbicides in large quantities in Alsace region for maize crops (alachlor, metolachlor and atrazine). Maximum concentrations for these herbicides have been measured during intensive applications periods on maize crops following by rapid decrease immediately after use. For Alachlor, most important peaks have been observed between 21 and 28 April 2003 (3327 ng L -1 at Erstein and 5590 ng L -1 at Strasbourg). This is also the case for Metolachlor where most important peak was observed during the same week. Concentrations of pesticides measured out of application periods were very low for many pesticides and some others where never detected

  4. Pesticides in streams of the western Lake Michigan drainages, Wisconsin and Michigan, 1993-95

    USGS Publications Warehouse

    Sullivan, Daniel J.; Richards, Kevin D.

    1996-01-01

    During 1993-95, water samples were collected at nine sites on eight streams in the Western Lake Michigan Drainages to attempt to determine pesticide concentrations. The sampling effort was part of the U.S. Geological Survey's National Water- Quality Assessment (NAWQA) Program. Pesticides analyzed for were 58 herbicides and 30 insecticides. Pesticides are used extensively in the study area; application of herbicides to corn and soybeans accounts for most of the use. Herbicides were detected more frequently and generally at higher concentrations than insecticides. The herbicide atrazine is applied to more acreage in Wisconsin than all other pesticides and was detected in 142 of 143 samples. The herbicides simazine, metolachlor, cyanazine, prometon, and alachlor were detected in more than half of the samples. The presence of these compounds in the sampled streams, is related to agricultural use. Two streams in forested basins in the northern part of the study area were sampled and found to contain low concentrations of atrazine. Atmospheric deposition is the likely source; atrazine has been detected in rain fall in northeastern Wisconsin. Herbicide concentrations in agricultural basins were highest in samples collected during storm runoff following application. Concentrations decreased over the growing season as herbicides broke down and increased ground cover reduced runoff. The U.S. Environmental Protection Agency (USEPA) drinking-water standard for atrazine was exceeded in eight samples, and the standard for alachlor was exceeded in two samples. All exceedances occurred during brief periods of high streamflow in June and July at two streams that drain primarily agricultural basins. Herbicide data for the Western Lake Drainages and other NAWQA study units indicate that concentrations in streams are as much as two orders of magnitude higher in areas where agricultural land contains a high percentage of row crops especially corn and soybeans than in areas where

  5. Factors affecting herbicide yields in the Chesapeake Bay watershed, June 1994

    USGS Publications Warehouse

    Hainly, R.A.; Kahn, J.M.

    1996-01-01

    Median concentrations and instantaneous yields of alachlor, metolachlor, atrazine, cyanazine, and simazine were generally highest at sites in the Lower Susquehanna River Basin and in agricultural subbasins. Instantaneous herbicide yields are related to land use, hydrogeologic setting, streamflow yield, and agricultural row cropping practices. The significance of these relations may be affected by the interdependence of the factors. The percentage of basin area planted in corn is the most influential factor in the prediction of herbicide yield. Instantaneous yields of all five herbicides measured in June 1994 related poorly to averaged 199094 herbicide use. Annually averaged herbicide-use data are too general to use as a predictor for short-term herbicide yields. An evaluation of factors affecting herbicide yields could be refined with more-current land use and land cover information and a more accurate estimate of the percentage of basin area planted in corn. Factors related to herbicide yields can be used to predict herbicide yields in other basins within the Chesapeake Bay watershed and to develop an estimate of herbicide loads to Chesapeake Bay.Median concentrations and instantaneous yields of alachlor, metolachlor, atrazine, cyanazine, and simazine were generally highest at sites in the Lower Susquehanna River Basin and in agricultural subbasins. Instantaneous herbicide yields are related to land use, hydrogeologic setting, streamflow yield, and agricultural row cropping practices. The significance of these relations may be affected by the interdependence of the factors. The percentage of basin area planted in corn is the most influential factor in the prediction of herbicide yield. Instantaneous yields of all five herbicides measured in June 1994 related poorly to averaged 1990-94 herbicide use. Annually averaged herbicide-use data are too general to use as a predictor for short-term herbicide yields. An evaluation of factors affecting herbicide yields could

  6. Airborne pesticide residues along the Mississippi River

    USGS Publications Warehouse

    Majewski, M.S.; Foreman, W.T.; Goolsbys, D.A.; Nakagaki, N.

    1998-01-01

    The occurrence, concentration, and geographical distribution of agricultural pesticides were determined in air over the Mississippi River from New Orleans, LA, to St. Paul, MN, during the first 10 days of June 1994. Air samples were collected from a research vessel by pulling air through polyurethane foam plugs at about 100 L/min for up to 24 h. Each sample was analyzed for 42 pesticides and 3 pesticide transformation products. Twenty- five compounds-15 herbicides, 7 insecticides, and 3 pesticide transformation products-were detected in one or more samples with concentrations ranging from 0.05 to 80 ng/m3. Alachlor, chlorpyrifos, diazinon, fonofos, malathion, methyl parathion, metolachlor, metribuzin, pendimethalin, and trifluralin were detected in 80% or more of the samples. The highest concentrations for chlorpyrifos (1.6 ng/m3), diazinon (0.36 ng/m3), and malathion (4.6 ng/m3) all occurred near major metropolitan areas. These samples represent a 'snapshot in time', a spatial and temporal integration of which pesticides were present in the air during each sampling period. The occurrence and atmospheric concentrations of the observed pesticides were most closely related to their use on cropland within 40 km of the river.The occurrence, concentration, and geographical distribution of agricultural pesticides were determined in air over the Mississippi River from New Orleans, LA, to St. Paul, MN, during the first 10 days of June 1994. Air samples were collected from a research vessel by pulling air through polyurethane foam plugs at about 100 L/min for up to 24 h. Each sample was analyzed for 42 pesticides and 3 pesticide transformation products. Twenty-five compounds-15 herbicides, 7 insecticides, and 3 pesticide transformation products-were detected in one or more samples with concentrations ranging from 0.05 to 80 ng/m3. Alachlor, chlorpyrifos, diazinon, fonofos, malathion, methyl parathion, metolachlor, metribuzin, pendimethalin, and trifluralin were detected in

  7. Protective headgear for midwestern agriculture: a limited wear study.

    PubMed

    Stone, J F; Hanna, M; Guo, C; Imerman, P

    2001-03-01

    Baseball caps are popular with farm workers, but have been criticized because they do not sufficiently shade the face, neck, and ears. U.S. Environmental Protection Agency standards require workers to wear chemical-resistant hoods or chemical-resistant hats with wide brims during the application of pesticides whose labels call for head protection. In this study, four farm workers wore baseball caps and two alternative types of headgear with wide brims for 20 to 36 hours during planting of corn and soybeans to compare performance features and practicality. Afterwards, researchers analyzed the headgear fabrics by gas chromatography or high-performance liquid chromatography to determine the levels at which five herbicides were deposited on the headgear: 2,4-D, metolachlor, acetochlor, ethalfluralin, and glyphosate. Chemical analysis revealed that 12 percent of specimens had detectable residue: levels of glyphosate in the nanograms-per-square-centimeter (ng/cm2) range and levels of 2,4-D in the micrograms-per-square-centimeter (microgram/cm2) range. Workers, however, preferred the baseball caps because of problems with the wind and feelings of embarrassment about wearing other types of headgear. An acceptable, protective substitute for the baseball cap has yet to be designed.

  8. Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

    USGS Publications Warehouse

    Alvarez, D.A.; Cranor, W.L.; Perkins, S.D.; Clark, R.C.; Smith, S.B.

    2008-01-01

    Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants in the surface waters of three geographically distinct agricultural watersheds. A selection of current-use agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides, were targeted using the polar organic chemical integrative sampler (POCIS) and the semipermeable membrane device passive samplers. In addition to the chemical analysis, the Microtox assay for acute toxicity and the yeast estrogen screen (YES) were conducted as potential assessment tools in combination with the passive samplers. During the spring of 2004, the passive samplers were deployed for 29 to 65 d at Leary Weber Ditch, IN; Morgan Creek, MD; and DR2 Drain, WA. Chemical analysis of the sampler extracts identified the agrochemicals predominantly used in those areas, including atrazine, simazine, acetochlor, and metolachlor. Other chemicals identified included deethylatrazine and deisopropylatrazine, trifluralin, fluoranthene, pyrene, cis- and trans-nonachlor, and pentachloroanisole. Screening using Microtox resulted in no acutely toxic samples. POCIS samples screened by the YES assay failed to elicit a positive estrogenic response. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  9. Compound-specific stable isotope analysis of pesticides: a combined monitoring and modeling approach to assess pesticide fate and degradation at catchment scale

    NASA Astrophysics Data System (ADS)

    van Breukelen, B. M.; Lutz, S.; Van der Velde, Y.; Elsayed, O. F.; LeFrancq, M.; Payraudeau, S.; Imfeld, G.

    2014-12-01

    Compound-specific stable isotope analysis (CSIA) has proven useful in asessing the fate of groundwater contamination. However, although evidence of diffuse pesticide degradation is crucial, and CSIA methods have been developed for several pesticides, there is a clear lack of field CSIA data of pesticides. This study now presents the first analysis of field CSIA data from a 47-ha agricultural headwater catchment (Alteckendorf, Alsace, France) in the period March to August 2012. Measured stream concentrations of the two investigated chloroacetanilide herbicides (S-metolachlor and acetochlor) were highest (65 μg/L) following an intense rainfall event in the first month after herbicide application. Carbon isotope ratios increased with more than 2 ‰ in 3 months, which indicates the occurrence of herbicide degradation during transport to the stream. Previously, field CSIA data have also been simulated with reactive transport models to evaluate degradation of groundwater contaminants. This study now presents such a model-assisted interpretation of CSIA data for the first time at catchment scale, which aims at exploring the added value of CSIA in monitoring and modelling of pesticide pollution. The conceptual mathematical model succeeded in reproducing the general trend in concentrations and carbon isotope ratios of metolachlor. It also allowed for the quantification of metolachlor degradation (above 70 % during the study period), and yielded a mass export of 1.8 % of the applied pesticide, which is in agreement with the measured pesticide export. The field concentration and CSIA data informed the model building by indicating the importance of overland flow, and slow pesticide degradation in groundwater compared to the upper soil zone. Moreover, incorporation of the field CSIA data into model calibration slightly reduced model uncertainty in the quantification of pesticide degradation. We suggest that a finer temporal CSIA resolution than possible in this study

  10. Identification of new human pregnane X receptor ligands among pesticides using a stable reporter cell system.

    PubMed

    Lemaire, Géraldine; Mnif, Wissem; Pascussi, Jean-Marc; Pillon, Arnaud; Rabenoelina, Fanja; Fenet, Hélène; Gomez, Elena; Casellas, Claude; Nicolas, Jean-Claude; Cavaillès, Vincent; Duchesne, Marie-Josèphe; Balaguer, Patrick

    2006-06-01

    Pregnane X receptor (PXR, NR1I2) is activated by various chemically unrelated compounds, including environmental pollutants and drugs. We proceeded here to in vitro screening of 28 pesticides with a new reporter system that detects human pregnane X receptor (hPXR) activators. The cell line was obtained by a two-step stable transfection of cervical cancer HeLa cells. The first transfected cell line, HG5LN, contained an integrated luciferase reporter gene under the control of a GAL4 yeast transcription factor-binding site. The second cell line HGPXR was derived from HG5LN and stably expressed hPXR ligand-binding domain fused to GAL4 DNA-binding domain (DBD). The HG5LN cells were used as a control to detect nonspecific activities. Pesticides from various chemical classes were demonstrated, for the first time, to be hPXR activators: (1) herbicides: pretilachlor, metolachlor, and alachlor chloracetanilides, oxadiazon oxiconazole, and isoproturon urea; (2) fungicides: bupirimate and fenarimol pyrimidines, propiconazole, fenbuconazole, prochloraz conazoles, and imazalil triazole; and (3) insecticides: toxaphene organochlorine, permethrin pyrethroid, fipronil pyrazole, and diflubenzuron urea. Pretilachlor, metolachlor, bupirimate, and oxadiazon had an affinity for hPXR equal to or greater than the positive control rifampicin. Some of the newly identified hPXR activators were also checked for their ability to induce cytochrome P450 3A4 expression in a primary culture of human hepatocytes. HGPXR, with HG5LN as a reference, was grafted onto nude mice to assess compound bioavailability through in vivo quantification of hPXR activation. Altogether, our data indicate that HGPXR cells are an efficient tool for identifying hPXR ligands and establishing pesticides as hPXR activators.

  11. Pesticides in surface water, sediment, and rainfall of the northeastern Pantanal basin, Brazil.

    PubMed

    Laabs, Volker; Amelung, Wulf; Pinto, Alicio A; Wantzen, Matthias; da Silva, Carolina J; Zech, Wolfgang

    2002-01-01

    Within the last 25 years an intensive agriculture has developed in the highland regions of Mato Grosso state (Brazil), which involves frequent pesticide use in highly mechanized cash-crop cultures. To provide information on pesticide distribution and dynamics in the northeastern Pantanal basin (located in southern Mato Grosso), we monitored 29 pesticides and 3 metabolites in surface water, sediment, and rainwater of the study area during the main application season. In environmental samples, 19 pesticides and 3 metabolites were detected in measurable quantities, resulting in at least one pesticide detection in 68% of surface water samples (n = 139), 62% of sediment samples (n = 26), and 87% of rainwater samples (n = 91). Surface water samples were most frequently contaminated by endosulfan compounds (alpha-, beta-, -sulfate), ametryn, metolachlor, and metribuzin, although in low (< 0.1 microgram L-1) concentrations. Sediment samples exhibited concentrations up to 4.5 micrograms kg-1 of p,p'-DDT, p,p'-DDE, endosulfan-sulfate, beta-endosulfan, and ametryn. In contrast, rainwater was polluted with substantial amounts of endosulfan, alachlor, metolachlor, trifluralin, monocrotofos, and profenofos (maximum concentrations = 0.3 to 2.3 micrograms L-1) in the highlands. Lowland rainwater samples taken 75 km from the next application area contained 5- to 10-fold lower mean pesticide concentration than in the highlands. Cumulative deposition rates of the pesticide sum within the study period ranged from 423 micrograms m-2 in the highlands to 14 micrograms m-2 in the lowlands. The atmospheric input of pesticides to ecosystems seemed to be of higher relevance in the tropical study area than known from temperate regions. PMID:12371181

  12. Pesticide concentrations in wetlands on the Lake Traverse Indian Reservation, South and North Dakota, July 2015

    USGS Publications Warehouse

    Carter, Janet M.; Thompson, Ryan F.

    2016-05-04

    During July 2015, water samples were collected from 18 wetlands on the Lake Traverse Indian Reservation in northeastern South Dakota and southeastern North Dakota and analyzed for physical properties and 54 pesticides. This study by the U.S. Geological Survey in cooperation with the Sisseton-Wahpeton Oyate was designed to provide an update on pesticide concentrations of the same 18 wetlands that were sampled for a reconnaissance-level assessment during July 2006. The purpose of this report is to present the results of the assessment of pesticide concentrations in selected Lake Traverse Indian Reservation wetlands during July 2015 and provide a comparison of pesticide concentrations between 2006 and 2015.Of the 54 pesticides that were analyzed for in the samples collected during July 2015, 47 pesticides were not detected in any samples. Seven pesticides—2-chloro-4-isopropylamino-6-amino-s-triazine (CIAT); 2,4–D; acetachlor; atrazine; glyphosate; metolachlor; and prometon—were detected in the 2015 samples with estimated concentrations or concentrations greater than the laboratory reporting level, and most pesticides were detected at low concentrations in only a few samples. Samples from all wetlands contained at least one detected pesticide. The maximum number of pesticides detected in a wetland sample was six, and the median number of pesticides detected was three.The most commonly detected pesticides in the 2015 samples were atrazine and the atrazine degradate CIAT (also known as deethylatrazine), which were detected in 14 and 13 of the wetlands sampled, respectively. Glyphosate was detected in samples from 11 wetlands, and metolachlor was detected in samples from 10 wetlands. The other detected pesticides were 2,4–D (4 wetlands), acetochlor (3 wetlands), and prometon (1 wetland).The same pesticides that were detected in the 2006 samples were detected in the 2015 samples, with the exception of simazine, which was detected only in one sample in 2006

  13. Simultaneous determination of herbicide residues in tobacco using ultraperformance convergence chromatography coupled with solid-phase extraction.

    PubMed

    Guo, Weiyun; Bian, Zhaoyang; Zhang, Daohong; Tang, Gangling; Liu, Wei; Wang, Jianlong; Li, Zhonghao; Yang, Fei

    2015-03-01

    A time-saving and organic solvent efficient method to simultaneously determine six kinds of herbicide residues in tobacco using solid-phase extraction for sample clean-up and preconcentration and the highly sensitive ultraperformance convergence chromatography method was developed. Parameters for ultraperformance convergence chromatography, including the choice of stationary phase and modifiers, autobackpressure regulator pressure, column temperature, and the flow rate of mobile solvents, were optimized. The herbicide residues of napropamide, alachlor, quizalofop-ethyl, diphenamid, metolachlor, and clomazone in tobacco samples were successfully separated and detected at levels as low as 0.0043-0.0086 mg/kg within 5 min using a nonpolar high strength silica C18 selectivity for bases column and methanol as the cosolvent of the mobile phase of carbon dioxide (75-99.9%, v/v). Analysis of tobacco samples had recoveries of 69.8-95.0%, limit of quantitation of 0.0127-0.0245 mg/kg, limit of detection of 0.0043-0.0086 mg/kg, and correlation coefficient of >0.9990. Results support this method as an efficient alternative to current methodologies for the determination of herbicide residues in tobacco.

  14. Net photosynthesis and respiration of sago pondweed (Potamogeton pectinatus) exposed to herbicides

    USGS Publications Warehouse

    Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Hughes, Jane S.; Biddinger, Gregory R.; Mones, Eugene

    1995-01-01

    We determined net photosynthesis and respiration rates for sago pondweed (potamogeton pectinatus) exposed to various concentrations of 11 herbicides widely used in Maryland during the past decade. Net photosynthesis and respiration were determined by measuring changes in the. oxygen content of solutions containing dilutions of technical grade herbicides. At 20-22? C and 58 umol/m2/sec of photosynthetically active radiation (PAR), oxygen production of undosed plants averaged 0.72-2.03 mg/g fresh wt/h. Respiration rates of undosed plants averaged 0.46-0.60 mg O2/g fresh wt/h. Nominal herbicide concentrations (ng/L) that reduced net photosynthesis by 5O percent (IC5O) were: metribuzin, 8; atrazine, 29; cyanazine, 32; linuron, 70; simazine, 164; and paraquat, 240. IC5O values for 2,4-D, acifluorfen, glyphosate and metolachlor exceeded the maximum test concentration of 10,000 ng/L. The IC5O value for alachlor was estimated to be between 1,000 and 10,000 ng/L. None of the herbicides tested had a significant effect on dark respiration.

  15. Integrated use of biomarkers and bioaccumulation data in Zebra mussel (Dreissena polymorpha) for site-specific quality assessment.

    PubMed

    Binelli, A; Ricciardi, F; Riva, C; Provini, A

    2006-01-01

    One of the useful biological tools for environmental management is the measurement of biomarkers whose changes are related to the exposure to chemicals or environmental stress. Since these responses might vary with different contaminants or depending on the pollutant concentration reached in the organism, the support of bioaccumulation data is needed to prevent false conclusions. In this study, several persistent organic pollutants -- 23 polychlorinated biphenyl (PCB) congeners, 11 polycyclic aromatic hydrocarbons (PAHs), six dichlorodiphenyltricholroethane (DDT) relatives, hexachlorobenzene (HCB), chlorpyrifos and its oxidized metabolite -- and some herbicides (lindane and the isomers alpha, beta, delta; terbutilazine; alachlor; metolachlor) were measured in the soft tissues of the freshwater mollusc Zebra mussel (Dreissena polymorpha) from 25 sampling sites in the Italian portions of the sub-alpine great lakes along with the measure of ethoxyresorufin dealkylation (EROD) and acetylcholinesterase (AChE) activity. The linkage between bioaccumulation and biomarker data allowed us to create site-specific environmental quality indexes towards man-made chemicals. This classification highlighted three different degrees of xenobiotic contamination of the Italian sub-alpine great lakes: a high water quality in Lake Lugano with negligible pollutant levels and no effects on enzyme activities, an homogeneous poor quality for Lakes Garda, Iseo and Como, and the presence of some xenobiotic point-sources in Lake Maggiore, whose ecological status could be jeopardized, also due to the heavy DDT contamination revealed since 1996.

  16. BOREAS TGB-7 Dry Deposition Herbicide and Organochlorine Flux Data

    NASA Technical Reports Server (NTRS)

    Waite, Don; Conrad, Sara K. (Editor); Hall, Forrest G. (Editor)

    2000-01-01

    The BOREAS TGB-7 team measured the concentration and flux of several agricultural pesticides in air, rainwater, and dry deposition samples in order to determine the associated yearly deposition rates. This data set contains information on the dry deposition flux of seven herbicides [2,4- dichlorophenoxyacidic_acid (2,4-D), bromoxynil, dicamb, 2-methyl-4-chlorophenoxyacetic acid (MCPA), triallate, trifluralin, and diclop-methyl] known to appear in the atmosphere of the Canadian prairies. Also, the concentration of three herbicides (atrazine, alachlor, and metolachlor), two groups of insecticides (lindane and breakdown products and dichloro-diphenyl-trichloroethane (DDT) and breakdown products), and several polychlorinated biphenyls commonly used in the central United States was measured. All of these chemicals are reported, in the literature, to be transported in the atmosphere. Many have been reported to occur in boreal and arctic food chains. The sampling was carried out from 16-Jun to 13-Aug-1993 and 04-May to 20-Jul-1994 at the BOREAS site in the Prince Albert National Park (Waskesiu). The data are stored in tabular ASCII files.

  17. BOREAS TGB-7 Rainwater Herbicide and Organochlorine Concentration Data

    NASA Technical Reports Server (NTRS)

    Waite, Don; Conrad, Sara K. (Editor); Hall, Forrest G. (Editor)

    2000-01-01

    The BOREAS TGB-7 team measured the concentration and flux of several agricultural pesticides in air and rainwater samples in order to determine the associated yearly deposition rates. This data set contains information on the rainwater concentration of seven herbicides [2,4- dichlorophenoxyacidic_acid (2,4-D), bromoxynil, dicamb, 2-methyl-4-chlorophenoxyacetic acid (MCPA), triallate, trifluralin, and diclop-methyl] known to appear in the atmosphere of the Canadian prairies. Also, the concentration of three herbicides (atrazine, alachlor, and metolachlor), two groups of insecticides (lindane and breakdown products and dichloro-diphenyl-trichloroethane (DDT) and breakdown products), and several polychlorinated biphenyls commonly used in the central United States was measured. All of these chemicals are reported, in the literature, to be transported in the atmosphere. Many have been reported to occur in boreal and arctic food chains. The sampling was carried out from 16-Jun to 13-Aug-1993 and 04-May to 20-Jul-1994 at the BOREAS site in the Prince Albert National Park (Waskesiu). The data are stored in tabular ASCII files.

  18. BOREAS TGB-7 Ambient Air Herbicide and Organochlorine Concentration Data

    NASA Technical Reports Server (NTRS)

    Waite, Don; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB)-7 team measured the concentration and flux of several agricultural pesticides in air, rainwater, and dry deposition samples in order to determine the associated yearly deposition rates. This data set contains information on the ambient air concentration of seven herbicides [2,4- dichlorophenoxyacidic_acid (2,4-D), bromoxynil, dicamb, 2-methyl-4-chlorophenoxyacetic acid (MCPA), triallate, trifluralin, and diclop-methyl] known to appear in the atmosphere of the Canadian prairies. Also, the concentration of three herbicides (atrazine, alachlor, and metolachlor), two groups of insecticides (lindane and breakdown products and dichloro-diphenyl-trichloroethane (DDT) and breakdown products), and several polychlorinated biphenyls commonly used in the central United States was measured. All of these chemicals are reported, in the literature, to be transported in the atmosphere. Many have been reported to occur in boreal and arctic food chains. The sampling was carried out from 16-Jun to 13-Aug-1993 and 04-May to 20-Jul-1994 at the BOREAS site in the Prince Albert National Park (Waskesiu). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884).

  19. Factors affecting leaching in agricultural areas and an assessment of agricultural chemicals in the ground water of Kansas

    USGS Publications Warehouse

    Perry, C.A.; Robbins, F.V.; Barnes, P.L.

    1988-01-01

    As assessment of hydrologic factors and agricultural practices that may affect the leaching of agricultural chemicals to groundwater was conducted to evaluate the extent and severity of chemical contamination of groundwater resources in Kansas. The climate of a particular area determines the length of the growing season and the availability of water, at the surface and in the ground, for the growth of plants. Climate, together with surficial geology, soil, and principal aquifers, determines the types of crops to be planted,types of tillage, conservation and irrigation practices, and affects the quantity and method of application of agricultural chemicals. Examination of groundwater nitrate-nitrogen data collected from 766 wells throughout Kansas during 1976-81 indicated that 13 of 14 geohydrologic regions had wells producing samples that exceeded the 10-mg/L drinking water standard determined by the U.S. Environmental Protection Agency. One or more herbicides were detected in water samples from 11 of 56 wells during 1985-86 located in areas susceptible to agricultural leaching. Atrazine was the most common herbicide that was detected; it was detected in water at 9 of 11 wells. Cyanazine was detected in water at three wells; metolachlor at two wells; and metribuzin, alachlor, simazine, and propazine were detected at one well each. (USGS)

  20. Determination of trace levels of herbicides and their degradation products in surface and ground waters by gas chromatography/ion-trap mass spectrometry

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Leiker, T.J.

    1990-01-01

    A rapid, specific and highly sensitive method is described for the determination of several commonly used herbicides and their degradation products in surface and ground waters by using gas chromatography/ion-trap mass spectrometry. The compounds included atrazine, and its degradation products desethylatrazine and desisopropylatrazine; Simazine; Cyanazine; Metolachlor; and alachlor and its degradation products, 2-chloro-2', 6'-diethylacetanilide, 2-hydroxy-2', 6'-diethylacetanilide and 2,6-diethylaniline. The method was applied to surface-water samples collected from 16 different stations along the lower Mississippi River and its major tributaries, and ground-water samples beneath a cornfield in central Nebraska. Average recovery of a surrogate herbicide, terbuthylazine, was greater than 99%. Recoveries of the compounds of interest from river water spiked at environmental levels are also presented. Full-scan mass spectra of these compounds were obtained on 1 ng or less of analyte. Data were collected in the full-scan acquisition mode. Quantitation was based on a single characteristic ion for each compound. The detection limit was 60 pg with a signal-to-noise ratio of greater than 10:1.

  1. Trends in pesticide concentrations and use for major rivers of the United States.

    PubMed

    Ryberg, Karen R; Gilliom, Robert J

    2015-12-15

    Trends in pesticide concentrations in 38 major rivers of the United States were evaluated in relation to use trends for 11 commonly occurring pesticide compounds. Pesticides monitored in water were analyzed for trends in concentration in three overlapping periods, 1992-2001, 1997-2006, and 2001-2010 to facilitate comparisons among sites with variable sample distributions over time and among pesticides with changes in use during different periods and durations. Concentration trends were analyzed using the SEAWAVE-Q model, which incorporates intra-annual variability in concentration and measures of long-term, mid-term, and short-term streamflow variability. Trends in agricultural use within each of the river basins were determined using interval-censored regression with high and low estimates of use. Pesticides strongly dominated by agricultural use (cyanazine, alachlor, atrazine and its degradate deethylatrazine, metolachlor, and carbofuran) had widespread agreement between concentration trends and use trends. Pesticides with substantial use in both agricultural and nonagricultural applications (simazine, chlorpyrifos, malathion, diazinon, and carbaryl) had concentration trends that were mostly explained by a combination of agricultural-use trends, regulatory changes, and urban use changes inferred from concentration trends in urban streams. When there were differences, concentration trends usually were greater than use trends (increased more or decreased less). These differences may occur because of such factors as unaccounted pesticide uses, delayed transport to the river through groundwater, greater uncertainty in the use data, or unquantified land use and management practice changes.

  2. Regression models for estimating herbicide concentrations in U.S. streams from watershed characteristics

    USGS Publications Warehouse

    Larson, S.J.; Gilliom, R.J.

    2001-01-01

    Regression models were developed for estimating stream concentrations of the herbicides alachlor, atrazine, cyanazine, metolachlor, and trifluralin from use-intensity data and watershed characteristics. Concentrations were determined from samples collected from 45 streams throughout the United States during 1993 to 1995 as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA). Separate regression models were developed for each of six percentiles (10th, 25th, 50th, 75th, 90th, 95th) of the annual distribution of stream concentrations and for the annual time-weighted mean concentration. Estimates for the individual percentiles can be combined to provide an estimate of the annual distribution of concentrations for a given stream. Agricultural use of the herbicide in the watershed was a significant predictor in nearly all of the models. Several hydrologic and soil parameters also were useful in explaining the variability in concentrations of herbicides among the streams. Most of the regression models developed for estimation of concentration percentiles and annual mean concentrations accounted for 50 percent to 90 percent of the variability among streams. Predicted concentrations were nearly always within an order of magnitude of the measured concentrations for the model-development streams, and predicted concentration distributions reasonably matched the actual distributions in most cases. Results from application of the models to streams not included in the model development data set are encouraging, but further validation of the regression approach described in this paper is needed.

  3. Evaluation of herbicides for use in transplanting leucaena leucocephala and prosopis alba on semi-arid lands without irrigation

    SciTech Connect

    Felker, P.; Smith, D.; Smith, M.; Bingham, R.L.; Reyes, I.

    1984-01-01

    Five herbicides were applied to plots at 2 rates in April 1982, and 3-month old seedlings planted 2 days later. Basal diameter was measured after 110 days and converted to dry weight using published equations. Percent weed cover was recorded 45, 75, and 105 days after planting. All herbicides increased survival over untreated controls. The greatest biomass production of both species was obtained with oryzalin treatment at 2.8 kg/ha active ingredient, which increased production 4-5X compared with control plots. Oryzalin was second to napropamide (2.24 kg/ha active ingredient) in grass control and equal to oxyfluorfen (1.12 kg/ha active ingredient) in forb control, oxyfluorfen at this rate also gave the second best biomass production. Oryzalin increased survival from 71 to 87% for Leucaena and from 81-94% for Prosopis, and is considered to be the best herbicide tested, followed by oxyfluorfen and metolachlor. Alachlor was considered to be too short-lived and napropamide too expensive.

  4. A multi-residue method for determination of 70 organic micropollutants in surface waters by solid-phase extraction followed by gas chromatography coupled to tandem mass spectrometry.

    PubMed

    Terzopoulou, Evangelia; Voutsa, Dimitra; Kaklamanos, George

    2015-01-01

    A multi-residue method, based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), has been developed for the determination of 70 organic micropollutants from various chemical classes (organochlorinated, organophosphorous, triazines, carbamate and urea, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pharmaceuticals, phenols, etc.) in surface waters. A single-step SPE extraction using OASIS HLB cartridges was employed for the recovery of target micropollutants. The method has been validated according to monitoring performance criteria of the Water Framework Directive, taking into account the approved guidelines on quality assurance and quality control. The recoveries ranged from 60 to 110 %, the coefficient of variation from 0.84 to 27.4 %, and the uncertainty from 6 to 37 %. The LOD varied from 6.0 to 40 ng/L. The limits of quantification for the priority pollutants anthracene, alachlor, atrazine, benzo(a)pyrene, chlorfenvinphos, diuron, isoproturon, nonylphenol, simazine, and terbutryn fulfill the criterion of <30 % of the relevant environmental standards. The method was employed to investigate the water quality in the basin of a transboundary river, Strymonas, in NE Greece during three sampling campaigns conducted in the year 2013. Thirty-nine compounds were detected in the river water. Metolachlor, diuron, isoproturon, salicylic acid, chlorfenvinphos, 1,2-benzanthracene, pyrene, diflubenzuron, and carbaryl exhibited the highest detection frequencies.

