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Sample records for alachlor butachlor metolachlor

  1. 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

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

    USGS Publications Warehouse

    Graham, W.H.; Graham, D.W.; DeNoyelles, F., Jr.; 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

  3. 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).

  4. 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 ...

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

    USGS Publications Warehouse

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

    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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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. PMID:26368393

  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. ANALYTICAL METHOD DEVELOPMENT FOR ALACHLOR ESA AND OTHER ACETANILIDE PESTICIDE TRANSFORMATION PRODUCTS

    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 herbicides currently registered for use in the U.S. are: alachlor, acetochlor, metolachlor, propachlor, dimethenamid and fluf...

  14. Comparative proteome analysis of butachlor-degrading bacteria

    NASA Astrophysics Data System (ADS)

    Wang, Jinhua; Lu, Yitong; Chen, Yingying

    2008-01-01

    A Pseudomonas putida strain, named ER1, was isolated from an agricultural soil and found to actively degrade the herbicide butachlor. The enzyme extracted from ER1 could degrade butachlor. Furthermore, incubation of ER1 in a medium containing 50 mg/kg of butachlor after 3 days resulted in the high butachlor-degrading enzyme activity of ER1. Response of ER1 to butachlor might be related to changes in protein composition at both quantitative and qualitative levels. Total proteins were extracted from control strain (incubated in the medium without butachlor) and the treated strain (incubated in the medium with butachlor). The proteins were separated by two-dimensional gel electrophoresis. Of the total number of ER1 protein, 11 spots were significantly changed under butachlor stress. Analysis by matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry coupled with database searching allowed the function of some proteins which were similar to the hydrolases activity or oxidoreductase activity.

  15. REMOVAL OF ALACHLOR FROM DRINKING WATER

    EPA Science Inventory

    Alachlor (Lasso) is a pre-emergent herbicide used in the production of corn and soybeans. U.S. EPA has studied control of alachlor in drinking water treatment processes to define treatability before setting maximum contaminant levels and to assist water utilities in selecting con...

  16. Biodegradation of alachlor by soil streptomycetes.

    PubMed

    Durães Sette, L; Mendonça Alves Da Costa, L A; Marsaioli, A J; Manfio, G P

    2004-06-01

    Streptomycetes resistant to the herbicide alachlor [2-chloro-2',6'-diethyl- N-(methoxymethyl) acetanilide] were used in degradation assays to characterize the products of alachlor biodegradation. Of six strains tested, Streptomyces sp. LS166, LS177, and LS182 were able to grow at an alachlor concentration of 144 mg l(-1) and degraded approximately 60-75% of the alachlor in 14 days, as evaluated by high performance liquid chromatography. The alachlor biodegradation products were identified by gas chromatography-mass spectrometry based on mass spectral data and fragmentation patterns. All compounds detected in these assays were similar for all streptomycetes strains tested, and involved dechlorination with subsequent N-dealkylation and cyclization of the remaining N-substituent with one of the ethyl groups to produce indole and quinoline derivatives. The enzymatic pathway used by Streptomyces sp. LS182 did not generate DEA (2',6'-diethylaniline), a carcinogenic derivative of alachlor reported in other studies. Given the high degradation rates observed here, the Streptomyces strains tested may be useful in the degradation/detoxification processes of alachlor. PMID:14727088

  17. 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. PMID:12491727

  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. Herbicide transport trends in Goodwater Creek experimental watershed II: acetochlor, alachlor, metolachlor, and metribuzin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers in the Midwestern United States continue to be reliant on soil-applied herbicides for weed control in row crop production, and herbicide contamination of surface waters. Runoff-prone watersheds remain an environmental problem. The primary objective of this study was to analyze trends in conc...

  20. Metabolism of metolachlor by fungal cultures.

    PubMed

    Sanyal, D; Kulshrestha, G

    2002-01-30

    Metabolism of metolachlor was studied using a mixed fungal culture isolated from a metolachlor-acclimated field soil. The culture rapidly degraded metolachlor with a half-life of 3.5 days in broth. Aspergillus flavus and A. terricola purified from the mixed culture also metabolized metolachlor effectively. Five metabolites obtained were identified by co-chromatography on HPLC by comparing with authentic standards and by GC-MS. Hydrolytic dechlorination, N-dealkylation, and amide bond cleavage appeared to be the dominant transformations involved in the metabolism. Metabolites, 6-methyl 2-ethyl acetanilide and 6-methyl 2-ethyl aniline, identified in this study are new metabolites of metolachlor being reported from any mixed or pure microbial cultures. The mixed culture could degrade 99% of metolachlor at a fortification level as high as 100 microg mL(-)(1). PMID:11804520

  1. 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

  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. Comprehensive spectroscopic probing the interaction and conformation impairment of bovine serum albumin (BSA) by herbicide butachlor.

    PubMed

    Liu, Xiaoyi; Ling, Zhaoxing; Zhou, Xing; Ahmad, Farooq; Zhou, Ying

    2016-09-01

    Butachlor is an effective herbicide to deal with undesired weeds selectively and is used at high levels in Asian countries. However, its interaction and impairment effect on BSA was still not clear. In this study, we investigated the interaction between butachlor and bovine serum albumin (BSA) by multi-spectroscopic methods including UV absorption, circular dichroism (CD) spectra, Fourier transform infrared (FTIR) spectra and fluorescence spectra under physiological conditions (pH=7.4). The results revealed that there was a static quenching of BSA induced by butachlor stemmed from the formation of complex. Based on thermodynamic data, the interaction of butachlor with BSA was due to happen, and van der Waals force as well as hydrogen bond were the major forces contributed to the interaction. The binding constant Kb and number of binding site of butachlor with BSA were 5.158×10(5) and 1.372 at 303K, respectively. The distance r between donor (BSA) and acceptor (butachlor) was 0.113nm, obtained according to the Förster theory. The results revealed that butachlor induced conformational changes in BSA but the secondary structure of BSA was still retained. In addition, the microenvironment around chromophore residues of BSA, for example, tryptophan, changed as well, resulting from the formation of more hydrogen bonds. PMID:27419617

  4. The toxic mechanism of high lethality of herbicide butachlor in marine flatfish flounder, Paralichthys olivaceus

    NASA Astrophysics Data System (ADS)

    Guo, Huarong; Yin, Licheng; Zhang, Shicui; Feng, Wenrong

    2010-09-01

    The toxic mechanism of herbicide butachlor to induce extremely high lethality in marine flatfish flounder, Paralichthys Olivaceus, was analyzed by histopathological examination, antioxidant enzymes activities and ATP content assay. Histopathological examination of gill, liver and kidney of exposed fishes showed that gill was a target organ of butachlor. The butachlor seriously impaired the respiration of gills by a series of lesions such as edema, lifting and detachment of lamellar epithelium, breakdown of pillar cells, and blood congestion. The dysfunction of gill respiration caused suffocation to the exposed flounder with extremely high acute lethality. Antioxidant enzyme activity assay of the in vitro cultured flounder gill (FG) cells exposed to butachlor indicated that butachlor markedly inhibited the antioxidant enzyme activities of Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX). Furthermore, along with the decline of antioxidant enzyme activities, ATP content in the exposed FG cells decreased, too. This infers that the oxidative stress induced by butachlor can inhibit the production of cellular ATP. Similar decrease of ATP content was also observed in the exposed flounder gill tissues. Taken together, as in FG cells, butachlor possibly induced a short supply of ATP in pillar cells by inhibiting the antioxidant enzyme activities and then affecting the contractibility of the pillar cells, which in turn resulted in the blood congestion and suffocation of exposed flounder.

  5. Exposure to butachlor causes thyroid endocrine disruption and promotion of metamorphosis in Xenopus laevis.

    PubMed

    Li, Shuying; Li, Meng; Wang, Qiangwei; Gui, Wenjun; Zhu, Guonian

    2016-06-01

    Butachlor is extensively applied in rice paddy ecosystem in china, and has been widespread contaminant in the aquatic environment. Here, Xenopus laevis was used for the evaluation of teratogenesis developmental toxicity, and disruption of thyroid system when exposure to different concentrations of butachlor by window phase exposure. Acute toxicity investigation shown that 96 h-LC50 value of butachlor was 1.424 mg L(-1) and 0.962 mg L(-1) for tadpoles (starting from stages 46/47) and embryos (starting from stages 8/9), respectively. Exposure to butachlor caused malformation, including abnormal eye, pericardial edema, enlarged proctodaeum and bent tail. Window phase exposure test indicated that butachlor significantly promote the contents of whole-body thyroid hormones (THs, T3 and T4) at higher levels, indicating thyroid endocrine disruption. At 7 days, exposure to butachlor up-regulated the mRNA expression of genes involved in THs synthesis and metabolism (tshα, tg, tpo and dio1) and THs receptors (trα and trβ). At 14 days, up-regulation of the mRNA expression of genes related to THs synthesis and metabolism (tshα, tshβ, tg, tpo, dio1, dio2 and ttr) and THs receptors (trβ) were also observed after the exposure to butachlor. At 21 days, butachlor up-regulated the mRNA expression of tshα, tg, tpo genes and down-regulated the mRNA expression of tshβ, tg, dio1, ttr and trα genes. These results showed that butachlor could change the mRNA expression of genes involved in the HPT axis and increase whole-body thyroid hormones levels of X. laevis tadpoles in a dose- and time-dependent manner, causing thyroid endocrine disruption and developmental toxicity. PMID:26971167

  6. Combined effects of cadmium and butachlor on soil enzyme activities and microbial community structure

    NASA Astrophysics Data System (ADS)

    Wang, Jinhua; Lu, Yitong; Shen, Guoqing

    2007-02-01

    The combined effects of cadmium (Cd, 10 mg/kg of soil) and butachlor (5, 10 and 50 mg/kg of soil) on enzyme activities and microbial community structure were assessed in phaeozem soil. The result showed that phosphatase activities were decreased in soils with Cd (10 mg/kg of soil) alone whereas urease acitivities were unaffected by Cd. Urease and phosphatase activities were significantly reduced by high butachlor concentration (50 mg/kg of soil). When Cd and butachlor concentrations in soils were added at milligram ratio of 2:1 or 1:2, urease and phosphatase activities were decreased, while enzyme activities were greatly improved at the ratio of 1:5. This study indicates that the combined effects of Cd and butachlor on soil urease and phosphatase activities depend largely on the addition concentration ratios to soils. The random amplified polymorphic DNA (RAPD) analysis showed that the changes occurring in RAPD profiles of different treated samples included variation in loss of normal bands and appearance of new bands compared with the control soil. The RAPD fingerprints showed substantial differences between the control and treated soil samples, with apparent changes in the number and size of amplified DNA fragments. The results showed that the addition of high concentration butachlor and the combined applied Cd and butachlor significantly affected the diversity of microbial community. The present results suggest that RAPD analysis in conjunction with other biomarkers such as soil enzyme parameter etc. would prove a powerful ecotoxicological tool.

  7. Clastogenicity of pentachlorophenol, 2,4-D and butachlor evaluated by Allium root tip test.

    PubMed

    Ateeq, Bushra; Abul Farah, M; Niamat Ali, M; Ahmad, Waseem

    2002-02-15

    The meristematic mitotic cells of Allium cepa is an efficient cytogenetic material for chromosome aberration assay on environmental pollutants. For assessing genotoxicity of pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (butachlor), 50% effective concentration (EC(50)), c-mitosis, stickiness, chromosome breaks and mitotic index (MI) were used as endpoints of genotoxicity. EC(50) values for PCP and butachlor are 0.73 and 5.13 ppm, respectively. 2,4-D evidently induced morphological changes at higher concentrations. Some changes like crochet hooks, c-tumours and broken roots were unique to 2,4-D at 5-20 ppm. No such abnormalities were found in PCP and butachlor treated groups, however, root deteriorated and degenerated at higher concentrations (<3 ppm) in PCP. MI in 2,4-D showed a low average of 14.32% followed by PCP (19.53%), while in butachlor it was recorded 71.6%, which is near to the control value. All chemicals induced chromosome aberrations at statistically significant level. The highest chromosome aberration frequency (11.90%) was recorded in PCP at 3 ppm. Large number of c-mitotic anaphases indicated that butachlor acts as potent spindle inhibitor, whereas, breaks, bridges, stickiness and laggards were most frequently found in PCP showing that it is a potent clastogen. PMID:11815249

  8. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., calculated as alachlor in or on the following raw agricultural commodities. Commodity Parts per million Beans, dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  9. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., calculated as alachlor in or on the following raw agricultural commodities. Commodity Parts per million Beans, dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  10. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., calculated as alachlor in or on the following raw agricultural commodities. Commodity Parts per million Beans, dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  11. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., calculated as alachlor in or on the following raw agricultural commodities. Commodity Parts per million Beans, dry 0.1 Beans, succulent lima 0.1 Cattle, fat 0.02 Cattle, meat byproducts 0.02 Cattle, meat 0.02...

  12. 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

  13. 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.

  14. Impacts of the herbicide butachlor on the larvae of a paddy field breeding frog (Fejervarya limnocharis) in subtropical Taiwan

    USGS Publications Warehouse

    Liu, Wan-Yi; Wang, Ching-Yuh; Wang, Tsu-Shing; Fellers, Gary M.; Lai, Bo-Chi; Kam, Yeong-Choy

    2011-01-01

    Butachlor is the most commonly used herbicide on paddy fields in Taiwan and throughout Southeast Asia. Since paddy fields provide habitat for pond breeding amphibians, we examined growth, development, time to metamorphosis, and survival of alpine cricket frog tadpoles (Fejervarya limnocharis) exposed to environmentally realistic concentrations of butachlor. We documented negative impacts of butachlor on survival, development, and time to metamorphosis, but not on tadpole growth. The 96 h LC50 for tadpoles was 0.87 mg/l, much lower than the 4.8 mg/l recommended dosage for application to paddy fields. Even given the rapid breakdown of butachlor, tadpoles would be exposed to concentrations in excess of their 96 h LC50 for an estimated 126 h. We also documented DNA damage (genotoxicity) in tadpoles exposed to butachlor at concentrations an order of magnitude less than the 4.8 mg/l recommended application rate. We did not find that butachlor depressed cholinesterase activity of tadpoles, unlike most organophosphorus insecticides. We conclude that butachlor is likely to have widespread negative impacts on amphibians occupying paddy fields with traditional herbicide application.

  15. Joint acute toxicity of the herbicide butachlor and three insecticides to the terrestrial earthworm, Eisenia fetida.

    PubMed

    Wang, Yanhua; Cang, Tao; Yu, Ruixian; Wu, Shenggan; Liu, Xinju; Chen, Chen; Wang, Qiang; Cai, Leiming

    2016-06-01

    The herbicide butachlor and three insecticides phoxim, chlorpyrifos, and lambda-cyhalotrhin are widely used pesticides with different modes of action. As most previous laboratory bioassays for these pesticides have been conducted solely based on acute tests with a single compound, only limited information is available on the possible combined toxicity of these common chemicals to soil organisms. In this study, we evaluated their mixture toxicity on the terrestrial earthworm, Eisenia fetida, with binary, ternary, and quaternary mixtures. Two different types of bioassays were employed in our work, including a contact filter paper toxicity test and a soil toxicity test. Mixture toxicity effects were assessed using the additive index method. For all of the tested binary mixtures (butachlor-phoxim, butachlor-chlorpyrifos, and butachlor-lambda-cyhalothrin), significant synergistic interactions were observed after 14 days in the soil toxicity assay. However, greater additive toxicity was found after 48 h in the contact toxicity bioassay. Most of the ternary and quaternary mixtures exhibited significant synergistic effects on the worms in both bioassay systems. Our findings would be helpful in assessing the ecological risk of these pesticide mixtures to soil invertebrates. The observed synergistic interactions underline the necessity to review soil quality guidelines, which are likely underestimating the adverse combined effects of these compounds. PMID:26946506

  16. Metolachlor and its metabolites in tile drain and stream runoff in the canajoharie creek watershed

    USGS Publications Warehouse

    Phillips, P.J.; Wall, G.R.; Thurman, E.M.; Eckhardt, D.A.; Vanhoesen, J.

    1999-01-01

    Water samples collected during April-November 1997 from tile drains beneath cultivated fields in central New York indicate that two metabolites of the herbicide metolachlor-metolachlor ESA (ethanesulfonic acid) and OA (oxanilic acid) can persist in agricultural soils for 4 or more years after application and that fine-grained soils favor the transport of metolachlor ESA over metolachlor and metolachlor OA. Concentrations of metolachlor ESA from the tile drains ranged from 3.27 to 23.4 ??g/L (200 1800 times higher than those of metolachlor), metolachlor OA concentrations ranged from 1.14 to 13.5 ??g/L, and metolachlor concentrations ranged from less than 0.01 to 0.1 ??g/L. In the receiving stream, concentrations of metolachlor ESA were always below 0.6 ??g/L except during a November storm, when concentrations reached 0.85 ??g/L. Concentrations of metolachlor ESA in the stream were 2 45 times higher than those of metolachlor, reflecting the greater relative concentrations of metolachlor in surface water runoff than in tile drain runoff. These results are consistent with findings in other studies that acetanilide herbicide degredates are found in much higher concentrations than parent compounds in both surface water and groundwater.Water samples collected during April-November 1997 from tile drains beneath cultivated fields in central New York indicate that two metabolites of the herbicide metolachlor-metolachlor ESA (ethanesulfonic acid) and OA (oxanilic acid)-can persist in agricultural soils for 4 or more years after application and that fine-grained soils favor the transport of metolachlor ESA over metolachlor and metolachlor OA. Concentrations of metolachlor ESA from the tile drains ranged from 3.27 to 23.4 ??g/L (200-1800 times higher than those of metolachlor), metolachlor OA concentrations ranged from 1.14 to 13.5 ??g/L, and metolachlor concentrations ranged from less than 0.01 to 0.1 ??g/L. In the receiving stream, concentrations of metolachlor ESA were

  17. 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...

  18. Boule gene expression underpins the meiotic arrest in spermatogenesis in male rainbow trout (Oncorhynchus mykiss) exposed to DEHP and butachlor.