  5. Groundwater pesticide levels and the association with Parkinson disease.

    PubMed

    James, Katherine A; Hall, Deborah A

    2015-01-01

    It is unclear whether exposure to environmentally relevant levels of pesticides in groundwater is associated with an increased risk of Parkinson disease (PD). The purpose of this study was to examine the relationship between PD and pesticide levels in groundwater. This cross-sectional study included 332 971 Medicare beneficiaries, including 4207 prevalent cases of PD from the 2007 Colorado Medicare Beneficiary Database. Residential pesticide levels were estimated from a spatial model based on 286 well water samples with atrazine, simazine, alachlor, and metolachlor measurements. A logistic regression model with known PD risk factors was used to assess the association between residential groundwater pesticide levels and prevalent PD. We found that for every 1.0 µg/L of pesticide in groundwater, the risk of PD increases by 3% (odds ratio = 1.03; 95% confidence interval: 1.02-1.04) while adjusting for age, race/ethnicity, and gender suggesting that higher age-standardized PD prevalence ratios are associated with increasing levels of pesticides in groundwater. PMID:25939349

  6. Pesticides in Iowa precipitation

    USGS Publications Warehouse

    Nations, B.K.; Hallberg, G.R.

    1992-01-01

    Rainfall was sampled for pesticides to assess their occurrence in precipitation and potential impacts on water resources. Three areas in Iowa were sampled; two localities were in rural settings, and a third in an urban area. Fourteen pesticides, including ten herbicides and four insecticides, were detected from October 1987 through September 1990. Atrazine, alachlor, cyanazine, and metolachlor were the most commonly detected, with one or more of these four herbicides found in almost every rainfall sample during the growing season. Concentrations of individual pesticides ranged from 0.1 ??g L-1 to 40.0 ??g L-1, with most detections under 1.0 ??g L-1. Pesticide detections in rainfall began in April and ended in July or August, probably related to the timing of chemical application and greater volatilization rates during warmer weather. Samples from the urban site had detections of the same agricultural chemicals found at the rural sites, but in lesser quantities. In addition to the commonly detected herbicides, three of the four insecticides detected in rainfall were only found in urban samples. Two of these have urban as well as agricultural uses. Some variation of pesticide detections were seen at the three sampling localities, related to regional and local use patterns. Concentrations were greater at sampling sites near fields where pesticides are applied, suggesting that local volatilization and distance of transport affect the concentrations in rainfall. Pesticide concentrations were highest at the beginning of a rainfall event with concentrations becoming lower in samples taken later in the event.

  7. Herbicide transport in rivers: Importance of hydrology and geochemistry in nonpoint-source contamination

    USGS Publications Warehouse

    Squillace, P.J.; Thurman, E.M.

    1992-01-01

    Alachlor, atrazine, cyanazine, metolachlor, and metribuzin were measured at six sites during 1984 and 1985 in large subbasins within the Cedar River, IA. A computer model separated the Cedar River discharge hydrograph into groundwater and overland-flow components. The concentration of herbicides in the river when groundwater was the major flow component was less than 1.0 μg/L and averaged 0.2 μg/L. The maximum concentrations of herbicides occurred when overland flow was the major component of river discharge, exceeding 50 pg/L for total herbicides. About 6% of the annual river load of atrazine was transported with the groundwater component, while 94% was transported with overland flow. From 1.5 to 5% of the atrazine applied during the year was transported from the basin. Atrazine concentrations in the river in- creased according to the discharge divided by the drainage area. This correlation indicates that rivers with large normalized 2-year peak flows have the potential to transport large concentrations of herbicides. A diagrammatic model of nonpoint-source transport of herbicides was developed that suggests that sorbed transport from fields occurs during episodes of overland flow with rapid dissolution of herbicides downstream. 

  8. Assessing the quality of freshwaters in a protected area within the Tagus River basin district (central Portugal).

    PubMed

    Silva, Emília; Pereira, Ana Carina; Estalagem, Soraia Patrícia; Moreira-Santos, Matilde; Ribeiro, Rui; Cerejeira, Maria José

    2012-01-01

    Water-sediment quality was assessed in an agricultural zone of a protected area within the Tagus River basin district (central Portugal) combining chemical analysis to 12 pesticide compounds and whole toxicity testing using the bacterium , the algae , the crustacean , and the midge . The herbicides alachlor, atrazine ethofumesate, metolachlor, terbuthylazine, the insecticides chlorfenvinphos and chlorpyrifos, and the metabolite 3,4-dichloroaniline were detected in surface water samples at four sites and in groundwater samples from six wells, during four sampling occasions. Measured concentrations were compared with parametric values for human consumption, groundwater quality standards, and environmental quality standards applicable to surface water established in European Union legislation. Most severe adverse effects were noted on the growth of and lethality of in nondiluted water samples. Taking into account the values calculated by the method of toxic unit summation for pesticide mixtures, it was not possible to link the pesticides found to the toxicity detected in the water samples. Conducting this study with chemical analyses and biotests provided a more comprehensive quality assessment and realistic picture of the environmental samples analyzed, although additional studies are needed to evaluate the performance of mixture models for predicting mixture toxicity. This study underlines the importance of chemical analysis and whole toxicity testing as tools for assessing the impact of human activity on the status of water, mainly in protected zones. PMID:23099932

  9. Simultaneous determination of herbicide residues in tobacco using ultraperformance convergence chromatography coupled with solid-phase extraction.

    PubMed

    Guo, Weiyun; Bian, Zhaoyang; Zhang, Daohong; Tang, Gangling; Liu, Wei; Wang, Jianlong; Li, Zhonghao; Yang, Fei

    2015-03-01

    A time-saving and organic solvent efficient method to simultaneously determine six kinds of herbicide residues in tobacco using solid-phase extraction for sample clean-up and preconcentration and the highly sensitive ultraperformance convergence chromatography method was developed. Parameters for ultraperformance convergence chromatography, including the choice of stationary phase and modifiers, autobackpressure regulator pressure, column temperature, and the flow rate of mobile solvents, were optimized. The herbicide residues of napropamide, alachlor, quizalofop-ethyl, diphenamid, metolachlor, and clomazone in tobacco samples were successfully separated and detected at levels as low as 0.0043-0.0086 mg/kg within 5 min using a nonpolar high strength silica C18 selectivity for bases column and methanol as the cosolvent of the mobile phase of carbon dioxide (75-99.9%, v/v). Analysis of tobacco samples had recoveries of 69.8-95.0%, limit of quantitation of 0.0127-0.0245 mg/kg, limit of detection of 0.0043-0.0086 mg/kg, and correlation coefficient of >0.9990. Results support this method as an efficient alternative to current methodologies for the determination of herbicide residues in tobacco. PMID:25546570

  10. Solid-phase extraction and gas chromatography-tandem mass spectrometry method for the simultaneous determination of several pesticides in water.

    PubMed

    Penetra, A; Vale Cardoso, V; Ferreira, E; Benoliel, M J

    2010-01-01

    Contamination of surface and groundwater sources with pesticide residues has been of great concern for a long time and it is a major challenge for the preservation and sustainability of the environment. In order to accomplish the requirements of the European Directive 98/83/EC, we developed and validated an analytical method based on the combination of gas chromatography and tandem quadrupole mass spectrometry (GC-MS/MS) using solid-phase extraction as sample preparation. In this work nine pesticides were studied: molinate, simazine, atrazine, terbuthylazine, diazinon, alachlor, metalaxyl, metolachlor and pendimethalin. In order to get the best sensitivity and selectivity for each pesticide, several parameters of the tandem mass spectrometry were optimized using the MRM mode. Good linearity of the detector response was found for all pesticides at concentrations within the tested working range, with linear determination coefficients higher than 0.9988. Recoveries studies in several matrices with different fortification levels were performed, with recoveries between 77 and 115% with RSD lower than 9.5%. The MQLs obtained for these compounds were between 0.013 microg L(-1) and 0.022 microg L(-1), which were much lower than the maximum level established by the European legislation.

  11. A multi-residue method for determination of 70 organic micropollutants in surface waters by solid-phase extraction followed by gas chromatography coupled to tandem mass spectrometry.

    PubMed

    Terzopoulou, Evangelia; Voutsa, Dimitra; Kaklamanos, George

    2015-01-01

    A multi-residue method, based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), has been developed for the determination of 70 organic micropollutants from various chemical classes (organochlorinated, organophosphorous, triazines, carbamate and urea, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pharmaceuticals, phenols, etc.) in surface waters. A single-step SPE extraction using OASIS HLB cartridges was employed for the recovery of target micropollutants. The method has been validated according to monitoring performance criteria of the Water Framework Directive, taking into account the approved guidelines on quality assurance and quality control. The recoveries ranged from 60 to 110 %, the coefficient of variation from 0.84 to 27.4 %, and the uncertainty from 6 to 37 %. The LOD varied from 6.0 to 40 ng/L. The limits of quantification for the priority pollutants anthracene, alachlor, atrazine, benzo(a)pyrene, chlorfenvinphos, diuron, isoproturon, nonylphenol, simazine, and terbutryn fulfill the criterion of <30 % of the relevant environmental standards. The method was employed to investigate the water quality in the basin of a transboundary river, Strymonas, in NE Greece during three sampling campaigns conducted in the year 2013. Thirty-nine compounds were detected in the river water. Metolachlor, diuron, isoproturon, salicylic acid, chlorfenvinphos, 1,2-benzanthracene, pyrene, diflubenzuron, and carbaryl exhibited the highest detection frequencies. PMID:25109470

  12. Investigation of factors affecting terrestrial passive sampling device performance and uptake rates in laboratory chambers

    SciTech Connect

    Johnson, K.A.; Weisskopf, C.P.

    1995-12-31

    A rapid sampling method using passive sampling devices (PSDS) for soil contaminant characterization shows extreme promise. The use of PSDs increases ease and speed of analysis, decreases solvent usage and cost, and minimizes the transport of contaminated soils. Time and cost savings allow a high sampling frequency, providing a more thorough site characterization than traditional methods. The authors have conducted both laboratory and field studies with terrestrial PSDS. Laboratory studies demonstrated the concentration and moisture dependence of sampler uptake and provided an estimate of the optimal field sampling time for soils contaminated with polychlorinated biphenyls (PCBs). These PSDs were also used to accurately estimate PCB concentrations at hazardous waste site where concentrations ranged from 0.01 to 200 ug PCB/g soil. However, PSDs in the field had sampling rates approximately three times greater than in the laboratory. As a result several factors affecting PSD sampling rates and/or performance in laboratory chambers were evaluated. The parameters investigated were soil bulk density or compactness, chamber size and air flow. The chemicals used in these studies included two PCB congeners (52 and 153), three organochlorine pesticides (DDT, dieldrin and methoxychlor), three organophosphate pesticides (chlorpyrifos, diazinon and terbufos) and three herbicides (alachlor, atrazine and metolachlor).

  13. Groundwater pesticide levels and the association with Parkinson disease.

    PubMed

    James, Katherine A; Hall, Deborah A

    2015-01-01

    It is unclear whether exposure to environmentally relevant levels of pesticides in groundwater is associated with an increased risk of Parkinson disease (PD). The purpose of this study was to examine the relationship between PD and pesticide levels in groundwater. This cross-sectional study included 332 971 Medicare beneficiaries, including 4207 prevalent cases of PD from the 2007 Colorado Medicare Beneficiary Database. Residential pesticide levels were estimated from a spatial model based on 286 well water samples with atrazine, simazine, alachlor, and metolachlor measurements. A logistic regression model with known PD risk factors was used to assess the association between residential groundwater pesticide levels and prevalent PD. We found that for every 1.0 µg/L of pesticide in groundwater, the risk of PD increases by 3% (odds ratio = 1.03; 95% confidence interval: 1.02-1.04) while adjusting for age, race/ethnicity, and gender suggesting that higher age-standardized PD prevalence ratios are associated with increasing levels of pesticides in groundwater.

  14. Assessing the quality of freshwaters in a protected area within the Tagus River basin district (central Portugal).

    PubMed

    Silva, Emília; Pereira, Ana Carina; Estalagem, Soraia Patrícia; Moreira-Santos, Matilde; Ribeiro, Rui; Cerejeira, Maria José

    2012-01-01

    Water-sediment quality was assessed in an agricultural zone of a protected area within the Tagus River basin district (central Portugal) combining chemical analysis to 12 pesticide compounds and whole toxicity testing using the bacterium , the algae , the crustacean , and the midge . The herbicides alachlor, atrazine ethofumesate, metolachlor, terbuthylazine, the insecticides chlorfenvinphos and chlorpyrifos, and the metabolite 3,4-dichloroaniline were detected in surface water samples at four sites and in groundwater samples from six wells, during four sampling occasions. Measured concentrations were compared with parametric values for human consumption, groundwater quality standards, and environmental quality standards applicable to surface water established in European Union legislation. Most severe adverse effects were noted on the growth of and lethality of in nondiluted water samples. Taking into account the values calculated by the method of toxic unit summation for pesticide mixtures, it was not possible to link the pesticides found to the toxicity detected in the water samples. Conducting this study with chemical analyses and biotests provided a more comprehensive quality assessment and realistic picture of the environmental samples analyzed, although additional studies are needed to evaluate the performance of mixture models for predicting mixture toxicity. This study underlines the importance of chemical analysis and whole toxicity testing as tools for assessing the impact of human activity on the status of water, mainly in protected zones.

  15. Mineralization of the s-triazine ring of atrazine by stable bacterial mixed cultures.

    PubMed Central

    Mandelbaum, R T; Wackett, L P; Allan, D L

    1993-01-01

    Enrichment cultures containing atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) at a concentration of 100 ppm (0.46 mM) as a sole nitrogen source were obtained from soils exposed to repeated spills of atrazine, alachlor, and metolachlor. Bacterial growth occurred concomitantly with formation of metabolites from atrazine and subsequent biosynthesis of protein. When ring-labeled [14C]atrazine was used, 80% or more of the s-triazine ring carbon atoms were liberated as 14CO2. Hydroxyatrazine may be an intermediate in the atrazine mineralization pathway. More than 200 pure cultures isolated from the enrichment cultures failed to utilize atrazine as a nitrogen source. Mixing pure cultures restored atrazine-mineralizing activity. Repeated transfer of the mixed cultures led to increased rates of atrazine metabolism. The rate of atrazine degradation, even at the elevated concentrations used, far exceeded the rates previously reported in soils, waters, and mixed and pure cultures of bacteria. PMID:8328795

  16. Regional patterns of pesticide concentrations in surface waters of New York in 1997

    USGS Publications Warehouse

    Phillips, P.J.; Eckhardt, D.A.; Freehafer, D.A.; Wall, G.R.; Ingleston, H.H.

    2002-01-01

    The predominant mixtures of pesticides found in New York surface waters consist of five principal components. First, herbicides commonly used on corn (atrazine, metolachlor, alachlor, cyanazine) and a herbicide degradate (deethylatrazine) were positively correlated to a corn-herbicide component, and watersheds with the highest corn-herbicide component scores were those in which large amounts of row crops are grown. Second, two insecticides (diazinon and carbaryl) and one herbicide (prometon) widely used in urban and residential settings were positively correlated to an urban/residential component. Watersheds with the highest urban/residential component scores were those with large amounts of urban and residential land use. A third component was related to two herbicides (EPTC and cyanazine) used on dry beans and corn, the fourth to an herbicide (simazine) and an insecticide (carbaryl) commonly used in orchards and vineyards, and the fifth to an herbicide (DCPA). Results of this study indicate that this approach can be used to: (1) identify common mixtures of pesticides in surface waters, (2) relate these mixtures to land use and pesticide applications, and (3) indicate regions where these mixtures of pesticides are commonly found.

  17. Distribution of major herbicides in ground water of the United States

    USGS Publications Warehouse

    Barbash, Jack E.; Thelin, Gail P.; Kolpin, Dana W.; Gilliom, Robert J.

    1999-01-01

    Frequencies of detection at or above 0.01 microgram per liter in shallow ground water beneath agricultural areas during the NAWQA study were significantly correlated with agricultural use in those areas for atrazine, cyanazine, alachlor, and metolachlor (P<0.05; Spearman rank correlations), but not for simazine (P>0.05). In urban areas, overall frequencies of detection of these five herbicides in shallow ground water were positively correlated with their total nonagricultural use nationwide (P=0.026; simple linear correlation). Multivariate statistical analysis indicated that frequencies of detection in shallow ground water beneath agricultural areas were positively correlated with half-lives for transformation in aerobic soil and agricultural use of the compounds (P≤0.0001 for both parameters). Although frequencies of detection were not significantly correlated with their subsurface mobility (Koc; P=0.19) or the median well depths of the sampled networks (P=0.72), the range of Koc values among the five herbicides and the range of well depths were limited.

  18. A field study to compare performance of stainless steel research monitoring wells with existing on-farm drinking water wells in measuring pesticide and nitrate concentrations.

    PubMed

    Smith, C N; Payne, W R; Pope, J D; Winkie, J H; Parrish, R S

    1999-02-01

    Existing drinking water wells are widely used for the collection of ground water samples to evaluate chemical contamination. A well comparison study was conducted to compare pesticide and nitrate-N data from specially designed stainless steel research monitoring wells with data from nearby existing on-farm drinking water wells. Results could help to determine whether adequate information concerning ground water contamination can be obtained from existing drinking water wells for use in making pollutant control decisions. The study was conducted during 1993-1994 in the Little Coharie Watershed, a 158 square mile area located in the coastal plain of eastern North Carolina. Statistical analysis indicated that research monitoring wells provided a greater probability of detecting pesticides in ground water than existing on-farm wells. Atrazine was the most frequently detected pesticide found in all wells, followed in order by fluometuron, carbofuran, metolachlor, alachlor, carbaryl, butylate, chlorothalonil, linuron and simazine. Ninety-seven percent of all wells had observed concentrations of nitrate-N, ranging from 0.1 to 30.1 mg/L. There was not a significant difference between research wells and existing wells for monitoring nitrate-N. Based on results of this study, existing drinking water wells can be used for monitoring nitrate; however, specialized stainless steel monitoring wells should be used for monitoring pesticides in ground water.

  19. Trends in pesticide concentrations and use for major rivers of the United States.

    PubMed

    Ryberg, Karen R; Gilliom, Robert J

    2015-12-15

    Trends in pesticide concentrations in 38 major rivers of the United States were evaluated in relation to use trends for 11 commonly occurring pesticide compounds. Pesticides monitored in water were analyzed for trends in concentration in three overlapping periods, 1992-2001, 1997-2006, and 2001-2010 to facilitate comparisons among sites with variable sample distributions over time and among pesticides with changes in use during different periods and durations. Concentration trends were analyzed using the SEAWAVE-Q model, which incorporates intra-annual variability in concentration and measures of long-term, mid-term, and short-term streamflow variability. Trends in agricultural use within each of the river basins were determined using interval-censored regression with high and low estimates of use. Pesticides strongly dominated by agricultural use (cyanazine, alachlor, atrazine and its degradate deethylatrazine, metolachlor, and carbofuran) had widespread agreement between concentration trends and use trends. Pesticides with substantial use in both agricultural and nonagricultural applications (simazine, chlorpyrifos, malathion, diazinon, and carbaryl) had concentration trends that were mostly explained by a combination of agricultural-use trends, regulatory changes, and urban use changes inferred from concentration trends in urban streams. When there were differences, concentration trends usually were greater than use trends (increased more or decreased less). These differences may occur because of such factors as unaccounted pesticide uses, delayed transport to the river through groundwater, greater uncertainty in the use data, or unquantified land use and management practice changes. PMID:26318227

  20. Fate and transport of pesticides in the ground water systems of southwest Georgia, 1993-2005.

    PubMed

    Dalton, Melinda S; Frick, Elizabeth A

    2008-01-01

    Modern agricultural practices in the United States have resulted in nearly unrivaled efficiency and productivity. Unfortunately, there is also the potential for release of these compounds to the environment and consequent adverse affects on wildlife and human populations. Since 1993, the National Water-Quality Assessment (NAWQA) program of the U.S. Geological Survey has evaluated water quality in agricultural areas to address these concerns. The objective of this study is to evaluate trends in pesticide concentrations from 1993-2005 in the surficial and Upper Floridan aquifers of southwest Georgia using pesticide and pesticide degradate data collected for the NAWQA program. There were six compounds-five herbicides and one degradate-that were detected in more than 20% of samples: atrazine, deethylatrazine (DEA), metolachlor, alachlor, floumeturon, and tebuthiuron. Of the 128 wells sampled during the study, only eight wells had pesticide concentrations that either increased (7) or decreased (1) on a decadal time scale. Most of the significant trends were increasing concentrations of pesticides in older water; median pesticide concentrations did not differ between the surficial and Upper Floridan aquifers from 1993 and 2005. Deethylatrazine, in the Upper Floridan aquifer, was the only compound that had a significant change (increase) in concentration during the study. The limited number of wells with increases in pesticide concentrations suggest that ground-water sources of these compounds are not increasing in concentration over the time scale represented in this study.

  1. Vertical gradients in water chemistry in the central High Plains aquifer, southwestern Kansas and Oklahoma panhandle, 1999

    USGS Publications Warehouse

    McMahon, Peter B.

    2001-01-01

    in sediments of Permian age by ground water was the likely source of calcium, sulfate, sodium, and chloride in those waters. Calcium-sodium-sulfate waters dominated, and concentrations of dissolved solids were as large as 4,916 mg/L near the water table in the area of downward leakage. Dissolution of minerals in sedimentary deposits of marine origin in upstream areas of the Arkansas River drainage were the likely sources of calcium, sodium, and sulfate in those waters. Nitrate was detected throughout the aquifer and the background concentration was estimated to be 2.45 mg/L as N. The largest nitrate concentrations (8.28, 22, and 54.4 mg/L as N) occurred in recently recharged water collected adjacent to irrigated fields. Three pesticides (atrazine, metolachlor, simazine) and five pesticide degradation products (alachlor ethanesulfonic acid, alachlor oxanilic acid, deethylatrazine, metolachlor ethanesulfonic acid, metolachlor oxanilic acid) were detected in recently recharged water from six water-table wells. Five of the six wells were adjacent to irrigated fields. These data indicate that concentrations of nitrate and pesticides increased over time in some areas of the aquifer as a result of agricultural activities. Results from this study indicate that vertical gradients in water chemistry existed in the central High Plains aquifer. The chemical gradients resulted from chemical inputs to the aquifer from underlying sediments of Permian age, from the Arkansas River, and from agricultural activities. In areas where those chemical inputs occurred, water quality in the aquifer was impaired and may not have been suitable for some intended uses.

  2. Use of a Metolachlor Metabolite (MESA) to Assess Agricultural Nitrate-N Fate and Transport in Choptank River Watershed, Maryland USA

    NASA Astrophysics Data System (ADS)

    McCarty, Greg; Hapeman, Cathleen; Rice, Clifford; Hively, Dean; McConnell, Laura; Sadeghi, Ali; Lang, Megan; Whitall, David; Bialek, Krystyna; Downey, Peter

    2014-05-01

    A majority of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on biological assessments. The Choptank River estuary, a Bay tributary on the eastern shore, is an example, where crop production in upland areas of the watershed contribute significant loads of nutrients to streams. We used a novel approach based on the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl) -6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. The observed inverse relationship (R2 = 0.65, p < 0.001) accounts for not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N fate within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R2 ≤ 0.99) for all eight sampling dates except one where R2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay.

  3. Use of a metolachlor metabolite (MESA) to assess agricultural nitrate-n fate and transport in choptank river watershed, Maryland USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A majority of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on biological assessments. The Choptank River estuary, a Bay tributary on the eastern shore, is an example, where crop production in upland areas of the watershed contribute significant loads of nutrien...

  4. DEGRADATION OF ATRAZINE, METOLACHLOR, AND PENDIMETHALIN IN PESTICIDE-CONTAMINATED SOILS: EFFECTS OF AGED RESIDUES ON SOIL RESPIRATION AND PLANT SURVIVAL. (R825549C045)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Concentrations of nutrients, pesticides, and suspended sediment in the karst terrane of the Sinking Creek basin, Kentucky, 2004

    USGS Publications Warehouse

    Crain, Angela S.

    2006-01-01

    Water samples were collected in streams and springs in the karst terrane of the Sinking Creek Basin in 2004 as part of study in cooperation with the Kentucky Department of Agriculture. A total of 48 water samples were collected at 7 sites (4 springs, 2 streams, and 1 karst window) from April through November 2004. The karst terrane of the Sinking Creek Basin (also known as Boiling Spring Basin) encompasses about 125 square miles in Breckinridge County and portions of Meade and Hardin Counties in Kentucky. Fourteen pesticides were detected of the 52 pesticides analyzed in the stream and spring samples. Of the 14 detected pesticides, 12 were herbicides and 2 were insecticides. The most commonly detected pesticides?atrazine, simazine, metolachlor, and acetochlor?were those most heavily used on crops during the study. Atrazine was detected in 100 percent of all samples; simazine, metolachlor, and acetochlor were detected in more than 35 percent of all samples. The pesticide-transformation compound, deethylatrazine, was detected in 98 percent of the samples. Only one nonagricultural herbicide, prometon, was detected in more than 30 percent of the samples. Malathion, the most commonly detected insecticide, was found in 4 percent of the samples, which was followed by carbofuran (2 percent). Most of the pesticides were present in low concentrations; however, atrazine was found in springs exceeding the U.S. Environmental Protection Agency?s (USEPA) standards for drinking water. Atrazine exceeded the USEPA?s maximum contaminant level 2 times in 48 detections. Concentrations of nitrate greater than 10 milligrams per liter (mg/L) were not found in water samples from any of the sites. Concentrations of nitrite plus nitrate ranged from 0.21 to 3.9 mg/L at the seven sites. The median concentration of nitrite plus nitrate for all sites sampled was 1.5 mg/L. Concentrations of nitrite plus nitrate generally were higher in the springs than in the main stem of Sinking Creek. Forty

  6. Pesticides and their metabolites in three small public water-supply reservoir systems, western New York, 1998-99

    USGS Publications Warehouse

    Phillips, Patrick J.; Eckhardt, David A.; Rosenmann, Larry

    2000-01-01

    Twenty five pesticides or pesticide metabolites were detected in samples collected from May, 1998 through January, 1999 in three small public- supply reservoirs in western New York.Samples were collected at tributaries and reservoir outlets for comparison with samples from the water-supply intakes. No samples from public-water-supply intakes exceeded any Federal or State water-quality standards, although some samples from tributaries did exceed a few standards. The maximum concentrations of the most frequently detected pesticides in water-supply intake samples were between 10 and 50 percent of the lowest applicable water quality standard. Pesticides that exceeded water-quality standards at the tributary sites were the herbicides atrazine, alachlor, and cyanazine, and the insecticide p,p?-DDE. Land use in the watersheds that surround these reservoirs is largely agricultural; thus, the results do not necessarily represent conditions in other water-supply reservoirs in New York State. The most frequently detected pesticides or pesticide metabolites were the corn herbicides atrazine and metolachlor, and two metabolites of metolachlor -metolachlor ethanesulfonic acid (ESA)and metolachlor oxanilic acid (OA). More than half of the samples from the three water-supply intake sites contained at least one of these compounds at concentrations greater than 0.2 ?g/L (micrograms per liter); the concentrations ranged from 0.01 to nearly 10 ?g/L. Many samples contained metabolites of other commonly used herbicides at concentrations greater than those of their parent compounds. Only two insecticides or insecticide metabolites were detected (carbofuran and p,p?-DDE and concentrations of these compounds were less than 0.1 ?g/L. The total concentration of pesticides and metabolites at the three water-supply intake sites are correlated with land use. The highest concentrations were in the watershed with the greatest percentage of row-crop land use,and the lowest concentrations were in

  7. Ground-Water Quality in the Upper Susquehanna River Basin, New York, 2004-05

    USGS Publications Warehouse

    Hetcher-Aguila, Kari K.; Eckhardt, David A.V.

    2006-01-01

    Water samples were collected from 20 production wells and 13 private residential wells throughout the upper Susquehanna River Basin (upstream from the Pennsylvania border) during the fall of 2004 and the spring of 2005 and analyzed to describe the chemical quality of ground water in the upper basin. Wells were selected to represent areas of greatest ground-water use and highest vulnerability to contamination, and to provide a representative sampling from the entire (4,516 square-mile) upper basin. Samples were analyzed for physical properties, nutrients, inorganic constituents, metals, radionuclides, pesticides, volatile organic compounds, and bacteria. The cations that were detected in the highest concentrations were calcium, magnesium, and sodium; the anions that were detected in the greatest concentrations were bicarbonate, chloride, and sulfate. The predominant nutrient was nitrate, the concentrations of which were greater in samples from sand and gravel aquifers than in samples from bedrock. The metals barium, boron, cobalt, copper, and nickel were detected in every sample; the metals with the highest concentrations were barium, boron, iron, manganese, strontium, and lithium. The pesticide compounds detected most frequently were atrazine, deethylatrazine, alachlor ESA, and two degradation products of metolachlor (metolachlor ESA and metolachlor OA); the compounds detected in highest concentration were metolachlor ESA and OA. Volatile organic compounds were detected in 11 samples, and concentrations of 3 of these compounds exceeded 1 microgram per liter (?g/L). Methyl tert-butyl ether (MTBE), a gasollline additive, was not detected in any sample. Several analytes were found in concentrations that exceeded Federal and New York State water-quality standards, which are typically identical. Chloride concentrations exceeded the U.S. Environmental Protection Agency (USEPA) Secondary Maximum Contaminant Level (SMCL) of 250 milligrams per liter (mg/L) in two samples

  8. A cocktail of contaminants: how mixtures of pesticides at low concentrations affect aquatic communities.

    PubMed

    Relyea, Rick A

    2009-03-01

    The ubiquity of anthropogenic chemicals in nature poses a challenge to understanding how ecological communities are impacted by them. While we are rapidly gaining an understanding of how individual contaminants affect communities, communities are exposed to suites of contaminants yet investigations of the effects of diverse contaminant mixtures in aquatic communities are rare. I examined how a single application of five insecticides (malathion, carbaryl, chlorpyrifos, diazinon, and endosulfan) and five herbicides (glyphosate, atrazine, acetochlor, metolachlor, and 2,4-D) at low concentrations (2-16 p.p.b.) affected aquatic communities composed of zooplankton, phytoplankton, periphyton, and larval amphibians (gray tree frogs, Hyla versicolor, and leopard frogs, Rana pipiens). Using outdoor mesocosms, I examined each pesticide alone, a mix of insecticides, a mix of herbicides, and a mix of all ten pesticides. Individual pesticides had a wide range of direct and indirect effects on all trophic groups. For some taxa (i.e., zooplankton and algae), the impact of pesticide mixtures could largely be predicted from the impacts of individual pesticides; for other taxa (i.e., amphibians) it could not. For amphibians, there was an apparent direct toxic effect of endosulfan that caused 84% mortality of leopard frogs and an indirect effect induced by diazinon that caused 24% mortality of leopard frogs. When pesticides were combined, the mix of herbicides had no negative effects on the survival and metamorphosis of amphibians, but the mix of insecticides and the mix of all ten pesticides eliminated 99% of leopard frogs. Interestingly, these mixtures did not cause mortality in the gray tree frogs and, as a result, the gray tree frogs grew nearly twice as large due to reduced competition with leopard frogs. In short, wetland communities can be dramatically impacted by low concentrations of pesticides (both separate and combined) and these results offer important insights for the

  9. Pesticide Urinary Metabolite Levels of Children in Eastern North Carolina Farmworker Households

    PubMed Central

    Arcury, Thomas A.; Grzywacz, Joseph G.; Barr, Dana B.; Tapia, Janeth; Chen, Haiying; Quandt, Sara A.

    2007-01-01

    Background In this investigation we documented the pesticide urinary metabolite levels of farmworker children in North Carolina, determined the number of different metabolites detected for each child, and delineated risk factors associated with the number of metabolites. Methods Urine samples were collected from 60 Latino farmworker children 1–6 years of age (34 female, 26 male). Interviews were completed by their mothers in Spanish. We analyzed urine samples for 14 pesticide metabolites, including the organophosphate pesticides chlorpyrifos, coumaphos, diazinon, isazaphos, malathion, pirimiphos, and parathion and its methyl counterpart; a common metabolite of at least 18 pyrethroid insecticides; the repellent DEET; and the herbicides 2,4,5-trichlorphenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, acetochlor, atrazine, and metolachlor. Predictors included measures of paraoccupational, residential, and environmental exposure, child characteristics, and mother characteristics. Results Thirteen metabolites were present in the urine samples. Organophosphate pesticide metabolites were detected in a substantial proportion of children, particularly metabolites of parathion/methyl parathion (90.0%; geometric mean 1.00 μg/L), chlorpyrifos/chlorpyrifos methyl (83.3%; geometric mean 1.92 μg/L), and diazinon (55.0%; geometric mean 10.56 μg/L). The number of metabolites detected ranged from 0 to 7, with a mode of 4 detected (28.3%). Boys, children living in rented housing, and children with mothers working part-time had more metabolites detected. Conclusions Children in farmworker homes experience multiple sources of pesticide exposure. Pesticides may remain in their environments for long periods. Environmental and occupational health changes are needed to address these exposures. Research is needed with more precise measures of exposure and on the health effects of concurrent exposure to multiple pesticides. PMID:17687456

  10. Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

    PubMed

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei; Cui, Zhongli

    2015-12-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02' in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase.

  11. Concentration of Selected Sulfonylurea, Sulfonamide, and Imidazolinone Herbicides, Other Pesticides, and Nutrients in 71 Streams, 5 Reservoir Outflows, and 25 Wells in the Midwestern United States, 1998

    USGS Publications Warehouse

    Battaglin, William A.; Furlong, Edward T.; Burkhardt, Mark R.

    2001-01-01

    Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are recently developed herbicides that function by inhibiting the action of a key plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but crop and non-crop plants demonstrate a wide range in sensitivity to SUs, SAs, and IMIs, with over a 10,000-fold difference in observed toxicity levels for some compounds. SUs, SAs, and IMIs are applied either pre- or post-emergence to crops commonly at 1/50th or less of the rate of other herbicides. Little is known about their occurrence, fate, or transport in surface water or ground water in the United States. To obtain information on the occurrence of SU, SA, and IMI herbicides in the Midwestern United States, 214 water samples were collected from 76 surface-water and 25 ground-water sites in 1998. These samples were analyzed for 16 SU, SA, and IMI herbicides by using highperformance liquid chromatography/mass spectrometry. Samples also were analyzed for 46 pesticides and pesticide degradation products and 13 herbicides and 10 herbicide degradates. At least 1 of the 16 SUs, SAs, or IMIs was detected at or above the method reporting limit of 0.010 microgram per liter (ug/L) in 83 percent of 133 stream samples. Imazethapyr was detected most frequently (69 percent of samples), followed by flumetsulam (65 percent of samples) and nicosulfuron (53 percent of samples). At least one SU, SA, or IMI herbicide was detected at or above the method reporting limit in 6 of 8 reservoir samples and 5 of 25 ground-water samples. SU, SA, and IMI herbicides occurred less frequently and at a fraction (often 1/50th or less) of the concentrations of other herbicides such as atrazine. Acetochlor, atrazine, cyanazine, and metolachlor were all detected in 95 percent or more of 136 stream samples.

  12. Metabolic Pathway Involved in 2-Methyl-6-Ethylaniline Degradation by Sphingobium sp. Strain MEA3-1 and Cloning of the Novel Flavin-Dependent Monooxygenase System meaBA

    PubMed Central

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei

    2015-01-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02′ in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase. PMID:26386060

  13. Identifying sources of emerging organic contaminants in a mixed use watershed using principal components analysis.

    PubMed

    Karpuzcu, M Ekrem; Fairbairn, David; Arnold, William A; Barber, Brian L; Kaufenberg, Elizabeth; Koskinen, William C; Novak, Paige J; Rice, Pamela J; Swackhamer, Deborah L

    2014-01-01

    Principal components analysis (PCA) was used to identify sources of emerging organic contaminants in the Zumbro River watershed in Southeastern Minnesota. Two main principal components (PCs) were identified, which together explained more than 50% of the variance in the data. Principal Component 1 (PC1) was attributed to urban wastewater-derived sources, including municipal wastewater and residential septic tank effluents, while Principal Component 2 (PC2) was attributed to agricultural sources. The variances of the concentrations of cotinine, DEET and the prescription drugs carbamazepine, erythromycin and sulfamethoxazole were best explained by PC1, while the variances of the concentrations of the agricultural pesticides atrazine, metolachlor and acetochlor were best explained by PC2. Mixed use compounds carbaryl, iprodione and daidzein did not specifically group with either PC1 or PC2. Furthermore, despite the fact that caffeine and acetaminophen have been historically associated with human use, they could not be attributed to a single dominant land use category (e.g., urban/residential or agricultural). Contributions from septic systems did not clarify the source for these two compounds, suggesting that additional sources, such as runoff from biosolid-amended soils, may exist. Based on these results, PCA may be a useful way to broadly categorize the sources of new and previously uncharacterized emerging contaminants or may help to clarify transport pathways in a given area. Acetaminophen and caffeine were not ideal markers for urban/residential contamination sources in the study area and may need to be reconsidered as such in other areas as well. PMID:25135154

  14. Herbicides and herbicide degradates in shallow groundwater and the Cedar River near a municipal well field, Cedar Rapids, Iowa

    USGS Publications Warehouse

    Boyd, R.A.

    2000-01-01

    Water samples were collected near a Cedar Rapids, Iowa municipal well field from June 1998 to August 1998 and analyzed for selected triazine and acetanilide herbicides and degradates. The purpose of the study was to evaluate the occurrence of herbicides and herbicide degradates in the well field during a period following springtime application of herbicides to upstream cropland. The well field is in an alluvial aquifer adjacent to the Cedar River. Parent herbicide concentrations generally were greatest in June, and decreased in July and August. Atrazine was most frequently detected and occurred at the greatest concentrations; acetochlor, cyanazine and metolachlor also were detected, but at lesser concentrations than atrazine. Triazine degradate concentrations were relatively small (<0.50 ??g/l) and generally decreased from June to August. Although the rate of groundwater movement is relatively fast (approx. 1 m per day) in the alluvial aquifer near the Cedar River, deethylatrazine (DEA) to atrazine ratios in groundwater samples collected near the Cedar River indicate that atrazine and DEA probably are gradually transported into the alluvial aquifer from the Cedar River. Deisopropylatrazine (DIA) to DEA ratios in water samples indicate most DIA in the Cedar River and alluvial aquifer is produced by atrazine degradation, although some could be from cyanazine degradation. Acetanilide degradates were detected more frequently and at greater concentrations than their corresponding parent herbicides. Ethanesulfonic-acid (ESA) degradates comprised at least 80% of the total acetanilide-degradate concentrations in samples collected from the Cedar River and alluvial aquifer in June, July and August; oxanilic acid degradates comprised less than 20% of the total concentrations. ESA-degradate concentrations generally were smallest in June and greater in July and August. Acetanilide degradate concentrations in groundwater adjacent to the Cedar River indicate acetanilide

  15. Gene Expression and Microscopic Analysis of Arabidopsis Exposed to Chloroacetanilide Herbicides and Explosive Compounds. A Phytoremediation Approach1

    PubMed Central

    Mezzari, Melissa P.; Walters, Katherine; Jelínkova, Marcela; Shih, Ming-Che; Just, Craig L.; Schnoor, Jerald L.

    2005-01-01

    Understanding the function of detoxifying enzymes in plants toward xenobiotics is of major importance for phytoremediation applications. In this work, Arabidopsis (Arabidopsis thaliana; ecotype Columbia) seedlings were exposed to 0.6 mm acetochlor (AOC), 2 mm metolachlor (MOC), 0.6 mm 2,4,6-trinitrotoluene (TNT), and 0.3 mm hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In vivo glutathione (GSH) conjugation reactions of AOC, MOC, RDX, and TNT were studied in root cells using a multiphoton microscope. In situ labeling with monochlorobimane, used as a competitive compound for conjugation reactions with GSH, confirmed that AOC and MOC are conjugated in Arabidopsis cells. Reverse transcription-PCR established the expression profile of glutathione S-transferases (GSTs) and nitroreductases enzymes. Genes selected for this study were AtGSTF2, AtGSTU1, AtGSTU24, and two isoforms of 12-oxophytodienoate reductase (OPR1 and OPR2). The five transcripts tested were induced by all treatments, but RDX resulted in low induction. The mRNA level of AtGSTU24 showed substantial increase for all chemicals (23-fold induction for AOC, 18-fold for MOC, 5-fold for RDX, and 40-fold for TNT). It appears that GSTs are also involved in the conjugation reactions with metabolites of TNT, and to a lesser extent with RDX. Results indicate that OPR2 is involved in plant metabolism of TNT (11-fold induction), and in oxidative stress when exposed to AOC (7-fold), MOC (9-fold), and RDX (2-fold). This study comprises gene expression analysis of Arabidopsis exposed to RDX and AOC, which are considered significant environmental contaminants, and demonstrates the importance of microscopy methods for phytoremediation investigations. PMID:15923336

  16. A pesticide monitoring survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment.

    PubMed

    Papadakis, Emmaluel N; Vryzas, Zisis; Kotopoulou, Athena; Kintzikoglou, Katerina; Makris, Konstantinos C; Papadopoulou-Mourkidou, Euphemia

    2015-06-01

    A pesticide monitoring study covering the main rivers and lakes of Northern Greece (Macedonia, Thrace and Thessaly) was undertaken. A total of 416 samples were collected over a 1.5-year sampling period (September 1999- February 2001) from six rivers and ten lakes. The water samples were analyzed with an off-line solid phase extraction technique coupled with a gas chromatography ion trap mass spectrometer using an analytical method for 147 pesticides and their metabolites, including organochlorines, organophosphates, triazines, chloroacetanilides, pyrethroids, carbamates, phthalimides and other pesticides (herbicides, insecticides and fungicides). Based on the pesticide survey results, a human health carcinogenic and non-carcinogenic risk assessment was conducted for adults and children. Ecotoxicological risk assessment was also conducted using default endpoint values and the risk quotient method. Results showed that the herbicides metolachlor, prometryn, alachlor and molinate, were the most frequently detected pesticides (29%, 12.5%, 12.5% and 10%, respectively). They also exhibited the highest concentration values, often exceeding 1 μg/L. Chlorpyrifos ethyl was the most frequently detected insecticide (7%). Seasonal variations in measured pesticide concentrations were observed in all rivers and lakes. The highest concentrations were recorded during May-June period, right after pesticide application. Concentrations of six pesticides were above the maximum allowable limit of 0.1 μg/L set for drinking water. Alachlor, atrazine and a-HCH showed unacceptable carcinogenic risk estimates (4.5E-06, 4.6E-06 and 1.3E-04, respectively). Annual average concentrations of chlorpyriphos ethyl (0.031 μg L), dicofol (0.01 μg/L), dieldrin (0.02 μg/L) and endosulfan a (0.065 μg/L) exceeded the EU environmental quality standards. The risk quotient estimates for the insecticides chorpyrifos ethyl, diazinon and parathion methyl and herbicide prometryn were above acceptable risk

  17. A pesticide monitoring survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment.

    PubMed

    Papadakis, Emmaluel N; Vryzas, Zisis; Kotopoulou, Athena; Kintzikoglou, Katerina; Makris, Konstantinos C; Papadopoulou-Mourkidou, Euphemia

    2015-06-01

    A pesticide monitoring study covering the main rivers and lakes of Northern Greece (Macedonia, Thrace and Thessaly) was undertaken. A total of 416 samples were collected over a 1.5-year sampling period (September 1999- February 2001) from six rivers and ten lakes. The water samples were analyzed with an off-line solid phase extraction technique coupled with a gas chromatography ion trap mass spectrometer using an analytical method for 147 pesticides and their metabolites, including organochlorines, organophosphates, triazines, chloroacetanilides, pyrethroids, carbamates, phthalimides and other pesticides (herbicides, insecticides and fungicides). Based on the pesticide survey results, a human health carcinogenic and non-carcinogenic risk assessment was conducted for adults and children. Ecotoxicological risk assessment was also conducted using default endpoint values and the risk quotient method. Results showed that the herbicides metolachlor, prometryn, alachlor and molinate, were the most frequently detected pesticides (29%, 12.5%, 12.5% and 10%, respectively). They also exhibited the highest concentration values, often exceeding 1 μg/L. Chlorpyrifos ethyl was the most frequently detected insecticide (7%). Seasonal variations in measured pesticide concentrations were observed in all rivers and lakes. The highest concentrations were recorded during May-June period, right after pesticide application. Concentrations of six pesticides were above the maximum allowable limit of 0.1 μg/L set for drinking water. Alachlor, atrazine and a-HCH showed unacceptable carcinogenic risk estimates (4.5E-06, 4.6E-06 and 1.3E-04, respectively). Annual average concentrations of chlorpyriphos ethyl (0.031 μg L), dicofol (0.01 μg/L), dieldrin (0.02 μg/L) and endosulfan a (0.065 μg/L) exceeded the EU environmental quality standards. The risk quotient estimates for the insecticides chorpyrifos ethyl, diazinon and parathion methyl and herbicide prometryn were above acceptable risk

  18. Quality-assurance design applied to an assessment of agricultural pesticides in ground water from carbonate bedrock aquifers in the Great Valley of eastern Pennsylvania

    USGS Publications Warehouse

    Breen, Kevin J.

    2000-01-01

    Assessments to determine whether agricultural pesticides are present in ground water are performed by the Commonwealth of Pennsylvania under the aquifer monitoring provisions of the State Pesticides and Ground Water Strategy. Pennsylvania?s Department of Agriculture conducts the monitoring and collects samples; the Department of Environmental Protection (PaDEP) Laboratory analyzes the samples to measure pesticide concentration. To evaluate the quality of the measurements of pesticide concentration for a groundwater assessment, a quality-assurance design was developed and applied to a selected assessment area in Pennsylvania. This report describes the quality-assurance design, describes how and where the design was applied, describes procedures used to collect and analyze samples and to evaluate the results, and summarizes the quality assurance results along with the assessment results. The design was applied in an agricultural area of the Delaware River Basin in Berks, Lebanon, Lehigh, and Northampton Counties to evaluate the bias and variability in laboratory results for pesticides. The design?with random spatial and temporal components?included four data-quality objectives for bias and variability. The spatial design was primary and represented an area comprising 30 sampling cells. A quality-assurance sampling frequency of 20 percent of cells was selected to ensure a sample number of five or more for analysis. Quality-control samples included blanks, spikes, and replicates of laboratory water and spikes, replicates, and 2-lab splits of groundwater. Two analytical laboratories, the PaDEP Laboratory and a U.S. Geological Survey Laboratory, were part of the design. Bias and variability were evaluated by use of data collected from October 1997 through January 1998 for alachlor, atrazine, cyanazine, metolachlor, simazine, pendimethalin, metribuzin, and chlorpyrifos. Results of analyses of field blanks indicate that collection, processing, transport, and laboratory

  19. Occurrence of pesticides in transboundary aquifers of North-eastern Greece.

    PubMed

    Vryzas, Zisis; Papadakis, Emmanuel N; Vassiliou, George; Papadopoulou-Mourkidou, Euphemia

    2012-12-15

    A five-year groundwater monitoring program undertaken in Evros (north-east Greece), showed a diversification in the levels of pesticide residues detected in adjacent transboundary aquifers. During the first two years 37 wells, including irrigation, drinking water and artesian wells were monitored while the next three years the survey was focused on the 11 most contaminated wells. The presence of pesticide residues was also monitored in the phreatic horizon (shallow groundwater) of four experimental boreholes drilled in the respective margins of four fields. Among the compounds found alachlor, metolachlor, atrazine, desethylatrazine (DEA), desisopropylatrazine (DIA) and caffeine were constantly detected. Pesticide concentrations were much lower (up to 1.54 μg/L) in the water of the monitored drinking water wells (deep groundwater aquifers) compared to those found in the phreatic horizon (experimental boreholes) of the respective areas (up to 5.20 μg/L). DEA to atrazine concentration ratios (DAR) determined for the phreatic horizon of the three boreholes and respective wells were lower than 1, indicating that preferential flow was the cause of the fast downward movement of atrazine to the phreatic horizon. In contrast the DAR for the fourth borehole and the adjacent well were greater than 1 indicating the absence of preferential flow of atrazine. Catabolic processes of the soil converted atrazine to DEA which is more mobile than atrazine itself through chromatographic (darcian) flow. This differential behavior of pesticides in adjacent aquifers (3 km) was further investigated by determining the apparent age of water in the two wells. The apparent age of the water present in the first aquifer was 21.7 years whereas the apparent age of that in the second aquifer was approximately 1.2 years. The faster replenishing rate of the latter is an indication that this aquifer is very vulnerable to contamination with pollutants present in the infiltrated soil water. PMID

  20. Pesticides in Streams in Central Nebraska

    USGS Publications Warehouse

    Stamer, J.K.; Wieczorek, Michael E.

    1995-01-01

    Contamination of surface and ground water from non-point sources is a national issue. Examples of nonpoint-source contaminants from agricultural activities are pesticides, which include fungicides, herbicides, and insecticides; sediment; nutrients (nitrogen and phosphorus); and fecal bacteria. Of these contaminants, pesticides receive the most attention because of the potential toxicity to aquatic life and to humans. Most farmers use pesticides to increase crop yields and values. Herbicides prevent or inhibit the growth of weeds that compete for nutrients and moisture needed by the crops. Herbicides are applied before, during, or following planting. In addition to agricultural use, herbicides are used in urban areas, often in larger rates of application, for weed control such as among rights-of-way. Alachlor, atrazine, cyanazine, and metolachlor, which are referred to as organonitrogen herbicides, were the four most commonly applied herbicides (1991) in the Central Nebraska Basins (CNB). These herbicides are used for corn, sorghum, and soybean production. Atrazine was the most extensively applied pesticide (1991) in central Nebraska. Insecticides are used to protect the crop seeds in storage prior to planting and also to protect the plants from destruction once the seeds have germinated. Like herbicides, insecticides are also used in urban areas to protect lawns, trees, and ornamentals. Many of the 46 pesticides shown in the table have either a Maximum Contaminant Level (MCL) of Health Advisory Level (HAL) established by the U.S. Environmental Protection Agency (USEPA) for public water supplies. The purposes of this Fact Sheet are to (1) to provide water-utility managers, water-resources planners and managers, and State regulators an improved understanding of the distributions of concentrations of pesticides in streams and their relation to respective drinking-water regulations or criteria, and (2) to describe concentrations of pesticides in streams draining a

  1. Relationships between land uses and rainwater quality in a southcentral Pennsylvania watershed

    USGS Publications Warehouse

    Shertzer, R.H.; Hall, D.W.; Steffy, S.A.; Kime, R.A.

    1998-01-01

    Spatial and temporal variability in rainfall concentrations of nutrients, major ions, and herbicides was monitored at 7 locations in or near the Conodoguinet Creek watershed in southcentral Pennsylvania from 1991-1993. Results were used to (1) compare precipitation quality in forested, agricultural and urban areas, and (2) assess the practicality of using volunteer citizen monitoring in such a study. As indicated in previous studies, sulfate and nitrogen concentrations in precipitation were linked to sample pH. Concentrations of major ions in precipitation appeared to relate more to regional influences rather than local influences. However, concentrations of herbicides in precipitation may have been influenced by both regional and local use which caused compounds like atrazine, deethylatrazine, propazine, simazine, metolachlor, alachlor, ametryn, and prometon to be present in detectable concentrations in rainfall. Seasonality was evident in nitrogen, sulfate, pH, and herbicide data and was suggested in calcium, iron, manganese, magnesium, orthophosphate, and chloride data. Agricultural weed control activities were probably responsible for the seasonal pattern in pesticide data which peaked in May and June. Tropical storm Danielle may have caused the apparent seasonal patterns for the other nine parameters. This storm did not follow the typical west to east movement pattern and consequently produced rainfall of relative high quality. A variety of quality assurance checks indicated that trained volunteer citizen monitors were successful participants in this intensive and extensive scientific study, collecting good quality samples in a timely manner. Without this kind of volunteer help, it is extremely difficult to complete studies that require sampling in response to natural events such as rainfall.

  2. Pesticides in shallow groundwater in the Delmarva Peninsula

    USGS Publications Warehouse

    Koterba, M.T.; Banks, W.S.L.; Shedlock, R.J.

    1993-01-01

    A regional study of the areal and depth distribution of pesticides in shallow groundwater in the Delmarva Peninsula of Delaware, Maryland, and Virginia was done to (i) relate the pesticides detected to landscape and shallow subsurface features, and (ii) evaluate aquifer vulnerability and the potential contamination of drinking-water supplies. Water samples collected at 100 wells from 1988 to 1990 were analyzed for concentrations of 36 pesticides, four metabolites, and other constituents. The most commonly detected residues were atrazine, cyanazine, simazine, alachlor, metolachlor, and dicamba. Concentrations were low; few exceeded 3 ??g L-1. Most detections correlate with the intensive use of these herbicides in three widely distributed and commonly rotated crops-corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and small grain-particularly if grown in well- drained soils. Most detections occurred in samples collected from shallow wells screened within 10 m of the overlying water table. The shallow depth distribution of most residues is consistent with their suspected history of use (ca. 20 yr), and patterns in shallow groundwater flow in the surficial aquifer in the study area. The areal and depth distributions of detectable residues in groundwater did not correlate with a vulnerability index, nor any of the component scores developed to estimate that index using the DRASTIC method. The shallow depth of most detections also indicates why few samples from water-supply wells in this study had measurable concentrations of pesticides; most supply wells are deeper than 10 m below the water table. The low number of contaminated samples from supply wells implies that deep groundwater currently (1992) used for drinking generally does not contain detectable pesticide residues.

  3. Water-quality assessment of the Kentucky River basin, Kentucky; nutrients, sediments, and pesticides in streams, 1987-90

    USGS Publications Warehouse

    Haag, K.H.; Porter, S.D.

    1995-01-01

    The U.S. Geological Survey investigated the water quality of the Kentucky River Basin in Kentucky as part of the National Water Quality Assessment program. Data collected during 1987-90 were used to describe the spatial and temporal variability of nutrients, suspended sediment, and pesticides in streams. Concentrations of phosphorus were signifi- cantly correlated with urban and agricultural land use. The high phosphorus content of Bluegrass Region soils was an important source of phosphorus in streams. At many sites in urban areas, all of the stream nitrogen load was attributable to wastewater- treatment-plant effluent. Tributary streams affected by agricultural sources of nutrients contained higher densities of phytoplankton than streams that drained forested areas. Data indicate that a consid- erable percentage of total nitrogen was transported as algal biomass during periods of low discharge. Average suspended-sediment concentrations for the study period were positively correlated with dis- charge. There was a downward trend in suspended- sediment concentrations downstream in the Kentucky River main stem during the study. Although a large amount of suspended sediment originates in the Eastern Coal Field Region, contributions of suspended sediment from the Red River and other tributary streams of the Knobs Region also are important. The most frequently detected herbicides in water samples were atrazine, 2,4-D, alachlor, metolachlor, and dicamba. Diazinon, malathion, and parathion were the most frequently detected organo- phosphate insecticides in water samples. Detectable concentrations of aldrin, chlordane, DDT, DDE, dieldrin, endrin, endosulfan, heptachlor, heptachlor epoxide, and lindane were found in streambed- sediment samples.

  4. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

    USGS Publications Warehouse

    Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

    1995-01-01

    A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

  5. Ground-water quality in the Lake Champlain basin, New York, 2004

    USGS Publications Warehouse

    Nystrom, Elizabeth A.

    2006-01-01

    Water samples were collected from 11 public-supply wells and 11 private domestic wells in the Lake Champlain basin in New York during the fall of 2004 to characterize the chemical quality of ground water. Wells were selected for sampling based on location and focused on areas of greatest ground-water use. Samples were analyzed for 219 physical properties and constituents, including inorganic compounds, nutrients, metals, radionuclides, pesticides and pesticide degradates, volatile organic compounds, and bacteria. Sixty-eight constituents were detected at concentrations above laboratory reporting levels. The cation and anion with the highest median concentration were calcium (34.8 mg/L) bicarbonate (134 mg/L), respectively. The predominant nutrient was nitrate, which was detected in 14 (64 percent) of the 22 samples. The two metals with the highest median concentrations were iron (175 ?g/L) and strontium (124 ?g/L); concentrations of iron, manganese, aluminum, and zinc exceeded U.S. Environmental Protection Agency secondary drinking-water standards in one or more samples. Radon concentrations were less than 1,000 picocuries per liter (pCi/L) in most samples, but concentrations as high as 6,900 pCi/L were detected and, in eight samples, exceeded the U.S. Environmental Protection Agency proposed maximum contaminant level (300 pCi/L) for radon. The most frequently detected pesticides were degradates of the broadleaf herbicides metolachlor, alachlor, and atrazine. Volatile organic compounds were detected in only three samples; those that were detected typically were fuel oxygenates, such as methyl tert-butyl ether. Coliform bacteria were detected in four samples, two of which also tested positive for E. coli.

  6. Atmospheric pressure glow discharge desorption mass spectrometry for rapid screening of pesticides in food.

    PubMed

    Jecklin, Matthias Conradin; Gamez, Gerardo; Touboul, David; Zenobi, Renato

    2008-09-01

    Flowing afterglow atmospheric pressure glow discharge tandem mass spectrometry (APGD-MS/MS) is used for the analysis of trace amounts of pesticides in fruit juices and on fruit peel. The APGD source was rebuilt after Andrade et al. (Andrade et al., Anal. Chem. 2008; 80: 2646-2653; 2654-2663) and mounted onto a hybrid quadrupole time-of-flight mass spectrometer. Apple, cranberry, grape and orange juices as well as fruit peel and salad leaves were spiked with aqueous solutions containing trace amounts of the pesticides alachlor, atrazine, carbendazim, carbofuran, dinoseb, isoproturon, metolachlor, metolcarb, propoxur and simazine. Best limits of determination (LODs) of pesticides in the fruit juices were achieved for metolcarb (1 microg/L in apple juice), carbofuran and dinoseb (2 microg/L in apple juice); for the analysis of apple skin best LODs were 10 pg/cm(2) of atrazine, metolcarb and propoxur which corresponds to an estimated concentration of 0.01 microg/kg apple, taking into account the surface area and the weight of the apple. The measured LODs were within or below the allowed maximum residue levels (MRLs) decreed by the European Union (1-500 microg/kg for pesticides in fruit juice and 0.01-5 microg/kg for apple skin). No sample pretreatment (extraction, pre-concentration, chromatographic separation) was necessary to analyze these pesticides by direct desorption/ionization using APGD-MS and to identify them using MS/MS. This makes APGD-MS a powerful high-throughput tool for the investigation of very low amounts of pesticides in fruit juices and on fruit peel/vegetable skin. PMID:18697232

  7. Water-quality assessment of the Albemarle-Pamlico drainage basin, North Carolina and Virginia; characterization of suspended sediment, nutrients, and pesticides

    USGS Publications Warehouse

    Harned, Douglas; McMahon, Gerard; Spruill, T.B.; Woodside, M.D.

    1995-01-01

    The 28,000-square-mile Albemarle-Pamlico drainage basin includes the Roanoke, Dan, Chowan Tar, and Neuse Rivers. The basin extends through four physiographic provinces in North Carolina and Virginia-Valley and Ridge, Blue Ridge, Piedmont and Coastal Plain. The spatial and temporal trends in ground-water and riverine water quality in the study area were characterized by using readily available data sources The primary data sources that were used included the U.S. Geological Survey's National Water Data Storage and Retrieval System (WATSTORE) database, the U.S. Environmental Protection Agency's Storage and Retrieval System (STORET) database, and results of a few investigations of pesticide occurrence. The principal water-quality constituents examined were suspended sediment, nutrients, and pesticides. The data examined generally spanned the period from 1950 to 1993. The only significant trends in suspended sediment were detected at three Chowan River tributary sites which showed long-term decreases. Suspended- and total-solids concentrations have decreased throughout the Albemarle-Pamlico drainage basin. The decreases are probably a result of (1) construction of new lakes and ponds in the basin, which trap solids, (2) improved agricultural soil management, and (3) improved wastewater treatment. Nutrient point sources are much less than nonpoint nutrient sources at the eight NASQAN basins examined for nutrient loads. The greatest nitrogen inputs are associated with crop fertilizer and biological nitrogen fixation by soybeans and peanuts, whereas atmospheric and animal-related nitrogen inputs are comparable in magnitude. The largest phosphorus inputs are associated with animal wastes. The most commonly detected pesticides in surface water in the STORET database were atrazine and aldrin.Intensive organonitrogen herbicide sampling of Chicod Creek in 1992 showed seasonal variations in pesticide concentration. The most commonly detected herbicides were atrazine, alachlor

  8. Removal of mixed pesticides from aqueous solutions using organoclays: evaluation of equilibrium and kinetic model.

    PubMed

    Saha, Ajoy; Ahammed Shabeer Tp; Gajbhiye, V T; Gupta, Suman; Kumar, Rajesh

    2013-07-01

    Removal of mixed pesticides, namely alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, p,p'-DDT and two metabolites p,p'-DDE and endosulfan sulphate from aqueous solution by batch adsorption onto three commercial organo-modified montmorillonite clays [modified with octadecylamine (ODA-M), modified with dimethyl- dialkylamine (DMDA-M) and modified with octadecylamine and aminopropyltriethoxysilane (ODAAPS-M)] were investigated. Effect of process variables, mainly contact time and initial concentration of mixed pesticides, on adsorption phenomenon were evaluated. To understand the adsorption kinetic pseudo-first-order and pseudo-second-order models were tested. The pseudo-second-order model provided the best fit for explaining adsorption kinetics, on the basis of high correlation coefficient (r) and normalized percent deviation values. The adsorption equilibrium was explained by the Freundlich isotherm (r = 0.951-0.992). High values (0.17-0.52 mg g⁻¹) of Freundlich constant (K(f)) indicated higher affinity of pesticides towards all three organoclays, as a result of hydrophobic interaction between the adsorbent/adsorbate systems. Pesticides with high octanol-water partition coefficient (K(ow)) and low water solubility showed faster adsorption with higher K(f) values as compared to the pesticides with low K(ow) and high water solubility. The order of organoclays for removal efficiency of mixed pesticide was ODAAPS-M > DMDA-M > ODA-M. These findings may find application to decontaminate or treat mixed pesticide contaminated industrial/agricultural waste waters. PMID:23728289

  9. Spatial and temporal distribution of pesticide air concentrations in Canadian agricultural regions

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Tuduri, Ludovic; Harner, Tom; Blanchard, Pierrette; Waite, Don; Poissant, Laurier; Murphy, Clair; Belzer, Wayne; Aulagnier, Fabien; Li, Yi-Fan; Sverko, Ed

    The Canadian Pesticide Air Sampling Campaign was initiated in 2003 to assess atmospheric levels of pesticides, especially currently used pesticides (CUPs) in agricultural regions across Canada. In the first campaign during the spring to summer of 2003, over 40 pesticides were detected. The spatial and temporal distribution of pesticides in the Canadian atmosphere was shown to reflect the pesticide usage in each region. Several herbicides including triallate, bromoxynil, MCPA, 2,4-D, dicamba, trifluralin and ethalfluralin were detected at highest levels at Bratt's Lake, SK in the prairie region. Strong relationships between air concentrations and dry depositions were observed at this site. Although no application occurred in the Canadian Prairies in 2003, high air concentrations of lindane ( γ-hexachlorocyclohexane) were still observed at Bratt's Lake and Hafford, SK. Two fungicides (chlorothalonil and metalaxyl) and two insecticides (endosulfan and carbofuran) were measured at highest levels at Kensington, PEI. Maximum concentrations of chlorpyrifos and metolachlor were found at St. Anicet, QC. The southern Ontario site, Egbert showed highest concentration of alachlor. Malathion was detected at the highest level at the west coast site, Abbotsford, BC. In case of legacy chlorinated insecticides, high concentrations of DDT, DDE and dieldrin were detected in British Columbia while α-HCH and HCB were found to be fairly uniform across the country. Chlordane was detected in Ontario, Québec and Prince Edward Island. This study demonstrates that the sources for the observed atmospheric occurrence of pesticides include local current pesticide application, volatilization of pesticide residues from soil and atmospheric transport. In many instances, these data represent the first measurements for certain pesticides in a given part of Canada.

  10. Removal of mixed pesticides from aqueous solutions using organoclays: evaluation of equilibrium and kinetic model.

    PubMed

    Saha, Ajoy; Ahammed Shabeer Tp; Gajbhiye, V T; Gupta, Suman; Kumar, Rajesh

    2013-07-01

    Removal of mixed pesticides, namely alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, p,p'-DDT and two metabolites p,p'-DDE and endosulfan sulphate from aqueous solution by batch adsorption onto three commercial organo-modified montmorillonite clays [modified with octadecylamine (ODA-M), modified with dimethyl- dialkylamine (DMDA-M) and modified with octadecylamine and aminopropyltriethoxysilane (ODAAPS-M)] were investigated. Effect of process variables, mainly contact time and initial concentration of mixed pesticides, on adsorption phenomenon were evaluated. To understand the adsorption kinetic pseudo-first-order and pseudo-second-order models were tested. The pseudo-second-order model provided the best fit for explaining adsorption kinetics, on the basis of high correlation coefficient (r) and normalized percent deviation values. The adsorption equilibrium was explained by the Freundlich isotherm (r = 0.951-0.992). High values (0.17-0.52 mg g⁻¹) of Freundlich constant (K(f)) indicated higher affinity of pesticides towards all three organoclays, as a result of hydrophobic interaction between the adsorbent/adsorbate systems. Pesticides with high octanol-water partition coefficient (K(ow)) and low water solubility showed faster adsorption with higher K(f) values as compared to the pesticides with low K(ow) and high water solubility. The order of organoclays for removal efficiency of mixed pesticide was ODAAPS-M > DMDA-M > ODA-M. These findings may find application to decontaminate or treat mixed pesticide contaminated industrial/agricultural waste waters.