    PubMed

    Ahmadivand, Sohrab; Farahmand, Hamid; Teimoori-Toolabi, Ladan; Mirvaghefi, Alireza; Eagderi, Soheil; Geerinckx, Tom; Shokrpoor, Sara; Rahmati-Holasoo, Hooman

    2016-01-01

    Boule, the ancestor of the DAZ (Deleted in AZoospermia) gene family, in most organisms is mainly involved in male meiosis. The present study investigates the effects of the plasticizer DEHP (50mg/kg body weight) and herbicide butachlor (0.39mg/L) on male rainbow trout (Oncorhynchus mykiss) for a 10-day period in two independent experiments. The results showed that plasma testosterone (T) concentrations were significantly lower in fish exposed to either DEHP or butachlor compared to the control fish (P<0.05). Fish showed a significantly elevated hepatosomatic index (HSI) in the butachlor treatment (P<0.05). However, no significant difference was observed in HSI values in the DEHP treatment (P>0.05). In addition, no significant differences were found in the gonadosomatic index (GSI) in both DEHP and butachlor treatments (P>0.05). Histologically, testes of male trout in the control groups were well differentiated and filled with large numbers of cystic structures containing spermatozoa. In contrast, the testes of male trout contained mostly spermatocytes with few spermatozoa in both treated group, suggesting that DEHP and butachlor may inhibit the progression of meiosis. Also, boule gene expression was significantly lower in the testes of male trout affected by DEHP and butachlor in comparison with their control groups (P<0.05), which confirmed the meiotic arrest in affected trout. Based on the results, the present study demonstrated that DEHP and butachlor can inhibit the progression of spermatogenesis in male trout, potentially by causing an arrest of meiosis, maybe due to down-regulation of boule gene expression through T and/or IGF1 via ERK1/2 signaling in T-independent pathways. In addition, these results confirmed that boule can be considered as a predictive marker to assess meiotic efficiency. PMID:26027538

  19. Effect of Butachlor on Antioxidant Enzyme Status and Lipid Peroxidation in Fresh Water African Catfish, (Clarias gariepinus)

    PubMed Central

    Farombi, E. O.; Ajimoko, Y. R.; Adelowo, O. A.

    2008-01-01

    The present study was undertaken to evaluate the influence of butachlor, a widely used herbicide, on antioxidant enzyme system and lipid peroxidation formation in African cat fish (Clarias gariepinus). Fish were exposed to sub-lethal concentrations of butachlor 1, 2, 2.5 ppm and sacrificed 24hrs after treatment. A significant increase in malondialdehyde formation was observed in the liver, kidney, gills and heart of the fish following exposure to different concentrations of butachlor. Superoxide dismutase and catalase activities increased in the liver and kidney but decreased in the gills and heart in a concentration-dependent pattern. Glutathione level and glutathione-S-transferase activities increased (P<0.05) in the liver but decreased in the kidneys, gills and heart when fishes were exposed to the three concentrations of butachlor. The results suggest that butachlor induced oxidative stress in the various tissues of the fish particularly in the kidney and as such the organ may be subjected to severe oxidative toxicity due to depressed glutathione detoxification system. PMID:19151438

  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. 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

  3. Potentiation effect of metolachlor on toxicity of organochlorine and organophosphate insecticides in earthworm Eisenia andrei.

    PubMed

    Stepić, Sandra; Hackenberger, Branimir K; Velki, Mirna; Hackenberger, Davorka K; Lončarić, Zeljka

    2013-07-01

    Acetylcholinesterase, glutathione-S-transferase and catalase activities were determined in earthworms Eisenia andrei exposed to insecticides (endosulfan, temephos, malathion, pirimiphos-methyl) alone and in a binary combination with the herbicide metolachlor. Metolachlor individually was not acutely toxic, even at high concentrations applied; however, in the treated earthworms metolachlor enhanced the toxicity of endosulfan and temephos by significantly reducing the acetylcholinesterase activity. In binary combination with malathion and pirimiphos-methyl, metolachlor did not increase toxicity. The potentiation character of metolachlor is specific rather than general, and probably depends on the chemical structure of pesticides in the mixture. PMID:23666323

  4. 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

  5. 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.

  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. Soil moisture and metolachlor volatilization observations over three years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatilization of pesticides from agricultural land is of a concern because of potentially detrimental environmental and ecological impacts. A 3-year study was conducted to focus on the impact of surface soil water on metolachlor volatilization from a single field with different surface soil water r...

  8. 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...

  9. 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…

  10. 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...

  11. COMETABOLISM OF LOW CONCENTRATIONS OF PROPACHLOR, ALACHLOR, AND CYCLOATE IN SEWAGE AND LAKE WATER

    EPA Science Inventory

    Low concentrations of propachlor (2-chloro-N-isopropylacetanilide) and alachlor (2-chlor-2', 6'-diethyl-N-(methoxymethyl)acetanilide) were not mineralized, cycloate (S-ethyl-N-ethylthiocyclohexanecarbamate) was slowly or not mineralized, and aniline and cyclohexylamine were readi...

  12. 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. PMID:25996814

  13. Protocatechuic Acid Promoted Alachlor Degradation in Fe(III)/H2O2 Fenton System.

    PubMed

    Qin, Yaxin; Song, Fahui; Ai, Zhihui; Zhang, Pingping; Zhang, Lizhi

    2015-07-01

    In this study, we demonstrate that protocatechuic acid (PCA) can significantly promote the alachlor degradation in the Fe(III)/H2O2 Fenton oxidation system. It was found that the addition of protocatechuic acid could increase the alachlor degradation rate by 10 000 times in this Fenton oxidation system at pH = 3.6. This dramatic enhancement of alachlor degradation was attributed to the complexing and reduction abilities of protocatechuic ligand, which could form stable complexes with ferric ions to prevent their precipitation and also accelerate the Fe(III)/Fe(II) cycle to enhance the ·OH generation. Meanwhile, the Fe(III)/PCA/H2O2 system could also work well at near natural pH even in the case of PCA concentration as low as 0.1 mmol/L. More importantly, both alachlor and PCA could be effectively mineralized in this Fenton system, suggesting the environmental benignity of PCA/Fe(III)/H2O2 Fenton system. We employed gas chromatography-mass spectrometry to identify the degradation intermediates of alachlor and then proposed a possible alachlor degradation mechanism in this novel Fenton oxidation system. This study provides an efficient way to remove chloroacetanilide herbicides, and also shed new insight into the possible roles of widely existed phenolic acids in the conversion and the mineralization of organic contaminants in natural aquatic environment. PMID:26066010

  14. Influence of rhizosphere microbial ecophysiological parameters from different plant species on butachlor degradation in a riparian soil.

    PubMed

    Yang, Changming; Wang, Mengmeng; Li, Jianhua

    2012-01-01

    Biogeochemical processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. However, little research has been reported on the microbial process and degradation potential of herbicide in a riparian soil. Field sampling and incubation experiments were conducted to investigate differences in microbial parameters and butachlor degradation in the riparian soil from four plant communities in Chongming Island, China. The results suggested that the rhizosphere soil had significantly higher total organic C and water-soluble organic C relative to the nonrhizosphere soil. Differences in rhizosphere microbial community size and physiological parameters among vegetation types were significant. The rhizosphere soil from the mixed community of Phragmites australis and Acorus calamus had the highest microbial biomass and biochemical activity, followed by A. calamus, P. australis and Zizania aquatica. Microbial ATP, dehydrogenase activity (DHA), and basal soil respiration (BSR) in the rhizosphere of the mixed community of P. australis and A. calamus were 58, 72, and 62% higher, respectively, than in the pure P. australis community. Compared with the rhizosphere soil of the pure plant communities, the mixed community of P. australis and A. calamus displayed a significantly greater degradation rate of butachlor in the rhizosphere soil. Residual butachlor concentrations in rhizosphere soil of the mixed community of P. australis and A. calamus and were 48, 63, and 68% lower than three pure plant communities, respectively. Butachlor degradation rates were positively correlated to microbial ATP, DHA, and BSR, indicating that these microbial parameters may be useful in assessing butachlor degradation potential in the riparian soil. PMID:22565253

  15. 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.

  16. 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. PMID:26581606

  17. 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.

  18. 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

  19. In vivo percutaneous absorption and skin decontamination of alachlor in rhesus monkey.

    PubMed

    Wester, R C; Melendres, J; Maibach, H I

    1992-05-01

    The objectives of this study were to determine the percutaneous absorption of alachlor relative to formulation dilution with water, and to determine the ability of soap and water, and of water only, to remove alachlor from skin, relative to time. Alachlor is a preemergence herbicide. The in vivo percutaneous absorption of alachlor in rhesus monkeys was 17.3 +/- 3.3, 15.3 +/- 3.9, and 21.4 +/- 14.2% for 24-h skin exposure to Lasso formulation diluted 1:20, 1:40, and 1:80, respectively. In vivo, there was no support for increased alachlor skin absorption with water dilution, as previously reported for in vitro absorption. The average in vivo absorption of 18% applied dose over 24 h (0.75%/h) was similar to the maximum in vitro rate of 0.8%/h using human skin and human plasma as receptor fluid. Dose accountability in vivo was 80.6-95.2%. [14C]Alachlor in Lasso diluted 1:20 with water was placed on rhesus monkeys at concentrations of 23 micrograms/10 microliters/cm2. Skin decontamination at 0 h with soap and water (50% Ivory liquid 1:1 v/v with water) removed 73 +/- 15.8% (n = 4) of the applied dose with the first wash; this increased to a total of 82.3 +/- 14.8% with two additional washes. Decontamination after 1 h removed 87.5 +/- 12.4% with three successive washes. After 3 h decontamination ability decreased, and after 24 h only 51.9 +/- 12.2% could be recovered with three successive washes. Using water only, at 0 h 36.6 +/- 12.3% alachlor was removed with the first wash and the total increased to 56.0 +/- 14.0% with two additional washes. At 24 h the total amount decreased to 28.7 +/- 12.2% for three successive washes. Alachlor as Lasso in field-use rate (11 micrograms/cm2) and undiluted (217 and 300 micrograms/cm2) proportions were left on rhesus monkey skin for 12 h and decontaminated with soap and water (10% Ivory liquid v/v with water). Continual successive washes (6-8 in sequence) recovered 80-90% of the skin-applied alachlor. These results suggest that simple

  20. 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

  1. METABOLISM OF ALACHLOR AND PROPACHLOR IN SUSPENSIONS OF PRETREATED SOILS AND IN SAMPLES FROM GROUND WATER AQUIFERS

    EPA Science Inventory

    Suspensions of soils treated in the field with alachlor (2-chloro-2',6'diethyl-N-(methoxymethyl)acetanilide) and propachlor (2-chlor-N-isopropylacetanilide) were tested for their ability to metabolize these herbicides. Less than 8% of (14)C ring-labeled alachlor was mineralized i...

  2. 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.

  3. 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

  4. Biodegradation of alachlor in liquid and soil cultures under variable carbon and nitrogen sources by bacterial consortium isolated from corn field soil

    PubMed Central

    2013-01-01

    Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. The main objectives of this research were focused on isolating bacterial consortium capable of alachlor biodegradation, assessing the effects of carbon and nitrogen sources on alachlor biodegradation and evaluating the feasibility of using bacterial consortium in soil culture. Kavar corn field soil with a long history of alachlor application in Fars province of Iran has been explored for their potential of alachlor biodegradation. The influence of different carbon compounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds), the effect of nitrogen sources (ammonium nitrate and urea) and different pH (5.5-8.5) on alachlor removal efficiency by the bacterial consortium in liquid culture were investigated. After a multi-step enrichment program 100 days of acclimation, a culture with the high capability of alachlor degradation was obtained (63%). Glucose and sodium citrate had the highest alachlor reduction rate (85%). Alachlor reduction rate increased more rapidly by the addition of ammonium nitrate (94%) compare to urea. Based on the data obtained in the present study, pH of 7.5 is optimal for alachlor biodegradation. After 30 days of incubation, the percent of alachlor reduction were significantly enhanced in the inoculated soils (74%) as compared to uninoculated control soils (17.67%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlor degradation in a polluted soil. PMID:23452801

  5. Atrazine and alachlor transport in claypan soils as influenced by differential antecedent soil water content.

    PubMed

    Kazemi, H V; Anderson, S H; Goyne, K W; Gantzer, C J

    2008-01-01

    Increased attention to ground water contamination has encouraged an interest in mechanisms of solute transport through soils. Few studies have investigated the effect of the initial soil water content on the transport and degradation of herbicides for claypan soils. We investigated the effect of claypan soils at initial field capacity vs. permanent wilting level on atrazine and alachlor transport. The soil studied was Mexico silt loam (fine, smectitic, mesic Aeric Vertic Epiaqualf) with a subsoil clay content, primarily montmorillonite, of >40%. Strontium bromide, atrazine, and alachlor were applied to plots; half were at field capacity (Wet treatment), and half were near the permanent wilting point (Dry treatment). Soil cores were removed at selected depths and times, and cores were analyzed for bromide and herbicide concentrations. Bromide, atrazine, and alachlor were detected at the 0.90-m depth in dry plots within 15 d after experiment initiation. Bromide was detected 0.15 m deeper (P < 0.05) in the Dry compared with the Wet treatment at 1, 7, and 60 d after application and >0.30 m deeper (P < 0.01) in the Dry treatment at 15 and 30 d after application; similar treatment results were found for atrazine and alachlor, although on fewer dates with significant differences. The mobility order of the applied chemicals was bromide > atrazine > alachlor. The atrazine apparent half-life was significantly longer in the Dry plots compared with the Wet plots. The retardation factor determined from the relative velocity of each herbicide to that of bromide was higher for alachlor than for atrazine. This study identifies the impact that shrinkage cracks have for different moisture conditions on preferential transport of herbicides in claypan soils. PMID:18574193

  6. Interaction of flumioxazin with dimethenamid or metolachlor in peanut (Arachis hypogaea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in various peanut growing regions of Texas and Georgia to study peanut response to flumioxazin alone or in combination with dimethenamid or metolachlor. In southern Texas during 1997, flumioxazin plus metolachlor resulted in greater than 45% peanut stunt, while flumioxaz...

  7. Metolachlor formulation and ground cover effects on cotton and weed growth - greenhouse experiments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metolachlor is an important tool for managing glyphosate-resistant pigweeds. Cover crop residues in conservation tillage impede the effectiveness of metolachlor. Greenhouse experiments were conducted to evaluate the influence of cover crops with the following ground covers: no cover, full cover, and...

  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. Comparision of atrazine and metolachlor affinity for bermudagrass ( Cynodon dactylon L.) and two soils.

    PubMed

    Dozier, M C; Senseman, S A; Hoffman, D W; Baumann, P A

    2002-10-01

    Given that bermudagrass is being used as one of the grasses of choice in grass filter strip plantings as an acceptable grass to reduce off-target losses of herbicides, laboratory experiments were conducted to determine and compare the relative affinity of bermudagrass, a Weswood soil, and a Houston Black soil for atrazine (6-chloro- N-ethyl- N-isopropyl-1,3,5-triazine-2,4-diamine) and metolachlor (2-chloro- N-(2-ethyl-6-methylphenyl)- N-(2-methoxy-1-methyethyl) acetamide). Experiments were also conducted to determine if the presence of one herbicide affects the relative affinity of the other compound to these sorbents. The experiments were carried out using radiolabeled atrazine and metolachlor. Results were reported in disintegrations min(-1) (dpms) and converted to K(d) to determine and compare relative affinity. Both K(d) values for relative affinity of atrazine (86.2) and metolachlor (131.5) to bermudagrass were significantly greater than those of the two soils, Weswood (atrazine, 20.0 and metolachlor, 28.4) and Houston Black (atrazine, 35.8 and metolachlor, 33.5). The two compounds were also mixed together to mimic the common practice of applying atrazine and metolachlor simultaneously as a tank mix. Relative affinity of atrazine to any of the sorbents was not affected by the presence of metolachlor. Similarly, when comparing the affinity of metolachlor alone to that of metolachlor with atrazine present in the solution, no significant differences were observed for bermudagrass or the Weswood soil. However, on the Houston Black soil, the presence of atrazine significantly increased the soil's affinity for metolachlor. PMID:12202924

  10. Cu/Zn-superoxide dismutase and glutathione are involved in response to oxidative stress induced by protein denaturing effect of alachlor in Saccharomyces cerevisiae.

    PubMed

    Rattanawong, Kasidit; Kerdsomboon, Kittikhun; Auesukaree, Choowong

    2015-12-01

    Alachlor is a widely used pre-emergent chloroacetanilide herbicide which has been shown to have many harmful ecological and environmental effects. However, the mechanism of alachlor-induced oxidative stress is poorly understood. We found that, in Saccharomyces cerevisiae, the intracellular levels of reactive oxygen species (ROS) including superoxide anions were increased only after long-term exposure to alachlor, suggesting that alachlor is not a pro-oxidant. It is likely that alachlor-induced oxidative stress may result from protein denaturation because alachlor rapidly induced an increased protein aggregation, leading to upregulation of SSA4 and HSP82 genes encoding heat shock proteins (Hsp) of Hsp70 and Hsp90 family, respectively. Although only SOD1 encoding Cu/Zn-superoxide dismutase (SOD), but not SOD2 encoding Mn-SOD, is essential for alachlor tolerance, both SODs play a crucial role in reducing alachlor-induced ROS. We found that, after alachlor exposure, glutathione production was inhibited while its utilization was increased, suggesting the role of glutathione in protecting cells against alachlor, which becomes more important when lacking Cu/Zn-SOD. Based on our results, it seems that alachlor primarily causes damages to cellular macromolecules such as proteins, leading to an induction of endogenous oxidative stress, of which intracellular antioxidant defense systems are required for elimination. PMID:26518674

  11. RESPIRATION AND OSMOREGULATION OF THE ESTUARINE CRAB RHITHROPANOPEUS HARRISII (GOULD): EFFECTS OF THE HERBICIDE ALACHLOR

    EPA Science Inventory

    The effects of a sudden decrease in salinity and exposure to sublethal concentrations of the herbicide, Alachlor, on osmoregulation and respiration of the crab, Rhithropanopeus harrisii, were studied. 2. Crabs were hyperosmotic regulators at salinities below 24 ppt and became hyp...

  12. Effects of (Anti) Androgenic Endocrine Disruptors (DEHP and Butachlor) on Immunoglobulin M (IgM) and Leukocytes Counts of Male Rainbow Trout (Oncorhynchus mykiss).