  11. Water-quality assessment of the Kentucky River basin, Kentucky; results of investigations of surface-water quality, 1987-90

    USGS Publications Warehouse

    Haag, K.H.; Garcia, Rene; Jarrett, G.L.; Porter, S.D.

    1995-01-01

    The U.S. Geological Survey investigated the water quality of the Kentucky River Basin in Kentucky as part of the National Water-Quality Assessment program. Data collected during 1987-90 were used to describe the spatial and temporal variability of water-quality constituents including metals and trace elements, nutrients, sediments, pesticides, dissolved oxygen, and fecal-coliform bacteria. Oil-production activities were the source of barium, bromide, chloride, magnesium, and sodium in several watersheds. High concentrations of aluminum, iron, and zinc were related to surface mining in the Eastern Coal Field Region. High concentrations of lead and zinc occurred in streambed sediments in urban areas, whereas concentrations of arsenic, strontium, and uranium were associated with natural geologic sources. Concentrations of phosphorus were significantly correlated with urban and agricultural land use. The high phosphorus content of Bluegrass Region soils was an important source of phosphorus in streams. At many sites in urban areas, most of the stream nitrogen load was attributable to wastewater-treatment-plant effluent. Average suspended-sediment concentrations were positively correlated with discharge. There was a downward trend in suspended-sediment concentrations downstream in the Kentucky River main stem during the study. The most frequently detected herbicides in water samples were atrazine, 2,4-D, alachlor, metolachlor, and dicamba. Diazinon, malathion, and parathion were the most frequently detected organophosphate insecticides in water samples. Detectable concentrations of aldrin, chlordane, DDT, DDE, dieldrin, endrin, endosulfan, heptachlor, and lindane were found in streambed-sediment samples. Dissolved-oxygen concentrations were sometimes below the minimum concentration needed to sustain aquatic life. At some sites, high concentrations of fecal-indicator bacteria were found and water samples did not meet sanitary water-quality criteria.

  12. Occurrence of pesticides in transboundary aquifers of North-eastern Greece.

    PubMed

    Vryzas, Zisis; Papadakis, Emmanuel N; Vassiliou, George; Papadopoulou-Mourkidou, Euphemia

    2012-12-15

    A five-year groundwater monitoring program undertaken in Evros (north-east Greece), showed a diversification in the levels of pesticide residues detected in adjacent transboundary aquifers. During the first two years 37 wells, including irrigation, drinking water and artesian wells were monitored while the next three years the survey was focused on the 11 most contaminated wells. The presence of pesticide residues was also monitored in the phreatic horizon (shallow groundwater) of four experimental boreholes drilled in the respective margins of four fields. Among the compounds found alachlor, metolachlor, atrazine, desethylatrazine (DEA), desisopropylatrazine (DIA) and caffeine were constantly detected. Pesticide concentrations were much lower (up to 1.54 μg/L) in the water of the monitored drinking water wells (deep groundwater aquifers) compared to those found in the phreatic horizon (experimental boreholes) of the respective areas (up to 5.20 μg/L). DEA to atrazine concentration ratios (DAR) determined for the phreatic horizon of the three boreholes and respective wells were lower than 1, indicating that preferential flow was the cause of the fast downward movement of atrazine to the phreatic horizon. In contrast the DAR for the fourth borehole and the adjacent well were greater than 1 indicating the absence of preferential flow of atrazine. Catabolic processes of the soil converted atrazine to DEA which is more mobile than atrazine itself through chromatographic (darcian) flow. This differential behavior of pesticides in adjacent aquifers (3 km) was further investigated by determining the apparent age of water in the two wells. The apparent age of the water present in the first aquifer was 21.7 years whereas the apparent age of that in the second aquifer was approximately 1.2 years. The faster replenishing rate of the latter is an indication that this aquifer is very vulnerable to contamination with pollutants present in the infiltrated soil water.

  13. Herbicide and nitrate distribution in central Iowa rainfall

    SciTech Connect

    Hatfield, J.L.; Prueger, J.H.; Pfeiffer, R.L.; Wesley, C.K.

    1996-03-01

    Herbicides are detected in rainfall; however, these are a small fraction of the total applied. This study was designed to evaluate monthly and annual variation in atrazine (6-chloro-N-ethyl-N{prime}-(1-methylethyl)-1,3,5-triazine-2,4-diamine), alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide), metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide), and NO{sub 3}-N concentrations in rainfall over Walnut Creek watershed south of Ames, IA. The study began in 1991 and continued through 1994. Within the watershed, two wet/dry precipitation samplers were positioned 4 km apart. Detections varied during the year with >90% of the herbicide detections occurring in April through early July. Concentrations varied among events from nondetectable amounts to concentrations of 154 {mu}g L{sup {minus}1}, which occurred when atrazine was applied during an extremely humid day immediately followed by rainfall of <10 mm that washed spray drift from the atmosphere. This was a local scale phenomenon, because the other collector had a more typical concentration of 1.7 {mu}g L{sup {minus}1} with an 8-mm rainfall. VAriation between the two collectors suggests that local scale meteorological processes affect herbicide movement. Yearly atrazine deposition totals were >100 {mu}g m{sup {minus}2} representing <0.1% of the amount applied. Nitrate-N concentrations in precipitation were uniformly distributed throughout the year and without annual variation in the concentrations. Deposition rates of NO{sub 3}-N were about 1.2 g m{sup {minus}2}. Annual loading onto the watershed was about 25% of the amount applied from all forms of N fertilizers. Movement and rates of deposition provide an understanding of the processes and magnitude of the impact of agriculture on the environment. 7 refs., 5 figs., 3 tabs.

  14. Agricultural chemicals in near-surface aquifers in the mid-continental United States, 1991

    SciTech Connect

    Kolpin, D.W. ); Burkart, M.R. )

    1993-03-01

    The occurrence and distribution of selected herbicides, atrazine metabolites, and nitrate were determined for unconsolidated and bedrock aquifers within 50 feet of land surface (near-surface) in the corn and soybean producing region of the mid-continental US. At least one herbicide or atrazine metabolite was detected (reporting limit, 0.05 micrograms per liter) in 24 percent of 579 water samples collected during the spring and summer of 1991. No herbicide exceeded maximum contaminant levels or health advisories. Most frequently detected was desethylatrazine (18.1 percent) followed by atrazine (17.4 percent), deisopropylatrazine (5.7 percent) and prometon (5.0 percent). Metolachlor, alachlor, metribuzin, simazine, and cyanazine were found in fewer than 3 percent of the samples. Excess nitrate (more than 3.0 mg/L) was found in 29 percent of the samples; 6 percent exceeded 10 mg/L. Few herbicide detections or excess nitrate concentrations occurred in the eastern part of the study region even though this area had an intense use of herbicides and nitrogen-fertilizer. The source of prometon, the second most frequently detected herbicide, may be associated with nonagricultural land use such as golf courses and residential areas. Significant seasonal differences between the spring and summer sampling periods were found in herbicide detections, but not in excess nitrate. The frequency of herbicide detections and excess nitrate were greater in near-surface unconsolidated aquifers than found in near-surface bedrock aquifers. Depth to the top of the aquifer was inversely related to the frequency of both herbicide detection and excess nitrate. The proximity of sampling sites to streams affected the frequency of herbicide detection.

  15. Hydrogeology, herbicides and nutrients in ground water and springs, and relation of water quality to land use and agricultural practices near Carlisle, Pennsylvania

    USGS Publications Warehouse

    Hippe, D.J.; Witt, E. C.; Giovannitti, R.M.

    1994-01-01

    Discharge and water-quality data collected in two adjacent karst-spring basins in Cumberland County, Pa., from May 1990 through April 1991 were used to (1) describe the hydrogeology of the area; (2) determine the concentrations of selected herbicides, herbicide-soil metabolites, and nutrients in water from wells and discharges from springs, (3) determine herbicide and nutrient discharges from springs; and (4) determine the relation of ground-water quality to land use and agricultural practices in the spring basins. The study area is underlain by a regolith-mantled carbonate-rock aquifer system. Agricultural land, forest, and residential land are the principal land uses. Herbicides are applied primarily to cornfields. Cyanazine, atrazine, metolachlor, and alachlor account for about 90 percent of the documented herbicide use on cropland. Daily mean discharge of Alexanders and Mount Rock Springs was 3.8 and 3.7 cubic feet per second, and total discharge was 1,390 and 1,370 cubic feet per second-days. Increases in discharge were related to individual periods of precipitation, but maximum flow rates lagged precipitation periods by 2 to 5 days. The recharge area to each spring is estimated to be 2.8 square miles. Atrazine was the only herbicide in common use that was detected in discharges from springs. Atrazine and the atrazine soil-metabolite deethylatrazine (DEA) were detected in spring discharges for the duration of the study. Changes in atrazine and DEA concentrations in the discharges from springs were minimal, and no flush of herbicides from the springs followed application. Temporal variation in constituent discharges was related mostly to changes in spring flow; the largest daily constituent discharges coincided with periods of increased spring flow during the winter and early spring. Atrazine and DEA discharged from Alexanders Spring and Mount Rock Spring were about 0.5 and 0.6 percent of the estimated annual atrazine use on row crops in their respective

  16. Determination of enzyme kinetics and glutathione conjugates of chlortetracycline and chloroacetanilides using liquid chromatography-mass spectrometry.

    PubMed

    Farkas, Michael; Berry, James O; Aga, Diana S

    2007-07-01

    Glutathione S-transferases (GSTs) isolated from chlortetracycline (CTC)-treated maize catalyzed the conjugation of glutathione (GSH) with CTC, producing stable conjugates that were structurally characterized using liquid chromatography-ion-trap mass spectrometry (LC-IT-MS). Enzyme-mediated dechlorination of CTC resulted during GSH conjugation as revealed by the mass spectra of the CTC-GSH conjugate, which was characterized by the loss of the chlorine isotopic signature, and shorter chromatographic retention time relative to the chlorinated parent compound. Several fragmentation patterns in the mass spectrum of the CTC-GSH conjugate can be used to verify the identity of the enzyme reaction products. The expected molecular ion [M + H](+) of the CTC-GSH conjugate (m/z 751) with chlorine removal was not observed in the positive electrospray ionization. Instead, a base peak of m/z 677, corresponding to the loss of glycine (MW = 75 Da), was observed. When m/z 677 was subjected to further fragmentation, characteristic peaks corresponding to the loss of glutamic acid (m/z = 129) and water (m/z 18) were observed in the MS/MS spectrum. The catalytic activity of the CTC-induced GST towards dechlorination of chloroacetanilide herbicides (alachlor, metolachlor and propachlor), which are known to be detoxified in plants via the glutathione pathway, was also evaluated in vitro. Glutathione conjugates of chloroacetanilides also showed the losses of m/z 129 and m/z 18 that are characteristic of GSH conjugates when characterized by LC-IT-MS. Interestingly, the sensitivity of LC-IT-MS made it possible, for the first time, to detect chloroacetanilides that are conjugated with two GSH molecules, in addition to the known single GSH conjugates. This research demonstrates a more sensitive and specific method of measuring enzyme reaction products using LC-IT-MS.

  17. Fate and transport of pesticides in the ground water systems of southwest Georgia, 1993-2005

    USGS Publications Warehouse

    Dalton, M.S.; Frick, E.A.

    2008-01-01

    Modern agricultural practices in the United States have resulted in nearly unrivaled efficiency and productivity. Unfortunately, there is also the potential for release of these compounds to the environment and consequent adverse affects on wildlife and human populations. Since 1993, the National Water-Quality Assessment (NAWQA) program of the U.S. Geological Survey has evaluated water quality in agricultural areas to address these concerns. The objective of this study is to evaluate trends in pesticide concentrations from 1993-2005 in the surficial and Upper Floridan aquifers of southwest Georgia using pesticide and pesticide degradate data collected for the NAWQA program. There were six compounds - five herbicides and one degradate - that were detected in more than 20% of samples: atrazine, deethylatrazine (DEA), metolachlor, alachlor, floumeturon, and tebuthiuron. Of the 128 wells sampled during the study, only eight wells had pesticide concentrations that either increased (7) or decreased (1) on a decadal time scale. Most of the significant trends were increasing concentrations of pesticides in older water; median pesticide concentrations did not differ between the surficial and Upper Floridan aquifers from 1993 and 2005. Deethylatrazine, in the Upper Floridan aquifer, was the only compound that had a significant change (increase) in concentration during the study. The limited number of wells with increases in pesticide concentrations suggest that ground-water sources of these compounds are not increasing in concentration over the time scale represented in this study. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  18. Removal of Pesticides and Inorganic Contaminants in Anaerobic and Aerobic Biological Contactors

    EPA Science Inventory

    This presentation contains data on the removal of pesticides (acetochlor, clethodim, dicrotophos), ammonia, nitrate, bromate and perchlorate through aerobic and anaerobic biological treatment processes.

  19. An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers, 1992-2001 and 2002-2011

    USGS Publications Warehouse

    Stone, Wesley W.; Gilliom, Robert J.; Martin, Jeffrey D.

    2014-01-01

    This report provides an overview of the U.S. Geological Survey National Water-Quality Assessment program and National Stream Quality Accounting Network findings for pesticide occurrence in U.S. streams and rivers during 2002–11 and compares them to findings for the previous decade (1992–2001). In addition, pesticide stream concentrations were compared to Human Health Benchmarks (HHBs) and chronic Aquatic Life Benchmarks (ALBs). The comparisons between the decades were intended to be simple and descriptive. Trends over time are being evaluated separately in a series of studies involving rigorous trend analysis. During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time. In contrast, alachlor, chlorpyrifos, cyanazine, diazinon, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams during the second decade than during the first decade. During 2002–11, only one stream had an annual mean pesticide concentration that exceeded an HHB. In contrast, 17 percent of agriculture land-use streams and one mixed land-use stream had annual mean pesticide concentrations that exceeded HHBs during 1992–2001. The difference between the first and second decades in terms of percent of streams exceeding HHBs was attributed to regulatory changes. During 2002–11, nearly two-thirds of agriculture land-use streams and nearly one-half of mixed land-use streams exceeded chronic ALBs. For urban land use, 90 percent of the streams exceeded a chronic ALB. Fipronil, metolachlor, malathion, cis-permethrin, and dichlorvos exceeded chronic ALBs for more than 10 percent of the streams. For agriculture and mixed land-use streams, the overall percent of streams that

  20. Anthropogenic Organic Compounds in Source and Finished Groundwater of Community Water Systems in the Piedmont Physiographic Province, Potomac River Basin, Maryland and Virginia, 2003-04

    USGS Publications Warehouse

    Banks, William S.L.; Reyes, Betzaida

    2009-01-01

    A source- and finished-water-quality assessment of groundwater was conducted in the Piedmont Physiographic Province of Maryland and Virginia in the Potomac River Basin during 2003-04 as part of the U.S. Geological Survey's National Water-Quality Assessment Program. This assessment used a two-phased approach to sampling that allowed investigators to evaluate the occurrence of more than 280 anthropogenic organic compounds (volatile organic compounds, pesticides and pesticide degradates, and other anthropogenic organic compounds). Analysis of waters from 15 of the largest community water systems in the study area were included in the assessment. Source-water samples (raw-water samples collected prior to treatment) were collected at the well head. Finished-water samples (raw water that had been treated and disinfected) were collected after treatment and prior to distribution. Phase one samples, collected in August and September 2003, focused on source water. Phase two analyzed both source and finished water, and samples were collected in August and October of 2004. The results from phase one showed that samples collected from the source water for 15 community water systems contained 92 anthropogenic organic compounds (41 volatile organic compounds, 37 pesticides and pesticide degradates, and 14 other anthropogenic organic compounds). The 5 most frequently occurring anthropogenic organic compounds were detected in 11 of the 15 source-water samples. Deethylatrazine, a degradate of atrazine, was present in all 15 samples and metolachlor ethanesulfonic acid, a degradate of metolachlor, and chloroform were present in 13 samples. Atrazine and metolachlor were present in 12 and 11 samples, respectively. All samples contained a mixture of compounds with an average of about 14 compounds per sample. Phase two sampling focused on 10 of the 15 community water systems that were selected for resampling on the basis of occurrence of anthropogenic organic compounds detected most

  1. Hydrogeology and Water Quality of the Pepacton Reservoir Watershed in Southeastern New York. Part 3. Responses of Stream Base-Flow Chemistry to Hydrogeologic Factors and Nonpoint-Sources of Contamination

    USGS Publications Warehouse

    Heisig, Paul M.; Phillips, Patrick J.

    2004-01-01

    -water quality, and stream base-flow water quality. Chloride and sodium, which are relatively conservative constituents, showed strong linear relations with annual estimates of road-salt application during all four sampling periods. Nonconservative constituents, such as the nutrients nitrate and orthophosphate, showed linear relations with manure production rate among farmed basins, but only at specific times of the year because of losses through biologic activity. Nitrate showed the strongest relation in winter because losses to biological activity were at a minimum. Orthophosphate showed the strongest relation in early summer, when hydrologic and chemical conditions appear to favor release from sediments. Atmospheric nitrogen deposition is an additional source of nitrogen that can be released from mature or stressed forested basins. Detections of herbicides (atrazine, metolachlor, simazine) and herbicide degradates ( Metolachlor ESA, alachlor ESA, deethylatrazine) in base flow were closely correlated with subbasins in which corn was grown during the study. Atrazine was detected at the farmed index site only in early summer, after application and two rain storms. This detection corresponded to the peak orthophosphate concentration. In contrast, metolachlor ESA was detected in nearly all farmedindex- subbasin samples and peaked in late summer, when percent base-flow contributions from farmed valley-bottom areas were likely highest. The implications of this study are that seasonal and more frequent base-flow surveys of water chemistry from small stream basins can help refine the understanding of local hydrogeologic systems and define the effects of nonpointsource contamination on base-flow water quality. The concentration of most nonpoint sources in valley-bottom or lower-hillside areas helped indicate the relative contributions of water from hillside and valley-bottom areas at different times of year. The positive correlations between the intensity of nonpoint-

  2. Novosphingobium chloroacetimidivorans sp. nov., a chloroacetamide herbicide-degrading bacterium isolated from activated sludge.

    PubMed

    Chen, Qing; Zhang, Jun; Wang, Cheng-Hong; Jiang, Jin; Kwon, Soon-Wo; Sun, Li-Na; Shen, Wen-Biao; He, Jian

    2014-08-01

    Strain BUT-14(T), a Gram-reaction-negative, non-spore-forming, ellipse-shaped bacterium, was isolated from activated sludge of a chloroacetamide-herbicides-manufacturing wastewater treatment facility. The strain was able to degrade more than 90% of butachlor, acetochlor and alachlor (100 mg l(-1)) within 5 days of incubation. The taxonomic position was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BUT-14(T) was a member of the genus Novosphingobium and showed the highest sequence similarities to Novosphingobium soli DSM 22821(T) (97.9%), N. naphthalenivorans KACC 15258(T) (97.4%), N. pentaromativorans JCM 12182(T) (97.4%) and N. barchaimii DSM 25411(T) (97.1%) and lower (<97%) sequence similarities to all other species of the genus Novosphingobium. Chemotaxonomic analysis revealed that strain BUT-14(T) possessed Q-10 as the predominant ubiquinone, spermidine as the major polyamine and C(18 : 1)ω7c (46.9%), C(17 : 1)ω6c (17.9%), summed feature 3, C(14 : 0) 2-OH (4.4%), C(15 : 0) 2-OH (3.1%) and C(16 : 0) (5.51%) as the major fatty acids. The polar lipids included lipid, glycolipid, phosphatidylglycerol, phospholipid, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and phospatidyldimethylethanolamine. Strain BUT-14(T) showed low DNA-DNA relatedness with N. soli DSM 22821(T) (41.5±2.9%), N. naphthalenivorans JCM 12182(T) (49.2±4.2%), N. pentaromativorans KACC 12295(T) (53.2±1.9%) and N. barchaimii DSM 25411 (51.2±4.5%). The DNA G+C content was 66±0.3 mol%. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic data and DNA-DNA hybridization supports the suggestion that strain BUT-14(T) represents a novel species of the genus Novosphingobium, for which the name Novosphingobium chloroacetimidivorans sp. nov. is proposed. The type strain is BUT-14(T) ( = CCTCC AB 2013086(T) = KACC 17147(T) = JCM 19923(T)).

  3. Seasonal exposures to triazine and other pesticides in surface waters in the western Highveld corn-production region in South Africa

    USGS Publications Warehouse

    Du Preez, L.H.; Jansen Van Rensburg, P.J.; Jooste, A.M.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G.; Solomon, K.R.

    2005-01-01

    The objective of this study was to characterize concentrations of atrazine, terbuthylazine, and other pesticides in amphibian habitats in surface waters of a corn-production area of the western Highveld region (North-West Province) of South Africa. The study was conducted from November 2001 to June 2002, coinciding with the corn-production season. Pesticide residues were measured at regular intervals in surface water from eight ponds, three in a non-corn-growing area (NCGA) and five within the corn-growing area (CGA). Measured atrazine concentrations differed significantly among sites and between samples. In the five CGA sites, the maximum atrazine concentrations measured during the study ranged from 1.2 to 9.3 ??g/L. Although no atrazine was recorded as being applied in the catchment of the three NCGA sites, maximum concentrations from 0.39 to 0.84 ??g/L were measured during the study, possibly as a result of atmospheric transport. Maximum measured concentrations of terbuthylazine ranged from 1.22 to 2.1 ??g/L in the NCGA sites and from 1.04 to 4.1 ??g/L in the CGA sites. The source of terbuthylazine in the NCGA sites may have been in use other than in corn. The triazine degradation products, deisopropylatrazine (DIA) and deethylatrazine (DEA) and diaminochlorotriazine (DACT) were also found in water from both the CGA and NCGA sites. Concentrations of DIA were ??? 1 ??g/L throughout the season, while DEA concentrations were mostly 2 ??g/L in some locations. Concentrations of DACT were highly variable (LOD to 8 ??g/L) both before and after planting and application, suggesting that they resulted from historical use of triazines in the area. Other herbicides such as simazine and acetochlor were only detected infrequently and pesticides such as S-metolachlor, cypermethrin, monocrotophos, and terbuphos, known to be used in the CGA, were not detected in any of the samples. Because of dilution by higher than normal rainfall in the study period, these concentrations may

  4. Glyphosate, other herbicides, and transformation products in Midwestern streams, 2002

    USGS Publications Warehouse

    Battaglin, W.A.; Kolpin, D.W.; Scribner, E.A.; Kuivila, K.M.; Sandstrom, M.W.

    2005-01-01

    The use of glyphosate has increased rapidly, and there is limited understanding of its environmental fate. The objective of this study was to document the occurrence of glyphosate and the transformation product aminomethylphosphonic acid (AMPA) in Midwestern streams and to compare their occurrence with that of more commonly measured herbicides such as acetochlor, atrazine, and metolachlor. Water samples were collected at sites on 51 streams in nine Midwestern states in 2002 during three runoff events: after the application of pre-emergence herbicides, after the application of post-emergence herbicides, and during harvest season. All samples were analyzed for glyphosate and 20 other herbicides using gas chromatography/mass spectrometry or high performance liquid chromatography/mass spectrometry. The frequency of glyphosate and AMPA detection, range of concentrations in runoff samples, and ratios of AMPA to glyphosate concentrations did not vary throughout the growing season as substantially as for other herbicides like atrazine, probably because of different seasonal use patterns. Glyphosate was detected at or above 0.1 μg/1 in 35 percent of pre-emergence, 40 percent of post-emergence, and 31 percent of harvest season samples, with a maximum concentration of 8.7 μg/1. AMPA was detected at or above 0.1 μg/1 in 53 percent of pre-emergence, 83 percent of post-emergence, and 73 percent of harvest season samples, with a maximum concentration of 3.6 μg/1. Glyphosate was not detected at a concentration at or above the U.S. Environmental Protection Agency's maximum contamination level (MCL) of 700 μg/1 in any sample. Atrazine was detected at or above 0.1 μg/1 in 94 percent of pre-emergence, 96 percent of post-emergence, and 57 percent of harvest season samples, with a maximum concentration of 55 μg/1. Atrazine was detected at or above its MCL (3 μg/1) in 57 percent of pre-emergence and 33 percent of post-emergence samples

  5. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    NASA Astrophysics Data System (ADS)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  6. Compound-specific stable isotope analysis of herbicides in stream water: a combined monitoring and modeling approach to assess pollutant degradation at catchment scale

    NASA Astrophysics Data System (ADS)

    Lutz, Stefanie; Van der Velde, Ype; Elsayed, Omniea; Imfeld, Gwenael; Lefrancq, Marie; Payraudeau, Sylvain; Van Breukelen, Boris

    2014-05-01

    Compound-specific stable isotope analysis (CSIA) measures the isotopic composition of a compound, i.e. the relative abundance of light and heavy stable isotopes of an element contained in the compound (e.g. 12C and 13C). As degradation processes may induce a change in isotopic composition (i.e. isotope fractionation), CSIA allows distinguishing degradation from non-destructive processes such as dilution or sorption. CSIA can be combined with model-assisted interpretation to evaluate degradation of contaminants in the environment. Although CSIA methods have also been developed for diffuse pollutants such as pesticides and nitrate, they have not yet been continuously applied in monitoring of diffuse pollution in surface water. Results of a virtual experiment of isotope fractionation at hillslope scale have suggested that CSIA qualifies as a feasible and useful complement to concentration measurements of diffuse pollutants (Lutz et al., 2013). We now present the first continuously measured concentration and carbon CSIA data of herbicides from a 49-ha agricultural catchment (Alsace, France). Stream concentrations of two chloroacetanilide herbicides, i.e. S-metolachlor and acetochlor, were highest (65 μg/L) following an extreme rainfall event in the first month after herbicide application, and subsequently decreased to background concentration level (0.1 μg/L). This decrease was accompanied by an increase of more than 2 ‰ in carbon isotope ratios, which was also observed in surface runoff samples from a plot experiment in the study catchment. The increase of carbon isotope ratios over time indicates the occurrence of herbicide degradation during transport to the stream, and thus demonstrates the advantage of CSIA over pesticide concentration measurements only. Despite providing evidence of herbicide degradation, the field CSIA data do not allow for a comprehensive characterization of herbicide sources, fate and transport in the study catchment. Therefore, we

  7. Contributing recharge areas, groundwater travel time, and groundwater water quality of the Missouri River alluvial aquifer near the City of Independence, Missouri, well field, 1997-2008

    USGS Publications Warehouse

    Kelly, Brian P.

    2011-01-01

    recharge area (CRA) of the Independence well field. Statistical summaries and the spatial and temporal variability of water quality in the Missouri River alluvial aquifer near the Independence well field were characterized from analyses of 598 water samples. Water-quality constituent groups include dissolved oxygen and physical properties, nutrients, major ions and trace elements, wastewater indicator compounds, fuel compounds, and total benzene, toluene, ethylbenzene, and xylene (BTEX), alachlor, and atrazine. The Missouri Secondary Maximum Contaminant Level (SMCL) for iron was exceeded in almost all monitoring wells. The Missouri Maximum Contaminant Level (MCL) for arsenic was exceeded 32 times in samples from monitoring wells. The MCL for barium was exceeded five times in samples from one monitoring well. The SMCL for manganese was exceeded 160 times in samples from all monitoring wells and the combined well-field sample. The most frequently detected wastewater indicator compounds were N,N-diethyl-meta-toluamide (DEET), phenol, caffeine, and metolachlor. The most frequently detected fuel compounds were toluene and benzene. Alachlor was detected in 22 samples and atrazine was detected in 37 samples and the combined well-field sample. The MCL for atrazine was exceeded in one sample from one monitoring well. Samples from monitoring wells with median concentrations of total inorganic nitrogen larger than 1 milligram per liter (mg/L) are located near agricultural land and may indicate that agricultural land practices are the source of nitrogen to groundwater. Largest median values of specific conductance; total inorganic nitrogen; dissolved calcium, magnesium, sodium, iron, arsenic, manganese, bicarbonate, and sulfate and detections of wastewater indicator compounds generally were in water samples from monitoring wells with CRAs that intersect the south bank of the Missouri River. Zones of higher specific conductance were located just upstream from the Independen

  8. Relation of pesticide concentrations to season, streamflow, and land use in seven New Jersey streams

    USGS Publications Warehouse

    Reiser, Robert G.

    1999-01-01

    The presence and variability of pesticides in seven New Jersey streams was documented by analyzing 146 samples collected from the streams from April 1996 through June 1998. The samples were analyzed for 85 pesticides, including 50 herbicides, 28 insecticides, and 7 degradation products, at method detection limits that ranged from 0.001 to 0.018 μg/L (micrograms per liter). Pesticides were frequently detected; however, concentrations were generally low. The pesticides most frequently detected were atrazine, in 97 percent of the samples; prometon, 96 percent; metolachlor, 95 percent; desethyl-atrazine, 91 percent; simazine, 88 percent; diazinon, 58 percent; alachlor, 56 percent; and carbaryl, 54 percent. Detection frequencies were highest during the growing season (April-September). At least one pesticide was detected in all but one of these samples, and 49 percent of the samples contained 9 or more pesticides. The numbers of pesticides detected at a given site ranged from 13 to 29. Ten pesticides were detected at concentrations that exceeded established water-quality criteria. Thirty-one of these detections were in samples collected during the growing season and one during the nongrowing season. The pesticides that exceeded the U.S. Environmental Protection Agency (USEPA) maximum contaminant level for drinking water were atrazine, which exceeded 3 μg/L in four samples, and alachlor, 2 μg/L in two samples. Cyanazine exceeded the USEPA liftime health advisory level (HAL) of 1 μg/L in two samples. These eight detections occurred during runoff shortly after spring pesticide applications and represent a potential threat to municipal water supplies in the Raritan River basin. Concentrations of chlorpyrifos, chlorthalonil, diazinon, ethyl-parathion, and methyl-azinphos exceeded the chronic life criteria for the protection of aquatic life (ACQR) in 20 samples at four sites during the growing season. Dieldrin was detected in four samples and DDE in two samples at

  9. Assessment of the reproductive and developmental toxicity of pesticide/fertilizer mixtures based on confirmed pesticide contamination in California and Iowa groundwater.

    PubMed

    Heindel, J J; Chapin, R E; Gulati, D K; George, J D; Price, C J; Marr, M C; Myers, C B; Barnes, L H; Fail, P A; Grizzle, T B

    1994-05-01

    Pesticides and fertilizers, as used in modern agriculture, contribute to the overall low-level contamination of groundwater sources. In order to determine the potential of pesticide and fertilizer mixtures to produce reproductive or developmental toxicity at concentrations up to 100 x the median level found in groundwater, we prepared and studied two mixtures of pesticides and a fertilizer (ammonium nitrate). One mixture containing aldicarb, atrazine, dibromochloropropane, 1,2-dichloropropane, ethylene dibromide, and simazine plus ammonium nitrate was considered to be a representative of groundwater contamination in California (CAL). The other, containing alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate, simulated groundwater contamination in Iowa (IOWA). Each mixture was administered in the drinking water of either Swiss CD-1 mice during a Reproductive Assessment by Continuous Breeding study or pregnant Sprague-Dawley rats (gd 6-20) at three dose levels (1x, 10x, and 100x) where 1x was the median concentration of each pesticide component as determined in the groundwater surveys in California or Iowa. Unlike conventional toxicology studies, the purpose of this study was to evaluate the health effects of realistic human concentrations. Thus, the testing concentrations are probably well below the maximally tolerated dose. Propylene glycol was used as the solubilizer for the pesticides in drinking water formulations in both studies. In the reproductive study, neither mixture caused any clinical signs of toxicity, changes in food or water consumption, or body weight in either F0 or F1 mice at doses up to 100x the median groundwater concentrations. There were no treatment-related effects on fertility or any measures of reproductive performance of either the F0 or the F1 generation mice exposed to either CAL or IOWA at up to 100x. Similarly, measures of spermatogenesis, epididymal sperm concentration, percentage motile sperm, percentage

  10. Compilation of Data to Support Development of a Pesticide Management Plan by the Yankton Sioux Tribe, Charles Mix County, South Dakota

    USGS Publications Warehouse

    Schaap, Bryan D.