    PubMed

    Ahmadivand, Sohrab; Farahmand, Hamid; Mirvaghefi, Alireza; Eagderi, Soheil; Zargar, Ashkan

    2015-06-01

    The effect of two anti-androgenic endocrine disrupting compounds, i.e. the plasticizer di (2-ethylhexyl) phthalate (DEHP) and herbicide butachlor, were evaluated for their effects on immunoglobulin M (IgM) and leukocytes in male rainbow trout. Also, plasma testosterone (T) concentration was measured to confirm their anti-androgenic effects. In the first experiment, trout were treated with 50 mg/kg (body weight) DEHP intraperitoneally, and in the second one, fish were exposed to 0.39 mg/L butachlor for 10 days. The results showed that T concentrations and white blood cells were significantly lower in fish exposed to either DEHP or butachlor compared to control fish (p < 0.05). Fish showed significantly elevated neutrophil levels and decreased lymphocyte levels in the butachlor (p < 0.05); however, no significant difference was observed in lymphocyte and neutrophils values in the DEHP treatment (p > 0.05). In addition, no significant differences were found in IgM, eosinophil and monocyte parameters in either DEHP or butachlor treatments (p > 0.05). These results confirmed that leukocytes counts can be considered as a novel marker of immunotoxicity triggered by (anti) androgenic endocrine disruptors. PMID:25708297

  13. Managing metolachlor and atrazine leaching losses using lignite fly ash.

    PubMed

    Ghosh, Rakesh Kumar; Singh, Neera

    2012-10-01

    Application of low cost amendment for pesticide retention in soil is an important area of research in environmental sciences. The present study reports the potential of coal fly ash (Inderprastha and Badarpur), a waste from thermal power stations, for retaining soil applied metolachlor and atrazine within the application zone. Both the fly ashes were highly effective in reducing the leaching losses of metolachlor and atrazine and at 2% and 5% fly ash amendment levels the herbicides were retained in the top 15 cm profile of the column. However, fly ashes varied in their capacity in reducing the downward mobility of herbicides, as the Inderprastha fly ash was more effective than the Badarpur fly ash. Although fly ash contained heavy metals like Cr, Cu or Pb, but they were not detected in the leachate. Also, concentration of other metals like Zn, Mn and Fe in leachate decreased after fly ash amendment. Results of this study have implications in reducing the leaching losses of these herbicides in agricultural soils. PMID:22854744

  14. 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).

  15. Behavior of butachlor and pyrazosulfuron-ethyl in paddy water using micro paddy lysimeters under different temperature conditions in spring and summer.

    PubMed

    Ok, Junghun; Doan, Nguyen Hai; Watanabe, Hirozumi; Thuyet, Dang Quoc; Boulange, Julien

    2012-08-01

    The behavior of butachlor and pyrazosulfuron-ethyl in paddy water was investigated using micro paddy lysimeters with prescribed hydrological conditions under ambient temperature in spring and summer for simulating two rice crop seasons. Although they were not significantly different, the dissipation of both herbicides in paddy water in the summer experiment was faster than in the spring experiment. The half-lives (DT(50)) in paddy water for spring and summer experiments were 3.2 and 2.5 days for butachlor, and 3.1 and 1.6 days for pyrazosulfuron-ethyl, respectively. PMID:22696099

  16. 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 ...

  17. Photodegradation of metolachlor applying UV and UV/H2O2.

    PubMed

    Wu, Changlong; Shemer, Hilla; Linden, Karl G

    2007-05-16

    Metolachlor is one of the most widely used herbicides in the world for controlling weeds. It has been detected in both ground and surface waters in the United States, and there are rising concerns in regard to its health risks and in developing effective treatment processes for its removal from water. Degradation of metolachlor via ultraviolet (UV) photolysis and an UV/hydrogen peroxide advanced oxidation process (AOP) was studied. The quantum yield of metolachlor at 254 nm was found to be 0.302 +/- 0.001 mol E-1 through direct UV photolysis in the range of pH 6-8. The second-order rate constant of the reaction between metolachlor and hydroxyl radical was determined to be 9.07 (+/-0.21) x 10(9) M-1 s-1 by using a competition kinetics model that utilized nitrobenzene as a reference compound. In addition, these parameters were successfully applied in modeling the kinetics of elimination of metolachlor using an UV/H2O2 process in both laboratory and natural waters. The formation of several photolysis byproducts was identified using gas chromatography/mass spectrometry, and a scheme for the metolachlor photodegradation pathway is proposed. PMID:17447786

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

    PubMed

    Novick, N J; Alexander, M

    1985-04-01

    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

  19. 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

  20. 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

  1. Enhancing metolachlor destruction rates with aluminum and iron salts during zerovalent iron treatment.

    PubMed

    Satapanajaru, T; Comfort, S D; Shea, P J

    2003-01-01

    Pesticide-contaminated soil may require remediation to mitigate ground and surface water contamination. We determined the effectiveness of zerovalent iron (Fe(0)) to dechlorinate metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methyl ethyl) acetamide] in the presence of aluminum and iron salts. By treating aqueous solutions of metolachlor with Fe(0), we found destruction kinetics were greatly enhanced when Al, Fe(II), or Fe(II) salts were added, with the following order of destruction kinetics observed: Al2(SO4)3 > AlCl3 > Fe2(SO4)3 > FeCl3. A common observation was the formation of green rusts, mixed Fe(II)-Fe(III) hydroxides with interlayer anions that impart a greenish-blue color. Central to the mechanism responsible for enhanced metolachlor loss may be the role these salts play in facilitating Fe(II) release. By tracking Al and Fe(II) in a Fe(0) + Al2(SO4)3 treatment of metolachlor, we observed that Al was readily sorbed by the corroding iron with a corresponding release of Fe(II). The manufacturing process used to produce the Fe(0) also profoundly affected destruction rates. Metolachlor destruction rates with salt-amended Fe(0) were greater with annealed iron (indirectly heated under a reducing atmosphere) than unannealed iron. Moreover, the optimum pH for metolachlor dechlorination in water and soil differed between iron sources (pH 3 for unannealed, pH 5 for annealed). Our results indicate that metolachlor destruction by Fe(0) treatment may be enhanced by adding Fe or Al salts and creating pH and redox conditions favoring the formation of green rusts. PMID:14535314

  2. Effects of Atrazine, Metolachlor, Carbaryl and Chlorothalonil on Benthic Microbes and Their Nutrient Dynamics

    PubMed Central

    Elias, Daniel; Bernot, Melody J.

    2014-01-01

    Atrazine, metolachlor, carbaryl, and chlorothalonil are detected in streams throughout the U.S. at concentrations that may have adverse effects on benthic microbes. Sediment samples were exposed to these pesticides to quantify responses of ammonium, nitrate, and phosphate uptake by the benthic microbial community. Control uptake rates of sediments had net remineralization of nitrate (−1.58 NO3 µg gdm−1 h−1), and net assimilation of phosphate (1.34 PO4 µg gdm−1 h−1) and ammonium (0.03 NH4 µg gdm−1 h−1). Metolachlor decreased ammonium and phosphate uptake. Chlorothalonil decreased nitrate remineralization and phosphate uptake. Nitrate, ammonium, and phosphate uptake rates are more pronounced in the presence of these pesticides due to microbial adaptations to toxicants. Our interpretation of pesticide availability based on their water/solid affinities supports no effects for atrazine and carbaryl, decreasing nitrate remineralization, and phosphate assimilation in response to chlorothalonil. Further, decreased ammonium and phosphate uptake in response to metolachlor is likely due to affinity. Because atrazine target autotrophs, and carbaryl synaptic activity, effects on benthic microbes were not hypothesized, consistent with results. Metolachlor and chlorothalonil (non-specific modes of action) had significant effects on sediment microbial nutrient dynamics. Thus, pesticides with a higher affinity to sediments and/or broad modes of action are likely to affect sediment microbes' nutrient dynamics than pesticides dissolved in water or specific modes of action. Predicted nutrient uptake rates were calculated at mean and peak concentrations of metolachlor and chlorothalonil in freshwaters using polynomial equations generated in this experiment. We concluded that in natural ecosystems, peak chlorothalonil and metolachlor concentrations could affect phosphate and ammonium by decreasing net assimilation, and nitrate uptake rates by decreasing remineralization

  3. Use of diatom motility features as endpoints of metolachlor toxicity.

    PubMed

    Coquillé, Nathalie; Jan, Gwilherm; Moreira, Aurélie; Morin, Soizic

    2015-01-01

    Many recent ecotoxicological studies suggest a relationship between freshwater contamination and increasing abundances of motile diatoms (potentially able to move). The capacity to escape would present advantages to species in polluted environments. However, actual motility as a response to toxicants had not been described and required experimental validation. We designed a specific experiment to assess how a field-isolated diatom (Gomphonema gracile) distributes energy to in situ resistance (increased population growth or photosynthesis) and escape (behavioral changes), when exposed to increasing concentrations of the herbicide metolachlor. We report here the dose-time dependent responses of G. gracile populations. They coped with low contamination by resisting in situ, with early hormetic responses highlighted by stimulation of chlorophyll-a fluorescence. At a higher dose, harmful impacts were observed on growth after a few days, but an earlier behavioral response suggested that higher motility (percentage of motile individuals and mean distance crossed) could be involved in escape. Our findings bring new arguments to support the implementation of real measurements instead of motility traits in toxicity assessment. Specifically, motion descriptors have been used as early-warning indicators of contamination in our study. Further works should address the reliability of these endpoints in more complex conditions (interspecific variability, behavior in the field). PMID:25481786

  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. 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

  6. 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...

  7. 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

  8. 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.

  9. 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...

  10. Mineral contributions to atrazine and alachlor sorption in soil mixtures of variable organic carbon and clay content

    NASA Astrophysics Data System (ADS)

    Grundl, Tim; Small, Greg

    1993-09-01

    A sediment mixing approach was taken to systematically vary the organic carbon (oc) and clay content (cm) of a suite of organic-poor, clay-rich sediments. Organic carbon content ranged from 3.2% to 0.4% and clay content ranged from 24% to 51%. Atrazine and alachlor were shown to sorb to both natural organic carbon and clay minerals. Partition coefficients to natural organic carbon ( Koc) were found to be 217 and 412 L/kg organic carbon for atrazine and alachlor, respectively. Partition coefficients to the clay fraction were found to be 3.5 and 4.9 L/kg clay for atrazine and alachlor, respectively. When expressed in terms of surface area, the partition coefficients to clay for atrazine and alachlor were 1.80·10 -5 and 2.51·10 -5 L/m 2 clay, respectively. Critical cm/oc ratios at which mineral phase sorption accounts for 50% of the total are defined. Implications for the modelling of herbicide movement in the subsurface if mineral phase sorption is ignored is discussed.

  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. 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...

  13. TRANSPORT AND FATE OF ATRAZINE AND METOLACHLOR IN A RIPARIAN WETLAND SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffer areas are widely touted for their ability to mitigate pollutants from agricultural fields. We are studying this abatement process for the pesticides atrazine and metolachlor, using a highly instrumented riparian wetland site located in Beltsville, Maryland. This site has clearly del...

  14. 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. 

  15. 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.

  16. Phytotoxicity of atrazine, s-metolachlor and permethrin to Typha latifolia (Linneaus) germination and seedling growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytotoxicity assessments were performed to compare responses of Typha latifolia (L.) seeds to atrazine (only) and atrazine + S-metolachlor exposure concentrations of 0.03, 0.3, 3, and 30 mg L-1, as well as permethrin exposure concentrations of 0.008, 0.08, 0.8, and 8 mg L-1. All atrazine + S-metol...

  17. 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...

  18. ATRAZINE AND METOLACHLOR IN SURFACE RUNOFF UNDER TYPICAL RAINFALL CONDITIONS IN SOUTHERN LOUISIANA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report here runoff of atrazine and metolachlor from 0.21 ha plots laid out on Mississippi River alluvial soil. In the study, conducted over a three-season period characterized by rainfall close to the 30-year average, we have gathered data on persistence in the top 2.5 cm layer of soil and in t...

  19. Evaluation of different algal species sensitivity to mercury and metolachlor by PAM-fluorometry.

    PubMed

    Juneau, P; Dewez, D; Matsui, S; Kim, S G; Popovic, R

    2001-11-01

    In this study, the pulse-amplitude-modulation (PAM)-fluorometric method was used to evaluate the difference in the sensitivity to mercury (Hg) and metolachlor of six algal species: Ankistrodesmus falcatus, Selenastrum capricornutum, Chlorella vulgaris, Nannoplankton (PLS), Microcystis aeruginosa and Pediastrum biwae. We found that the fluorescence parameters (phiM, the maximal photosystem II (PSII) quantum yield, phi'M, the operational PSII quantum yield at steady state of electron transport, Q(P), the photochemical quenching value, and Q(N), the non-photochemical quenching value) were appropriate indicators for inhibitory effects of mercury but only phi'M and Q(N) were useful for metolachlor. The examined algal species showed very different levels of sensitivity to the effect of Hg and of metolachlor. The most sensitive species to Hg and metolachlor were respectively M. aeruginosa and A. falcatus, while the least sensitive were C. vulgaris and P. biwae. We interpreted these differences by the action mode of pollutants and by the different metabolism properties and morphological characteristics between algal species. These results related to fluorescence parameters may offer useful tool to be used in bioassay for different pollutants. Heterogeneous algal sensitivity to the same pollutant suggests the need to use a battery of species to evaluate the effects of mixtures of pollutants in aquatic systems. PMID:11680755

  20. Assessment of best management practice effects on metolachlor mitigation in an agricultural watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beasley Lake watershed in the Mississippi Delta is a 915 ha intensively cultivated watershed (49-78% in row crop production) that was monitored for the herbicide metolachlor from 1998-2009. As part of the USDA Conservation Effects Assessment Program (CEAP), the watershed was assessed for the effecti...

  1. Spatial variability of atrazine and metolachlor dissipation on dryland no-tillage crop fields in Colorado.

    PubMed

    Bridges, Melissa; Henry, W Brien; Shaner, Dale L; Khosla, R; Westra, Phil; Reich, Robin

    2008-01-01

    An area of interest in precision farming is variable-rate application of herbicides to optimize herbicide use efficiency and minimize negative off-site and non-target effects. Site-specific weed management based on field scale management zones derived from soil characteristics known to affect soil-applied herbicide efficacy could alleviate challenges posed by post-emergence precision weed management. Two commonly used soil-applied herbicides in dryland corn (Zea mays L.) production are atrazine and metolachlor. Accelerated dissipation of atrazine has been discovered recently in irrigated corn fields in eastern Colorado. The objectives of this study were (i) to compare the rates of dissipation of atrazine and metolachlor across different soil zones from three dryland no-tillage fields under laboratory incubation conditions and (ii) to determine if rapid dissipation of atrazine and/or metolachlor occurred in dryland soils. Herbicide dissipation was evaluated at time points between 0 and 35 d after soil treatment using a toluene extraction procedure with GC/MS analysis. Differential rates of atrazine and metolachlor dissipation occurred between two soil zones on two of three fields evaluated. Accelerated atrazine dissipation occurred in soil from all fields of this study, with half-lives ranging from 1.8 to 3.2 d in the laboratory. The rapid atrazine dissipation rates were likely attributed to the history of atrazine use on all fields investigated in this study. Metolachlor dissipation was not considered accelerated and exhibited half-lives ranging from 9.0 to 10.7 d in the laboratory. PMID:18948474

  2. 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

  3. 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

  4. 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.

  5. 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

  6. Kinetic study of heterogeneous ozonolysis of alachlor, trifluralin and terbuthylazine adsorbed on silica particles under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Pflieger, Maryline; Monod, Anne; Wortham, Henri

    To better understand the atmospheric behaviour of pesticides, heterogeneous ozonolysis of three herbicides (alachlor, terbuthylazine and trifluralin) adsorbed on silica particles were performed in a flow reactor. The experimental setup used in this study and previously validated ( Pflieger et al., 2009) has been specially developed to investigate extremely slow reactivity. The pesticides were adsorbed on particles using a gas/solid adsorption equilibrium, in order to simulate atmospheric conditions. After exposure to ozone concentrations ranging from 5 to 41 ppm during 90 min to 6 h, the kinetics were calculated by comparing the initial and the remaining amounts of pesticides adsorbed on silica particles. This work offers the first results of heterogeneous ozonolysis of alachlor and trifluralin adsorbed on mineral particles. Although alachlor and terbuthylazine were expected to react with ozone, no degradation was observed which leads to a lifetime higher than 8 months towards ozonolysis (for 40 ppb of O 3). A significant degradation of trifluralin adsorbed on silica particles by heterogeneous ozonolysis was observed. The experimental data could be fit by both the Langmuir-Rideal and the Langmuir-Hinshelwood models resulting in atmospheric lifetimes (towards heterogeneous ozonolysis) of 40 and 32 days respectively (for 40 ppb of O 3). These results are discussed and compared to other studies.

  7. 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. PMID:21802202

  8. 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

  9. 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

  10. Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures.

    PubMed

    Karami, Ali; Karbalaei, Samaneh; Zad Bagher, Fariba; Ismail, Amin; Simpson, Stuart L; Courtenay, Simon C

    2016-08-01

    Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure. PMID:27182978

  11. 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

  12. Herbicide solubilization in micelle-clay composites as a basis for controlled release sulfentrazone and metolachlor formulations.

    PubMed

    Ziv, Dana; Mishael, Yael G

    2008-10-01

    Sulfentrazone and metolachlor have been detected in groundwater due to extensive leaching. To reduce herbicide leaching and increase weed control, we have developed, designed, and tested controlled release formulations (CRFs) for both herbicides based on their solubilizion in cationic micelles and adsorption of the mixed micelles (surfactant and herbicide) on a clay mineral, montmorillonite. A better understanding of solubilizing anionic (sulfentrazone) and nonionic (metolachlor) organic molecules in cationic micelles was reached. The percent of active ingredient in the formulations was much higher than previously designed CRFs due to the enhanced solubilization of the herbicides in the micelles and due to their adsorption on the clay. Both CRFs demonstrated controlled release (compared to the commercial formulations) when applied to a thin soil layer. A bioassay in soil columns determined that the new sulfentrazone and metolachlor CRFs significantly improve weed control and reduce leaching (for the latter) in comparison with the commercial formulations. PMID:18781765

  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. 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.

  15. 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.

  16. 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.

  17. Effects of an atrazine, metolachlor, and fipronil mixture on Hyalella azteca (Saussure) in a modified backwater wetland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a mixture of three pesticides, atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first two hours...

  18. Runoff and Leaching of Metolachlor from Mississippi River Alluvial Soil during Seasons of Average and Below-Average Rainfall

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The movement of metolachlor via runoff and leaching from plots planted to corn on Mississippi River alluvial soil (Commerce silt loam) was measured for a six-year period, 1995-2000. The first three years were characterized by normal rainfall volume, the second three years by reduced rainfall. The ...

  19. 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.

  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. 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

  2. Runoff and drainage losses of atrazine, metribuzin, and metolachlor in three water management systems.

    PubMed

    Gaynor, J D; Tan, C S; Drury, C F; Welacky, T W; Ng, H Y F; Reynolds, W D

    2002-01-01

    Rainfall can transport herbicides from agricultural land to surface waters, where they become an environmental concern. Tile drainage can benefit crop production by removing excess soil water but tile drainage may also aggravate herbicide and nutrient movement into surface waters. Water management of tile drains after planting may reduce tile drainage and thereby reduce herbicide losses to surface water. To test this hypothesis we calculated the loss of three herbicides from a field with three water management systems: free drainage (D), controlled drainage (CD), and controlled drainage with subsurface irrigation (CDS). The effect of water management systems on the dissipation of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine), metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazine-5(4H)-one), and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] in soil was also monitored. Less herbicide was lost by surface runoff from the D and CD treatments than from CDS. The CDS treatment increased surface runoff, which transported more herbicide than that from D or CD treatments. In one year, the time for metribuzin residue to dissipate to half its initial value was shorter for CDS (33 d) than for D (43 d) and CD (46 d). The half-life of atrazine and metolachlor were not affected by water management. Controlled drainage with subsurface irrigation may increase herbicide loss through increased surface runoff when excessive rain is received soon after herbicide application. However, increasing soil water content in CDS may decrease herbicide persistence, resulting in less residual herbicide available for aqueous transport. PMID:11841063

  3. Sorption of acetochlor, S-metolachlor, and atrazine in surface and subsurface soil horizons of Argentina.

    PubMed

    Bedmar, Francisco; Daniel, Peter E; Costa, José L; Giménez, Daniel

    2011-09-01

    Understanding herbicide sorption within soil profiles is the first step to predicting their behavior and leaching potential. Laboratory studies were conducted to determine the influence of surface and subsurface soil properties on acetochlor, atrazine, and S-metolachlor sorption. Soil samples were taken from horizons A, B, and C of two loamy soils of the humid pampas of Argentina under no-till management; horizon A was divided into two layers, A(0) (0-5 cm) and A(1) (5 cm to the full thickness of an A horizon). Sorption isotherms were determined from each sampled horizon using the batch equilibrium method and seven concentrations (0, 0.1, 0.5, 2.0, 5.0, 10.0, and 20.0 mg L(-1)). Sorption affinity of herbicides was approximated by the Freundlich equation. The sorption strength K(f) (mg(1 - 1/n) kg(-1) L(1/n) ) over the soils and horizons studied followed the order S-metolachlor (16.51-29.19) > atrazine (4.85-12.34) ≥ acetochlor (5.17-11.97), which was closely related to the hydrophobicity of herbicides expressed as octanol-water partition coefficient (K(OW) ). The K(f) values of the three herbicides were positively correlated with soil organic carbon, with a significance of p < 0.01. Values of K(f) for the three herbicides decreased with depth in the two soils, indicating greater sorption onto surficial soil horizons and possibly a delayed transport toward subsurface soils and subsequent pollution of groundwater. PMID:21692102

  4. 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

  5. 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.

  6. 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.

  7. A Novel Aldo-Keto Reductase (AKR17A1) of Anabaena sp. PCC 7120 Degrades the Rice Field Herbicide Butachlor and Confers Tolerance to Abiotic Stresses in E. coli.

    PubMed

    Agrawal, Chhavi; Sen, Sonia; Yadav, Shivam; Rai, Shweta; Rai, Lal Chand

    2015-01-01

    Present study deals with the identification of a novel aldo/keto reductase, AKR17A1 from Anabaena sp. PCC7120 and adds on as 17th family of AKR superfamily drawn from a wide variety of organisms. AKR17A1 shares many characteristics of a typical AKR such as- (i) conferring tolerance to multiple stresses like heat, UV-B, and cadmium, (ii) excellent activity towards known AKR substrates (isatin and 2-nitrobenzaldehyde), and (iii) obligate dependence on NADPH as a cofactor for enzyme activity. The most novel attribute of AKR17A1, first reported in this study, is its capability to metabolize butachlor, a persistent rice field herbicide that adversely affects agro-ecosystem and non-target organisms. The AKR17A1 catalyzed- degradation of butachlor resulted into formation of 1,2-benzene dicarboxylic acid and 2,6 bis (1,1, dimethylethyl) 4,-methyl phenol as the major products confirmed by GC-MS analysis. PMID:26372161

  8. A Novel Aldo-Keto Reductase (AKR17A1) of Anabaena sp. PCC 7120 Degrades the Rice Field Herbicide Butachlor and Confers Tolerance to Abiotic Stresses in E. coli

    PubMed Central

    Agrawal, Chhavi; Sen, Sonia; Yadav, Shivam; Rai, Shweta; Rai, Lal Chand

    2015-01-01

    Present study deals with the identification of a novel aldo/keto reductase, AKR17A1 from Anabaena sp. PCC7120 and adds on as 17th family of AKR superfamily drawn from a wide variety of organisms. AKR17A1 shares many characteristics of a typical AKR such as— (i) conferring tolerance to multiple stresses like heat, UV-B, and cadmium, (ii) excellent activity towards known AKR substrates (isatin and 2-nitrobenzaldehyde), and (iii) obligate dependence on NADPH as a cofactor for enzyme activity. The most novel attribute of AKR17A1, first reported in this study, is its capability to metabolize butachlor, a persistent rice field herbicide that adversely affects agro-ecosystem and non-target organisms. The AKR17A1 catalyzed- degradation of butachlor resulted into formation of 1,2-benzene dicarboxylic acid and 2,6 bis (1,1, dimethylethyl) 4,-methyl phenol as the major products confirmed by GC-MS analysis. PMID:26372161

  9. Weed Management and Crop Response with Glyphosate, S-metolachlor, Trifloxysulfuron, Prometryn, and MSMA in Glyphosate-Resistant Cotton (Gossypium hirsutum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in five states at six locations from 2002 through 2003 to evaluate weed control and cotton response to EPOST, POST, and LAYBY systems utilizing glyphosate-TM (trimethylsulfonium salt), s-metolachlor, trifloxysulfuron, prometryn, and MSMA. Early-season cotton injury and ...

  10. 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

  11. 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

  12. 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.

  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. 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

  15. 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.

  16. Does S-Metolachlor Affect the Performance of Pseudomonas sp. Strain ADP as Bioaugmentation Bacterium for Atrazine-Contaminated Soils?

    PubMed Central

    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 (∼107 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. PMID:22615921

  17. 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.

  18. 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

  19. TREATING SOIL SOLUTION SAMPLERS TO PREVENT MICROBIAL REMOVAL OF ANALYTES

    EPA Science Inventory

    Soil microorganisms colonizing soil water sampling devices (lysimeters) reduced concentrations of biodegradable organic chemicals, including 2,4-dichlorophenoxy-acetic acid methyl ester, alachlor, methyl m-chlorobenzoate, and metolachlor as water entered through porous ceramic cu...

  20. 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. PMID:26491727

  1. 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

  2. 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.

  3. 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. PMID:11253005

  4. New method for the determination of metolachlor and buprofezin in natural water using orthophthalaldehyde by thermochemically-induced fluorescence derivatization (TIFD).

    PubMed

    Mendy, Alphonse; Thiaré, Diène Diégane; Sambou, Souleymane; Khonté, Abdourahmane; Coly, Atanasse; Gaye-Seye, Mame Diabou; Delattre, François; Tine, Alphonse

    2016-05-01

    Herbicide metolachlor (MET) and insecticide buprofezin (BUP) were determined in natural waters by means of a newly-developed, simple and sensitive thermochemically-induced fluorescence derivatization (TIFD) method. The TIFD approach is based on the thermolysis transformation of naturally non-fluorescent pesticides into fluorescent complex O-phthalaldehyde-thermoproduct(s) in water at 70°C for MET and at 80°C for BUP. The TIFD method was optimized with respect to the temperature, pH, complex formation kinetic and pesticides concentrations. The limit of detection (LOD=0.8ngmL(-1) for MET and 3.0ngmL(-1) for BUP) and quantification (LOQ=2.6ngmL(-1) for MET and 9.5 ngmL(-1) for BUP) values were low, and the relative standard deviation (RSD) values were small (between 1.2% and 1.8%), which indicates a good analytical sensitivity and a great repeatability of TIFD method. Recovery studies were performed on spiked well, sea and draining waters samples collected in the Niayes area by using the solid phase extraction (SPE) procedure. Satisfactory recovery results (84-118%) were obtained for the determination of MET and BUP in these natural waters. PMID:26946028

  5. Toxicity assessment of the maize herbicides S-metolachlor, benoxacor, mesotrione and nicosulfuron, and their corresponding commercial formulations, alone and in mixtures, using the Microtox(®) test.

    PubMed

    Joly, Pierre; Bonnemoy, Frédérique; Charvy, Jean-Christophe; Bohatier, Jacques; Mallet, Clarisse

    2013-11-01

    The Microtox(®) test, using the prokaryote Vibrio fischeri, was employed to assess the toxicity of the maize herbicides S-metolachlor, benoxacor, mesotrione and nicosulfuron, and their formulated compounds: Dual Gold Safeneur(®), Callisto(®) and Milagro(®); alone and in mixtures. For each compound we obtained original IC50 values, with consistent higher toxicities for formulated compounds compared to active ingredients alone. Mixtures of the four herbicides, prepared according to application doses encountered in agriculture, were found to be toxic at a lower concentration than single molecules. Mesotrione and nicosulfuron mixture appeared to be highly toxic to V. fischeri, however, this recommended post-emergence combination for maize crops got its toxicity decreased in formulated compound mixtures, suggesting that chemical interactions could potentially reduce the toxicity. Data comparisons to theoretical models showed a good prediction of mixture toxicity by Concentration Addition concept. Results seemed to exclude any synergistic effects on V. fischeri for the tested herbicide mixtures. Additional work coupling these bioassay data to ecosystemic level studies (aquatic and soil compartments) and data on additives and degradation products toxicity, will help to fill the gap in our knowledge of the environmental impact of these xenobiotics and in the choice of a more sustainable use of pesticides. PMID:24075530

  6. 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. PMID:18373350

  7. 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

  8. Leaching of S-metolachlor, terbuthylazine, desethyl-terbuthylazine, mesotrione, flufenacet, isoxaflutole, and diketonitrile in field lysimeters as affected by the time elapsed between spraying and first leaching event.

    PubMed

    Milan, Marco; Ferrero, Aldo; Fogliatto, Silvia; Piano, Serenella; Vidotto, Francesco

    2015-01-01

    The effect of elapsed time between spraying and first leaching event on the leaching behavior of five herbicides (terbuthylazine, S-metolachlor, mesotrione, flufenacet, and isoxaflutole) and two metabolites (desethyl-terbuthylazine and diketonitrile) was evaluated in a 2011-2012 study in northwest Italy. A battery of 12 lysimeters (8.4 m(2) long with a depth of 1.8 m) were used in the study, each filled with silty-loam soil and treated during pre-emergence with the selected herbicides by applying a mixture of commercial products Lumax (4 L ha(-1)) and Merlin Gold (1 L ha(-1)). During treatment periods, no gravity water was present in lysimeters. Irrigation events capable of producing leaching (40 mm) were conducted on independent groups of three lysimeters on 1 day after treatment (1 DAT), 7 DAT, 14 DAT, and 28 DAT. The series was then repeated 14 days later. Leachate samples were collected a few days after irrigation; compounds were extracted by solid phase extraction and analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. Under study conditions, terbuthylazine and S-metolachlor showed the highest leaching potentials. Specifically, S-metolachlor concentrations were always found above 0.25 µg L(-1). Desethyl-terbuthylazine was often detected in leached waters, in most cases at concentrations above 0.1 µg L(-1). Flufenacet leached only when irrigation occurred close to the time of herbicide spraying. Isoxaflutole and mesotrione were not measured (<0.1 µg L(-1)), while diketonitrile was detected in concentrations above 0.1 µg L(-1) on 1 DAT in 2011 only. PMID:26252079

  9. A comparative assessment of the transformation products of S-metolachlor and its commercial product Mercantor Gold(®) and their fate in the aquatic environment by employing a combination of experimental and in silico methods.

    PubMed

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

    2015-02-15

    Even appropriately used, pesticides can enter the surface and groundwater by several routes where photochemical degradation along with biotic processes contributes to their fate, resulting sometimes in the formation of stable transformation products (TPs). Yet, little is known about S-metolachlor (SM) transformation in the aquatic environment. Furthermore, commercial formulation of a pesticide might have different physical and biological properties compared to its pure grade. The present study assessed the biodegradability of the pure SM and its commercial product Mercantor Gold(®) (MG) by employing two OECD biodegradation (301D, F) tests. Photolysis in water was investigated by using a Xe lamp. Subsequently the biodegradability of the photolysis mixtures was examined. The primary elimination of SM was monitored and structures of its TPs were elucidated by HPLC-UV-MS/MS. Additionally, a set of in silico prediction programs was applied for supporting analytical results and toxicity assessment of SM and TPs. S-metolachlor and Mercantor Gold(®) were not biodegraded. HPLC-UV analysis showed higher elimination of SM in MG compared to pure SM during photolysis. A total of 10 photo-TPs of SM and MG were identified. According to MS data and in silico predictions, chemical structures were proposed for all found photo-TPs. Likewise for the parent compounds, no biodegradation has been observed for their photo-TPs. However, in the 301F test new bio-TPs have been generated from photo-TPs which were observed for the first time according to authors' best knowledge. The results suggest that the MG formulation does not affect the biodegradation process, but it influences the photolysis efficiency and potentially might result in faster formation of TPs in the environment. This study also demonstrates that photo-TPs can be further transformed into new products due to bacterial activity in the water phase. Moreover biotransformation might lead to an increased toxicity compared with

  10. Hydrologic data for a study of pre-Illinoian glacial till in Linn County, Iowa, water year 1991

    USGS Publications Warehouse

    Bowman, P.R.

    1992-01-01

    Herbicide concentrations in rainfall ranged from 0.05 to 1.3 micrograms per liter. Herbicides detected in the largest concentrations included alachlor, atrazine, and metolachlor. Metribuzin was the only herbicide detected in ground-water samples at a concentration of 0.10 micrograms per liter in water from one observation well.

  11. 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...

  12. 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.

  13. 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...

  14. 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 ...

  15. 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 ...

  16. 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.

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

    PubMed

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

    2004-04-01

    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

  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. 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.

  20. 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.

  1. 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.

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., field, forage 2.0 Corn, field, grain 0.2 Corn, field, pop 0.2 Corn, field, stover 2.0 Corn, pop, stover... seed 0.03 Cowpea, forage 5.0 Cowpea, hay 5.0 Egg 0.02 Goat, fat 0.02 Goat, meat byproducts 0.02 Goat..., meat 0.02 Sheep, fat 0.02 Sheep, meat byproducts 0.02 Sheep, meat 0.02 Sorghum grain, forage...

  3. 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.

  4. 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

  5. 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.

  6. Overexpression of a specific soybean GmGSTU4 isoenzyme improves diphenyl ether and chloroacetanilide herbicide tolerance of transgenic tobacco plants.

    PubMed

    Benekos, Kostantinos; Kissoudis, Christos; Nianiou-Obeidat, Irini; Labrou, Nikolaos; Madesis, Panagiotis; Kalamaki, Mary; Makris, Antonis; Tsaftaris, Athanasios

    2010-10-01

    Plant glutathione transferases (GSTs) superfamily consists of multifunctional enzymes and forms a major part of the plants herbicide detoxification enzyme network. The tau class GST isoenzyme GmGSTU4 from soybean, exhibits catalytic activity towards the diphenyl ether herbicide fluorodifen and is active as glutathione-dependent peroxidase (GPOX). Transgenic tobacco plants of Basmas cultivar were generated via Agrobacterium transformation. The aim was to evaluate in planta, GmGSTU4's role in detoxifying the diphenyl ether herbicides fluorodifen and oxyfluorfen and the chloroacetanilides alachlor and metolachlor. Transgenic tobacco plants were verified by PCR and Southern blot hybridization and expression of GmGSTU4 was determined by RT-PCR. Leaf extracts from transgenic plants showed moderate increase in GST activity towards CDNB and a significant increase towards fluorodifen and alachlor, and at the same time an increased GPOX activity towards cumene hydroperoxide. GmGSTU4 overexpressing plants when treated with 200 μM fluorodifen or oxyfluorfen exhibited reduced relative electrolyte leakage compared to wild type plants. Moreover all GmGSTU4 overexpressing lines exhibited significantly increased tolerance towards alachlor when grown in vitro at 7.5 mg/L alachlor compared to wild type plants. No significant increased tolerance was observed to metolachlor. These results confirm the contribution of this particular GmGSTU4 isoenzyme from soybean in the detoxification of fluorodifen and alachlor, and provide the basis towards the development of transgenic plants with improved phytoremediation capabilities for future use in environmental cleanup of herbicides. PMID:20638428

  7. 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.

  8. 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.

  9. 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. PMID:25817759

  10. Effect of prairie grass on the dissipation, movement, and bioavailability of selected herbicides in prepared soil columns.

    PubMed

    Belden, Jason B; Phillips, Todd A; Coats, Joel R

    2004-01-01

    Phytoremediation of pesticide-contaminated sites using a prairie grass mixture (big bluestem, yellow indiangrass, and switch grass) has been suggested as a low-cost in situ remediation strategy. In this study, the proposed phytoremediation technique was applied to artificially prepared soil columns that were fortified with high concentrations of four herbicides (atrazine, alachlor, metolachlor, and pendimethalin). The fate and toxicity of the herbicides were compared with results from soil columns lacking vegetation. After either 150 or 240 d of phytoremediation, soils were watered with 7.5 cm of water, and leachate was collected. Columns were then divided into three sections (top, middle, bottom). For each section of the column, chemical analysis (ethyl acetate and water extractions), earthworm accumulation tests, and lettuce seedling growth tests were performed. The leachate was chemically analyzed and tested for chronic toxicity to algae. Atrazine and alachlor degraded rapidly in the column, and the total amount recoverable was less than 2% of applied. After 250 d, vegetation reduced the total recoverable amounts of metolachlor and pendimethalin by 78 and 39%, respectively. Metolachlor was the only compound found in leachate, and the amounts recovered were reduced 5- to 20-fold by vegetation. Vegetation decreased the bioavailability of pendimethalin as measured by 8-d, earthworm bioaccumulation factors (BAFs) and lettuce seedling growth assays. Decreases in mobility and bioavailability indicate that this technique may stabilize pesticide residues in addition to increasing dissipation rates. PMID:14768876

  11. 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).