    2004-01-01

    The U.S. Environmental Protection Agency is working with the Yankton Sioux Tribe to develop a pesticide management plan to reduce potential for contamination of ground water that may result from the use of registered pesticides. The purpose of this study was to compile technical information to support development of a pesticide management plan by the Yankton Sioux Tribe for the area within the Yankton Sioux Reservation, Charles Mix County, South Dakota. Five pesticides (alachlor, atrazine, cyanazine, metolachlor, and simazine) were selected by the U.S. Environmental Protection Agency for the management plan approach because they had been identified as probable or possible human carcinogens and they often had been associated with ground-water contamination in many areas and at high concentrations. This report provides a compilation of data to support development of a pesticide management plan. Available data sets are summarized in the text of this report, and actual data sets are provided in one Compact Disk?Read-Only Memory that is included with the report. The compact disk contains data sets pertinent to the development of a pesticide management plan. Pesticide use for the study area is described using information from state and national databases. Within South Dakota, pesticides commonly are applied to corn and soybean crops, which are the primary row crops grown in the study area. Water-quality analyses for pesticides are summarized for several surface-water sites. Pesticide concentrations in most samples were found to be below minimum reporting levels. Topographic data are presented in the form of 30-meter digital elevation model grids and delineation of drainage basins. Geohydrologic data are provided for the surficial deposits and the bedrock units. A high-resolution (30-by-30 meters) land-cover and land-use database is provided and summarized in a tabular format. More than 91 percent of the study area is used for row crops, pasture, or hay, and almost 6

  11. Occurrence and transport of agricultural chemicals in the Mississippi River basin, July through August 1993

    USGS Publications Warehouse

    Goolsby, Donald A.; Battaglin, William A.; Thurman, E. Michael

    1993-01-01

    Heavy rainfall and severe flooding in the upper Mississippi River Basin from mid-June through early August 1993 flushed extraordinarily large amounts of agricultural chemicals (herbicides and nitrate) into the Mississippi River, many of its tributaries, and, ultimately, the Gulf of Mexico. Even though extremely high streamflows were recorded during the flood in 1993, concentrations of herbicides, such as atrazine, alachlor, cyanazine, and metolachlor, were similar to the maximum concentrations measured during spring and summer 1991 and 1992. It was anticipated that the higher streamflows during the flood would dilute the concentrations of herbicides that are usually flushed into streams in late spring and summer. Instead, concentrations were similar to those measured during much lower flows, but the daily loads of herbicides transported in some reaches of the Mississippi River were higher than those measured in 1991 and 1992. The total atrazine load transported to the Gulf of Mexico from April through August 1993 (539,000 kilograms) was about 80 percent higher than that for the same period in 1991 and 235 percent higher than for the same period in 1992. The concentrations of atrazine and cyanazine in a few individual samples exceeded health-based limits for drinking water. However, because drinking-water regulations are based on the average of at least four quarterly samples, the annual average concentrations in the Mississippi River probably will not exceed these limits for 1993. Nitrate concentrations were similar to those measured during spring and summer 1991 and 1992. The loads of nitrate-nitrogen transported into the Gulf of Mexico during July and August 1993 were as much as 5,734 metric tons per day. These loads generally are similar to those measured in spring 1991 and 1992 but larger than those measured in summer 1991 and 1992. The total nitrate-nitrogen load transported to the Gulf of Mexico from April through August 1993 (827,000 metric tons) was about

  12. Probability of detecting atrazine/desethyl-atrazine and elevated concentrations of nitrate in ground water in Colorado

    USGS Publications Warehouse

    Rupert, Michael G.

    2003-01-01

    Draft Federal regulations may require that each State develop a State Pesticide Management Plan for the herbicides atrazine, alachlor, metolachlor, and simazine. Maps were developed that the State of Colorado could use to predict the probability of detecting atrazine and desethyl-atrazine (a breakdown product of atrazine) in ground water in Colorado. These maps can be incorporated into the State Pesticide Management Plan and can help provide a sound hydrogeologic basis for atrazine management in Colorado. Maps showing the probability of detecting elevated nitrite plus nitrate as nitrogen (nitrate) concentrations in ground water in Colorado also were developed because nitrate is a contaminant of concern in many areas of Colorado. Maps showing the probability of detecting atrazine and(or) desethyl-atrazine (atrazine/DEA) at or greater than concentrations of 0.1 microgram per liter and nitrate concentrations in ground water greater than 5 milligrams per liter were developed as follows: (1) Ground-water quality data were overlaid with anthropogenic and hydrogeologic data using a geographic information system to produce a data set in which each well had corresponding data on atrazine use, fertilizer use, geology, hydrogeomorphic regions, land cover, precipitation, soils, and well construction. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Relations were observed between ground-water quality and the percentage of land-cover categories within circular regions (buffers) around wells. Several buffer sizes were evaluated; the buffer size that provided the strongest relation was selected for use in the logistic regression models. (3) Relations between concentrations of atrazine/DEA and nitrate in ground water and atrazine use, fertilizer use, geology, hydrogeomorphic regions, land cover, precipitation, soils, and well-construction data were evaluated, and several preliminary multivariate models with various

  13. Analysis of polar organic contaminants in surface water of the northern Adriatic Sea by solid-phase extraction followed by ultrahigh-pressure liquid chromatography-QTRAP® MS using a hybrid triple-quadrupole linear ion trap instrument.

    PubMed

    Loos, Robert; Tavazzi, Simona; Paracchini, Bruno; Canuti, Elisabetta; Weissteiner, Christof

    2013-07-01

    Water-soluble polar organic contaminants are discharged by rivers, cities, and ships into the oceans. Little is known on the fate, pollution effects, and thresholds of toxic chemical mixtures in the marine environment. A new trace analytical method was developed for the multi-compound analysis of polar organic chemical contaminants in marine waters. The method is based on automated solid-phase extraction (SPE) of one-liter water samples followed by ultrahigh-pressure liquid chromatography triple-quadrupole linear ion-trap mass spectrometry (UHPLC-QTRAP(®) MS). Marine water samples from the open Adriatic Sea taken 16 km offshore from Venice (Italy) were analyzed. Method limits of quantification (LOQs) in the low picogram per liter (pg/l) concentration range were achieved. Among the 67 target chemicals analyzed, 45 substances could be detected above the LOQ. The chemicals detected at the highest concentrations were caffeine (up to 367 ng/l), nitrophenol (36 ng/l), 2,4-dinitrophenol (34 ng/l), 5-methyl-1H-benzotriazole (18.5 ng/l), sucralose (11 ng/l), 1H-benzotriazole (9.2 ng/l), terbuthylazine (9 ng/l), alachlor (7.7 ng/l), atrazine-desisopropyl (6.6 ng/l), diethyltoluamide (DEET) (5.0 ng/l), terbuthylazine-desethyl (4.3 ng/l), metolachlor (2.8 ng/l), perfluorooctanoic acid (PFOA) (2.5 ng/l), perfluoropentanoic acid (PFPeA) (2.3 ng/l), linuron (2.3 ng/l), perfluorohexanoic acid (PFHxA) (2.2 ng/l), diuron (2.0 ng/l), perfluorohexane sulfonate (PFHxS) (1.6 ng/l), simazine (1.6 ng/l), atrazine (1.5 ng/l), and perfluorooctane sulfonate (PFOS) (1.3 ng/l). Higher concentrations were detected during summer due to increased levels of tourist activity during this period.

  14. Ground-Water Quality Beneath Irrigated Cropland of the Northern and Southern High Plains Aquifer, Nebraska and Texas, 2003-04

    USGS Publications Warehouse

    Stanton, Jennifer S.; Fahlquist, Lynne

    2006-01-01

    A study of the quality of ground water beneath irrigated cropland was completed for the northern and southern High Plains aquifer. Ground-water samples were collected from 30 water-table monitoring wells in the northern agricultural land-use (NAL) study area in Nebraska in 2004 and 29 water-table monitoring wells in the southern agricultural land-use (SAL) study area in Texas in 2003. The two study areas represented different agricultural and hydrogeologic settings. The primary crops grown in the NAL study area were corn and soybeans, and the primary crop in the SAL study area was cotton. Overall, pesticide and fertilizer application rates were larger in the NAL study area. Also, precipitation and recharge rates were greater in the NAL study area, and depths to water and evapotranspiration rates were greater in the SAL study area. Ground-water quality beneath irrigated cropland was different in the two study areas. Nitrate concentrations were larger and pesticide detections were more frequent in the NAL study area. Nitrate concentrations in NAL samples ranged from 1.96 to 106 mg/L (milligrams per liter) as nitrogen, with a median concentration of 10.6 mg/L. Water in 73 percent of NAL samples had at least one pesticide or pesticide degradate detected. Most of the pesticide compounds detected (atrazine, alachlor, metolachlor, simazine, and degradates of those pesticides) are applied to corn and soybean fields. Nitrate concentrations in SAL samples ranged from 0.96 to 21.6 mg/L, with a median of 4.12 mg/L. Water in 24 percent of SAL samples had at least one pesticide or pesticide degradate detected. The pesticide compounds detected were deethylatrazine (a degradate of atrazine and propazine), propazine, fluometuron, and tebuthiuron. Most of the pesticides detected are applied to cotton fields. Dissolved-solids concentrations were larger in the SAL area and were positively correlated with both nitrate and chloride concentrations, suggesting a combination of human and

  15. Cloud point extraction with surfactant derivatization as an enrichment step prior to gas chromatographic or gas chromatography-mass spectrometric analysis.

    PubMed

    Takagai, Yoshitaka; Hinze, Willie L

    2009-08-15

    Cloud point extraction (CPE) using Triton X-114 was successfully applied as an extractive preconcentration step prior to gas chromatographic-mass spectrometric analysis. No liquid chromatographic or back-extraction steps were required to remove the target analyte(s) from the surfactant-rich extractant phase. Instead a post-extraction derivatization step is employed in which the surfactant of the surfactant-rich phase is reacted with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) prior to injection into the gas chromatograph. Such derivatization of the Triton X-114 surfactant following CPE was found to provide improved chromatographic performance yielding a reasonable elution time window that is free of derivatized surfactant signals, reproducible analyte retention times, and quantitative results. Mixtures of polycyclic aromatic hydrocarbons (PAHs), herbicides, and profens were utilized to demonstrate the feasibility and performance of this approach. The retention times of six PAHs (acenaphthene, acenaphthylene, anthracene, biphenyl, dibenzofuran, and fluorene) were found to be very reproducible with relative standard deviations (RSDs) in the range of 0.5-0.8%. Quantitative gas chromatography-mass spectrometry (GC/MS) analysis of a herbicide test mixture (composed of alachlor, atrazine, butachlor, hexachlorocyclopentadiene, metolachlor, and simazine) following their CPE from spiked water samples yielded detection limits in the range of 6.6-97 ng/L (except for that of hexachlorocyclopentadiene which was 482 ng/L). The enrichment factors achieved for these herbicides ranged from 17 to 33. The recovery of the herbicides from spiked water samples ranged from 90 to 100% except for simazine and atrazine which were 50% and 74%, respectively. The BSFTA derivatization step can serve not only to derivatize the surfactant but also appropriate nonvolatile (or less volatile) analytes. An ibuprofen and flurbiprofen test mix was utilized to demonstrate this feature. The

  16. Nutrients, suspended sediment, and pesticides in water of the Red River of the North Basin, Minnesota and North Dakota, 1990-2004

    USGS Publications Warehouse

    Christensen, V.G.

    2007-01-01

    Nutrient, suspended sediment, and pesticide data from 1990 through 2004 in the Red River of the North Basin were compiled, summarized, and compared to historical data. Streamflow varied widely throughout the basin during the 1990-2004 study period. For 19 of 22 streamflow sites, median annual streamflow during the study period exceeded the long-term average streamflow. High streamflow can have a substantial effect on water quality. In water samples from selected surface-water sites, nitrite plus nitrate concentrations ranged from less than 0.005 to 7.7 milligrams per liter; total Kjeldahl nitrogen concentrations ranged from 0.1 to 7.5 milligrams per liter; total phosphorus concentrations ranged from less than 0.005 to 4.14 milligrams per liter; and dissolved phosphorus concentrations ranged from 0.003 to 4.13 milligrams per liter. Surface-water samples from the Pembina River basin generally had higher nitrite plus nitrate, total phosphorus, and suspended sediment concentrations compared to samples from other Red River Basin sites. Historical data from 1970 through 1990 showed relatively high nitrite plus nitrate and suspended sediment concentrations in samples from some Pembina River sites; in contrast to the 1990-2004 period, total phosphorus concentrations from the 1970-90 period generally were highest at Red River of the North sites. Nitrate concentrations in ground-water samples for the 1990-2004 period were highest in Sheridan County, North Dakota and Marshall and Otter Tail Counties in Minnesota. Concentrations of nitrate in ground water in Marshall and Otter Tail Counties corresponded to relatively high reported fertilizer applications during 2002; however, Sheridan County did not have the high fertilizer applications in 2002 compared to other North Dakota and Minnesota counties. The most frequently detected pesticides or pesticide metabolites were 2, 4-D, bentazon, de-ethylatrazine, metolachlor, picloram, and triallate in surface water and alachlor

  17. Occurrence and distribution of selected contaminants in public drinking-water supplies in the surficial aquifer in Delaware

    USGS Publications Warehouse

    Ferrari, Matthew J.

    2001-01-01

    Water samples were collected from August through November 2000 from 30 randomly selected public drinking-water supply wells screened in the unconfined aquifer in Delaware, and analyzed to assess the occurrence and distribution of selected pesticide compounds, volatile organic compounds, major inorganic ions, and nutrients. Water from a subset of 10 wells was sampled and analyzed for radium and radon. The average age of ground water entering the well screens in all the wells was determined to be generally less than 20 years. Low concentrations of pesticide compounds and volatile organic compounds were detected throughout the State of Delaware, with several compounds often detected in each water sample. Pesticide and metabolite (pesticide degradation products) concentrations were generally less than 1 microgram per liter, and were detected in sam-ples from 27 of 30 wells. Of the 45 pesticides and 13 metabolites analyzed, 19 compounds (13 pesticides and 6 metabolites) were detected in at least 1 of the 30 samples. Desethylatrazine, alachlor ethane sulfonic acid, metolachlor ethane sulfonic acid, metolachlor, and atrazine were the most frequently detected pesticide compounds, and were present in at least half the samples. None of the pesticide detections was above the U.S. Environmental Protection Agency's Primary Maximum Contaminant Levels or Health Advisories. Volatile organic compounds also were present at low concentrations (generally less than 1 microgram per liter) in samples from all 30 wells. Of the 85 volatile organic com-pounds analyzed, 34 compounds were detected in at least 1 of the 30 samples. Chloroform, tetrachloroethene, and methyl tert-butyl ether were the most frequently detected volatile organic compounds, and were found in at least half the samples. None of the volatile organic compound detections was above U.S. Environmental Protection Agency's Primary Maximum Contaminant Levels or Health Advisories. A few samples contained compounds with

  18. Relation of Land Use to Streamflow and Water Quality at Selected Sites in the City of Charlotte and Mecklenburg County, North Carolina, 1993-98

    USGS Publications Warehouse

    Bales, Jerad D.; Weaver, J. Curtis; Robinson, Jerald B.

    1999-01-01

    were several times greater than median concentrations in small Piedmont streams but almost an order of magnitude less than total phosphorus concentrations in Charlotte streams during the late 1970's. Bacteria concentrations are not correlated to streamflow. The highest bacteria levels were found in 'first-flush' samples. Higher fecal coliform concentrations were associated with residential land use. Chromium, copper, lead, and zinc occurred at all sites in concentrations that exceeded the North Carolina ambient water-quality standards. The median chromium concentration in the developing basin was more than double the median concentration at any other site. As with chromium, the maximum copper concentration in the developing basin was almost an order of magnitude greater than maximum concentrations at other sites. The highest zinc concentration also occurred in the developing basin. Samples were analyzed for 121 organic compounds and 57 volatile organic compounds. Forty-five organic compounds and seven volatile organic compounds were detected. At least five compounds were detected at all sites, and 15 or more compounds were detected at all sites except two mixed land-use basins. Atrazine, carbaryl, and metolachlor were detected at eight sites, and 90 percent of all samples had measurable amounts of atrazine. About 60 percent of the samples had detectable levels of carbaryl and metolachlor. Diazinon and malathion were measured in samples from seven sites, and methyl parathion, chlorpyrifos, alachlor, and 2,4-D were detected at four or more sites. The fewest compounds were detected in the larger, mixed land-use basins. Residential basins and the developing basin had the greatest number of detections of organic compounds. The pH of wet atmospheric deposition in three Charlotte basins was more variable than the pH measured at a National Atmospheric Deposition Program (NADP)site in Rowan County. Summer pH values were significantly lower than pH meas

  19. Shallow ground-water quality in selected agricultural areas of south-central Georgia, 1994

    USGS Publications Warehouse

    Crandall, C.A.

    1996-01-01

    agricultural activities on ground-water quality. Samples from 30 percent of the wells exceeded the maximum contaminant level (MCL) for nitrate in drinking water (10 mg/L as N). Nitrogen isotope ratios ranged from 2.4 to 9.0 parts per thousand and indicate that most nitrogen in shallow ground water is probably from inorganic fertilizer. In addition, nitrate concentrations were positively correlated (p-values all less than 0.01) with concentrations of some of the major ingredients in fertilizer, such as potassium, calcium, magnesium, manganese, and chloride, and with values of specific conductance. Concentrations of pesticides and volatile organic compounds, detected in samples from 11 wells, were all below the MCLs. Of these constituents, only alachlor, metolachlor, metribuzin, toluene, benzene, and methyl chloride were detected in ground water at concentrations that ranged from 0.01 to 1.0 mg/L (micrograms per liter). Maximum concentrations of 1.0 mg/L of metolachlor and toluene were detected in two wells. Radon concentrations ranged from 530 to 1,400 pCi/L (picocuries per liter), exceeding the proposed MCL of 300 pCi/L in all samples; the median concentration was 1,000 pCi/L.

  20. Comparison of rat olfactory mucosal responses to carcinogenic and non-carcinogenic chloracetanilides

    PubMed Central

    Genter, M.B.; Warner, B.M.; Medvedovic, M.; Sartor, M.A.

    2009-01-01

    Alachlor and butachlor are chloracetanilide herbicides that induce olfactory tumors in rats, whereas propachlor does not. The mechanism by which alachlor induces tumors is distinct from many other nasal carcinogens, in that alachlor induces a gradual de-differentiation of the olfactory mucosa (OM) to a more respiratory-like epithelium, in contrast to other agents that induce cytotoxicity, followed by an aberrant regenerative response. We studied biochemical and genomic effects of these compounds to identify processes that occur in common between alachlor- and butachlor-treated rats. Because we have previously shown that matrix metalloproteinase-2 (MMP2) is activated in OM by alachlor, in the present studies we evaluated both MMP2 activation and changes in OM gene expression in response to carcinogenic and non-carcinogenic chloracetanilide treatments. All three chloracetanilides activated MMP2, and > 300 genes were significantly up- or downregulated between control and alachlor-treated rats. The most significantly regulated gene was vomeromodulin, which was dramatically upregulated by alachlor and butachlor treatment (>60-fold), but not by propachlor treatment. Except for similar gene responses in alachlor- and butachlor-treated rats, we did not identify clear-cut differences that would predict OM carcinogenicity in this study. PMID:19425180

  1. IMPROVING STRUCTURE-LINKED ACCESS TO PUBLICLY AVAILABLE CHEMICAL TOXICITY INFORMATION

    EPA Science Inventory

    Hepatotoxicity of the Herbicide Alachlor Associated with Glutathione Depletion, Oxidative Damage and Protein S-Cysteinyl Adduction.

    Toxicity of the herbicide alachlor (2-chloro-2',6'-diethtl-N-[methoxtmethtl]-acetanilide) has been attributed to cytochrome P450-dependent me...

  2. Water-quality assessment of the Ozark Plateaus study unit, Arkansas, Kansas, Missouri, and Oklahoma- summary of information on pesticides, 1970-90

    USGS Publications Warehouse

    Bell, Richard W.; Joseph, Robert L.; Freiwald, David A.

    1996-01-01

    water, was found in 15 of 95 samples from 15 of 79 wells with concentrations ranging from 0.1 to 8.2 micrograms per liter. Metolachlor, alachlor, and prometon were detected more than once with maximum concentrations less than 1.0 micrograms per liter, except for prometon (2.4 micrograms per liter). Chlordane was the pesticide having the most number of detections in bed sediment and biological tissue. Chlordane was detected in 12 of 73 samples from 10 of 45 bed-sediment sites with concentrations ranging from 2.0 to 240 micrograms per kilogram. In biological tissue, chlordane was found in 93 of 151 samples from 39 of 53 sites with concentrations ranging from 0.009 to 8.6 milligrams per kilogram. Other pesticides or pesticide metabolites detected more than once in bed sediment include DDT, DDD, p,p'-DDE, DDE, and hexachlorobenzene and in biological tissue include DDT, p,p'-DDE, and hexachlorobenzene. Quality criteria or standards have been established for 15 of the pesticides detected in the study unit. For surface-water samples, the drinking water maximum contaminant level for alachlor was exceeded in one sample from one site in 1982. For ground-water samples, the drinking water maximum contaminant level for atrazine was exceeded in four samples from four wells in 1990. For biological-tissue samples collected during the years 1982-89, the fish tissue action levels for chlordane (19 sites; 26 samples), heptachlor epoxide (3 sites; 3 samples), p,p'-DDE (2 sites; 2 samples), dieldrin (2 sites, 2 samples), and mirex (1 site; 1 sample) were exceeded. For bed-sediment samples, quality criteria or standards were not exceeded for any pesticide. Pesticides do not pose any widespread or persistent problems in the study unit, based on the limited number of samples that exceeded quality criteria and standards.

  3. Altitude, age, and quality of groundwater, Papio-Missouri River Natural Resources District, eastern Nebraska, 1992 to 2009

    USGS Publications Warehouse

    McGuire, Virginia L.; Ryter, Derek W.; Flynn, Amanda S.

    2012-01-01

    the 21 pesticides detected (alachlor, atrazine, and metolachlor) have established health-based criteria; all detections of these compounds were at concentrations less than their USEPA standards. From 2007 to 2009, 1 or more pesticide compounds were detected in 16 of the 82 network wells and in 18 of the 26 wells in well nests. From 2007 to 2009, the individual pesticide compounds that were detected most frequently were alachlor ethane sulfonic acid, a degradate of alachlor; deethylcyanazine acid, a degradate of cyanazine; and atrazine. Analytes with concentrations that exceeded 30 percent of the applicable Nebraska Title-118 standard were identified so that the PMRNRD can plan to monitor groundwater in the area and consider possible actions should the analyte concentrations continue to rise. The analytical results from the most recent samples collected in the network wells and all the wells in well nests from 1992 to 2009 indicate that, in at least 1 sample, there was a concentration that exceeded 30 percent of the Nebraska Title-118 standard for at least 1 of 3 major ions (chloride, fluoride, and sulfate), 1 nutrient (nitrate-N), 1 pesticide (atrazine), or 3 trace elements (arsenic, iron, and manganese). In addition, 30 percent of the USEPA MCL or Nebraska Title-118 standard for gross alpha activity likely was exceeded in samples from three wells screened in the Dakota aquifer. Study findings indicate that some alternatives to the current PMRNRD groundwater-sampling approach that could be considered are to collect fewer samples for nutrient analysis and to collect samples periodically for determining concentrations of additional analytes, particularly the analytes with concentrations that were at least 30 percent or more than the Nebraska Title-118 standard.

  4. Hydrogeology, Chemical Characteristics, and Transport Processes in the Zone of Contribution of a Public-Supply Well in York, Nebraska

    USGS Publications Warehouse

    Landon, Matthew K.; Clark, Brian R.; McMahon, Peter B.; McGuire, Virginia L.; Turco, Michael J.

    2008-01-01

    aquifers (hereinafter, confined unmixed wells). Delta 18O and delta D values for a minority of wells in the confined aquifers were intermediate between those for the unconfined shallow wells and those for the confined unmixed wells. These intermediate values were consistent with mixing of water from unconfined and confined aquifers (hereinafter, confined mixed wells). Oxidation-reduction conditions were primarily oxic in the unconfined aquifer and variably reducing in the confined aquifers. Trace amounts of volatile organic compounds (VOC), particularly tetrachloroethylene (PCE) and trichloroethylene (TCE), were widely detected in unconfined shallow urban wells and indicated the presence of young urban recharge waters in most confined mixed wells. The presence of degradation products of agricultural pesticides (acetochlor and alachlor) in some confined mixed wells suggests that some fraction of the water in these wells also was the result of recharge in agricultural areas. In the unconfined aquifer, age-tracer data (chlorofluorocarbon and sulfur hexafluoride data, and tritium to helium-3 ratios) fit a piston-flow model, with apparent recharge ages ranging from 7 to 48 years and generally increasing with depth. Age-tracer data for the confined aquifers were consistent with mixing of 'old' water, not containing modern tracers recharged in the last 60 years, and exponentially-mixed 'young' water with modern tracers. Confined unmixed wells contained less than (=) 97% of old water. Confined mixed wells contained >30% young water and mean ages ranged from 12 to 14 years. Median concentrations of nitrate (as nitrogen, hereinafter, nitrate-N) were 17.3 and 16.0 mg/L (milligram per liter) in unconfined shallow urban and agricultural wells, respectively, indicating a range of likely nitrate sources. Septic systems are most numerous near the edge of the urban area and appear to be

  5. Metolachor-ESA as a marker for nitrate flux in a first-order stream and riparian zones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There appears to be a connection with nitrate cycling in subsurface systems of the soil and metolachlor ethane sulfonic acid (MESA) which is a major environmental metabolite of metolachlor. This linkage has the potential to better define agricultural inputs of nitrate versus non-agricultural source...

  6. Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July

    USGS Publications Warehouse

    Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.

    2014-01-01

    High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at

  7. Water resources on and near the Nottawaseppi Huron band of Potawatomi indian tribal lands, Calhoun County, Michigan, 2000-03

    USGS Publications Warehouse

    Weaver, T.L.; Healy, D.; Sabin, T.G.

    2005-01-01

    . Atrazine and metolachlor were detected in all samples, and the atrazine degradate deethylatrazine was detected in all samples from Pine Creek and Athens & Indian Creek Drain. Another atrazine degradate (2-hydroxy-atrazine, or OIET) was detected five of the six times that it was included in the analyses. A single sample collected from Athens & Indian Creek Drain in May 2001 had relatively higher concentrations of acetochlor, atrazine, CIAT (deethylatrazine), and diuron than the other sampling sites did during the study. Analysis for various species of mercury was completed on samples collected at Pine Creek and Athens & Indian Creek Drain in July 2003, and results were similar to those typical of unimpaired streams in the Midwest. None of the surface-water sites had major ion, nutrient, or trace-element concentrations that exceeded Michigan Department of Environmental Quality standards for nonpotable surface water. USGS also collected 11 ground-water samples from 7 wells on or adjacent to the traditional reservation in 2003. Two wells were sampled twice, and a single well was sampled three times, in order to document any chemical changes that might have occurred as a result of aquifer recharge, which most typically occurs in late winter to spring in the southern Lower Peninsula of Michigan. Samples were analyzed for 184 pesticides and degradates and caffeine. There were five detections of four pesticides or degradates, but none of the detected chemicals are included in current U.S. Environmental Protection Agency drinking-water standards. The remaining 181 analytes were below laboratory reporting limits.

  8. Pesticides in groundwater in the Anacostia River and Rock Creek watersheds in Washington, D.C., 2005 and 2008

    USGS Publications Warehouse

    Koterba, Michael T.; Dieter, Cheryl A.; Miller, Cherie V.

    2010-01-01

    preliminary review of the data collected in 2005 and 2008 indicated that differences in the surficial geology, land use (as a surrogate for pesticide use), and above-average precipitation for most of 2004 through 2008, as well as differences in the number and performance of USGS laboratory methods used, could have led to more pesticides detected in groundwater samples collected in 2008 than in groundwater samples collected in 2005. Thus, although data from both years of collection were used for interpretive analysis, emphasis was placed on the analysis of the data obtained in 2008. The presence of pesticides in shallow groundwater (less than approximately 100 ft (feet), or 30 m (meters), below land surface) indicated at least the upper surficial aquifer in Washington, D.C. was susceptible to contamination. One or more herbicides or insecticides were detected in groundwater samples collected from 50 percent of the shallow wells sampled in 2005, and from 62 percent of the shallow wells sampled in 2008. Differences among types of pesticides in shallow groundwater were apparent. The most frequently detected class of herbicides was the s-triazine compounds-atrazine, simazine, or prometon, or the atrazine-degradate compounds-2-chloro-4-ethylamino-6-amino-s-triazine (desethylatrazine or CIAT) and 2-chloro-4-isopropylamino-6-amino-s-triazine (hydroxyatrazine or OIET). The next most frequently detected classes of herbicides were the chloroacetanilides, including metolachlor and acetochlor, and the ureic herbicides, including diuron (and degradate, 3,4-dichloroaniline), fluometuron, metsulfuron methyl, sulfameturon, bromacil, and tebuthiuron. Insecticides also were detected, but less frequently than herbicides, with one or more insecticides present in groundwater samples from 38 percent of shallow wells sampled in 2008. Detected insecticides included parent or degradate compounds commonly used for either nonspecific or haustellate (sucking) insects, including chlorpyri

  9. Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July

    USGS Publications Warehouse

    Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.

    2014-01-01

    High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at

  10. Studies on the mechanisms of action of the herbicide safener CGA-92194

    SciTech Connect

    Zama, P.

    1986-01-01

    CGA-92194 is a herbicide safener that is used as a seed dressing agent to protect grain sorghum against metolachlor injury. The potential adverse phytotoxic effects and the mechanisms of the protective action of this safener were studied in laboratory experiments. Adverse phytotoxicity was assessed by comparing CGA-92194 and the herbicide safeners cyometrinil and flurazole for their effects on CO/sub 2/ fixation, protein, DNA, RNA and lipid synthesis of enzymatically isolated leaf cells of soybean. The safening action mechanisms of CGA-92194 were studied by examining the potential interactions of this safener with metolachlor at the levels of uptake and macromolecular syntheses in enzymatically isolated leaf mesophyll protoplasts of grain sorghum. When CGA-92194 and metolachlor were given simultaneously, CGA-92194 enhanced /sup 14/C-metolachlor uptake into the sorghum protoplasts in a concentration-dependent pattern. Treatments with metolachlor and CGA-92194 in combination inhibited the incorporation of /sup 14/C-uracil, /sup 3/H-thymidine and /sup 14/C-acetate into sorghum protoplast macromolecules less than metolachlor given alone, suggesting the potential involvement of a competitive antagonism in CGA-92194 mechanism of action. The metabolic activity and growth of sorghum seedlings grown from CGA-92194-pretreated seeds were lower than that of seedlings grown from untreated seeds at 10 or 20 days after planting. These results indicate that a safener-induced stimulation of the spontaneous or enzymatic conjugation of metolachlor with GSH is most likely involved in CGA-92194 protective action.

  11. Atmospheric transport, deposition, and fate of triazine herbicides and their metabolites in pristine areas at Isle Royale National Park

    USGS Publications Warehouse

    Thurman, E.M.; Cromwell, A.E.

    2000-01-01

    layer of the lakes increased during deposition periods and decreased later in the year. The fate of triazines in shallow lakes suggests faster degradation and shorter half-lives, while deeper lakes have residence times for atrazine that may exceed 10 years.Rainfall samples were collected at Isle Royale National Park, located in Lake Superior, and triazine herbicides were identified and quantified. Water samples were also collected from pristine lakes and analyzed for the presence of herbicides, and long-range atmospheric transport was determined using air-parcel, back-trajectory analysis. Results indicated that deposition was seasonal, with maximum concentrations occurring during the first week of June. Atrazine had the largest mass deposited on Isle Royal. Atrazine and deethylatrazine were the only herbicides detected in the surface-water samples. The annual mass of herbicides deposited by rainfall was calculated at 13.4, 3.7, and 54.0 ??g/m2, for 1992, 1993, and 1994, respectively. The source of the herbicides was attributed to Wisconsin, Minnesota, and Iowa, which are high-use areas for herbicides such as alachlor, atrazine, cyanazine, and metolachlor.

  12. Water quality and possible sources of nitrate in the Cimarron Terrace Aquifer, Oklahoma, 2003

    USGS Publications Warehouse

    Masoner, Jason R.; Mashburn, Shana L.