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

    PubMed

    Hancock, Tracy C; Sandstrom, Mark W; Vogel, Jason R; Webb, Richard M T; Bayless, E Randall; Barbash, Jack 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 micromol 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). PMID:18453430

  13. 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

  14. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., nongrass, group 18 1.0 Cattle, fat 0.02 Cattle, kidney 0.20 Cattle, liver 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0 Corn, field, grain 0.10 Corn..., undelinted seed 0.10 Dillweed 0.50 Egg 0.02 Goat, fat 0.02 Goat, kidney 0.20 Goat, liver 0.05 Goat, meat...

  15. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., nongrass, group 18 1.0 Cattle, fat 0.02 Cattle, kidney 0.20 Cattle, liver 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0 Corn, field, grain 0.10 Corn..., fat 0.02 Goat, kidney 0.20 Goat, liver 0.05 Goat, meat 0.02 Goat, meat byproducts, except kidney...

  16. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., nongrass, group 18 1.0 Cattle, fat 0.02 Cattle, kidney 0.20 Cattle, liver 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0 Corn, field, grain 0.10 Corn..., fat 0.02 Goat, kidney 0.20 Goat, liver 0.05 Goat, meat 0.02 Goat, meat byproducts, except kidney...

  17. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., nongrass, group 18 1.0 Cattle, fat 0.02 Cattle, kidney 0.20 Cattle, liver 0.05 Cattle, meat 0.02 Cattle, meat byproducts, except kidney and liver 0.04 Corn, field, forage 6.0 Corn, field, grain 0.10 Corn..., fat 0.02 Goat, kidney 0.20 Goat, liver 0.05 Goat, meat 0.02 Goat, meat byproducts, except kidney...

  18. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., field, stover 6.0 Corn, pop, grain 0.10 Corn, pop, stover 6.0 Corn, sweet, forage 6.0 Corn, sweet, kernel plus cob with husks removed 0.10 Corn, sweet, stover 6.0 Cotton, gin byproducts 4.0 Cotton....04 Milk 0.02 Nut, tree, group 14 0.10 Okra 0.50 Peanut 0.20 Peanut, hay 20 Peanut, meal 0.40 Potato...

  19. 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)....

  20. Metolachlor and chlorothalonil dissipation in gypsum-amended soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many cropping systems incorporate pesticides individually or as tank mixtures pre- and or at planting followed by sequential application of other pesticides during the growing season. Additionally fertilizers and amendments may be applied. Previous studies demonstrate significant interactive affects...

  1. 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...

  2. 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.

  3. 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

  4. 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).

  5. Natural attenuation of chloroacetinilide herbicides in aquatic systems

    USGS Publications Warehouse

    Graham, D.W.; Graham, W.H.; DeNoyelles, F., Jr.; 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

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

    USGS Publications Warehouse

    Ator, Scott; Denver, Judith

    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.

  13. 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.

  14. 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.

  15. ALACHLOR AND ATRAZINE BIODEGRADATION UNDER DENITRIFYING ELECTRON ACCEPTOR CONDITIONS. (R825549C037)

    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...

  16. 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.

  17. Herbicides in ground water beneath Nebraska's Management Systems Evaluation Area.

    PubMed

    Spalding, Roy F; Exner, Mary E; Snow, Daniel D; Cassada, David A; Burbach, Mark E; Monson, Stephen J

    2003-01-01

    Profiles of ground water pesticide concentrations beneath the Nebraska Management Systems Evaluation Area (MSEA) describe the effect of 20 yr of pesticide usage on ground water in the central Platte Valley of Nebraska. During the 6-yr (1991-1996) study, 14 pesticides and their transformation products were detected in 7848 ground water samples from the unconfined water table aquifer. Triazine and acetamide herbicides applied on the site and their transformation products had the highest frequencies of detection. Atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] concentrations decreased with depth and ground water age determined with 3H/3He dating techniques. Assuming equivalent atrazine input during the past 20 yr, the measured average changes in concentration with depth (age) suggest an estimated half-life of >10 yr. Hydrolysis of atrazine and deethylatrazine (DEA; 2-chloro-4-amino-6-isopropylamino-s-triazine) to hydroxyatrazine [6-hydroxy-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] appeared to be the major degradation route. Aqueous hydroxyatrazine concentrations are governed by sorption on the saturated sediments. Atrazine was detected in the confined Ogallala aquifer in ultra-trace concentrations (0.003 microg L(-1)); however, the possibility of introduction during reverse circulation drilling of these deep wells cannot be eliminated. In fall 1997 sampling, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] was detected in 57% of the 230 samples. Metolachlor oxanilic acid [(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl) amino]oxo-acetic acid] was detected in most samples. In ground water profiles, concentrations of metolachlor ethane sulfonic acid [2-[(ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxo-ethanesulfonic acid] exceeded those of deethylatrazine. Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] was detected in <1% of the samples; however, alachlor

  18. 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.

  19. 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

  20. 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.

  1. 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.

  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. 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

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. Degradation of the Herbicide Metolachlor in Drummer Soil Under Different Redox Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the role of microorganisms and effect of soil environmental conditions on herbicide fate is critical for stewardship of herbicide use in cropping systems. As compared to the modernized perceptions of soil redox status, diminutive progress has been made in characterizing the impact of a...

  11. Spatial variability of atrazine and metolachlor dissipation on dryland no-tillage crop fields in Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An area of interest in precision farming is variable rate application of herbicides to optimize herbicide use efficiency and minimize negative off-site and non-target effects. Two commonly used soil applied herbicides in dryland corn production are atrazine (6-chloro-4-(ethylamino)-6-isopropylamin...

  12. 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...

  13. 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...

  14. 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...

  15. Water, sediment, and metolachlor transport between wide- and narrow row cotton production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting cotton [Gossypium hirsutum (L.)] in narrow rather than wide rows could reduce erosion and off-site agrochemical transport, but this hypothesis needs to be evaluated under Mid-South cropping conditions. Field studies were conducted near Stoneville, MS on a Dundee silty clay loam from 2006 t...

  16. 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...

  17. Fungicide Dissipation and Impact on Metolachlor Aerobic Soil Degradation and Soil Microbial Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticides are typically applied as mixtures and or sequentially to soil during crop production. A common scenario is herbicide application at planting followed by sequential fungicide applications post-emergence. Fungicides depending on their spectrum of activity may alter and impact soil microbial...

  18. Fate and efficacy of metolachlor granular and emulsifiable concentrate formulations in a conservation-tillage system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of genetically modified cultivars resistant to the herbicide glyphosate (N-phosphonomethyl-glycine) is strongly associated with conservation-tillage (CsT) adoption for maize (Zea mays L.), soybean (Glycine max L.), and cotton (Gossypium hirsutum L.) cultivation. Due to emergence of glyphosate-re...

  19. 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.

  20. 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.

  1. FIELD STUDY TO EVALUATE LEACHING OF ALDICARB, METOLACHLOR, AND BROMIDE IN SANDY LOAM SOIL

    EPA Science Inventory

    Transport and transformation of pesticides used in agricultural situations are subject to variability from several sources that are impossible to simulate in laboratory settings. his study was conducted to characterize pesticide leaching behavior under conventional cropping condi...

  2. Metolachlor and Tillage Impacts on Microbial Dynamics During a Cotton Growing Season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The benefits of conservation tillage including reduced erosion and runoff and increased soil organic carbon (OC) are well documented. However, relatively little is known about the interactive effects on soil pesticide dissipation and microbial ecology. A field study was conducted in 2007 which exami...

  3. 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...

  4. 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. PMID:24388901

  5. Variability of atmospheric pesticide concentrations between urban and rural areas during intensive pesticide application

    NASA Astrophysics Data System (ADS)

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

    Intensive pesticide use leads to the contamination of water, soil and atmosphere. Atmospheric transport is responsible for pesticide dispersal over long distances. In this study, we evaluate the local dispersal of pesticides from agricultural to urban areas. For this purpose, three high-volume samplers, each equipped with a glass fiber filter and XAD-2 resin for the sampling of particulate and gas phase have been placed in a south-west transect (predominant wind direction) characteristic of rural and urban areas. The urban site (Strasbourg centre) is situated in the middle of two rural sites. Samples were taken simultaneously at three sites during pesticide treatments in autumn and spring 2002-2003. Sampling took place for 24 h at a flow rate of 10-15 m 3 h -1. The pesticides studied were those commonly used in the Alsace region for all crops (maize, cereal, vines …). Many of the pesticides analysed in atmospheric samples were not detected or observed very episodically at very low concentrations. For metolachlor, alachlor, trifluralin, atrazine and diflufenican, higher concentrations were observed, essentially during the application of these compounds. Moreover, some "spraying peaks" were observed for alachlor in the south rural site (near crops) at a level of 31 ng m -3 on 16-17 May 2003. These results show site and time dependence of atmospheric contamination by pesticides. A limited dispersal was also observed especially in the urban area during the application periods of pesticides.

  6. 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.

  7. Herbicides in the Pecatonica, Trempealeau, and Yahara Rivers in Wisconsin, May 1997-July 1998

    USGS Publications Warehouse

    Graczyk, David J.; Vanden Brook, James P.; Rheineck, Bruce D.

    1999-01-01

    In 1997, Wisconsin farmers applied 8.7 million pounds of herbicides on corn. The five most commonly applied herbicides (in lb (pounds) of active ingredient per acre) on corn in 1997 were atrazine, metolachlor, acetochlor, alachlor and cyanazine. A 1996 study by the U.S. Geological Survey (USGS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) found that the most heavily applied agricultural herbicides were detected more frequently and at higher concentrations in the Pecatonica and Yahara Rivers in southern Wisconsin than the less heavily applied herbicides (Graczyk and Vanden Brook, 1997). The calculated herbicide loads a from May 15 to July 15, 1996 at the Pecatonica River ranged from 47.2 lb of alachlor to 484 lb of atrazine. For the Yahara River, loads ranged from 36.1 lb of alachlor to 289 lb of atrazine. The yields b (load per square mile) for atrazine were similar in the two water- sheds. This result was unexpected because the use of atrazine is prohibited on 94 percent of the Yahara River Watershed, but on only 4 percent of the Pecatonica River watershed. The unexpected atrazine result led to a continuation of the study in 1997 and 1998, when samples were collected again at the two sites sampled in 1996, and at a site in the upper third of the Yahara River Watershed that is entirely under atrazine use prohibition. For comparison purposes, a site in west-central Wisconsin also was sampled to determine herbicide loads and yields in another geographic area in the state

  8. 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. PMID:24631619

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. SCREENING RHIZOSPHERE SOIL SAMPLES FOR THE ABILITY TO MINERALIZE ELEVATED CONCENTRATIONS OF ATRAZINE AND METOLACHLOR. (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...

  15. Utilizing Vegetative Buffer Strips to Remove Dissolved and Sediment-Bound Atrazine, Metolachlor and Glyphosate from Surface Water Runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple species vegetative buffer strips (VBS) have been recommended as a cost-effective approach to mitigate herbicide transport in surface runoff derived from agronomic operations. However, the effect of buffer designs and species composition on reducing herbicide transport has not been well doc...

  16. UTILIZING VEGETATIVE BUFFER STRIPS TO REMOVE DISSOLVED AND SEDIMENT-BOUND ATRAZINE, METOLACHLOR AND GLYPHOSATE FROM SURFACE RUNOFF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple species vegetative buffer strips (VBS) have been recommended as a cost-effective approach to mitigate herbicide transport in surface runoff derived from agronomic operations. However, the effect of buffer designs and species composition on reducing herbicide transport has not been well docu...

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Net photosynthesis and respiration of sago pondweed (Potamogeton pectinatus) exposed to herbicides

    USGS Publications Warehouse

    Fleming, W.J.; Ailstock, M.S.; Momot, J.J.

    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.

  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. PMID:25109470

  5. 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).

  6. 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.

  7. 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).

  8. 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.

  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. 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. PMID:16966160

  11. Distribution of agrochemicals in the lower Mississippi River and its tributaries

    USGS Publications Warehouse

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

    1990-01-01

    The Mississippi River and its tributaries drain extensive agricultural regions of the Mid-Continental United States. Millions of pounds of herbicides are applied annually in these areas to improve crop yields. Many of these compounds are transported into the river from point and nonpoint sources, and eventually are discharged into the Gulf of Mexico. Studies being conducted by the U.S. Geological Survey along the lower Mississippi River and its major tributaries, representing a 2000 km river reach, have confirmed that several triazine and acetanilide herbicides and their degradation products are ubiquitous in this riverine system. These compounds include atrazine and its degradation products desethyl and desisopropylatrazine, cyanazine, simazine, metolachlor, and alachlor and its degradation products 2-chloro-2',6'-diethylacetanilide, 2-hydroxy-2',6-diethylacetanilide and 2,6-diethylaniline. Loads of these compounds were determined at 16 different sampling stations. Stream-load calculations provided information concerning (a) conservative or nonconservative behavior of herbicides; (b) point sources or nonpoint sources; (c) validation of sampling techniques; and (d) transport past each sampling station.

  12. Comparison of two screening bioassays, based on the frog sciatic nerve and yeast cells, for the assessment of herbicide toxicity.

    PubMed

    Papaefthimiou, Chrisovalantis; Cabral, Maria de Guadalupe; Mixailidou, Christina; Viegas, Cristina A; Sá-Correia, Isabel; Theophilidis, George

    2004-05-01

    Two different test systems, one based on the isolated sciatic nerve of an amphibian and the other on a microbial eukaryote, were used for the assessment of herbicide toxicity. More specifically, we determined the deleterious effects of increasing concentrations of herbicides of different chemical classes (phenoxyacetic acids, triazines, and acetamides), and of 2,4-dichlorophenol (2,4-DCP), a degradation product of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), on electrophysiological parameters and the vitality of the axons of the isolated sciatic nerve of the frog (Rana ridibunda) and on the growth curve of the yeast Saccharomyces cerevisiae based on microtiter plate susceptibility assays. The no-observed-effect-concentration (NOEC), defined as the maximum concentration of the tested compound that has no effect on these biological parameters, was estimated. In spite of the different methodological approaches and biological systems compared, the NOEC values were identical and correlated with the lipophilicity of the tested compounds. The relative toxicity established here, 2,4-DCP > alachlor, metolachlor > metribuzin > 2,4-D, 2-methyl-4-chlorophenoxyacetic acid (MCPA), correlates with the toxicity indexes reported in the literature for freshwater organisms. Based on these results, we suggest that the relatively simple, rapid, and low-cost test systems examined here may be of interest as alternative or complementary tests for toxicological assessment of herbicides. PMID:15180372

  13. 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.

  14. 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. 

  15. 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

  16. 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)

  17. 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

  18. 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.

  19. 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.

  20. Pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in transport in two Atlantic coastal plain tributaries and loadings to Chesapeake Bay

    USGS Publications Warehouse

    Foster, G.D.; Miller, C.V.; Huff, T.B.; Roberts, E., Jr.

    2003-01-01

    Concentrations of current-use pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine (OC) insecticides were determined above the reach of tide in the Chesterville Branch and Nanticoke River on the eastern shore of Chesapeake Bay during base-flow and storm-flow hydrologic regimes to evaluate mass transport to Chesapeake Bay. The two rivers monitored showed relatively high concentrations of atrazine, simazine, alachlor, and metolachlor in comparison to previously investigated western shore tributaries, and reflected the predominant agricultural land use in the eastern shore watersheds. The four current use pesticides showed the greatest seasonal contribution to annual loadings to tidal waters of Chesapeake Bay from the two rivers, and the relative order of annual loadings for the other contaminant classes was PAHs > PCBs > OC insecticides. Annual loadings normalized to the landscape areas of selected Chesapeake Bay watersheds showed correlations to identifiable source areas, with the highest pesticide yields (g/km2/yr) occurring in eastern shore agricultural landscapes, and the highest PAH yields derived from urban regions.

  1. Propachlor degradation by a soil bacterial community.

    PubMed Central

    Villarreal, D T; Turco, R F; Konopka, A

    1991-01-01

    Soil from a pesticide disposal site was used to enrich for microorganisms that degraded the acylanilide herbicide propachlor (2-chloro-N-isopropylacetanilide). After seven transfers of the enrichment, the culture contained about six strains. The highest yield of microbial biomass occurred if just two of these isolates, strains DAK3 and MAB2, were inoculated into a mineral salts medium containing propachlor. When only strain DAK3 was grown on propachlor, a metabolite (2-chloro-N-isopropylacetamide) was released into the medium. Strain MAB2 could grow on this metabolite. The results of morphological and physiological tests suggest that strains DAK3 and MAB2 most closely resemble species belonging to the genera Moraxella and Xanthobacter, respectively. Strain DAK3 can respire and grow on N-substituted acylanilides containing methyl, ethyl, or isopropyl substitutions, but is incapable of respiration or growth on acetanilide, aniline, or the acylanilide herbicides alachlor and metolachlor. Strain DAK3 appears to use the aromatic C atoms of propachlor for growth, as suggested by the growth yield on propachlor and the induction of catechol 2,3-oxygenase activity in acylanilide-grown cells. PMID:1768085

  2. Propachlor degradation by a soil bacterial community.

    PubMed

    Villarreal, D T; Turco, R F; Konopka, A

    1991-08-01

    Soil from a pesticide disposal site was used to enrich for microorganisms that degraded the acylanilide herbicide propachlor (2-chloro-N-isopropylacetanilide). After seven transfers of the enrichment, the culture contained about six strains. The highest yield of microbial biomass occurred if just two of these isolates, strains DAK3 and MAB2, were inoculated into a mineral salts medium containing propachlor. When only strain DAK3 was grown on propachlor, a metabolite (2-chloro-N-isopropylacetamide) was released into the medium. Strain MAB2 could grow on this metabolite. The results of morphological and physiological tests suggest that strains DAK3 and MAB2 most closely resemble species belonging to the genera Moraxella and Xanthobacter, respectively. Strain DAK3 can respire and grow on N-substituted acylanilides containing methyl, ethyl, or isopropyl substitutions, but is incapable of respiration or growth on acetanilide, aniline, or the acylanilide herbicides alachlor and metolachlor. Strain DAK3 appears to use the aromatic C atoms of propachlor for growth, as suggested by the growth yield on propachlor and the induction of catechol 2,3-oxygenase activity in acylanilide-grown cells. PMID:1768085

  3. 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.

  4. 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.

  5. 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...

  6. 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...

  7. 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

  8. Water-Quality Assessment of the Trinity River Basin, Texas - Pesticides in Streams Draining an Urban and an Agricultural Area, 1993-95

    USGS Publications Warehouse

    Land, Larry F.; Brown, Mariann F.

    1996-01-01

    Water and bed-sediment samples from streams draining an urban and an agricultural area in the Trinity River Basin, Texas, were analyzed. The samples were collected during March 1993?September 1995 by the Trinity River Basin study-unit team of the National Water-Quality Assessment Program. A comparison of pesticide data for water samples from seven streams in the Dallas-Fort Worth urban area with five streams in an agricultural area in the west-central part of the Trinity River Basin showed detections of 24 herbicides in urban-area streams and 19 herbicides in agricultural-area streams and 10 insecticides in each area. Atrazine, a herbicide, was detected in all samples from both areas. Diazinon, an insecticide, was detected in all samples collected in urban-area streams and in about 60 percent of the samples collected in agricultural-area streams. Concentrations of alachlor, atrazine, fluometuron, metolachlor, and pendimethalin (herbicides) were always greater in agricultural-area streams, and prometon and simazine concentrations were always greater in urban-area streams. Atrazine was the only herbicide with concentrations greater than a health advisory limit of 3 micrograms per liter. Concentrations were greater in about 20 percent of the samples; all were in the agricultural area and occurred during spring and during higher streamflow. Diazinon was the only insecticide with concentrations greater than the health advisory of 0.6 microgram per liter. Concentrations were greater in about 15 percent of the samples from the urban area. All exceedances were during spring through early fall and during all ranges of streamflow. In the agricultural area, atrazine and metolachlor concentrations peaked during spring and early summer and increased with increasing streamflow; in the urban area, carbaryl, chlorpyrifos, and diazinon peaked in April and remained relatively high during the summer and increased with increasing streamflow. A comparison of pesticide data for

  9. 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)). PMID

  10. 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

  11. 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.

  12. 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.

  13. Effects of low-dose exposure to pesticide mixture on physiological responses of the Pacific oyster, Crassostrea gigas.

    PubMed

    Geret, F; Burgeot, T; Haure, J; Gagnaire, B; Renault, T; Communal, P Y; Samain, J F

    2013-12-01

    This study investigated the effects on the physiology of Pacific oyster, Crassostrea gigas, of a mixture of pesticides containing 0.8 μg L(-1) alachlor, 0.6 μg L(-1) metolachlor, 0.7 μg L(-1) atrazine, 0.6 μg L(-1) terbuthylazine, 0.5 μg L(-1) diuron, 0.6 μg L(-1) fosetyl aluminum, 0.05 μg L(-1) carbaryl, and 0.7 μg L(-1) glyphosate for a total concentration of 4.55 μg L(-1) . The total nominal concentration of pesticides mixture corresponds to the pesticide concentrations in the shellfish culture area of the Marennes-Oleron basin. Two varieties of C. gigas were selected on the foreshore, based on their characteristics in terms of resistance to summer mortality, to assess the effects of the pesticide mixture after 7 days of exposure under controlled conditions. The early effects of the mixture were assessed using enzyme biomarkers of nitrogen metabolism (GS, glutamine synthetase), detoxification metabolism (GST, glutathione S-transferase), and oxidative stress (CAT, catalase). Sublethal effects on hemocyte parameters (phagocytosis and esterase activity) and DNA damages (DNA adducts) were also measured. Changes in metabolic activities were characterized by increases in GS, GST, and CAT levels on the first day of exposure for the "resistant" oysters and after 3-7 days of exposure for the "susceptible" oysters. The formation of DNA adducts was detected after 7 days of exposure. The percentage of hemocyte esterase-positive cells was reduced in the resistant oysters, as was the hemocyte phagocytic capacity in both oyster varieties after 7 days of exposure to the pesticide mixture. This study highlights the need to consider the low doses and the mixture of pesticides to evaluate the effects of these molecules on organisms. PMID:22012874

  14. 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. PMID:17592585

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Composition, distribution, and characterization of suspected endocrine-disrupting pesticides in Beijing GuanTing Reservoir (GTR).

    PubMed

    Xue, Nandong; Xu, Xiaobai

    2006-05-01

    GuanTing Reservoir (GTR) is one of two main water resources for the agriculture, industry, and living uses of Beijing (China). As a result of extensive pollution over the last few decades (particularly the 1980s), the reservoir has not supplied potable water to Beijing city since 1997. Composition, distribution, and characterization of 31 suspected endocrine-disrupting pesticides in surface water, pore water, and surface sediments from the reservoir are reported in this study. An analytical procedure based on solid-phase extraction (SPE) technology and capillary gas chromatography with electron-capture detection has been developed for the simultaneous determination of the 31 suspected endocrine-disrupting pesticides including the compounds hexachlorocyclohexane, cyclodiene, diphenyl aliphatic, chlordane, and other selected pesticides (hexachlorobenzene, heptachlor, endrin aldehyde, hepachlor epoxide, dicofol, acetochlor, alachlor, metolachlor, chlorpyriphos, nitrofen, trifluralin, cypermethrin, fenvalerate, and deltamethrin). The result shows that the pesticide pollution is moderate in GTR and its tributaries, although pesticide residue values in a few sites are quite high when considering their endocrine-disrupting effects and chronic health effects. Among the analyzed pesticides, p,p'-DDE, o,p'-DDT, beta-HCH, endosulfan sulfate, and aldrin were the most abundant pesticides in water while o,p'-DOT, delta-HCH, beta-HCH, p,p'-DDE, p,p'-DDT, and endosulfan sulfate were the most abundant in sediment. The variation in concentration of pesticides among sites can be expected to be caused by several factors such as contaminants in the rivers and drainage of contaminated water from the surrounding agricultural fields. To reduce exposure to these endocrine-disrupting compounds, the abundant current use of pesticides in the area should be minimized. Regular monitoring is needed to manage the environmental hazards due to these pesticides. PMID:16446992

  20. 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

  1. Ultra-pressure liquid chromatography-electrospray tandem mass spectrometry for multiresidue determination of pesticides in water.

    PubMed

    Gervais, G; Brosillon, S; Laplanche, A; Helen, C

    2008-08-22

    A multiresidue analysis method has been developed for the determination of pesticides in water by ultra-performance liquid chromatography (UPLC) combined with tandem mass spectrometry (MS/MS). The selected pesticides represent a broad range of polarity and volatility [benzoylcyclohexanedione (mesotrione and sulcotrione); chloroacetamide (acetochlor, alachlor, dimethenamide, and metolachlor); phenoxyacetic acid (2,4-D and MCPA); phenoxypropionic (dichloprop and mecoprop); phenylurea (chlortoluron, diuron, isoproturon, linuron, and metoxuron); sulfonylurea (foramsulfuron, iodosulfuron, and nicolsulfuron); triazine (atrazine, cyanazine, desethylatrazine (DEA), desisopropylatrazine (DIA), simazine, and terbutylazine)]. The analytes were extracted using solid-phase extraction (SPE). The separation was carried out on an acquity UPLC BEH C18 column (1.7 microm, 50 mm x 1 mm ID) using a gradient elution profile and mobile phase consisting of 0.1% formic acid in water and acetonitrile. The pesticides were detected with a tandem mass spectrometer after being ionised positively or negatively (depending on the molecule) using an electrospray ionisation (ESI) source. To achieve the suitable extraction conditions for sample preparation, several parameters affecting the efficiency of SPE such as the nature of the sorbent and the eluent, extractant volume and pH were studied. The best recovery was obtained by the extraction with an Oasis HLB cartridge and 3 mL of a solution of acetonitrile/dichloromethane (1:1, v/v) at pH 2. The average recoveries of the pesticides in different samples ranged from 82 to 109%. The weight least squares (WLS) linear regression was used to calculate the limits of detection and quantification (LOD and LOQ) because the dispersion was heteroskedastic. All the pesticides could be correctly quantified at a concentration level of 50 ng L(-1) and most of them could be detected at a concentration inferior or equal to 8 ng L(-1). Efficiency and robustness of

  2. Impact of Temporal and Spatial Variations in agrochemical Fluxes within the Riparian Buffer on Exports from a First Order Watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both agricultural nitrogen and metolachlor ethane sulfonic acid (MESA), a prevalent metabolite of metolachlor, are primarily delivered to streams via groundwater flows. The ability of riparian ecosystems to remove agrochemicals from exfiltrating groundwater is a potentially important control on the...

  3. 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

  4. 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

  5. Pesticides in surface water of the Mid-Atlantic region

    USGS Publications Warehouse

    Ferrari, Matthew J.; Ator, Scott W.; Blomquist, Joel D.; Dysart, Joel E.

    1997-01-01

    Water-quality data from 463 surface-water sites were compiled and analyzed to document the occurrence and distribution of pesticides in surface water of the Mid-Atlantic region as part of the Mid-Atlantic Integrated Assessment program of the U.S. Environmental Protection Agency. Those data collected by the U.S. Geological Survey from October 1973 through March 1997 were used in the analyses. Data are available for a large part of the Mid-Atlantic region, but large spatial gaps in the data do exist. USGS data bases contained analyses of surface-water samples for 127 pesticide compounds, including 12 degradates, but only 16 of the compounds were commonly detected. Atrazine, metolachlor, simazine, prometon, alachlor, tebuthiuron, cyanazine, diazinon, carbaryl, chlorpyrifos, pendimethalin, 2,4-D, dieldrin, DCPA, metribuzin, and desethylatrazine (an atrazine degradate) were detected in more than 100 of the samples analyzed. At least one pesticide was detected in about 75 percent of the samples collected and at more than 90 percent of the sites sampled. Concentrations greater than the Federal Maximum Contaminant Level (MCL) for drinking water of 3 micrograms per liter (ug/L) for atrazine were found in 67 of 2,076 samples analyzed; concentrations greater than the MCL of 2ug/L for alachlor were found in 13 of 1,693 samples analyzed, and concentrations greater than the MCL of 4 ug/L for simazine were found in 17 of 1,995 samples analyzed. Concentrations of four pesticides were greater than Federal Health Advisory levels for drinking water, and concentrations of nine pesticides were greater than Federal Ambient Water-Quality Criteria for the Protection of Aquatic Organisms. Streams draining basins with different land uses tend to have different pesticide detection frequencies and median concentrations. Median concentrations of herbicides tend to be highest in streams draining basins in which the major land use is agriculture, whereas median concentrations of insecticides

  6. 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).

  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. 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

  9. 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

  10. 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

    In the United States, herbicides are among the most significant nonpoint-source pollutants and were applied to 95% of all fields in corn production and 97% of all fields in soybean production in 2003 and 2004. The United States Geological Survey (USGS) has conducted a study on select herbicides in the unsaturated zone under corn and soybean fields in three predominantly agricultural basins: Morgan Creek (Maryland), Leary Weber Ditch within Sugar Creek (Indiana), and Maple Creek (Nebraska). In 2004, the Morgan Creek and Leary Weber Ditch fields were in soybeans and the Maple Creek fields were in corn. The Maple Creek fields were irrigated, whereas those in Morgan Creek and Leary Weber Ditch were not. Similarities and differences in agricultural management practices, climatic conditions, and natural features, such as soil types and geology, were evaluated as part of the study. In general, the amounts of herbicides entering the unsaturated zone from rain in these basins were minor (1%) compared to amounts commonly applied to the land surface during agricultural practices. Few herbicides were detected on solid core samples from the unsaturated zones of these basins. An exception was found at a Morgan Creek site in an upland recharge area with sandier soils. Here, atrazine concentrations were highest in the near surface solids and decreased with depth. In the unsaturated-zone porewater of the Morgan Creek Basin, parent triazine and acetanilide herbicides were detected and only at the site in the upland recharge area at relatively low concentrations at depths greater than 4 meters, probably because these compounds had not been applied for several years. At the Morgan Creek and Leary Weber Ditch sites, acetanilide metabolites were frequently detected in the unsaturated-zone porewater. In general, the fraction of metolachlor ethane sulfonic acid (ESA) relative to the total mass of parent and metabolites increased with depth overall and at several individual sampling

  11. 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

  12. 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

  13. 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...

  14. 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.

  15. 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.

  16. 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...

  17. 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 ...

  18. VERIFICATION OF A TOXIC ORGANIC SUBSTANCE TRANSPORT AND BIOACCUMULATION MODEL

    EPA Science Inventory

    A field verification of the Toxic Organic Substance Transport and Bioaccumulation Model (TOXIC) was conducted using the insecticide dieldrin and the herbicides alachlor and atrazine as the test compounds. The test sites were two Iowa reservoirs. The verification procedure include...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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,

  9. 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

  10. 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.

  11. USE OF MARSH PLANTS FOR TOXICITY TESTING OF WATER AND SEDIMENT

    EPA Science Inventory

    The freshwater wetland plants, Echinochlo crusgalli crusgalli andEchinocloa crusgalli zelayensis, and the saltmarsh plant, Spartina alterniflora, were exposed to the herbicides, metolachlor and norflurazon, in two types of toxicity tests: eed germination and early seedling growth...

  12. 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

  13. 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.

  14. Current-use pesticides in inland lake waters, precipitation, and air from Ontario, Canada.

    PubMed

    Kurt-Karakus, Perihan Binnur; Teixeira, Camilla; Small, Jeff; Muir, Derek; Bidleman, Terry F

    2011-07-01

    Concentrations of current-use pesticides (CUPs) in water, zooplankton, precipitation, and air samples as well as stereoisomer fractions (SF; herbicidally active/total stereoisomers) of metolachlor were determined in water samples collected from 10 remote inland lakes in Ontario, Canada, between 2003 and 2005. The most frequently detected chemicals in lake water, precipitation, and air were α-endosulfan, atrazine, metolachlor, chlorpyrifos, chlorothalonil, and trifluralin, and α-endosulfan and chlorpyrifos were the chemicals detected frequently in zooplankton. Air concentrations of these CUPs were within the range of previously reported values for background sites in the Great Lakes basin. High detection frequency of CUPs in lake water and precipitation was attributed to high usage amounts, but some CUPs such as ametryn and disulfoton that were not used in Ontario were also detected. Mean bioaccumulation factors (wet wt) in zooplankton for endosulfan ranged from 160 to 590 and from 20 to 60 for chlorpyrifos. The overall median SF of metolachlor in precipitation samples (0.846) was similar to that of the commercial S-metolachlor (0.882). However, the median SF of metolachlor in water from all sampled inland lakes (0.806) was significantly lower compared with Ontario rivers (0.873) but higher compared with previous measurements in the Great Lakes (0.710). Lakes with smaller watershed areas showed higher SFs, supporting the hypothesis of stereoselective processing of deposited metolachlor within the watersheds, followed by transport to the lakes. PMID:21472774

  15. Effect of rice husk gasification residue application on herbicide behavior in micro paddy lysimeter.

    PubMed

    Ok, Junghun; Pisith, Sok; Watanabe, Hirozumi; Thuyet, Dang Quoc; Boulange, Julien; Takagi, Kazuhiro

    2015-06-01

    Effects of rice husk gasification residues (RHGR) application on the fate of herbicides, butachlor and pyrazosulfuron-ethyl, in paddy water were investigated using micro paddy lysimeters (MPLs). The dissipation of both herbicides in paddy water was faster in the RHGR treated MPL than in the control MPL. The average concentrations of butachlor and pyrazosulfuron-ethyl in paddy water in the lysimeter treated with RHGR during 21 days were significantly reduced by 51% and 48%, respectively, as compared to those in the lysimeter without RHGR application. The half-lives (DT50) of butachlor in paddy water for control and treatment were 3.1 and 2.3 days respectively, and these values of pyrazosulfuron-ethyl were 3.0 and 2.2 days, respectively. Based on this study, RHGR application in rice paddy environment is an alternative method to reduce the concentration of herbicide in paddy field water and consequently to reduce potential pollution to aquatic environment. PMID:25763539

  16. 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

  17. 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.

  18. 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

  19. Groundwater quality in the Columbia Plateau, Snake River Plain, and Oahu basaltic-rock and basin-fill aquifers in the Northwestern United States and Hawaii, 1992-2010

    USGS Publications Warehouse

    Frans, Lonna M.; Rupert, Michael G.; Hunt, Charles D., Jr.; Skinner, Kenneth D.

    2012-01-01

    decades in the oxygen-rich groundwater of the Columbia Plateau and the Snake River Plain, so prudent groundwater protection measures are critical to protect drinking water resources by reducing nitrate leaching from the land surface. Nitrate logistic regression models indicated that areas with a high percentage of land in crops (such as potatoes or sugarcane) and soils with low amounts of organic matter are most likely to have elevated nitrate concentrations in the groundwater. Areas where agricultural activities were absent had much lower probabilities of detecting elevated nitrate concentrations. The Columbia Plateau had a much higher probability of having elevated nitrate concentrations, with most of the land area having greater than a 50 percent probability of elevated nitrate concentrations. Oahu and the Snake River Plain had a much lower probability of having elevated nitrate concentrations because of their lower percentage of agricultural land. Pesticides were detected at many sites in groundwater of the Columbia Plateau, Snake River Plain, and Oahu but generally at low concentrations below human-health benchmarks. Atrazine and its degradate (a compound produced from the breakdown of a parent pesticide), deethylatrazine, were the most commonly detected pesticides in groundwater sampled in the Columbia Plateau and Snake River Plain. Bromacil was the most commonly detected pesticide on Oahu. The other pesticides most commonly detected in the study areas include simazine, hexazinone, metribuzin, diuron, prometon, metolachlor, p,p'-DDE, dieldrin, 2-4-D, and alachlor. DDE (a degradate of DDT) and dieldrin are still being detected in groundwater despite having been banned for more than 30 years. Codetection of multiple pesticides in water from a single well was common. The widespread occurrence of pesticides in groundwater in the study areas indicates that the groundwater is highly susceptible to pesticide contamination. Some pesticides were detected in groundwater

  20. SOC REJECTION BY NANOFILTRATION

    EPA Science Inventory

    A study was conducted to evaluate the rejection of six synthetic organic compounds (SOCs) from a potable water source by a nanofiltration membrane process. The S0Cs were ethylene dibromide (EDB), dibromochloropropane (DBCP), chlordane, heptachlor, methoxychlor and alachlor. To in...