    2004-01-01

    Water from the Cimarron terrace aquifer in northwest Oklahoma commonly has nitrate concentrations that exceed the maximum contaminant level of 10 milligrams per liter of nitrite plus nitrate as nitrogen (referred to as nitrate) set by the U.S. Environmental Protection Agency for public drinking water supplies. Starting in July 2003, the U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study in the Cimarron terrace aquifer to assess the water quality and possible sources of nitrate. A qualitative and quantitative approach based on multiple lines of evidence from chemical analysis of nitrate, nitrogen isotopes in nitrate, pesticides (indicative of cropland fertilizer application), and wastewater compounds (indicative of animal or human wastewater) were used to indicate possible sources of nitrate in the Cimarron terrace aquifer. Nitrate was detected in 44 of 45 ground-water samples and had the greatest median concentration (8.03 milligrams per liter) of any nutrient analyzed. Nitrate concentrations ranged from <0.06 to 31.8 milligrams per liter. Seventeen samples had nitrate concentrations exceeding the maximum contaminant level of 10 milligrams per liter. Nitrate concentrations in agricultural areas were significantly greater than nitrate concentrations in grassland areas. Pesticides were detected in 15 of 45 ground-water samples. Atrazine and deethylatrazine, a metabolite of atrazine, were detected most frequently. Deethylatrazine was detected in water samples from 9 wells and atrazine was detected in samples from 8 wells. Tebuthiuron was detected in water samples from 5 wells; metolachlor was detected in samples from 4 wells; prometon was detected in samples from 4 wells; and alachlor was detected in 1 well. None of the detected pesticide concentrations exceeded the maximum contaminant level or health advisory level set by the U.S. Environmental Protection Agency. Wastewater compounds were detected in 28 of

  13. Surface-water-quality assessment of the upper Illinois River Basin in Illinois, Indiana, and Wisconsin; results of investigations through April 1992

    USGS Publications Warehouse

    Schmidt, Arthur R.; Blanchard, Stephen F.

    1997-01-01

    A water-quality assessment of the upper Illinois River Basin (10,949 square miles) was conducted during water years 1987-91. This assessment involved interpretation of available data; 4 years of intensive data collection, including monthly sample collection at eight fixed-monitoring stations in the basin; and synoptic studies of selected water-quality constituents at many sites. The number of exceedances of water-quality criteria for chromium, copper, lead, mercury, silver, and zinc in water was essentially the same at similar stations between 1978-86 and 1987-90. For water and sediment, a large signature for many trace inorganic constituents was observed from the Chicago metropolitan area, mainly from the Des Plaines River Basin and continuing down the Illinois River. Loads of trace inorganic constituents in water were 2-13 times greater from the Chicago metropolitan area than from rural areas in the upper Illinois River Basin. Concentrations of cadmium, mercury, nickel, selenium, and zinc appeared to be relatively enriched in biota in the upper Illinois River Basin compared to other river basins. Biota from some urban sites were enriched with respect to several elements. For example, relatively large concentrations of cadmium, chromium, copper, lead, and nickel were observed in biota from sites in the Chicago River in the metropolitan area and the Calumet River. Results of pesticide sampling in 1988 and 1989 identified the pesticides bromacil, diazinon, malathion, prometon, and simazine as urban related and alachlor, atrazine, cyanazine, metolachlor, and metribuzin as agricultural related. Phenol concentrations never exceeded general-use and secondary-contact water-quality standards of 100 and 300 micrograms per liter, respectively. Pentachlorophenol concentrations observed at the Illinois River at Marseilles, Ill., between 1981 and 1992 decreased beginning in 1987. A breakdown product of the organochlorine pesticide dichloro-diphenyl-trichloroethane (DDT), p

  14. Reconnaissance of ground-water quality in the Papio-Missouri River Natural Resources District, eastern Nebraska, July through September 1992

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Ellis, M.J.

    1995-01-01

    A reconnaissance of ground-water quality was conducted in the Papio-Missouri River Natural Resources District of eastern Nebraska. Sixty-one irrigation, municipal, domestic, and industrial wells completed in the principal aquifers--the unconfined Elkhorn, Missouri, and Platte River Valley alluvial aquifers, the upland area alluvial aquifers, and the Dakota aquifer--were selected for water-quality sampling during July, August, and September 1992. Analyses of water samples from the wells included determination of dissolved nitrate as nitrogen and triazine and acetanilide herbicides. Waterquality analyses of a subset of 42 water samples included dissolved solids, major ions, metals, trace elements, and radionuclides. Concentrations of dissolved nitrate as nitrogen in water samples from 2 of 13 wells completed in the upland area alluvial aquifers exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level for drinking water of 10 milligrams per liter. Thirty-nine percent of the dissolved nitrate-as-nitrogen concentrations were less than the detection level of 0.05 milligram per liter. The largest median dissolved nitrate-as-nitrogen concentrations were in water from the upland area alluvial aquifers and the Dakota aquifer. Water from all principal aquifers, except the Dakota aquifer, had detectable concentrations of herbicides. Herbicides detected included alachlor (1 detection), atrazine (13 detections), cyanazine (5 detections), deisopropylatrazine (6 detections), deethylatrazine (9 detections), metolachlor (6 detections), metribuzin (1 detection), prometon (6 detections), and simazine (2 detections). Herbicide concentrations did not exceed U.S. Environmental Protection Agency Maximum Contaminant Levels for drinking water. In areas where the hydraulic gradient favors loss of surface water to ground water, the detection of herbicides in water from wells along the banks of the Platte River indicates that the river could act as a line source of

  15. Occurrence of selected pharmaceutical and non-pharmaceutical compounds, and stable hydrogen and oxygen isotope ratios, in a riverbank filtration study, Platte River, Nebraska, 2001 to 2003, Volume 1

    USGS Publications Warehouse

    Vogel, J.R.; Verstraeten, Ingrid M.; Coplen, T.B.; Furlong, E.T.; Meyer, M.T.; Barber, L.B.

    2005-01-01

    caffeine. Antibiotics were found in some of the wastewater samples and twice in Salt Creek. Antibiotics were not detected in any samples from the Platte River or the well field. Surface-water samples were analyzed for total organic carbon and ground-water samples were analyzed for dissolved organic carbon. Samples from all sites were analyzed for major ions. Herbicides commonly detected in surface, ground, and drinking water included acetachlor, alachlor, atrazine, and metolachlor as well as degradates of these compounds. Most of the samples from wastewater sites were found to contain predominantly acetamide degradates. High concentrations of several organic wastewater indicator compounds were detected at the wastewater sites and in Salt Creek. Several organic wastewater indicator compounds were detected multiple times in samples from the Platte River. Bromoform, a by-product of disinfection in the treatment plant, was found in samples from the finished drinking water. Stable hydrogen isotope ratios show a range in seasonal variation of -73.6 per mill to -38.1 per mill relative to Vienna Standard Mean Ocean Water (VSMOW) reference water and -69.2 per mill to -46.5 per mill for surface water and ground water, respectively. Oxygen isotope ratios for surface-water samples varied between -9.86 per mill and -5.05 per mill. Stable oxygen isotope ratios of ground waters varied between -9.62 per mill and -5.81 per mill.

  16. Probability of detecting atrazine/desethyl-atrazine and elevated concentrations of nitrate (NO2+NO3-N) in ground water in the Idaho part of the upper Snake River basin

    USGS Publications Warehouse

    Rupert, Michael G.

    1998-01-01

    Draft Federal regulations may require that each State develop a State Pesticide Management Plan for the herbicides atrazine, alachlor, cyanazine, metolachlor, and simazine. This study developed maps that the Idaho State Department of Agriculture might use to predict the probability of detecting atrazine and desethyl-atrazine (a breakdown product of atrazine) in ground water in the Idaho part of the upper Snake River Basin. These maps can be incorporated in the State Pesticide Management Plan and help provide a sound hydrogeologic basis for atrazine management in the study area. Maps showing the probability of detecting atrazine/desethyl-atrazine in ground water were developed as follows: (1) Ground-water monitoring data were overlaid with hydrogeologic and anthropogenic data using a geographic information system to produce a data set in which each well had corresponding data on atrazine use, depth to ground water, geology, land use, precipitation, soils, and well depth. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Individual (univariate) relations between atrazine/desethyl-atrazine in ground water and atrazine use, depth to ground water, geology, land use, precipitation, soils, and well depth data were evaluated to identify those independent variables significantly related to atrazine/ desethyl-atrazine detections. (3) Several preliminary multivariate models with various combinations of independent variables were constructed. (4) The multivariate models which best predicted the presence of atrazine/desethyl-atrazine in ground water were selected. (5) The multivariate models were entered into the geographic information system and the probability maps were constructed. Two models which best predicted the presence of atrazine/desethyl-atrazine in ground water were selected; one with and one without atrazine use. Correlations of the predicted probabilities of atrazine/desethyl-atrazine in ground water with

  17. Factors Affecting Occurrence and Distribution of Selected Contaminants in Ground Water From Selected Areas in the Piedmont Aquifer System, Eastern United States, 1993-2003

    USGS Publications Warehouse

    Lindsey, Bruce D.; Falls, William F.; Ferrari, Matthew J.; Zimmerman, Tammy M.; Harned, Douglas A.; Sadorf, Eric M.; Chapman, Melinda J.

    2006-01-01

    , dissolved oxygen concentration, lithology, depth to water, and soil-matrix characteristics. A linear regression model was used to determine that increases in the percentage of agricultural land use, the input of nitrogen from all sources, and dissolved oxygen were the most significant variables affecting increased concentration of nitrate. A logistic regression model was used to determine that those same factors were the most significant variables affecting whether or not the nitrate concentration would exceed 4 mg/L. Of the analysis of samples from 253 wells and 19 springs for 47 pesticides, no sample had a pesticide concentration that exceeded any USEPA MCL. The most frequently detected pesticide was desethyl atrazine, a degradation product of atrazine; the detection frequency was 47 percent. Other frequently detected pesticides included atrazine, metolachlor, simazine, alachlor, prometon, and dieldrin. Detection frequency was affected by the analytical reporting limits; the frequency of detection was somewhat lower when all pesticides were censored to the highest common detection limit. Source factors such as agricultural land use (for agricultural herbicides), urban land use (for insecticides), and the application rate were found to have positive statistical correlations with pesticide concentration. Transport factors such as depth to water and percentage of well-drained soils, sand, or silt typically were positively correlated with higher pesticide concentrations. Sampling for VOCs was conducted in 187 wells and 19 springs that were sampled for 59 VOCs. There were 137 detections of VOCs above the common censoring limit of 0.2 micrograms per liter. The most frequently detected VOCs were chloroform, a trihalomethane, and methyl-tert butyl ether (MTBE), a fuel oxygenate. Seventy-nine wells had at least one VOC detected. The detections were related to land use and well depth. Kendall's tau correlations indicated a significant positive correlation bet

  18. Factors Affecting Spatial and Temporal Variability in Nutrient and Pesticide Concentrations in the Surficial Aquifer on the Delmarva Peninsula

    USGS Publications Warehouse

    Debrewer, Linda M.; Ator, Scott W.; Denver, Judith M.

    2007-01-01

    milligrams per liter (as nitrogen). In addition to land use in the aquifer recharge area, concentrations of nitrate in ground water are related to regional patterns in soil drainage that affect underlying aquifer redox conditions. Over the peninsula, nitrate concentrations are not related to recharge date of the water, but are positively correlated with depth in shallow wells screened beneath agricultural areas. Nitrate concentrations increased in oxic areas (dissolved oxygen greater than 1 milligram per liter) of the deeper part of the surficial aquifer used for domestic supply by an average of about 2 milligrams per liter between 1988 and 2001, although no changes were apparent in shallower parts of the aquifer over that same period. Water in the surficial aquifer generally flows from land-surface recharge to surface-water discharge areas in less than 30 years. As a result, the entire flow system in the surficial aquifer has likely been affected by human activities on and near the land surface over the past several decades. Pesticide compounds occurred widely at low levels throughout the surficial aquifer. The most commonly used herbicides (metolachlor, alachlor, and atrazine) were the most commonly detected. These pesticides primarily occurred in ground water in the form of degradation products. The widespread occurrence of these and other pesticide compounds reflects their abundant use as well as chemical properties and aquifer characteristics that allow their movement into ground water. Mixtures of pesticides are common. Most samples contained at least 3 different compounds; several samples contained as many as 11. Pesticide concentrations in the surficial aquifer are relatively high beneath recharge areas with well-drained soils in the shallow part of the aquifer and in oxic environments throughout the surficial aquifer. Concentrations are generally below existing drinking-water standards, although standards are not available for all of the pesticide compound

  19. Occurrence and distribution of dissolved pesticides in the San Joaquin River basin, California

    USGS Publications Warehouse

    Panshin, Sandra Yvonne; Dubrovsky, Neil M.; Gronberg, JoAnn M.; Domagalski, Joseph L.

    1998-01-01

    The effects of pesticide application, hydrology, and chemical and physical properties on the occurrence of pesticides in surface water in the San Joaquin River Basin, California, were examined. The study of pesticide occurrence in the highly agricultural San Joaquin?Tulare Basins is part of the National Water-Quality Assessment Program of the U.S. Geological Survey. One hundred forty-three water samples were collected throughout 1993 from sites on the San Joaquin River and three of its tributaries: Orestimba Creek, Salt Slough, and the Merced River. Of the 83 pesticides selected for analysis in this study, 49 different compounds were detected in samples from the four sites and ranged in concentration from less than the detection limit to 20 micrograms per liter. All but one sample contained at least one pesticide, and more than 50 percent of the samples contained seven or more pesticides. Six compounds were detected in more than 50 percent of the samples: four herbicides (dacthal, EPTC, metolachlor, and simazine) and two insecticides (chlorpyrifos and diazinon). None of the measured concentrations exceeded U.S. Environmental Protection Agency drinking water criteria, and many of the measured concentrations were very low. The concentrations of seven pesticides exceeded criteria for the protection of freshwater aquatic life: azinphos-methyl, carbaryl, chlorpyrifos, diazinon, diuron, malathion, and trifluralin. Overall, some criteria for protection of aquatic life were exceeded in a total of 97 samples. Factors affecting the spatial patterns of occurrence of the pesticides in the different subbasins included the pattern of application and hydrology. Seventy percent of pesticides with known application were detected. Overall, 40 different pesticides were detected in Orestimba Creek, 33 in Salt Slough, and 26 in the Merced River. Samples from the Merced River had a relatively low number of detections, despite the high number (35) of pesticides applied, owing to the

  20. Occurrence and distribution of organic chemicals and nutrients and comparison of water-quality data from public drinking-water supplies in the Columbia aquifer in Delaware, 2000-08

    USGS Publications Warehouse

    Reyes, Betzaida

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey, conducted a groundwater-quality investigation to (a) describe the occurrence and distribution of selected contaminants, and (b) document any changes in groundwater quality in the Columbia aquifer public water-supply wells in the Coastal Plain in Delaware between 2000 and 2008. Thirty public water-supply wells located throughout the Columbia aquifer of the Delaware Coastal Plain were sampled from August through November of 2008. Twenty-two of the wells in the sampling network for this project were previously sampled in 2000. Eight new wells were selected to replace wells no longer in use. Groundwater collected from the wells was analyzed for the occurrence and distribution of selected pesticides, pesticide degradates, volatile organic compounds, nutrients, and major inorganic ions. Nine of the wells were analyzed for radioactive elements (radium-226, radium-228, and radon). Groundwater-quality data were compared for sites sampled in both 2000 and 2008 to document any changes in water quality. One or more pesticides were detected in samples from 29 of the 30 wells. There were no significant differences in pesticide and pesticide degradate concentrations and similar compounds were detected when comparing sampling results from 2000 and 2008. Pesticide and pesticide degradate concentrations were generally less than 1 microgram per liter. Twenty-four compounds, 14 pesticides, and 10 pesticide degradates were detected in at least one sample; the pesticide degradates, metolachlor ethanesulfonic acid, deethylatrazine, and alachlor ethanesulfonic acid were the most frequently detected compounds, each found in more than 50 percent of samples. Almost 80 percent of the detected pesticides were agricultural herbicides, which reflects the prevalence and wide distribution of agriculture in sampled areas, as well the dominance of

  1. Ground-Water Quality in the Mohawk River Basin, New York, 2006

    USGS Publications Warehouse

    Nystrom, Elizabeth A.

    2008-01-01

    exceeded established State or Federal drinking-water standards of 10 mg/L as N for nitrate and 1 mg/L as N for nitrite. Ammonia concentrations were higher in samples from bedrock wells (median 0.349 mg/L as N) than in those from samples from sand and gravel wells (median 0.006 mg/L as N). The trace elements with the highest concentrations were strontium (median 549 micrograms per liter [?g/L]), iron (median 143 ?g/L), boron (median 35 ?g/L), and manganese (median 31.1 ?g/L). Concentrations of several trace elements, including boron, copper, iron, manganese, and strontium, were higher in samples from bedrock wells than those from sand and gravel wells. The highest radon-222 activities were in samples from bedrock wells (maximum 1,360 pCi/L); 44 percent of all samples exceeded a proposed U.S. Environmental Protection Agency drinking water standard of 300 pCi/L. Nine pesticides and pesticide degradates were detected in six samples at concentrations of 0.42 ?g/L or less; all were herbicides or their degradates, and most were degradates of alachlor, atrazine, and metolachlor. Six volatile organic compounds were detected in four samples at concentrations of 0.8 ?g/L or less, including four trihalomethanes, tetrachloroethene, and toluene; most detections were in sand and gravel wells and none of the concentrations exceeded drinking water standards. Coliform bacteria were detected in six samples but fecal coliform bacteria, including Escherichia coli, were not detected in any sample.

  2. Assessment of nutrients, suspended sediment, and pesticides in surface water of the upper Snake River basin, Idaho and western Wyoming, water years 1991-95

    USGS Publications Warehouse

    Clark, Gregory M.

    1997-01-01

    proportion to its discharge (less than 1 percent), the Twin Falls sewage-treatment plant was a major source of total phosphorus (13 percent). A comparison of discharge and loading in water year 1995 with estimates of instream transport showed a good correlation (relative difference of less than 15 percent) for discharge, total organic nitrogen, dissolved nitrite plus nitrate, total nitrogen, and total phosphorus. Estimates of dissolved ammonia and suspended sediment loads correlated poorly with instream transport; relative differences were about 79 and 61 percent, respectively. The pesticides EPTC, atrazine, desethylatrazine, metolachlor, and alachlor were the most commonly detected in the upper Snake River Basin and accounted for about 75 percent of all pesticide detections. All pesticides detected were at concentrations less than 1 microgram per liter and below water-quality criteria established by the U.S. Environmental Protection Agency. In samples collected from two small agriculturally dominated tributary basins, the largest number and concentrations of pesticides were detected in May and June following early growing season applications. At one of the sites, the pesticide atrazine and its metabolite desethylatrazine were detected throughout the year. On the basis of 37 samples collected basinwide in May and June 1994, total annual subbasin applications and instantaneous instream fluxes of EPTC and atrazine showed logarithmic relations with coefficients of determination (R2 values) of 0.55 and 0.62, respectively. At the time of sampling, the median daily flux of EPTC was about 0.0001 percent of the annual quantity applied, whereas the median daily flux of atrazine was between 0.001 and 0.01 percent.

  3. Water Quality in a Wet Meadow, Platte River Valley, Central Nebraska

    USGS Publications Warehouse

    Emmons, Patrick J.

    1996-01-01

    . Atrazine was detected in water from all of the wells sampled in February and June and most of the wells sampled at other times, but only in concentrations of 0.1 to 0.6 micrograms per liter. Concentrations of the other pesticides analyzed, including alachlor, cyanazine, and metolachlor, were at or below the detection limit of 0.05 micrograms per liter. The highest concentrations of nitrate were found in water from the shallow wells (about 15 feet deep). The concentrations of nitrate as nitrogen in water from these wells ranged from 5 to 13 milligrams per liter in June. Concentrations of major cations and anions decreased and their ratios varied with depth. The major cations were calcium and sodium, and the major anions were sulfate and bicarbonate. Water from the shallowest wells was a mixed calcium sodium sulfate type, whereas the deepest alluvial-aquifer water was a calcium sulfate type. The water from the Ogallala Formation was a calcium bicarbonate type. The variability of the groundwater quality reflects seasonal changes in recharge to and evaporation from the alluvial aquifer and rates of movement and mixing within and between the aquifers.

  4. Monitoring of herbicide effect in maize based on electrical measurements

    NASA Astrophysics Data System (ADS)

    Cseresnyés, I.; Fekete, G.; Végh, K.; Székács, A.; Mörtl, M.; Rajkai, K.

    2012-07-01

    The effect of the herbicide acetochlor on root growth was studied by a non-destructive electrical impedance and capacitance method in pot experiments on maize. Acetochlor was applied both as single active ingredient and mixed with safener AD-67 in two dosages. Without safener addition, acetochlor had a permanent inhibiting effect on plant root expansion. The safener AD-67 was capable of providing protective effect against herbicide application. High correlations between root electrical impedance or capacitance and the root dry mass or surface area under our laboratory conditions were confirmed by plant harvest method. Root electrical impedance and capacitance measurements proved to be valid for monitoring the effect of the herbicide influencing root development and for distinguishing plant groups subjected to different stress conditions.

  5. Agricultural chemicals in groundwater of the midwestern United States: Relations to land use

    USGS Publications Warehouse

    Kolpin, D.W.

    1997-01-01

    To determine the relations between land use and concentrations of selected agricultural chemicals (nitrate, atrazine residue [atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) + deethylatrazinc (2-amino-4-chloro-6-isopropylamino-s-triazine) + deisopropylatrazine (2-amino-4-chloro-6-ethylamino-s-triazine)], and alachlor residue [alachlor, [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] + alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid)] in groundwater, detailed land use information based on accurate measurements from aerial photographs for the 1991 growing season was obtained within a 2-km radius surrounding 100 wells completed in near-surface unconsolidated aquifers in the midwestern USA. The most significant land use factors to the agricultural chemicals examined were: nitrate (amount of irrigated crop production, positive relation), atrazine residue (amount of irrigated crop production, positive relation), and alachlor residue (amount of highly erodible land, inverse relation). The investigation of smaller buffer sizes (size of circular area around sampled wells) proved insightful for this study. Additional land use factors having significant relations to all three agricultural chemicals were identified using these smaller buffer radii. The most significant correlations (correlation maxima) generally occurred at ≤500-m for nitrate and ≥1000-m for atrazine residue and alachlor residue. An attempt to improve the statistical relations to land use by taking hydrologic considerations into account (removing land outside the estimated most probable recharge area from the statistical analysis) was not as successful as anticipated. Only 45% of the nitrate, 32% of the atrazine residue, and 20% of the alachlor residue correlations were improved by a consideration of the estimated most probable recharge area.

  6. Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms.

    PubMed

    Paule, A; Roubeix, V; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L

    2013-11-15

    Ecotoxicological experiments have been performed in laboratory-scale microcosms to investigate the sensitivity of phototrophic biofilm communities to the alachlor herbicide, in relation to the stages of phototrophic biofilm maturation (age of the phototrophic biofilms) and physical structure (intact biofilm versus recolonization). The phototrophic biofilms were initially cultivated on artificial supports in a prototype rotating annular bioreactor (RAB) with Taylor-Couette type flow under constant operating conditions. Biofilms were collected after 1.6 and 4.4 weeks of culture providing biofilms with different maturation levels, and then exposed to nominal initial alachlor concentration of 10 μg L(-1) in either intact or recolonized biofilms for 15 days in microcosms (mean time-weighted average concentration - TWAC of 5.52 ± 0.74 μg L(-1)). At the end of the exposure period, alachlor effects were monitored by a combination of biomass descriptors (ash-free dry mass - AFDM, chlorophyll a), structural molecular fingerprinting (T-RFLP), carbon utilization spectra (Biolog) and diatom species composition. We found significant effects that in terms of AFDM, alachlor inhibited growth of the intact phototrophic biofilms. No effect of alachlor was observed on diatom composition or functional and structural properties of the bacterial community regardless of whether they were intact or recolonized. The intact three-dimensional structure of the biofilm did not appear to confer protection from the effects of alachlor. Bacterial community structure and biomass level of 4.4 weeks - intact phototrophic biofilms were significantly influenced by the biofilm maturation processes rather than alachlor exposure. The diatom communities which were largely composed of mobile and colonizer life-form populations were not affected by alachlor. This study showed that the effect of alachlor (at initial concentration of 10 μg L(-1) or mean TWAC of 5.52 ± 0.74 μg L(-1)) is mainly limited to

  7. Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms.

    PubMed

    Paule, A; Roubeix, V; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L

    2013-11-15

    Ecotoxicological experiments have been performed in laboratory-scale microcosms to investigate the sensitivity of phototrophic biofilm communities to the alachlor herbicide, in relation to the stages of phototrophic biofilm maturation (age of the phototrophic biofilms) and physical structure (intact biofilm versus recolonization). The phototrophic biofilms were initially cultivated on artificial supports in a prototype rotating annular bioreactor (RAB) with Taylor-Couette type flow under constant operating conditions. Biofilms were collected after 1.6 and 4.4 weeks of culture providing biofilms with different maturation levels, and then exposed to nominal initial alachlor concentration of 10 μg L(-1) in either intact or recolonized biofilms for 15 days in microcosms (mean time-weighted average concentration - TWAC of 5.52 ± 0.74 μg L(-1)). At the end of the exposure period, alachlor effects were monitored by a combination of biomass descriptors (ash-free dry mass - AFDM, chlorophyll a), structural molecular fingerprinting (T-RFLP), carbon utilization spectra (Biolog) and diatom species composition. We found significant effects that in terms of AFDM, alachlor inhibited growth of the intact phototrophic biofilms. No effect of alachlor was observed on diatom composition or functional and structural properties of the bacterial community regardless of whether they were intact or recolonized. The intact three-dimensional structure of the biofilm did not appear to confer protection from the effects of alachlor. Bacterial community structure and biomass level of 4.4 weeks - intact phototrophic biofilms were significantly influenced by the biofilm maturation processes rather than alachlor exposure. The diatom communities which were largely composed of mobile and colonizer life-form populations were not affected by alachlor. This study showed that the effect of alachlor (at initial concentration of 10 μg L(-1) or mean TWAC of 5.52 ± 0.74 μg L(-1)) is mainly limited to

  8. Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations

    USGS Publications Warehouse

    Shipitalo, Martin J.; Malone, Robert W.; Ma, Liwang; Nolan, Bernard T.; Kanwar, Rameshwar S.; Shaner, Dale L.; Pederson, Carl H.

    2016-01-01

    BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel-tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor, and metolachlor oxanilic acid (OXA). RESULTS The model accurately simulated field-measured metolachlor transport in drainage. A 3-yr simulation indicated that 50% residue removal decreased subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4 to 5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, ~ 2-fold reductions in OXA losses were simulated with residue removal. CONCLUSION RZWQM indicated that if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase due to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease due to the more rapid movement of the parent compound into the soil.

  9. Solute transport in eroded and rehabilitated prairie landforms. 2. Reactive solute.

    PubMed

    Papiernik, Sharon K; Koskinen, William C; Yates, Scott R

    2009-08-26

    The impact of varying soil, landscape, and climate conditions on the off-site transport of pesticides must be determined to develop improved pesticide management practices. This study quantified the rate of S-metolachlor dissipation after fall and spring application in eroded and rehabilitated landforms in which topsoil was moved from the lower slope to the upper slope. Fall-applied metolachlor provided no control of annual grasses because approximately 80% was removed from the root zone during the winter and early spring, presumably by leaching and runoff. S-Metolachlor dissipated in the spring with a DT(50) of 24-29 days. These results suggest that fall-applied metolachlor may not provide economic weed control and presents an increased risk of water contamination. Although landscape position and bulk soil movement within the landform had a large impact on soil properties, no significant differences in metolachlor dissipation between different landscape positions and between eroded and rehabilitated landforms were observed. PMID:19653695

  10. The behavior and bioactivity of imazaquin in soils

    SciTech Connect

    McKinnon, E.J.

    1989-01-01

    Laboratory studies were conducted to determine the adsorption and relative mobility of {sup 14}C-labelled imazaquin (2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imadazol-2-yl)-3-quinolinecarboxylic acid) and {sup 14}C labelled metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) on Norfolk sand loan (Typic Paleudult), Rion sandy clay loam (Typic Hapludult), Cape Fear sandy clay loam (Typic Umbraquult) and Webster clay loam (Typic Hapluquoll). Imazaquin was more mobile than metolachlor on all four soils. Soils high in humic matter content retained between 45 and 48% of the applied imazaquin and 93 and 97% of the applied metolachlor. The relative order of mobility of imazaquin in the soils was Rion = Norfolk > Cape Fear = Webster. The order for metolachlor in the soils was Rion > Norfolk > Cape Fear > Webster. Adsorption of imazaquin and metolachlor was inversely related to their mobility in the soil columns. Adsorption of imazaquin increased as the suspension pH decreased.

  11. DEVELOPMENT OF METHOD 535 FOR THE DETERMINATION OF CHLOROACETANILIDE AND OTHER ACETAMIDE HERBICIDE DEGRADATES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    EPA Method 535 has been developed in order to provide a method for the analysis of "Alachlor ESA and other acetanilide degradation products" which are listed on U.S. EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid phase extraction with a nonporous gr...

  12. Structure-toxicity relationship of chloroacetanilide herbicides: relative impact on soil microorganisms.

    PubMed

    Saha, Supradip; Dutta, Debashis; Karmakar, Rajib; Ray, Deb Prasad

    2012-09-01

    The research was carried out to ascertain the effect of three chloroacetanilide herbicides, alachlor, butachlor and pretilachlor on soil microbial biomass growth and activity. Laboratory experiments were performed in a silty clay loam soil to relate changes of soil enzymatic activity to the herbicide persistence under laboratory condition up to 42 days at three application rates. The results showed that all the three herbicides caused enhancement of dehydrogenase activity. Higher concentrations of herbicide resulted in enhancement of the enzymatic activity. In addition, a similar trend was observed in β-glucosidase and acid phosphatase activity, although urease activity decreased upon incubation for 42 days as compared with initial soil incubation values. Based on the extent of impact for dehydrogenase activity in soil, the order was pretilachlor>alachlor>butachlor; whereas in case of urease activity, the order changed to pretilachlor>butachlor>alachlor. The soil half-lives of alachlor, butachlor and pretilachlor respectively, were 9.3, 12.7 and 7.3 days, which could be accounted for in terms of their respective chemical structures, as well as variable adsorption, degradation, differential effects of the agents on soil microbes. Soil management practices and the differing physicochemical properties of the herbicides may contribute to their rates of decay in soil.

  13. EVALUATION OF GENETIC DAMAGE IN FISH EXPOSED TO PESTICIDES IN FIELD AQUATIC MICROCOSMS

    EPA Science Inventory

    Single cell gel electrophoresis (SCG) and micronucleus (MN) assays were used to measure DNA strand breaks and chromosomal damage in fish blood erythrocytes as biological indicators of exposure to alachlor and atrazine in a surrogate aquatic ecosystem. Caged common carp (Cyprinus...

  14. NOVEL CHROMATOGRAPHIC SEPARATION AND CARBON SOLID PHASE EXTRACTION OF ACETANILIDE HERBICIDE DEGRADATION PRODUCTS

    EPA Science Inventory

    Six acetanilide herbicides are currently registered for use in the U.S. Over the past several years, ethanesufonic acid (ESA) and oxanilic acid (OA) degradatoin products of these acetanilide herbicides have been found in U.S. ground waters and surface waters. "Alachlor ESA and ...

  15. Synergistic effects of a combined exposure to herbicides and an insecticide in Hyla versicolor

    USGS Publications Warehouse

    Mazanti, L.; Sparling, D.W.; Rice, C.; Bialek, K.; Stevenson, C.; Teels, B.; ,

    2003-01-01

    Combinations of the herbicides atrazine and metolachlor and the insecticide chlorpyrifos were tested under both laboratory and field conditions to determine their individual and combined effects on amphibian populations. In the lab Hyla versicolor tadpoles experienced 100% mortality when exposed to a high combination of the pesticides (2.0 mg/L atrazine, 2.54 mg/L metolachlor, 1.0 mg/L chlorpyrifos) whereas low concentrations of the pesticides (0.2 mg/L atrazine, 0.25 mg/L metolachlor, 0.1 mg/L chlorpyrifos) or high concentrations of either herbicides or insecticide alone caused lethargy, reduced growth and delayed metamorphosis but no significant mortality. In the field high herbicide, low insecticide and low herbicide, low insecticide mixtures significantly reduced amphibian populations compared to controls but in the low herbicide, low insecticide wetlands amphibian populations were able to recover through recruitment by the end of the season.

  16. Movement and dissipation of toxicants and water in natural soil environments

    SciTech Connect

    Weber, J.B.; Cassel, D.K.; Wollum, A.G.; Miller, C.T.