  1. TOXICITY, BIOCONCENTRATION, AND METABOLISM OF FIVE HERBICIDES IN FRESHWATER FISH

    EPA Science Inventory

    Acute and early life-stage toxicities were determined for the herbicides alachlor, bromacil, dinoseb, diuron, and propanil with the fathead minnow (Pimephales promelas). Uptake, bioconcentration potential, and elimination of 14C-labeled herbicides were studied in the same species...

  2. CURRENT-USE PESTICIDES: ASSESSING EXPOSURE AND SPERMATOXICITY

    EPA Science Inventory

    We recently reported that higher levels of urinary metabolite (mercapturates) of the current-use pesticides alachlor, atrazine and diazinon were significantly associated with decreased semen quality in fertile men from mid-Missouri. The primary goal of this stud...

  3. 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...

  4. 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...

  5. 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 ...

  6. 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.

  7. 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.

  8. 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

    2016-06-01

    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. PMID:26853603

  9. 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.

  10. 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.

  11. Effect of systemic herbicides on N2-fixing and phosphate solubilizing microorganisms in relation to availability of nitrogen and phosphorus in paddy soils of West Bengal.

    PubMed

    Das, Amal Chandra; Debnath, Anjan

    2006-11-01

    A field experiment has been conducted with four systemic herbicides viz., butachlor [N-(butoxymethyl)-2-chloro-2',6'-diethyl-acetanilide], fluchloralin [N-(2-chloroethyl)-(2,6-dinitro-N-propyl-4-trifluoromethyl) aniline], oxadiazon [5-terbutyl-3-(2,4-dichloro-5-isopro poxyphenyl)-1,3,4-oxadiazol-2-one] and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenyl)-4-(trifluoromethyl) benzene] at their recommended field rates (2.0, 1.5, 0.4 and 0.12kga.i.ha(-1), respectively) to investigate their effects on growth and activities of aerobic non-symbiotic N(2)-fixing bacteria and phosphate solubilizing microorganisms in relation to availability of nitrogen and phosphorus in the rhizosphere soils as well as yield of the rice crop (Oryza sativa L cv. IR-36). Application of herbicides, in general, highly stimulated the population and activities of the target microorganisms, which resulted in a greater amount of atmospheric nitrogen fixation and phosphate solubilization in the rhizosphere soils of the test crop. The greater microbial activities subsequently augmented the mineralization and availability of nitrogen and phosphorus in the soil solution, which in turn increased the yield of the crop. Among the herbicides, oxyfluorfen was most stimulative followed by fluchloralin and oxadiazon in augmenting the microbial activities in soil. Butachlor also accentuated the mineralization and availability of nitrogen due to higher incitement of non-symbiotic N(2)-fixing bacteria in paddy soil. The grain and straw yields of the crop were also significantly increased due to the application of oxyfluorfen (20.2% and 21%) followed by fluchloralin (13.1% and 15.4%) and butachlor (9.1% and 10.2%), respectively. PMID:16630642

  12. 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

  13. Comparative responses of river biofilms at the community level to common organic solvent and herbicide exposure.

    PubMed

    Paule, A; Roubeix, V; Swerhone, G D W; Roy, J; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L; Lawrence, J R

    2016-03-01

    Residual pesticides applied to crops migrate from agricultural lands to surface and ground waters. River biofilms are the first aquatic non-target organisms which interact with pesticides. Therefore, ecotoxicological experiments were performed at laboratory scale under controlled conditions to investigate the community-level responses of river biofilms to a chloroacetanilide herbicide (alachlor) and organic solvent (methanol) exposure through the development referenced to control. Triplicate rotating annular bioreactors, inoculated with river water, were used to cultivate river biofilms under the influence of 1 and 10 μg L(-1) of alachlor and 25 mg L(-1) of methanol. For this purpose, functional (thymidine incorporation and carbon utilization spectra) and structural responses of microbial communities were assessed after 5 weeks of development. Structural aspects included biomass (chlorophyll a, confocal laser scanning microscopy) and composition (fluor-conjugated lectin binding, molecular fingerprinting, and diatom species composition). The addition of alachlor resulted in a significant reduction of bacterial biomass at 1 μg L(-1), whereas at 10 μg L(-1), it induced a significant reduction of exopolymer lectin binding, algal, bacterial, and cyanobacterial biomass. However, there were no changes in biofilm thickness or thymidine incorporation. No significant difference between the bacterial community structures of control and alachlor-treated biofilms was revealed by terminal restriction fragment length polymorphism (T-RFLP) analyses. However, the methanol-treated bacterial communities appeared different from control and alachlor-treated communities. Moreover, methanol treatment resulted in an increase of bacterial biomass and thymidine incorporation as well. Changes in dominant lectin binding suggested changes in the exopolymeric substances and community composition. Chlorophyll a and cyanobacterial biomass were also altered by methanol. This study suggested

  14. HERBICIDE ABATEMENT BY A RIPARIAN WETLAND SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are touted for their ability to remove agricultural contaminants; however, little is known about the specific processes that function to arrest pesticide movement and transport. Five years of data have been gathered on the movement and fate of atrazine and metolachlor into a ripari...

  15. Weed Control and Yield Comparisons of Twin- and Single-row Glyphosate Resistant Cotton Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 2-yr field study was conducted during 2007 and 2008 at Stoneville, MS, to determine the effect of twin-row (two rows 38 cm apart on 102-cm beds) and single-row (on 102-cm beds) pattern and glyphosate POST applications with and without fluometuron + S-metolachlor PRE on cotton canopy closure, weed ...

  16. Mitigating agrichemicals from an artificial runoff event using a managed riverine wetland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the mitigation efficiency of a managed riverine wetland amended with a mixture of suspended sediment, two nutrients (nitrogen and phosphorus), and three pesticides (atrazine, metolachlor, and permethrin) during a simulated agricultural runoff event. Hydrologic management of the 500 m-lo...

  17. Preemergence herbicides influence sprig establishment of 'TifEagle' bermudagrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of weeds during bermudagrass (Cynodon dactylon x C. transvaalensis Burtt-Davy) putting green establishment can reduce growth and turf quality. Three field experiments were conducted in Georgia to investigate efficacy of dimethenamid, S-metolachlor, and oxadiazon on the establishment of...

  18. Fate of Herbicides and Their Degradation Products Entering a Forested Riparian Buffer Following Herbicides Application to an Adjacent Corn Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of two herbicides, atrazine and metolachlor, were followed as they entered and moved through a forested riparian wetland located in the mid-Atlantic coastal plain of Maryland. The herbicides were applied as pre-emergent treatments to a 20-ha corn field directly upgradient of the riparian w...

  19. 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.

  20. THROUGH-FALL VERSUS STEM FLOW PESTICIDE DEPOSITION TO A RIPARIAN BUFFER AREA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffer areas are widely touted for their ability to abate pollutants emerging from agricultural fields. We are studying this abatement process for the pesticides atrazine and metolachlor, using a heavily instrumented site located in Beltsville, Maryland. One of our overall goals in this st...

  1. Responses of Hyalella azteca and phytoplankton to a simulated agricultural runoff event in a managed backwater wetland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed the aqueous toxicity mitigation capacity of a hydrologically managed floodplain wetland following a synthetic runoff event amended with a mixture of sediments, nutrients (nitrogen and phosphorus), and pesticides (atrazine, S-metolachlor, and permethrin) using 48-h Hyalella azteca surviva...

  2. 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...

  3. 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...

  4. Efficiency of a modified backwater wetland in trapping a pesticide mixture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pesticide trapping efficiency of a modified backwater wetland amended with a mixture of three pesticides, atrazine, S-metolachlor, and fipronil, using a simulated runoff event, was examined. The 700 m long, 25 m wide wetland, located along the Coldwater River in Tunica County, Mississippi, USA,...

  5. Pesticide trapping efficiency of a modified backwater wetland using a simulated runoff event

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined the trapping efficiency of a modified backwater wetland amended with a mixture of three pesticides, atrazine, metolachlor, and fipronil, using a simulated runoff event. The 700 m long, 25 m wide wetland, located along the Coldwater River in Tunica County, Mississippi, was modifie...

  6. 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

  7. 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...

  8. Autumn vegetable response to residual herbicides applied the previous spring under low density polyethylene mulch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in 2002 and 2005 to evaluate autumn vegetable tolerance to residual herbicides applied the previous spring under low density polyethylene (LDPE) mulch. Spring applications of 1.12 kg/ha S-metolachlor, 0.027 kg/ha halosulfuron, 0.28 kg/ha sulfentrazone, and 1.12 kg/ha S...

  9. Residual herbicide dissipation for bare soil versus soil under low density polyethylene mulch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow nutsedge and purple nutsedge are the most common and troublesome vegetable weeds in the Southern US. Herbicides in low density polyethylene (LDPE) mulch systems are potential methyl bromide alternatives for nutsedge control. Halosulfuron-methyl, sulfentrazone, and s-metolachlor all have nutse...

  10. Herbicide Abatement by a Riparian Wetland System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers are touted for their ability to remove agricultural contaminants. However, little is known about the specific processes that function to arrest pesticide movement and transport. Five years of data have been gathered on the movement and fate of atrazine and metolachlor into a ripar...

  11. 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...

  12. Evaluation of the interrelationship between pesticide and turbulent energy fluxes and the implications for remotely-sensed estimates of pesticide volatilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the primary pathway for loss from agricultural systems, the volatilization of pesticides, such as Metolachlor and Atrazine, can adversely impact the quality of air and water, crop productivity, and public health. Nonetheless, effective methods for modeling volatilization and estimating the pestic...

  13. 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.

  14. 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.

  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. 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

  17. 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.

  18. Uptake of polycyclic aromatic hydrocarbon compounds by the gills of the bivalve mollusk Elliptio complanata.

    PubMed

    Birdsall, K; Kukor, J J; Cheney, M A

    2001-02-01

    Polycyclic aromatic hydrocarbons (PAHs) and herbicides are important contaminants of world water systems with effects on aquatic organisms. The uptake of naphthalene, anthracene, and chrysene by gills of the bivalve mollusk Elliptio complanata was determined. Additionally, the effects of paraquat, atrazine, alachlor, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol on the uptake of these compounds were also determined. The results indicate (1) the uptake of anthracene is approximately equivalent to that of chrysene and the uptake of either of these compounds is higher than that of naphthalene; (2) comparisons of uptakes with that of inulin, which occupies only extracellular space, show that all compounds studied are taken up; (3) the uptakes of naphthalene, anthracene, and chrysene are initially altered by the presence of herbicides such as paraquat, alachlor, 2,4-D, atrazine, and 2,4-dinitrophenol. PMID:11351430

  19. 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. PMID:25575291

  20. 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.

  1. 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.

  2. Occurrence of selected pesticides and their metabolites in near-surface aquifers of the midwestern United States

    USGS Publications Warehouse

    Kolpin, D.W.; Michael, Thurman E.; Goolsby, D.A.

    1996-01-01

    The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound. The metabolite alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid) was detected almost 10 times as frequently and at much higher concentrations than its parent compound alachlor (2-chloro-2‘,6‘-diethyl-N-(methoxymethyl)acetamide). The median detectable atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) concentration was almost half that of atrazine residue (atrazine plus the two atrazine metabolites analyzed). Cyanazine amide [2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-s-triazine] was detected almost twice as frequently as cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). Results show that information on pesticide metabolites is necessary to understand the environmental fate of pesticides. Consequently, if pesticide metabolites are not quantified, the effects of chemical use on groundwater quality would be substantially underestimated. Thus, continued research is needed to identify major degradation pathways for all pesticides and to develop analytical methods to determine their concentrations in water and other environmental media.

  3. 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.

  4. A clay-vesicle system for water purification from organic pollutants.

    PubMed

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

    2008-02-01

    Vesicle-clay complexes in which positively charged vesicles composed of didodecyldimethylammonium bromide (DDAB) were adsorbed on montmorillonite removed efficiently anionic (sulfentrazone, imazaquin) and neutral (alachlor, atrazine) pollutants from water. These complexes (0.5% w:w) removed 92-100% of sulfentrazone, imazaquin and alachlor and 60% of atrazine from a solution containing 10mg/L of it. A synergistic effect on the adsorption of atrazine was observed when all pollutants were present simultaneously (30 mg/L each), its percentage of removal being 85.5. Column filters (18 cm) filled with a mixture of quartz sand and vesicle-clay (100:1, w:w) were tested. For the passage of 1L (25 pore volumes) of a solution including all the pollutants at 10mg/L each, removal was complete for sulfentrazone and imazaquin, 94% for alachlor and 53.1% for atrazine, whereas removal was significantly less efficient when using activated carbon. A similar advantage of the vesicle-clay filter was observed for the capacities of removal. PMID:17915281

  5. Herbicide leaching as affected by macropore flow and within-storm rainfall intensity variation: a RZWQM simulation.

    PubMed

    Malone, Robert W; Weatherington-Rice, Julie; Shipitalo, Martin J; Fausey, Norman; Ma, Liwang; Ahuja, Lajpat R; Wauchope, R Don; Ma, Qingli

    2004-03-01

    Within-event variability in rainfall intensity may affect pesticide leaching rates in soil, but most laboratory studies of pesticide leaching use a rainfall simulator operating at constant rainfall intensity, or cover the soil with ponded water. This is especially true in experiments where macropores are present--macroporous soils present experimental complexities enough without the added complexity of variable rainfall intensity. One way to get around this difficulty is to use a suitable pesticide transport model, calibrate it to describe accurately a fixed-intensity experiment, and then explore the affects of within-event rainfall intensity variation on pesticide leaching through macropores. We used the Root Zone Water Quality Model (RZWQM) to investigate the effect of variable rainfall intensity on alachlor and atrazine transport through macropores. Data were used from an experiment in which atrazine and alachlor were surface-applied to 30 x 30 x 30 cm undisturbed blocks of two macroporous silt loam soils from glacial till regions. One hour later the blocks were subjected to 30-mm simulated rain with constant intensity for 0.5 h. Percolate was collected and analyzed from 64 square cells at the base of the blocks. RZWQM was calibrated to describe accurately the atrazine and alachlor leaching data, and then a median Mid-west variable-intensity storm, in which the initial intensity was high, was simulated. The variable-intensity storm more than quadrupled alachlor losses and almost doubled atrazine losses in one soil over the constant-intensity storm of the same total depth. Also rainfall intensity may affect percolate-producing macroporosity and consequently pesticide transport through macropores. For example, under variable rainfall intensity RZWQM predicted the alachlor concentration to be 2.7 microg ml(-1) with an effective macroporosity of 2.2 E(-4) cm(3) cm(-3) and 1.4 microg ml(-1) with an effective macroporosity of 4.6 E(-4) cm(3) cm(-3). Percolate

  6. Impact of glyphosate-tolerant soybean and glufosinate-tolerant corn production on herbicide losses in surface runoff.

    PubMed

    Shipitalo, Martin J; Malone, Robert W; Owens, Lloyd B

    2008-01-01

    Residual herbicides used in the production of soybean [Glycine max (L.) Merr] and corn (Zea mays L.) are often detected in surface runoff at concentrations exceeding their maximum contaminant levels (MCL) or health advisory levels (HAL). With the advent of transgenic, glyphosate-tolerant soybean and glufosinate-tolerant corn this concern might be reduced by replacing some of the residual herbicides with short half-life, strongly sorbed, contact herbicides. We applied both herbicide types to two chiseled and two no-till watersheds in a 2-yr corn-soybean rotation and at half rates to three disked watersheds in a 3-yr corn/soybean/wheat (Triticum aestivum L.)-red clover (Trifolium pratense L.) rotation and monitored herbicide losses in runoff water for four crop years. In soybean years, average glyphosate loss (0.07%) was approximately 1/7 that of metribuzin (0.48%) and about one-half that of alachlor (0.12%), residual herbicides it can replace. Maximum, annual, flow-weighted concentration of glyphosate (9.2 microg L(-1)) was well below its 700 microg L(-1) MCL and metribuzin (9.5 microg L(-1)) was well below its 200 microg L(-1) HAL, whereas alachlor (44.5 microg L(-1)) was well above its 2 microg L(-1) MCL. In corn years, average glufosinate loss (0.10%) was similar to losses of alachlor (0.07%) and linuron (0.15%), but about one-fourth that of atrazine (0.37%). Maximum, annual, flow-weighted concentration of glufosinate (no MCL) was 3.5 microg L(-1), whereas atrazine (31.5 microg L(-1)) and alachlor (9.8 microg L(-1)) substantially exceeded their MCLs of 3 and 2 microg L(-1), respectively. Regardless of tillage system, flow-weighted atrazine and alachlor concentrations exceeded their MCLs in at least one crop year. Replacing these herbicides with glyphosate and glufosinate can reduce the occurrence of dissolved herbicide concentrations in runoff exceeding drinking water standards. PMID:18268303

  7. 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.

  8. Atmospheric deposition of pesticides to an agricultural watershed of the Chesapeake Bay.

    PubMed

    Kuang, Zhihua; McConnell, Laura L; Torrents, Alba; Meritt, Donald; Tobash, Stephanie

    2003-01-01

    The Choptank River watershed, located on the Delmarva Peninsula of the Chesapeake Bay, is dominated by agricultural land use, which makes it vulnerable to runoff and atmospheric deposition of pesticides. Agricultural and wildlife areas are in close proximity and off-site losses of pesticides may contribute to toxic effects on sensitive species of plants and animals. High-volume air samples (n = 31) and event-based rain samples (n = 71) were collected from a single location in the watershed representing regional background conditions. Surface water samples were collected from eight stations in the tidal portion of the river on five occasions during 2000. Chlorothalonil, metolachlor, atrazine, simazine, endosulfan, and chlorpyrifos were frequently detected in the air and rain, with maximal concentrations during the period when local or regional crops were planted. The wet deposition load to the watershed was estimated at 150 +/- 16, 61 +/- 7, and 51 +/- 6 kg yr(-1) for chlorothalonil, metolachlor, and atrazine, respectively. The high wet deposition load compared with the estimated annual usage for chlorothalonil (13%) and endosulfan (14-90%) suggests an atmospheric source from outside the watershed. Net air-water gas exchange fluxes for metolachlor varied from -44 +/- 19 to 9.3 +/- 4.1 ng m(-2) d(-1) with negative values indicating net deposition. Wet deposition accounted for 3 to 20% of the total metolachlor mass in the Choptank River and was a more important source to the river than gas exchange. Estimates of herbicide flux presented here are probably a low estimate and actual rates may be significantly higher in areas closer to pesticide application. PMID:14535301

  9. 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.