    1993-02-01

    Movement and dissipation of three 14C-labeled herbicides (atrazine, metolachlor, primisulfuron), tritium, water, bromide and nitrate was investigated in natural Dothan loamy sand soil cores in the field using 20 cm i.d. by 90 cm long steel column lysimeters. Half-life values for the herbicides ranged from 3 to 6 days in the field lysimeters to 14 to 49 days in laboratory flasks. Several acrylic polymers reduced losses and mobility of metolachlor and primisulfuron but none were effective on atrazine. None of the polymers reduced bioactivity of the compounds. Sorption of metolachlor by samples from different soil depths was highly correlated with organic carbon content of the soil. Soil column lysimeters proved to be useful in carrying out material balance studies on the movement and dissipation of chemicals in natural cores of Dothan loamy sand in the field.

  17. Assessment of exposure to pesticides during mixing/loading and spraying of tomatoes in the open field.

    PubMed

    Aprea, Maria Cristina; Bosi, Anna; Manara, Michele; Mazzocchi, Barbara; Pompini, Alessandra; Sormani, Francesca; Lunghini, Liana; Sciarra, Gianfranco

    2016-01-01

    Some evidence of exposure-response of metolachlor and pendimethalin for lung cancer and an association of metribuzin with risk of glioma have been reported. The primary objectives in this study were to evaluate exposure and occupational risk during mixing/loading of pesticides and during their application to tomatoes cultivated in open fields. Sixteen farmers were sampled. Respiratory exposure was estimated by personal air sampling using fiberglass filters in a IOM device. Dermal exposure was assessed using skin pads and hand washing. Absorbed doses were estimated assuming 100% lung retention, and 50% or 10% skin absorption for metribuzin, and pendimethalin and metolachlor, respectively. The three pesticides were quantified by gas chromatography tandem mass spectrometry in all matrices. Metolachlor was used as a tracer of contamination of clothes and tractors unrelated to the exposure monitored. Respiratory exposure to metribuzin, used in granular form, was on average more than one order of magnitude higher than exposure to pendimethalin, used in the form of microencapsulated liquid. The actual doses were 0.067-8.08 µg/kg bw, 0.420-12.6 µg/kg bw, and 0.003-0.877 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. Dermal exposure was about 88% of the actual dose for metribuzin and more than 95%, for pendimethalin and metolachlor. For risk assessment, the total absorbed doses (sum of respiratory and skin absorbed doses) were compared with the AOEL for each compound. The actual and absorbed doses of the three pesticides were always lower than the acceptable operator exposure level (AOEL), which are reported to be 234 µg/kg bw, 20 µg/kg bw, and 150 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. In any case, personal protective equipment and spraying devices should be chosen with care to minimize exposure.

  18. Tillage management to mitigate herbicide loss in runoff under simulated rainfall conditions.

    PubMed

    Locke, Martin A; Zablotowicz, Robert M; Reddy, Krishna N; Steinriede, R Wade

    2008-02-01

    Conservation tillage mitigates soil loss in cropland because plant residues help protect the soil, but effects on pesticide movement in surface runoff are not as straightforward. Effects of soil disturbance on surface runoff loss of chlorimuron and alachlor were evaluated utilizing runoff trays. Soil in the trays was either disturbed (tilled) and kept bare or was not tilled, and existing decomposed plant residue was left on the surface. Rainfall (25mm, 20min) was simulated 1d after alachlor (2.8kg ha(-1)) or chlorimuron (54g ha(-1)) application, and runoff was collected. Runoff fractions were analyzed for herbicide and sediment. Total alachlor loss from bare plots was greater than that in no-tillage plots (4.5% vs. 2.3%, respectively). More than one-third of total alachlor lost from bare plots occurred in the first l of runoff, while no-tillage plots had less runoff volume with a more even distribution of alachlor concentration in the runoff during the rainfall simulation and subsequent runoff period. In contrast, more chlorimuron was lost from no-tillage plots than bare plots (12% vs. 1.5%) even though total runoff volume was lower in the no-tillage plots (10.6mm vs. 13.6mm). This was attributed to dense coverage with partially decomposed plant residue in no-tillage plots (1652kg ha(-1)) that intercepted chlorimuron. It was likely that chlorimuron, a polar compound, was more easily washed off surface plant residues and transported in runoff.

  19. Pesticide occurrence in groundwater in areas of high-density row crop production in Alabama, 2009

    USGS Publications Warehouse

    Moreland, Richard S.

    2011-01-01

    High-density row crop production occurs in three areas of Alabama that are underlain by productive aquifers, northern Alabama, southeastern Alabama, and Baldwin County in southwestern Alabama. The U.S. Geological Survey collected five groundwater samples from each of these three areas during 2009 for analysis of selected pesticides. Results of these analyses showed detections for 37 of 152 analytes. The three most frequently detected compounds were atrazine, 2-Chloro-4-isopropylamino-6-amino-triazine (CIAT), and metolachlor. The highest concentration for any analyte was 4.08 micrograms per liter for metolachlor.

  20. Occurrence of pesticides in groundwater underlying areas of high-density row-crop production in Alabama, 2009-2013

    USGS Publications Warehouse

    Welch, Heather L.

    2015-01-01

    Concentrations of metolachlor and atrazine have substantially decreased in the northern Alabama wells since 2000. A decline in use of metolachlor and atrazine from a high in the late-1990s and a high in 2004, respectively, in northern Alabama could account for the lower concentrations. Fluometuron use has also declined since 1998, but the relation between time and concentrations differed in the five northern Alabama wells. Fluometuron concentrations in three of the five wells have been decreasing over time, while concentrations in the remaining two wells have been increasing.

  1. Occurrence and distribution of organic chemicals and nutrients and comparison of water-quality data from public drinking-water supplies in the Columbia aquifer in Delaware, 2000-08

    USGS Publications Warehouse

    Reyes, Betzaida

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Delaware Department of Natural Resources and Environmental Control and the Delaware Geological Survey, conducted a groundwater-quality investigation to (a) describe the occurrence and distribution of selected contaminants, and (b) document any changes in groundwater quality in the Columbia aquifer public water-supply wells in the Coastal Plain in Delaware between 2000 and 2008. Thirty public water-supply wells located throughout the Columbia aquifer of the Delaware Coastal Plain were sampled from August through November of 2008. Twenty-two of the wells in the sampling network for this project were previously sampled in 2000. Eight new wells were selected to replace wells no longer in use. Groundwater collected from the wells was analyzed for the occurrence and distribution of selected pesticides, pesticide degradates, volatile organic compounds, nutrients, and major inorganic ions. Nine of the wells were analyzed for radioactive elements (radium-226, radium-228, and radon). Groundwater-quality data were compared for sites sampled in both 2000 and 2008 to document any changes in water quality. One or more pesticides were detected in samples from 29 of the 30 wells. There were no significant differences in pesticide and pesticide degradate concentrations and similar compounds were detected when comparing sampling results from 2000 and 2008. Pesticide and pesticide degradate concentrations were generally less than 1 microgram per liter. Twenty-four compounds, 14 pesticides, and 10 pesticide degradates were detected in at least one sample; the pesticide degradates, metolachlor ethanesulfonic acid, deethylatrazine, and alachlor ethanesulfonic acid were the most frequently detected compounds, each found in more than 50 percent of samples. Almost 80 percent of the detected pesticides were agricultural herbicides, which reflects the prevalence and wide distribution of agriculture in sampled areas, as well the dominance of

  2. Altitude, age, and quality of groundwater, Papio-Missouri River Natural Resources District, eastern Nebraska, 1992 to 2009

    USGS Publications Warehouse

    McGuire, Virginia L.; Ryter, Derek W.; Flynn, Amanda S.

    2012-01-01

    the 21 pesticides detected (alachlor, atrazine, and metolachlor) have established health-

  3. NTP technical report on the toxicity studies of Pesticide/Fertilizer Mixtures Administered in Drinking Water to F344/N Rats and B6C3F1 Mice.

    PubMed

    Yang, R.

    1993-08-01

    Toxicity studies were performed with pesticide and fertilizer mixtures representative of groundwater contamination found in California and Iowa. The California mixture was composed of aldicarb, atrazine, 1,2-dibromo-3-chloropropane, 1,2- dichloropropane, ethylene dibromide, simazine, and ammonium nitrate. The Iowa mixture contained alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate. The mixtures were administered in drinking water (with 512 ppm propylene glycol) to F344/N rats and B6C3F1 mice of each sex at concentrations ranging from 0.1x to 100x, where 1x represented the median concentrations of the individual chemicals found in studies of groundwater contamination from normal agricultural activities. This report focuses primarily on 26-week toxicity studies describing histopathology, clinical pathology, neurobehavior/neuropathology, and reproductive system effects. The genetic toxicity of the mixtures was assessed by determining the frequency of micronuclei in peripheral blood of mice and evaluating micronuclei and sister chromatid exchanges in splenocytes from female mice and male rats. Additional studies with these mixtures that are briefly reviewed in this report include teratology studies with Sprague-Dawley rats and continuous breeding studies with CD-1 Swiss mice. In 26-week drinking water studies of the California and the Iowa mixtures, all rats (10 per sex and group) survived to the end of the studies, and there were no significant effects on body weight gains. Water consumption was not affected by the pesticide/fertilizer contaminants, and there were no clinical signs of toxicity or neurobehavioral effects as measured by a functional observational battery, motor activity evaluations, thermal sensitivity evaluations, and startle response. There were no clear adverse effects noted in clinical pathology (including serum cholinesterase activity), organ weight, reproductive system, or histopathologic evaluations, although absolute

  4. Water-Quality Assessment of the Trinity River Basin, Texas - Nutrients and Pesticides in the Watersheds of Richland and Chambers Creeks, 1993-95

    USGS Publications Warehouse

    Land, L.F.

    1997-01-01

    from the sampling site. Herbicides were detected in the streams much more often than insecticides were. Nineteen herbicides and 9 insecticides were detected at the 08064100 Chambers Creek near Rice site. Atrazine and metolachlor, the most commonly detected herbicides, occurred in all samples at this site. Other herbicides detected in 25 percent or more of the samples were alachlor, fluometuron, prometon, simazine, trifluralin, and 2,4-D. At the beginning of the study, the number of herbicides detected in the five stream sites was 4 or 5. The greatest number of herbicides detected in the streams occurred in May samples, ranging from 7 to 10. The number of herbicides detected in the Richland-Chambers Reservoir ranged from 6 to 8. Generally, more herbicides were detected in high-streamflow samples than in low-streamflow samples. However, a consistent relation between the number of herbicides in samples and the percentage of cropland in a drainage area was not evident. At the beginning of the study, atrazine concentrations at the stream sites were less than 0.4 microgram per liter, except at one site. In the streams, concentrations peaked in March and April; the greatest peak concentration was 20 micrograms per liter. By the end of the study, atrazine concentrations decreased to less than 0.4 microgram per liter at all the stream sites. In the Richland-Chambers Reservoir, the concentrations were about 1 microgram per liter during February-March and about 3 micrograms per liter in June. Atrazine concentrations tended to increase with increasing streamflow. A consistent relation between atrazine concentrations and the percentage of cropland in a drainage area was not evident. The greatest number of insecticides detected in water samples was two. Diazinon, the most frequently detected insecticide, had slightly greater concentrations in May and June - between 0.01 and 0.02 microgram per liter. The only organochlorine insecticides detected in bed-sedime

  5. Quality of water on the Prairie Band Potawatomi Reservation, northeastern Kansas, February 1999 through February 2001

    USGS Publications Warehouse

    Trombley, T.J.

    2001-01-01

    concern on the reservation with fecal coliform concentrations ranging from 4 to greater than 31,000 colonies per 100 milliliters of water with a median concentration of 570 colonies per 100 milliliters. More than one-half of the surface-water-quality samples exceeded the Kansas Department of Health and Environment contact recreation criteria of 200 and 2,000 colonies per 100 milliliters of water and were collected mostly during the spring and summer. Two wells had sodium concentrations of about 10 times the U.S. Environmental Protection Agengy health advisory level (HAL) of 20 mg/L; concentrations ranged from 241 to 336 mg/L. In water from two wells, sulfate concentrations exceeded 800 mg/L, more than three times the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level (SMCL) for drinking water of 250 mg/L. All but two of the eight ground-water-quality samples had dissolved-solids concentrations exceeding the SMCL of 500 mg/L. The highest concentration of 2,010 mg/L was more than four times the SMCL. Dissolved boron concentrations exceeded the U.S. Environmental Protection Agency 600-?g/L HAL in water from two of the seven wells sampled. Because the HAL is for a lifetime of exposure, the anticipated health risk due to dissolved boron is low. Dissolved iron concentrations in ground-water samples exceeded the 300-?g/L SMCL for treated drinking water in three of the seven wells sampled. Dissolved manganese concentrations in water from the same three wells also exceeded the established SMCL of 50 ?g/L. Dissolved pesticides were not detected in any of the well samples; however, there were degradation products of the herbicides alachlor and metolachlor in several samples. Insecticides were not detected in any ground-water-quality samples. Low concentrations of E. coli and fecal coliform bacteria were detected in water from two wells, and E. coli was detected in water from one well. Much higher concentrations of E. coli, fecal coliform, and fecal strepto

  6. Sediment deposition and selected water-quality characteristics in Cedar Lake and Lake Olathe, Northeast Kansas, 2000

    USGS Publications Warehouse

    Mau, D.P.

    2002-01-01

    .91 pound per acre per year for Lake Olathe. Phosphorus yields in the Cedar Lake watershed were largest of the six Kansas impoundment watersheds recently studied. Concentrations of total ammonia plus organic nitrogen as nitrogen in bottom sediment increased from upstream to downstream in both Cedar Lake and Lake Olathe. Mean concentrations of total ammonia plus organic nitrogen as nitrogen (N) ranged from 2,000 to 2,700 milligrams per kilogram in bottom-sediment samples from Cedar Lake and from 1,300 to 2,700 milligrams per kilogram in samples from Lake Olathe. There was no statistical significance between total ammonia plus organic nitrogen as nitrogen and depth of bottom sediment. Concentrations of six trace elements in bottom sediment from Cedar Lake and Lake Olathe (arsenic, chromium, copper, lead, nickel, and zinc) exceeded the U.S. Environmental Protection Agency Threshold Effects Levels (TELs) sediment-quality guidelines for aquatic organisms in sediment except for one lead concentration. Probable Effects Levels (PELs) for trace elements, however, were not exceeded at either lake. Organochlorine and organophosphate insecticides were not detected in bottom-sediment samples from either Cedar Lake or Lake Olathe, but the acetanilide herbicides alachlor and metolachlor were detected in sediment from both lakes. The U.S. Environmental Protection Agency has not proposed TEL or PEL guideline concentrations for bottom sediment for any of the organophosphate, acetanilide, or triazine pesticides. The diatoms (microscopic, single-celled organisms) Cyclotella bodanica, an indicator of low organic-enriched water, and Cyclotella meneghiniana, an indicator of organic-enriched water, were both present in bottom sediment from Lake Olathe. The presence of both of these diatoms suggests varying periods of low and high eutrophication in Lake Olathe from 1956 to 2000. The concentrations of two species in bottom sediment from Cedar Lake, Aulacoseira cf alpigena and Cyclotella meneg

  7. Herbicides and degradates in shallow aquifers of Illinois: Spatial and temporal trends

    USGS Publications Warehouse

    Mills, P.C.; Kolpin, D.W.; Scribner, E.A.; Thurman, E.M.

    2005-01-01

    During the fall of 2000, the occurrence was examined of 16 herbicides and 13 herbicide degradates in samples from 55 wells in shallow aquifers underlying grain producing regions of Illinois. Herbicide compounds with concentrations above 0.05 ??g/L were detected in 56 percent of the samples. No concentrations exceeded regulatory drinking water standards. The six most frequently detected compounds were degradates. Water age was an important factor in determining vulnerability of ground water to transport of herbicide compounds. Unconsolidated aquifers, which were indicated to generally contain younger ground water than bedrock aquifers, had a higher occurrence of herbicides (73 percent of samples) than bedrock aquifers (22 percent). Temporal analysis to determine if changes in concentrations of selected herbicides and degradates could be observed over a near decadal period indicated a decrease in detection frequency (25 to 18 percent) between samplings in 1991 and 2000. Over this period, significant differences in concentrations were observed for atrazine (decrease) and total acetochlor (increase). The increase in acetochlor compound concentrations corresponds to an increase in acetochlor use during the study period, while the decrease in atrazine concentrations corresponds to relatively consistent use of atrazine. Changes in frequency of herbicide detection and concentration do not appear related to changes in land use near sampled wells.

  8. Data worth and prediction uncertainty for pesticide transport and fate models in Nebraska and Maryland, United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few studies have attempted to quantify mass balances of both pesticides and degradates in multiple agricultural settings of the United States. We used inverse modeling to calibrate the Root Zone Water Quality Model (RZWQM) for predicting the unsaturated-zone transport and fate of metolachlor, metola...

  9. Water-Quality Assessment of the Trinity River Basin, Texas - Pesticides in a Coastal Prairie Agricultural Area, 1994-95

    USGS Publications Warehouse

    Brown, M.F.

    1996-01-01

    Agriculture is a major land use in the coastal prairie area located in the southern part of the Trinity River Basin. Crops grown in the area include rice, sorghum, and soybeans. Pesticide- use estimates for the area show that compounds with the highest use are the herbicides: molinate, propanil, thiobencarb, metolachlor, acifluorfen, bentazon, and atrazine and the insecticides: carbaryl and methyl parathion. More than 20 pesticide samples collected from each of three streams in the coastal prairie resulted in detections of 29 different pesticide compounds. The most frequently detected compounds were the herbicides: atrazine, metolachlor, and molinate, which were detected in more than 75 percent of the samples. Herbicides were detected more frequently than insecticides. Maximum concentrations of atrazine, metolachlor, and molinate occurred in the spring and were 4, 1.9, and 200 micrograms per liter (?g/L), respectively. Almost all concentrations of atrazine and metolachlor were below drinking water standards; no standard is available for molinate. Concentrations and estimated loads and percent of applied compound lost to the streams were generally higher in the watersheds where more of the pesticides were applied to crops.

  10. Estimated annual agricultural pesticide use for counties of the conterminous United States, 2008-12

    USGS Publications Warehouse

    Baker, Nancy T.; Stone, Wesley W.

    2015-01-01

    Table 8: 2, 4-D through Chlorantraniliprole Table 9: Chlorethoxyfos through Diflufenzopyr Table 10: Dimethenamid through Gibberellic acid Table 11: Glufosinate through Metiram Table 12: Metolachlor through Propazine Table 13: Propiconazole through Triasulfuron Table 14: Tribenuron methyl through Zoxamide

  11. Solute Transport in Eroded and Rehabilitated Prairie Landforms. 2. Reactive Solute

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information regarding the impact of varying soil, landscape, and climate conditions on the off-site transport of pesticides is critical to the development of improved pesticide management practices. We quantified the rate of S-metolachlor dissipation after fall and spring application in eroded and r...

  12. Herbicide washoff from forest canopy through fall depends on rainfall dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fate of herbicides, atrazine and metolachlor, released to the atmosphere and deposited in rain was studied following their field application in a small agricultural watershed located in Maryland. We monitored delivery of herbicides in the rain in both open and closed canopy areas of a forested ripa...

  13. Responses of phytoplankton and Hyalella azteca to agrichemical mixtures in a constructed wetland mesocosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed the capability of a constructed wetland to mitigate toxicity of a variety of possible mixtures such as nutrients only (N, P), pesticides only (atrazine, S-metolachlor, permethrin), and nutrients+pesticides on phytoplankton chlorophyll a, 48 h aqueous Hyalella azteca survival, and 10 d se...

  14. Pesticides in surface water from three agricultural basins in south-central Georgia, 1993-97

    USGS Publications Warehouse

    Hatzell, H.H.

    1996-01-01

    Twenty-two of 43 pesticides analyzed were detected in 128 water samples collected from Tucsawhatchee Creek, the Little River, and the Withlacoochee River. These streams drain agricultural basins in south-central Georgia and were sampled from March 1993 through June 1995. Herbicides were detected more frequently than insecticides. The most frequently detected herbicides were atrazineand metolachlor and the most frequently detected insecticide was carbaryl. Pesticide concentrations in the three streams were low and did not exceed U.S. Environmental Protection Agency drinking water standards. The maximum pesticide concentration was 2.6 ug/L (micrograms per liter) for propargite, a miticide detected in only one sample. The maximum concentrations of the remaining 21 pesticides were less than 0.25 ug/L. The median concentrations were equal to the method detection limit for all pesticides except atrazine (0.008 ug/L) and metolachlor (0.012 ug/L). The ratio of herbicidedetections to nondetections was largest in the planting season, smaller in the harvest season and smallest in the fallow season for the three basins.The same pattern existed for the insecticide ratios in the Little River and the Withlacoochee River. Pairwise correlations between concentrations of atrazine and metolachlor and four parameters (discharge, and concentrations of dissolved organiccarbon, suspended organic carbon, and suspended fine sediment) were evaluated for each stream. The strongest correlations existed between metolachlor and mean daily discharge and metolachlor and fine sediment in the Withlacoochee River. The only significant correlation for the Little River was between atrazine and suspended fine sediment.

  15. Influence of watershed system management on herbicide concentrations in Mississippi Delta oxbow lakes.

    PubMed

    Zablotowicz, Robert M; Locke, Martin A; Krutz, L Jason; Lerch, Robert N; Lizotte, Richard E; Knight, Scott S; Gordon, R Earl; Steinriede, R Wade

    2006-11-01

    The Mississippi Delta Management Systems Evaluation Area (MD-MSEA) project was established in 1994 in three small watersheds (202 to 1,497 ha) that drain into oxbow lakes (Beasley, Deep Hollow, and Thighman). The primary research objective was to assess the implications of management practices on water quality. Monthly monitoring of herbicide concentrations in lake water was conducted from 2000 to 2003. Water samples were analyzed for atrazine, cyanazine, fluometuron, metolachlor, and atrazine metabolites. Herbicide concentrations observed in the lake water reflected cropping systems of the watershed, e.g., atrazine and metolachlor concentrations were associated with the level of corn and sorghum production, whereas cyanazine and fluometuron was associated with the level of glyphosate-sensitive cotton production. The dynamics of herbicide appearance and dissipation in lake samples were strongly influenced by herbicide use, lake hydrology, rainfall pattern, and land management practices. The highest maximum concentrations of atrazine (7.1 to 23.4 microg L(-1)) and metolachlor (0.7 to 14.9 microg L(-1)) were observed in Thighman Lake where significant quantities of corn were grown. Introduction of s-metolachlor and use of glyphosate-resistant cotton coincided with reduced concentration of metolachlor in lake water. Cyanazine was observed in two lakes with the highest levels (1.6 to 5.5 microg L(-1)) in 2000 and lower concentrations in 2001 and 2002 (<0.4 microg L(-1)). Reduced concentrations of fluometuron in Beasley Lake were associated with greater use of glyphosate-resistant cotton and correspondingly less need for soil-applied fluometuron herbicide. In contrast, increased levels of fluometuron were observed in lake water after Deep Hollow was converted from conservation tillage to conventional tillage, presumably due to greater runoff associated with conventional tillage. These studies indicate that herbicide concentrations observed in these three watersheds were

  16. Pesticide dose estimates for children of Iowa farmers and non-farmers.

    PubMed

    Curwin, Brian D; Hein, Misty J; Sanderson, Wayne T; Striley, Cynthia; Heederik, Dick; Kromhout, Hans; Reynolds, Stephen J; Alavanja, Michael C

    2007-11-01

    Farm children have the potential to be exposed to pesticides. Biological monitoring is often employed to assess this exposure; however, the significance of the exposure is uncertain unless doses are estimated. In the spring and summer of 2001, 118 children (66 farm, 52 non-farm) of Iowa farm and non-farm households were recruited to participate in a study investigating potential take-home pesticide exposure. Each child provided an evening and morning urine sample at two visits spaced approximately 1 month apart, with the first sample collection taken within a few days after pesticide application. Estimated doses were calculated for atrazine, metolachlor, chlorpyrifos, and glyphosate from urinary metabolite concentrations derived from the spot urine samples and compared to EPA reference doses. For all pesticides except glyphosate, the doses from farm children were higher than doses from the non-farm children. The difference was statistically significant for atrazine (p<0.0001) but only marginally significant for chlorpyrifos and metolachlor (p = 0.07 and 0.1, respectively). Among farm children, geometric mean doses were higher for children on farms where a particular pesticide was applied compared to farms where that pesticide was not applied for all pesticides except glyphosate; results were significant for atrazine (p = 0.030) and metolachlor (p = 0.042), and marginally significant for chlorpyrifos (p = 0.057). The highest estimated doses for atrazine, chlorpyrifos, metolachlor, and glyphosate were 0.085, 1.96, 3.16, and 0.34 microg/kg/day, respectively. None of the doses exceeded any of the EPA reference values for atrazine, metolachlor, and glyphosate; however, all of the doses for chlorpyrifos exceeded the EPA chronic population adjusted reference value. Doses were similar for male and female children. A trend of decreasing dose with increasing age was observed for chlorpyrifos.

  17. Bioremediation strategies for pesticide-contaminated sites

    SciTech Connect

    Chaplin-Anhalt, J.A.; Anderson, T.A.; Perkovich, B.S.

    1995-12-31

    As the number of pesticide-contaminated sites at places such as agrochemical dealerships continues to grow there is an urgent need to find methods of remediation. Soils from two pesticide-contaminated sites, Alpha and Bravo, were analyzed using gas chromatography. The contaminants and their concentrations ({mu}g/g) were as follows: atrazine (0.1 to 24), metolachlor (2 to 121), trifluralin (1 to 244), and pendimethalin (5 to 334). A radiotracer study was conducted to determine the fate of a combined application of atrazine and metolachlor at a concentration of 50 {mu}g/g each. The mixture was applied to Alpha and Bravo nonvegetated soils and Kochia scoparia rhizosphere soils. After 30 d incubation in Bravo soil, mineralization of metolachlor was minimal with less than 1% recovered as {sup 14}CO{sub 2}. Metolachlor degradation in the rhizosphere soil was greater than in nonvegetated soils with 56% and 100% of metolachlor remaining, respectively, after 30 d. Atrazine mineralization was as high as 62% of the applied {sup 14}C. Additional soil from Bravo was treated with 50 {mu}g/g of unlabeled atrazine. The soil was divided into three treatments and a control with three replicates each. Each treatment involved inoculation of 100 g of Bravo soil with 2 g from one of three soils determined in our laboratory to have enhanced atrazine degradative capabilities. Soils were incubated for 15 or 35 d. The soils will be analyzed by gas chromatography to determine which, if any, of the inoculants increase the degradation of atrazine.

  18. Detection of Pesticides and Pesticide Metabolites Using the Cross Reactivity of Enzyme Immunoassays

    USGS Publications Warehouse

    Thurman, E.M.; Aga, D.S.

    2001-01-01

    Enzyme immunoassay is an important environmental analysis method that may be used to identify many pesticide analytes in water samples. Because of similarities in chemical structure between various members of a pesticide class, there often may be an unwanted response that is characterized by a percentage of cross reactivity. Also, there may be cross reactivity caused by degradation products of the target analyte that may be present in the sample. In this paper, the concept of cross reactivity caused by degradation products or by nontarget analytes is explored as a tool for identification of metabolites or structurally similar compounds not previously known to be present in water samples. Two examples are examined in this paper from various water quality studies. They are alachlor and its metabolite, alachlor ethane sulfonic acid, and atrazine and its class members, prometryn and propazine. A method for using cross reactivity for the detection of these compounds is explained in this paper.

  19. Evaluating Microtox as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes.

    PubMed

    Lapertot, Milena; Ebrahimi, Sirous; Oller, Isabel; Maldonado, Manuel I; Gernjak, Wolfgang; Malato, Sixto; Pulgarín, César

    2008-03-01

    To shorten phototreatment time is of major concern for the cost and energy benefits of the xenobiotics degradation performed by photocatalytic processes. Using photo-Fenton and TiO(2) phototreatments, partially photodegraded solutions of 6 separate pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) were tested for biocompatibility, which was evaluated according to the Zahn-Wellens procedure. This study investigated if Microtox could be considered as a suitable global indicator capable of giving information on the evolution of biocompatibility of the water solution contaminated with organic pollutants during the phototreatment in order to promote biotreatment. The obtained results demonstrated that biodegradability increased significantly after short photo-Fenton treatment times for alachlor, diuron and pentachlorophenol. Uncertain results were obtained with atrazine and isoproturon. Microtox acute toxicity testing was shown to correctly represent dynamics and efficiency of phototreatment.

  20. Evaluating Microtox as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes.

    PubMed

    Lapertot, Milena; Ebrahimi, Sirous; Oller, Isabel; Maldonado, Manuel I; Gernjak, Wolfgang; Malato, Sixto; Pulgarín, César

    2008-03-01

    To shorten phototreatment time is of major concern for the cost and energy benefits of the xenobiotics degradation performed by photocatalytic processes. Using photo-Fenton and TiO(2) phototreatments, partially photodegraded solutions of 6 separate pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) were tested for biocompatibility, which was evaluated according to the Zahn-Wellens procedure. This study investigated if Microtox could be considered as a suitable global indicator capable of giving information on the evolution of biocompatibility of the water solution contaminated with organic pollutants during the phototreatment in order to promote biotreatment. The obtained results demonstrated that biodegradability increased significantly after short photo-Fenton treatment times for alachlor, diuron and pentachlorophenol. Uncertain results were obtained with atrazine and isoproturon. Microtox acute toxicity testing was shown to correctly represent dynamics and efficiency of phototreatment. PMID:18155146

  1. Organochlorine and organophosphorus pesticide residues in raw buffalo milk from agroindustrial areas in Assiut, Egypt.

    PubMed

    Shaker, Eman M; Elsharkawy, Eman E

    2015-01-01

    Raw buffalo milk samples from the agroindustrial zone in upper Egypt were analyzed for the presence of organochlorine and organophosphorus pesticides using gas chromatography-mass spectroscopy. Five organochlorine pesticides namely, alachlor, dieldrin, hexachlorobenzene, lindane and methoxychlor and three organophosphorus pesticides chlorpyrifos, malathion, and parathion-methyl were detected in the milk samples. In 44% of the samples, the concentrations of lindane and malathion residues exceeded tolerance levels set by the European Commission (EC) in 2008. In addition, the concentrations of chlorpyrifos, methoxychlor, and hexachlorobenzene residues exceeded the 2008 EC maximum residual limits (MRLs) by 33, 66, and 88% of the examined samples, respectively. However, the levels of alachlor, dieldrin, and parathion-methyl residues were below EC MRLs. The results of this study confirm the risks of pesticide residues exposure that threaten consumer health in Egypt. Thus, we recommend that pesticide residue monitoring programs be instituted in all the developing countries.

  2. Controlled release of water-soluble herbicides

    SciTech Connect

    Riggle, B.D.

    1985-01-01

    Pine kraft lignin was used to control the release of metribuzin (4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one) and alachlor (2-chloro-2',6'-diethyl-N-methoxy-methyl acetanalide). Soil thin layer chromatography (TLC) analysis using /sup 14/C-metribuzin and /sup 14/C-alachlor demonstrated that NB-5203-58 series and PC940 series kraft lignins could retard the mobility of both herbicides after multiple soil TLC plate developments with water. Soil column chromatography analysis demonstrated that PC940C could retard the mobility of both herbicides after soil column water leaching by positioning the herbicides in the top portion of the soil column where the PC940C-herbicide mixture had been applied. There was a concentration effect where, as more PC940C was used, more /sup 14/C-labelled herbicide was retained in the top portion of the soil columns. Soil column chromatography and soil TLC plate analysis demonstrated that /sup 3/H-PC940C was immobile. Finally, PC940C significantly reduced metribuzin related phytotoxicity to field and greenhouse grown soybeans (Glycine max (L.) Merr.) which had been treated with PC940C rates of 0.77 and 1.15 L/ha and metribuzin rates of 0.42 and 0.84 kg/ha. The results for /sup 14/C-metribuzin and /sup 14/C-alachlor as well as the reduction in metribuzin related phytotoxicity to soybeans suggests that PC940C can effectively control the release of metribuzin and alachlor.

  3. Herbicide and nitrate variation in alluvium underlying a cornfield at a site in Iowa County, Iowa

    USGS Publications Warehouse

    Kalkhoff, S.J.; Detroy, M.G.; Cherryholmes, K.; Kuzniar, R.L.

    1992-01-01

    A hydrologic investigation to determine vertical and seasonal variation of atrazine, alachlor, cyanazine, and nitrate at one location and to relate the variation to ground-water movement in the Iowa River alluvium was conducted in Iowa County, Iowa, from March 1986 to December 1987. Water samples were collected at discrete intervals through the alluvial sequence from the soil zone to the base of the aquifer. Alachlor, atrazine, and cyanazine were detected most frequently in the soil zone but also were present in the upper part of the alluvial aquifer. Alachlor was detected sporadically, whereas, atrazine, cyanazine, and nitrate were present throughout the year. In the alluvial aquifer, the herbicides generally were not detected during 1986 and were present in detectable concentrations for only a short period of time in the upper 1.6 meters of the aquifer during 1987. Nitrate was present throughout the alluvium and was stratified in the alluvial aquifer. The largest nitrate concentrations were detected in the middle part of the aquifer. Nitrate concentrations were variable only in the upper 2 meters of the aquifer. Vertical movement of herbicides and nitrate in the soil correlated with precipitation and degree of saturation. A clay layer retarded vertical movement of atrazine but not nitrate from the soil layer to the aquifer. Vertical movement could not account for the chemical variation in the alluvial aquifer.

  4. Human skin binding and absorption of contaminants from ground and surface water during swimming and bathing

    SciTech Connect

    Wester, R.C.; Maibach, H.I. )

    1989-10-01

    Contaminants exist in ground and surface water. Human skin has the capacity to bind and then absorb these contaminants into the body during swimming and bathing. Powdered human stratum corneum will bind both lipid-soluble (alachlor, polychlorinated biphenyls (PCBs), benzene) and water-soluble (nitroaniline) chemicals. In vitro (Human skin) and in vivo (Rhesus monkey) studies show that these chemicals readily distribute into skin, and then some of the chemical is absorbed into the body. Linearity in binding and absorption exists for nitroaniline over a 10-fold concentration range. Multiple exposure to benzene is at least cumulative. Binding and adsorption can be significant for exposures as short as 30 minutes, and will increase with time. Adsorption with water dilution increased for alachlor, but not for dinoseb. Soap reversed the partitioning of alachlor between human stratum corneum and water. The PCBs could be removed from skin by soap and water for up to 3 hours and the decontamination potential decreased, due to continuing skin absorption. The model that in vitro and in vivo systems used should permit easy estimation of this area of extensive human exposure effect on risk assessment. 5 refs., 9 tabs.

  5. Ground water contamination and costs of pesticide restrictions in the southeastern coastal plain

    SciTech Connect

    Danielson, L.E.; Carlson, G.A.; Liu, S.; Weber, J.B.; Warren, R.

    1993-01-01

    The project developed new methodology for estimating: (1) groundwater contamination potential (GWCP) in the Southeast Coastal Plain, and (2) the potential economic impacts of selected policies that restrict pesticide use. The potential for ground water contamination was estimated by use of a simple matrix for combining ratings for both soil leaching potential and pesticide leaching potential. Key soil variables included soil texture, soil acidity and organic matter content. Key pesticide characteristics included Koc, pesticide half-life, the rate of application and the fraction of the pesticide hitting the soil. Comparisons of pesticide use from various farmer and expert opinion surveys were made for pesticide groups and for individual pesticide products. Methodology for merging the GWCP changes and lost benefits from selected herbicide cancellations was developed using corn production in the North Carolina Coastal Plain. Economic evaluations of pesticide cancellations for corn included national and Coastal Plain estimates for atrazine; metolachlor; dicamba; dicamba and atrazine; and dicamba, atrazine and metolachlor.

  6. Occurrence and fate of pesticides in four contrasting agricultural settings in the United States

    USGS Publications Warehouse

    Steele, G.V.; Johnson, H.M.; Sandstrom, M.W.; Capel, P.D.; Barbash, J.E.

    2008-01-01

    Occurrence and fate of 45 pesticides and 40 pesticide degradates were investigated in four contrasting agricultural settings—in Maryland, Nebraska, California, and Washington. Primary crops included corn at all sites, soybeans in Maryland, orchards in California and Washington, and vineyards in Washington. Pesticides and pesticide degradates detected in water samples from all four areas were predominantly from two classes of herbicides—triazines and chloroacetanilides; insecticides and fungicides were not present in the shallow ground water. In most samples, pesticide degradates greatly exceeded the concentrations of parent pesticide. In samples from Nebraska, the parent pesticide atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] was about the same concentration as the degradate, but in samples from Maryland and California atrazine concentrations were substantially smaller than its degradate. Simazine [6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine], the second most detected triazine, was detected in ground water from Maryland, California, and Washington. Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] rarely was detected without its degradates, and when they were detected in the same sample metolachlor always had smaller concentrations. The Root-Zone Water-Quality Model was used to examine the occurrence and fate of metolachlor at the Maryland site. Simulations accurately predicted which metolachlor degradate would be predominant in the unsaturated zone. In analyses of relations among redox indicators and pesticide variance, apparent age, concentrations of dissolved oxygen, and excess nitrogen gas (from denitrification) were important indicators of the presence and concentration of pesticides in these ground water systems.

  7. Occurrence of selected trace elements and organic compounds and their relation to land use in the Willamette River basin, Oregon, 1992-94

    USGS Publications Warehouse

    Anderson, C.W.; Rinella, F.A.; Rounds, S.A.

    1996-01-01

    Results from repeated samplings at two sites during sequential storms in the fall of 1994 indicated that concentrations and loads of several constituents, including suspended sediment, suspended organic carbon, DDT, metolachlor, and atrazine were highest during peak flows of the first or second significant storms of the fall. Samplings during subsequent storms indicated that instantaneous concentrations and loads were generally reduced; however, data were not sufficient to compare overall transport during sequential storms.

  8. Pesticides in streams in New Jersey and Long Island, New York, and relation to land use

    USGS Publications Warehouse

    Reiser, Robert G.; O'Brien, Anne K.

    1999-01-01

    Only three of the seven most frequently detected compounds?atrazine, metolachlor, and carbaryl?are among the seven most heavily applied pesticides in New Jersey. This is because detection frequencies are the result of physical and chemical properties of the pesticide compounds as well as application rates. Water solubility and soil-adsorption coefficients appear to be the two physical properties of pesticides that most influence their presence in streams.

  9. Modeling water infiltration and pesticides transport in unsaturated zone of a sedimentary aquifer

    NASA Astrophysics Data System (ADS)

    Sidoli, Pauline; Angulo-Jaramillo, Rafael; Baran, Nicole; Lassabatère, Laurent

    2015-04-01

    Groundwater quality monitoring has become an important environmental, economic and community issue since increasing needs drinking water at the same time with high anthropic pressure on aquifers. Leaching of various contaminants as pesticide into the groundwater is closely bound to water infiltration in the unsaturated zone which whom solute transport can occur. Knowledge's about mechanisms involved in the transfer of pesticides in the deep unsaturated zone are lacking today. This study aims to evaluate and to model leaching of pesticides and metabolites in the unsaturated zone, very heterogeneous, of a fluvio-glacial aquifer, in the South-East of France, where contamination of groundwater resources by pesticides is frequently observed as a consequence of intensive agricultural activities. Water flow and pesticide transport were evaluated from column tests under unsaturated conditions and from adsorption batch experiments onto the predominant lithofacies collected, composed of a mixture of sand and gravel. A maize herbicide, S-metolachlor, applied on the study site and worldwide and its two major degradation products (metolachlor ethanesulfonic acid and metolachlor oxanilic acid) were studied here. A conservative tracer, bromide ion, was used to determine water dispersive parameters of porous media. Elution curves were obtained from pesticide concentrations analyzed by an ultra-performance liquid chromatography system interfaced to a triple quadrupole mass spectrometer and from bromide concentrations measured by ionic chromatography system. Experimental data were implemented into Hydrus to model flow and solute transfer through a 1D profile in the vadose zone. Nonequilibrium solute transport model based on dual-porosity model with mobile and immobile water is fitting correctly elution curves. Water dispersive parameters show flow pattern realized in the mobile phase. Exchanges between mobile and immobile water are very limited. Because of low adsorptions onto

  10. Sensitivity of freshwater periphytic diatoms to agricultural herbicides.

    PubMed

    Debenest, T; Pinelli, E; Coste, M; Silvestre, J; Mazzella, N; Madigou, C; Delmas, F

    2009-06-01

    The biomonitoring of pesticide pollution in streams and rivers using algae such as diatoms remains difficult. The responses of diatom communities to toxic stress in stream water are disturbed by the variations of environmental parameters. In this study, periphytic algae collected in situ were exposed under controlled conditions to two major herbicides used in French agriculture (isoproturon and s-metolachlor). Three exposure regimes were tested: 5 and 30 microg L(-1) for 6 days and 30 microg L(-1) for 3 days followed by a recovery period of 3 days. The algal biomasses were assessed from pigment concentrations (chlorophyll a and c) and from live cell density. The highest concentration (30 microg L(-1)) of isoproturon inhibited the biomass increase statistically significantly. In periphyton exposed to 5 and 30 microg L(-1) of s-metolachlor, chlorophyll c concentration and live cell density were also statistically significantly lower than in the control. Periphyton left to recover after reduced exposure duration (3 days) showed higher growth rates after treatment with s-metolachlor than with isoproturon. Taxonomic identifications showed that species like Melosira varians, Nitzschia dissipata and Cocconeis placentula were not affected by the herbicide exposure. Other species like Eolimna minima and Navicula reichardtiana were more sensitive. Studying diatoms according to their trophic mode showed that facultative heterotroph species were statistically significantly favoured by isoproturon exposure at the highest concentration. Results obtained with s-metolachlor exposure showed a disturbance of cell multiplication rather than that of photosynthesis. These results suggest that photosynthesis inhibitors like isoproturon favour species able to survive when the autotroph mode is inhibited. PMID:19342109

  11. Ground-water quality in alluvial aquifers in the eastern Iowa basins, Iowa and Minnesota

    USGS Publications Warehouse

    Sadorf, Eric M.; Linhart, S. Michael

    2000-01-01

    The effects of land use on ground-water quality also were examined. There was a positive correlation between percentage of land used for soybean production and concentrations of metolachlor, metolachlor ethanesulfonic acid, and metolachlor oxanilic acid in ground-water samples.Data from this study and from previous studies in the Eastern Iowa Basins were compared statistically by well type (domestic, municipal, and monitoring wells). Well depths were significantly greater in domestic and municipal wells than in monitoring wells. pH, calcium, sulfate, chloride, and atrazine concentrations were significantly higher in municipal-well samples than in domestic-well samples. pH and sulfate concentrations were significantly higher in municipal-well samples than in monitoring-well samples. Ammonia was significantly higher in domestic-well samples than in monitoring-well samples, chloride was significantly higher in monitoring-well samples than in domestic-well samples, and fluoride was significantly higher in domestic-well samples than in municipal-well samples.

  12. Pesticides and their metabolites in community water-supply wells of central and western New York, August 1999

    USGS Publications Warehouse

    Eckhardt, David A.V.; Hetcher, Kari K.; Phillips, Patrick J.; Miller, Todd S.

    2001-01-01

    Ten pesticides and pesticide metabolites were detected in ground-water samples collected from each of 32 community water-supply (CWS) systems in central and west ern New York in August 1999. The sampling sites consisted of 30 wells that ranged from 23 to 120 feet in depth, and 2 springwater infiltration galleries. All wells tapped unconfined sand and gravel aquifers except one, wh ich was completed in karstic limestone. These systems were selected because they were deemed vulnerable to pesticide contamination; accordingly, the results are not considered representative of all CWS systems in New York. The samples were analyzed for 60 pesticides. Twenty-four of the 32 samples contained at least one pesticide, and one sample contained eight pesticides or pesticide metabolites. New York State and Federal water-quality standards were not exceeded in any sample collected in this study. All pesticides detected in the CWS wells are a specific class of herbicides that are used to control broadleaf weeds and undesirable grasses in agricultural fields, lawns, and other areas that require control of vegetation. The four compounds detected most frequently were the herbicides atrazine and metolachlor and their metabolites--deethylatrazine and metolachlor ESA. Maximum concentrations of the four compounds ranged from 0.088 micrograms per liter (?g/L) for deethylatrazine to 3.58 ?g/L for metolachlor ESA.

  13. [Study on usage of pesticides in various countries].

    PubMed

    Yamamoto, Miyako; Toda, Miou; Tanaka, Keiko; Sugita, Takiko; Sasaki, Shiho; Uneyama, Chikako; Morikawa, Kaoru

    2007-01-01

    Usage of pesticides in food items in export countries was studied, focusing items which Japan imports in large quantity. Japan has imported field crops such as wheat, corn and soy bean, and also grapefruit in large quantity on a weight base, mainly from United States, Australia and Canada. While, Japan has imported various kinds of vegetables in which China had the largest share. We collected usage data of pesticides for 44 food items of 17 countries of 2004. Pesticides which were used frequently (usage rank within top ten in each item/country) were dichlorvos, carbofuran, chlorpyrifos, dimethoate (insecticides), mancozeb, carbendazim, thiophanate-methyl, chlorthalonil (fungicides), glyphosate, 2,4-D, paraquat, acetochlor (herbicides). Carbendazim, thiophanate-methyl, acetochlor and dichlorvos were mainly used in China. Dithiocarbamates are used frequently in various food items in various countries, and also frequently detected in monitoring in foreign countries. Some pesticides such as bisultap, monosultap, etaboxam and triazmate were used only in certain countries, and available information on toxicity or analytical method was very limited. Some of pesticides described above have not been analyzed in the pesticide residue monitoring in Japan before 2005,however, many of them are subjects of analysis for import food after 2006 with the enforcement of positivelist system for residues of pesticide and veterinary medicines in food in Japan. PMID:18220053

  14. [Study on usage of pesticides in various countries].

    PubMed

    Yamamoto, Miyako; Toda, Miou; Tanaka, Keiko; Sugita, Takiko; Sasaki, Shiho; Uneyama, Chikako; Morikawa, Kaoru

    2007-01-01

    Usage of pesticides in food items in export countries was studied, focusing items which Japan imports in large quantity. Japan has imported field crops such as wheat, corn and soy bean, and also grapefruit in large quantity on a weight base, mainly from United States, Australia and Canada. While, Japan has imported various kinds of vegetables in which China had the largest share. We collected usage data of pesticides for 44 food items of 17 countries of 2004. Pesticides which were used frequently (usage rank within top ten in each item/country) were dichlorvos, carbofuran, chlorpyrifos, dimethoate (insecticides), mancozeb, carbendazim, thiophanate-methyl, chlorthalonil (fungicides), glyphosate, 2,4-D, paraquat, acetochlor (herbicides). Carbendazim, thiophanate-methyl, acetochlor and dichlorvos were mainly used in China. Dithiocarbamates are used frequently in various food items in various countries, and also frequently detected in monitoring in foreign countries. Some pesticides such as bisultap, monosultap, etaboxam and triazmate were used only in certain countries, and available information on toxicity or analytical method was very limited. Some of pesticides described above have not been analyzed in the pesticide residue monitoring in Japan before 2005,however, many of them are subjects of analysis for import food after 2006 with the enforcement of positivelist system for residues of pesticide and veterinary medicines in food in Japan.

  15. Estimates of pesticide concentrations and fluxes in two rivers of an extensive French multi-agricultural watershed: application of the passive sampling strategy.

    PubMed

    Poulier, Gaëlle; Lissalde, Sophie; Charriau, Adeline; Buzier, Rémy; Cleries, Karine; Delmas, François; Mazzella, Nicolas; Guibaud, Gilles

    2015-06-01

    In this study, the passive sampling strategy was evaluated for its ability to improve water quality monitoring in terms of concentrations and frequencies of quantification of pesticides, with a focus on flux calculation. Polar Organic Chemical Integrative Samplers (POCIS) were successively exposed and renewed at three sampling sites of an extensive French multi-agricultural watershed from January to September 2012. Grab water samples were recovered every 14 days during the same period and an automated sampler collected composite water samples from April to July 2012. Thirty-nine compounds (pesticides and metabolites) were analysed. DEA, diuron and atrazine (banned in France for many years) likely arrived via groundwater whereas dimethanamid, imidacloprid and acetochlor (all still in use) were probably transported via leaching. The comparison of the three sampling strategies showed that the POCIS offers lower detection limits, resulting in the quantification of trace levels of compounds (acetochlor, diuron and desethylatrazine (DEA)) that could not be measured in grab and composite water samples. As a consequence, the frequencies of occurrence were dramatically enhanced with the POCIS compared to spot sample data. Moreover, the integration of flood events led to a better temporal representation of the fluxes when calculated with the POCIS compared to the bimonthly grab sampling strategy. We conclude that the POCIS could be an advantageous alternative to spot sampling, offering better performance in terms of quantification limits and more representative data.

  16. New insights into the interactions between cork chemical components and pesticides. The contribution of π-π interactions, hydrogen bonding and hydrophobic effect.

    PubMed

    Olivella, M À; Bazzicalupi, C; Bianchi, A; Fiol, N; Villaescusa, I

    2015-01-01

    The role of chemical components of cork in the sorption of several pesticides has been investigated. For this purpose raw cork and three cork extracted fractions (i.e. cork free of aliphatic extractives, cork free of all extractives and cork free of all extractives and suberin) were used as sorbent of three ionic pesticides (propazine, 2,4-dichlorophenoxy acetic acid (2,4-D) and alachlor) and five non-ionic pesticides (chlorpyrifos, isoproturon, metamitron, methomyl and oxamyl) with a logKow within the range -0.47 to 4.92. The effect of cations on the ionic pesticides, propazine and 2,4-D sorption was also analyzed. Results indicated that the highest yields were obtained for chlorpyrifos and alachlor sorption onto raw cork (>55%). After removal of aliphatic extractives sorption of all pesticides increased that ranged from 3% for propazine to 31% for alachlor. In contrast, removal of phenolic extractives caused a sorption decrease. Low sorption yields were obtained for hydrophobic pesticides such as metamitron, oxamyl and methomyl (<11%) by using all cork fractions and extremely low when using raw cork (<1%). FTIR analysis was useful to indicate that lignin moieties were the main components involved on the sorption process. Modelling calculations evidenced that π-stacking interactions with the aromatic groups of lignin play a major role in determining the adsorption properties of cork toward aromatic pesticides. Results presented in this paper gain insights into the cork affinities for pesticides and the interactions involved in the sorption process and also enables to envisage sorption affinity of cork for other organic pollutants.

  17. New insights into the interactions between cork chemical components and pesticides. The contribution of π-π interactions, hydrogen bonding and hydrophobic effect.

    PubMed

    Olivella, M À; Bazzicalupi, C; Bianchi, A; Fiol, N; Villaescusa, I

    2015-01-01

    The role of chemical components of cork in the sorption of several pesticides has been investigated. For this purpose raw cork and three cork extracted fractions (i.e. cork free of aliphatic extractives, cork free of all extractives and cork free of all extractives and suberin) were used as sorbent of three ionic pesticides (propazine, 2,4-dichlorophenoxy acetic acid (2,4-D) and alachlor) and five non-ionic pesticides (chlorpyrifos, isoproturon, metamitron, methomyl and oxamyl) with a logKow within the range -0.47 to 4.92. The effect of cations on the ionic pesticides, propazine and 2,4-D sorption was also analyzed. Results indicated that the highest yields were obtained for chlorpyrifos and alachlor sorption onto raw cork (>55%). After removal of aliphatic extractives sorption of all pesticides increased that ranged from 3% for propazine to 31% for alachlor. In contrast, removal of phenolic extractives caused a sorption decrease. Low sorption yields were obtained for hydrophobic pesticides such as metamitron, oxamyl and methomyl (<11%) by using all cork fractions and extremely low when using raw cork (<1%). FTIR analysis was useful to indicate that lignin moieties were the main components involved on the sorption process. Modelling calculations evidenced that π-stacking interactions with the aromatic groups of lignin play a major role in determining the adsorption properties of cork toward aromatic pesticides. Results presented in this paper gain insights into the cork affinities for pesticides and the interactions involved in the sorption process and also enables to envisage sorption affinity of cork for other organic pollutants. PMID:25240950

  18. Nitrate and herbicide loading in two groundwater basins of Illinois' sinkhole plain

    USGS Publications Warehouse

    Panno, S.V.; Kelly, W.R.

    2004-01-01

    This investigation was designed to estimate the mass loading of nitrate (NO3-) and herbicides in spring water discharging from groundwater basins in an agriculturally dominated, mantled karst terrain. The loading was normalized to land use and NO3- and herbicide losses were compared to estimated losses in other agricultural areas of the Midwestern USA. Our study area consisted of two large karst springs that drain two adjoining groundwater basins (total area of 37.7 km2) in southwestern Illinois' sinkhole plain, USA. The springs and stream that they form were monitored for almost 2 years. Nitrate-nitrogen (NO3-N) concentrations at three monitoring sites were almost always above the background concentration (1.9 mg/l). NO3-N concentrations at the two springs ranged from 1.08 to 6.08 with a median concentration of 3.61 mg/l. Atrazine and alachlor concentrations ranged from <0.01 to 34 ??g/l and <0.01 to 0.98 ??g/l, respectively, with median concentrations of 0.48 and 0.12 ??g/l, respectively. Approximately 100,000 kg/yr of NO3-N, 39 kg/yr of atrazine, and 2.8 kg/yr of alachlor were discharged from the two springs. Slightly more than half of the discharged NO3- came from background sources and most of the remainder probably came from fertilizer. This represents a 21-31% loss of fertilizer N from the groundwater basins. The pesticide losses were 3.8-5.8% of the applied atrazine, and 0.05-0.08% of the applied alachlor. The loss of atrazine adsorbed to the suspended solid fraction was about 2 kg/yr, only about 5% of the total mass of atrazine discharged from the springs. ?? 2004 Elsevier B.V. All rights reserved.

  19. Pesticide sorption and leaching potential on three Hawaiian soils.

    PubMed

    Hall, Kathleen E; Ray, Chittaranjan; Ki, Seo Jin; Spokas, Kurt A; Koskinen, William C

    2015-08-15

    On the Hawaiian Islands, groundwater is the principal source of potable water and contamination of this key resource by pesticides is of great concern. To evaluate the leaching potential of four weak acid herbicides [aminocyclopyrachlor, picloram, metsulfuron-methyl, biologically active diketonitrile degradate of isoxaflutole (DKN)] and two neutral non-ionizable herbicides [oxyfluorfen, alachlor], their sorption coefficients were determined on three prevalent soils from the island of Oahu. Metsulfuron-methyl, aminocylcopyrachlor, picloram, and DKN were relatively low sorbing herbicides (K(oc) = 3-53 mL g(-1)), alachlor was intermediate (K(oc) = 120-150 mL g(-1)), and oxyfluorfen sorbed very strongly to the three soils (K(oc) > 12,000 mL g(-1)). Following determination of K(oc) values, the groundwater ubiquity score (GUS) indices for these compounds were calculated to predicted their behavior with the Comprehensive Leaching Risk Assessment System (CLEARS; Tier-1 methodology for Hawaii). Metsulfuron-methyl, aminocyclopyrachlor, picloram, and DKN would be categorized as likely leachers in all three Hawaiian soils, indicating a high risk of groundwater contamination across the island of Oahu. In contrast, oxyfluorfen, regardless of the degradation rate, would possess a low and acceptable leaching risk due to its high sorption on all three soils. The leaching potential of alachlor was more difficult to classify, with a GUS value between 1.8 and 2.8. In addition, four different biochar amendments to these soils did not significantly alter their sorption capacities for aminocyclopyrachlor, indicating a relatively low impact of black carbon additions from geologic volcanic inputs of black carbon. Due to the fact that pesticide environmental risks are chiefly dependent on local soil characteristics, this work has demonstrated that once soil specific sorption parameters are known one can assess the potential pesticide leaching risks.

  20. Nitrate and herbicide loading in two groundwater basins of Illinois' sinkhole plain

    NASA Astrophysics Data System (ADS)

    Panno, S. V.; Kelly, W. R.

    2004-05-01

    This investigation was designed to estimate the mass loading of nitrate (NO 3-) and herbicides in spring water discharging from groundwater basins in an agriculturally dominated, mantled karst terrain. The loading was normalized to land use and NO 3- and herbicide losses were compared to estimated losses in other agricultural areas of the Midwestern USA. Our study area consisted of two large karst springs that drain two adjoining groundwater basins (total area of 37.7 km 2) in southwestern Illinois' sinkhole plain, USA. The springs and stream that they form were monitored for almost 2 years. Nitrate-nitrogen (NO 3-N) concentrations at three monitoring sites were almost always above the background concentration (1.9 mg/l). NO 3-N concentrations at the two springs ranged from 1.08 to 6.08 with a median concentration of 3.61 mg/l. Atrazine and alachlor concentrations ranged from <0.01 to 34 μg/l and <0.01 to 0.98 μg/l, respectively, with median concentrations of 0.48 and 0.12 μg/l, respectively. Approximately 100,000 kg/yr of NO 3-N, 39 kg/yr of atrazine, and 2.8 kg/yr of alachlor were discharged from the two springs. Slightly more than half of the discharged NO 3- came from background sources and most of the remainder probably came from fertilizer. This represents a 21-31% loss of fertilizer N from the groundwater basins. The pesticide losses were 3.8-5.8% of the applied atrazine, and 0.05-0.08% of the applied alachlor. The loss of atrazine adsorbed to the suspended solid fraction was about 2 kg/yr, only about 5% of the total mass of atrazine discharged from the springs.

  1. Quality of ground water used for selected municipal water supplies in Iowa, 1982-96 water years

    USGS Publications Warehouse

    Schaap, B.D.; Linhart, S.M.

    1998-01-01

    Maps show the general location of wells that have been sampled in the various aquifers. Other maps show the location of wells where sulfate and nitrite plus nitrate concentrations exceed the respective Maximum Contaminant Levels and wells where concentrations of the pesticides alachlor, atrazine, or cyanazine exceeded the respective minimum reporting levels. The compact disc included with this report has information about water-quality properties and concentrations of dissolved solids, major ions, nutrients, trace elements, radionuclides, total organic carbon, pesticides, and synthetic organic compounds for water years 1982 through 1996.

  2. A summary of pesticides in ground-water data collected by government agencies in Indiana, December 1985 to April 1991

    USGS Publications Warehouse

    Risch, M.R.

    1994-01-01

    More than 1 pesticide was present in 16 of the 51 samples that had detections, for a total of 90 individual pesticide detections. Concentrations of the detected pesticides ranged from 0.04 to 49 micrograms per liter, and two-thirds of the detected concentrations were less than 1 microgram per liter. In about 29 percent of all detections, the concentration of 9 pesticides alachlor, aldrin, atrazine, dieldrin, EDB, heptachlor, heptachlor epoxide, simazine, and terbufos exceeded either the U.S. Environmental Protection Agency's Maximum Contaminant Level or adult lifetime Health Advisory.

  3. Batch vs continuous-feeding operational mode for the removal of pesticides from agricultural run-off by microalgae systems: A laboratory scale study.

    PubMed

    Matamoros, Víctor; Rodríguez, Yolanda

    2016-05-15

    Microalgae-based water treatment technologies have been used in recent years to treat different water effluents, but their effectiveness for removing pesticides from agricultural run-off has not yet been addressed. This paper assesses the effect of microalgae in pesticide removal, as well as the influence of different operation strategies (continuous vs batch feeding). The following pesticides were studied: mecoprop, atrazine, simazine, diazinone, alachlor, chlorfenvinphos, lindane, malathion, pentachlorobenzene, chlorpyrifos, endosulfan and clofibric acid (tracer). 2L batch reactors and 5L continuous reactors were spiked to 10 μg L(-1) of each pesticide. Additionally, three different hydraulic retention times (HRTs) were assessed (2, 4 and 8 days) in the continuous feeding reactors. The batch-feeding experiments demonstrated that the presence of microalgae increased the efficiency of lindane, alachlor and chlorpyrifos by 50%. The continuous feeding reactors had higher removal efficiencies than the batch reactors for pentachlorobenzene, chlorpyrifos and lindane. Whilst longer HRTs increased the technology's effectiveness, a low HRT of 2 days was capable of removing malathion, pentachlorobenzene, chlorpyrifos, and endosulfan by up to 70%. This study suggests that microalgae-based treatment technologies can be an effective alternative for removing pesticides from agricultural run-off.

  4. Occurrence of Atrazine and Related Compounds in Sediments of Upper Great Lakes.

    PubMed

    Guo, Jiehong; Li, Zhuona; Ranasinghe, Prabha; Bonina, Solidea; Hosseini, Soheil; Corcoran, Margaret B; Smalley, Colin; Kaliappan, Rajashankar; Wu, Yan; Chen, Da; Sandy, Andy L; Wang, Yawei; Rockne, Karl J; Sturchio, Neil C; Giesy, John P; Li, An

    2016-07-19

    Surface grab and core sediment samples were collected from Lakes Michigan, Superior, and Huron from 2010 to 2012, and concentrations of herbicides atrazine, simazine, and alachlor, as well as desethylatrazine (DEA), were determined. Concentrations of atrazine in surface grabs ranged from 0.01 to 1.7 ng/g dry weight and are significantly higher in the southern basin of Lake Michigan (latitude <44°) than other parts of the three lakes. The highest concentration of alachlor was found in sediments of Saginaw Bay in Lake Huron. The inventory and net fluxes of these herbicides were found to decline exponentially from the south to the north. The concentration ratio of DEA to atrazine (DEA/ATZ) increased with latitude, suggesting degradation of atrazine to DEA during atmospheric transport. DEA/ATZ also increased with sediment depth in the sediment cores. Diffusion of deposited herbicides from the upper sediment into deeper sediments has occurred, on the basis of the observed patterns of concentrations in dated sediment cores. Concentrations of atrazine in pore water were estimated and were higher than those reported for the bulk waters, suggesting the occurrence of solid-phase deposition of atrazine through the water column and that contaminated sediments act as a source releasing atrazine to the overlying water.

  5. Acute Oral Poisoning Due to Chloracetanilide Herbicides

    PubMed Central

    Seok, Su-Jin; Choi, Sang-Cheon; Yang, Jong-Oh; Lee, Eun-Young; Song, Ho-Yeon; Hong, Sae-Yong

    2012-01-01

    Chloracetanilide herbicides (alachlor, butachlor, metachlor) are used widely. Although there are much data about chronic low dose exposure to chloracetanilide in humans and animals, there are few data about acute chloracetanilide poisoning in humans. This study investigated the clinical feature of patients following acute oral exposure to chloracetanilide. We retrospectively reviewed the data on the patients who were admitted to two university hospitals from January 2006 to December 2010. Thirty-five patients were enrolled. Among them, 28, 5, and 2 cases of acute alachlor, metachlor, butachlor poisoning were included. The mean age was 49.8 ± 15.4 yr. The poison severity score (PSS) was 17 (48.6%), 10 (28.6%), 5 (14.3%), 2 (5.7%), and 1 (2.9%) patients with a PSS of 0, 1, 2, 3, and 4, respectively. The age was higher for the symptomatic patients (1-4 PSS) than that for the asymptomatic patients (0 PSS) (43.6 ± 15.2 vs 55.7 ± 13.5). The arterial blood HCO3 ¯ was lower in the symptomatic patients (1-4 PSS) than that in the asymptomatic patients (0 PSS). Three patients were a comatous. One patient died 24 hr after the exposure. In conclusion, although chloracetanilide poisoning is usually of low toxicity, elder patients with central nervous system symptoms should be closely monitored and cared after oral exposure. PMID:22323855

  6. Acute oral poisoning due to chloracetanilide herbicides.

    PubMed

    Seok, Su-Jin; Choi, Sang-Cheon; Gil, Hyo-Wook; Yang, Jong-Oh; Lee, Eun-Young; Song, Ho-Yeon; Hong, Sae-Yong

    2012-02-01

    Chloracetanilide herbicides (alachlor, butachlor, metachlor) are used widely. Although there are much data about chronic low dose exposure to chloracetanilide in humans and animals, there are few data about acute chloracetanilide poisoning in humans. This study investigated the clinical feature of patients following acute oral exposure to chloracetanilide. We retrospectively reviewed the data on the patients who were admitted to two university hospitals from January 2006 to December 2010. Thirty-five patients were enrolled. Among them, 28, 5, and 2 cases of acute alachlor, metachlor, butachlor poisoning were included. The mean age was 49.8 ± 15.4 yr. The poison severity score (PSS) was 17 (48.6%), 10 (28.6%), 5 (14.3%), 2 (5.7%), and 1 (2.9%) patients with a PSS of 0, 1, 2, 3, and 4, respectively. The age was higher for the symptomatic patients (1-4 PSS) than that for the asymptomatic patients (0 PSS) (43.6 ± 15.2 vs 55.7 ± 13.5). The arterial blood HCO₃⁻ was lower in the symptomatic patients (1-4 PSS) than that in the asymptomatic patients (0 PSS). Three patients were a comatous. One patient died 24 hr after the exposure. In conclusion, although chloracetanilide poisoning is usually of low toxicity, elder patients with central nervous system symptoms should be closely monitored and cared after oral exposure.