  10. 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

  11. Combined effects of pollutants and salinity on embryo-larval development of the Pacific oyster, Crassostrea gigas.

    PubMed

    Gamain, Perrine; Gonzalez, Patrice; Cachot, Jérôme; Pardon, Patrick; Tapie, Nathalie; Gourves, Pierre Yves; Budzinski, Hélène; Morin, Bénédicte

    2016-02-01

    For several years, low larval recruitment has been observed in Arcachon Bay, in southwest France. Exposure to pollutants could partly account for the reduction of early life stages of the Pacific oyster. This study evaluated the effects of copper and S-metolachlor in combination with salinity on the early life stages of Crassostrea gigas. Embryos were exposed to concentrations of copper (1, 10 and 50 μg L(-1)) or S-metolachlor (10, 100 and 1000 ng L(-1)) and six salinities (18, 21, 24, 27, 30 and 33 u.s.i). Embryotoxicity was measured by considering both the percentage of abnormalities and arrested development in D-shaped larvae. Embryo-larval development was only affected at salinities ≤24 u.s.i, which have never been observed during C. gigas reproduction period in Arcachon Bay. Both contaminants had an effect at environmental concentrations. Our results suggest that copper and metolachlor toxicity was enhanced with decreasing salinity. PMID:26583531

  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. High-resolution accurate mass spectrometry as a technique for characterization of complex lysimeter leachate samples.

    PubMed

    Hand, Laurence H; Marshall, Samantha J; Saeed, Mansoor; Earll, Mark; Hadfield, Stephen T; Richardson, Kevan; Rawlinson, Paul

    2016-06-01

    Lysimeter studies can be used to identify and quantify soil degradates of agrochemicals (metabolites) that have the potential to leach to groundwater. However, the apparent metabolic profile of such lysimeter leachate samples will often be significantly more complex than would be expected in true groundwater samples. This is particularly true for S-metolachlor, which has an extremely complex metabolic pathway. Consequently, it was not practically possible to apply a conventional analytical approach to identify all metabolites in an S-metolachlor lysimeter study, because there was insufficient mass to enable the use of techniques such as nuclear magnetic resonance. Recent advances in high-resolution accurate mass spectrometry, however, allow innovative screening approaches to characterize leachate samples to a greater extent than previously possible. Leachate from the S-metolachlor study was screened for accurate masses (±5 ppm of the nominal mass) corresponding to more than 400 hypothetical metabolite structures. A refined list of plausible metabolites was constructed from these data to provide a comprehensive description of the most likely metabolites present. The properties of these metabolites were then evaluated using a principal component analysis model, based on molecular descriptors, to visualize the entire chemical space and to cluster the metabolites into a number of subclasses. This characterization and principal component analysis evaluation enabled the selection of suitable representative metabolites that were subsequently used as exemplars to assess the toxicological relevance of the leachate as a whole. Environ Toxicol Chem 2016;35:1401-1412. © 2015 SETAC. PMID:26627902

  14. Cross-resistance pattern and alternative herbicides for Cyperus difformis resistant to sulfonylurea herbicides in Korea.

    PubMed

    Kuk, Yong In; Kim, Kyung Hyun; Kwon, Oh Do; Lee, Do Jin; Burgos, Nilda R; Jung, Sunyo; Guh, Ja Ock

    2004-01-01

    A Cyperus difformis L accession from Chonnam province, Korea was tested for resistance to the sulfonylurea herbicide, imazosulfuron. The accession was confirmed to be resistant (R) and was cross-resistant to other sulfonylurea herbicides, bensulfuron-methyl, cyclosulfamuron and pyrazosulfuron-ethyl, the pyrimidinyl thiobenzoate herbicide, bispyribac-sodium, and the imidazolinone herbicide imazapyr, but not to imazaquin. Multiple resistance was tested using twelve herbicides with target sites other than acetolactate synthase (ALS). The R biotype could be controlled by other herbicides with different modes of action such as butachlor, carfentrazone-ethyl, clomeprop, dithiopyr, esprocarb, mefenacet, oxadiazon, pretilachlor, pyrazolate and thiobencarb, applied to soil at recommended rates. Several sulfonylurea herbicide-based mixtures can control both the R and S biotypes of C difformis, except sulfonylurea plus dimepiperate, molinate or pyriftalid, and pyrazolate plus butachlor. Although mixtures of sulfonylurea herbicides might be more effective, they should be avoided and used only in special cases. In terms of in vitro ALS activity, the R biotype was 1139-, 3583-, 1482-, 416-, 5- and 9-fold more resistant to bensulfuron-methyl, cyclosulfamuron, imazosulfuron, pyrazosulfuron-ethyl, bispyribac-sodium and imazapyr, respectively, than the S biotype. The in vivo ALS activity of the R biotype was also less affected by the sulfonylurea herbicides, imazosulfuron and pyrazosulfuron-ethyl, than the S biotype. Results of in vitro and in vivo ALS assays indicated that the resistance mechanism of C difformis to ALS inhibitor herbicides was primarily due to an alteration in the target enzyme, ALS. Greenhouse experiments showed delayed flowering and reduced seed production of the R biotype, which could possibly result in reduced fitness. This unusual observation needs to be confirmed in field situations. PMID:14727745

  15. Distribution and risk assessment of 82 pesticides in Jiulong River and estuary in South China.

    PubMed

    Zheng, Senllin; Chen, Bin; Qiu, Xiaoyan; Chen, Meng; Ma, Zhiyuan; Yu, Xingguang

    2016-02-01

    To discover the distribution and risk of pesticides in Jiulong River and estuary, the residues of 102 pesticides were analyzed in water, sediment and clam samples collected from 35 sites in different seasons. A total number of 82 pesticides were detected and the occurrence and the risk to human and fish were assessed. Most of pesticides with high frequency were medium or low toxic except for DDTs. DDTs were the significant contaminant and the widely used dicofol was the new source of DDTs. The spatial and seasonal variation of pesticide distribution was linked with the distribution of orchards and farmlands. Health risk from river water consumption was low (RQ < 0.1) while that from clam consumption was medium (RQ = 0.84). Pesticides in water posed great risk to fish and among the 76 water samples analyzed, 65 of them showed high risk (RQ > 1) and 6 showed medium risk (0.1 ≤ QR < 1). The single chemical posed high risk to fish included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin, and those showed medium risk included dicofol, butachlor, isocarbophos, terbufos and cyhalothrin. There were 14 single pesticides detected with concentration above 100 ng L(-1) in this study and the pesticide with the highest concentration was procymidone (3904 ng L(-1)). Further experiments illustrated that procymidone could disrupt the expression of vitellogenin in the estuarine fish even at environmental concentrations. DDTs, dicofol, triazophos, isocarbophos, terbufos, cyfluthrin, bifenthrin, fenvalerate, cyhalothrin, butachlor and procymidone have become the significant pesticides and should be considered in aquatic ecosystem risk management. PMID:26461443

  16. Comparative losses of glyphosate and selected residual herbicides in surface runoff from conservation-tilled watersheds planted with corn or soybean.

    PubMed

    Shipitalo, Martin J; Owens, Lloyd B

    2011-01-01

    Residual herbicides regularly used in conjunction with conservation tillage to produce corn ( L.) and soybean [ (L.) Merr] are often detected in surface water at concentrations that exceed their U.S. maximum contaminant levels (MCL) and ecological standards. These risks might be reduced by planting glyphosate-tolerant varieties of these crops and totally or partially replacing the residual herbicides alachlor, atrazine, linuron, and metribuzin with glyphosate, a contact herbicide that has a short half-life and is strongly sorbed to soil. Therefore, we applied both herbicide types at typical rates and times to two chisel-plowed and two no-till watersheds in a 2-yr corn/soybean rotation and at half rates to three disked watersheds in a 3-yr corn/soybean/wheat-red clover ( L.- L.) rotation and monitored herbicide losses in surface runoff for three crop years. Average dissolved glyphosate loss for all tillage practices, as a percentage of the amount applied, was significantly less ( ≤ 0.05) than the losses of atrazine (21.4x), alachlor (3.5x), and linuron (8.7x) in corn-crop years. Annual, flow-weighted, concentration of atrazine was as high as 41.3 μg L, much greater than its 3 μg L MCL. Likewise, annual, flow-weighted alachlor concentration (MCL = 2 μg L) was as high as 11.2 and 4.9 μg L in corn- and soybean-crop years, respectively. In only one runoff event during the 18 watershed-years it was applied did glyphosate concentration exceed its 700 μg L MCL and the highest, annual, flow-weighted concentration was 3.9 μg L. Planting glyphosate-tolerant corn and soybean and using glyphosate in lieu of some residual herbicides should reduce the impact of the production of these crops on surface water quality. PMID:21712598

  17. 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. PMID:26024994

  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. 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

  20. 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.

  1. Residual and contact herbicide transport through field lysimeters via preferential flow.

    PubMed

    Malone, R W; Shipitalo, M J; Wauchope, R D; Sumner, H

    2004-01-01

    Usage of glyphosate [N-(phosphonomethyl)-glycine] and glufosinate [2-amino-4-(hydroxy-methylphosphinyl)butanoic acid] may reduce the environmental impact of agriculture because they are more strongly sorbed to soil and may be less toxic than many of the residual herbicides they replace. Preferential flow complicates the picture, because due to this process, even strongly sorbed chemicals can move quickly to ground water. Therefore, four monolith lysimeters (8.1 m(2) by 2.4 m deep) were used to investigate leaching of contact and residual herbicides under a worst-case scenario. Glufosinate, atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine), alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide], and linuron (3-3,4-dichlorophenyl-1-methoxy-1-methylurea) were applied in 1999 before corn (Zea mays L.) planting and glyphosate, alachlor, and metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] were applied in 2000 before soybean [Glycine max (L.) Merr.] planting. A high-intensity rainfall was applied shortly after herbicide application both years. Most alachlor, metribuzin, atrazine, and linuron losses occurred within 1.1 d of rainfall initiation and the peak concentration of the herbicides coincided (within 0.1 d of rainfall initiation in 2000). More of the applied metribuzin leached compared with alachlor during the first 1.1 d after rainfall initiation (2.2% vs. 0.035%, P < 0.05). In 1999, 10 of 24 discrete samples contained atrazine above the maximum contaminant level (atrazine maximum contaminant level [MCL] = 3 mug L(-1)) while only one discrete sample contained glufosinate (19 mug L(-1), estimated MCL = 150 mug L(-1)). The results indicate that because of preferential flow, the breakthrough time of herbicides was independent of their sorptive properties but the transport amount was dependent on the herbicide properties. Even with preferential flow, glyphosate and glufosinate were not transported to

  2. Ecotoxicological hazards of herbicides on biological attributes of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae).

    PubMed

    Hasan, Fazil; Ansari, M Shafiq

    2016-07-01

    Ecotoxic effects of commonly used herbicides i.e. glyphosate, atrazine, metribuzin, alachlor and 2, 4-D were evaluated on the biological and demographic parameters of Zygogramma bicolorata Pallister on parthenium in laboratory. The herbicides used in the bioassay were within a minimum range of their recommended field dose. In direct toxicity experiment, 2,4-D and alachlor caused the highest mortality of 3rd instars and prolonged the development time. Fecundity and eggs viability were also significantly reduced in all treatments. Indirect toxicity (carryover effect) was evaluated through life table analysis of F1 progenies developed from surviving 3rd instars treated for direct toxicity experiment. Incubation period and overall development time was considerably prolonged in all treatments especially in 2, 4-D treated group. Daily fecundity and population growth parameters were significantly lowest in 2, 4-D treated groups compared to other tested herbicides. A significantly greater number of females were produced in glyphosate treatment than other treatments. Based on the present study, none of the tested herbicide can be classified as safe to Zygogramma bicolorata, while glyphosate was found to be least toxic. Therefore, it can be concluded that application of field recommended dose of glyphosate might be used in integration with Z. bicolorata for effective management of parthenium, however this needs to be conducted under natural field conditions. PMID:27077536

  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. PMID:26882523

  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. PMID:27322944

  5. Degradates provide insight to spatial and temporal trends of herbicides in ground water

    USGS Publications Warehouse

    Kolpin, D.W.; Schnoebelen, D.J.; Thurman, E.M.

    2004-01-01

    During 2001, 86 municipal wells in Iowa were sampled and analyzed for 21 herbicide parent compounds and 24 herbicide degradates. The frequency of detection increased from 17% when only herbicide parent compounds were considered to 53% when both herbicide parents and degradates were considered. Thus, the transport of herbicide compounds to ground water is substantially underestimated when herbicide degradates are not considered. A significant difference in the results among the major aquifer types was apparent only when both herbicide parent compounds and their degradates were considered. In addition, including herbicide degradates greatly improved the statistical relation to the age of the water being sampled. When herbicide parent compounds are considered, only 40% of the wells lacking a herbicide detection could be explained by the age of the water predating herbicide use. However, when herbicide degradates were also considered, 80% of the ground water samples lacking a detection could be explained by the age of the water predating herbicide use. Finally, a temporal pattern in alachlor concentrations in ground water could only be identified when alachlor degradates were considered.

  6. Water purification from organic pollutants by optimized micelle-clay systems.

    PubMed

    Polubesova, Tamara; Nir, Shlomo; Zadaka, Dikla; Rabinovitz, Onn; Serban, Carina; Groisman, Ludmila; Rubin, Baruch

    2005-04-01

    Removal of anionic pollutants (imazaquin, sulfentrazone, sulfosulfuron) and neutral pollutants (alachlor, acetochlor, chlorotoluron, bromacil) from water by micelles preadsorbed on montmorillonite was studied. Micelles of octadecyltrimethylammonium and benzyldimethylhexadecylammonium (BDMHDA) were used. The micelle-clay systems (1% w/w) removed 87-99% of the pollutants from their water solutions containing 1-33 mg/L of herbicide. The nature of the headgroup of the organic cation, which forms the micelles, is critical. Desorption of imazaquin and acetochlor from 0.3% (w/w) suspension of BDMHDA-clay complex after 24 h was around 7% in the range of adsorbed amounts from 0.6 to 15.3 mg/g. These results indicate rather slow rates and small extents of release of pollutants from micelle-clay complexes. Column filters (25 cm) made of a mixture of quartz sand and BDMHDA micelle-clay complex at 100:1 w/w ratio removed at least 99% of above pollutants from initial solutions containing 10 mg/L; 99.5 and 97% of sulfosulfuron and alachlor were removed from their initial solutions containing 200 and 5 microg/L, respectively. These data indicate that micelle-clay complexes are very efficient for water purification from organic contaminants. PMID:15871274

  7. Adsorption of pesticides from water by functionalized organobentonites.

    PubMed

    Cruz-Guzmán, Marta; Celis, Rafael; Hermosín, M Carmen; Koskinen, William C; Cornejo, Juan

    2005-09-21

    Replacement of natural inorganic cations of clay minerals with organic cations has been proposed as a strategy to improve the adsorptive capacity of clay minerals for organic compounds, including pesticides. The organic cations most commonly used for this purpose have been quaternary ammonium ions containing alkyl or aryl chains without specific functional groups. In this work, we evaluated the ability of two bentonites (SWy-2 and SAz-1) exchanged with four natural organic cations containing diverse functional groups (L-carnitine, L-cysteine ethyl ester, L-cystine dimethyl ester, and thiamine) as adsorbents of pesticides varying in their chemical structures (simazine, hexazinone, triadimefon, alachlor, carbaryl, and imazethapyr). For comparison purposes, the adsorptive properties of two "classical" organobentonites, hexadecyltrimethylammonium- and phenyltrimethylammonium-exchanged bentonites, were also determined. Most organobentonites displayed higher affinity for the pesticides than the untreated bentonites, but the improvement in adsorption capacity varied depending on the characteristics of the pesticide and the interlayer organic cation. Triadimefon, carbaryl, and imazethapyr displayed the highest affinity for carnitine (K(f) = 229-2377)-, thiamine (K(f) = 83-354)-, and cystine (K(f) = 96-100)-treated bentonites, respectively, whereas alachlor was adsorbed similarly by all organobentonites. In general, pesticide adsorption-desorption hysteresis was greater for adsorbents with the highest adsorption capacities. The results demonstrate that selective modification of smectitic clay minerals with natural organic cations containing appropriate functional groups can be a useful strategy to improve their performance for the removal of specific pesticides from the environment. PMID:16159179

  8. Pressurized fluid extraction for quantitative recovery of chloroacetanilide and nitrogen heterocyclic herbicides in soil.

    PubMed

    Zhu, Y; Yanagihara, K; Guo, F; Li, Q X

    2000-09-01

    Pressurized fluid extraction (PFE) is a new sample extraction method operated at elevated temperatures and pressures with liquid solvents. The use of PFE was investigated for the extraction of four Hawaiian clayey soils fortified with the selected chloroacetanilide and nitrogen heterocyclic herbicides Alachlor, Bromacil, Hexazinone, Metribuzin, and Tebuthiuron. The effects of operation temperature, pressure, flush volume, and static cycles on PFE performance were studied. Water was the most effective modifier of PFE for quantitative recoveries of the five herbicides in soils. The simple extraction method required pretreatment of the soil with 37.6% water and subsequent two-static-cycle extraction with a total of 32 mL of acetone at 1500 psi and 100 degrees C. Average recoveries of Alachlor, Bromacil, Hexazinone, Metribuzin, and Tebuthiuron ranged from 93 to 103% by the water-assisted PFE, compared with only 68-83% recoveries of the corresponding chemicals when no water was used. The extraction time and total organic solvent consumption were reduced from 18 h and 300 mL by Soxhlet to 22 min or less and 80 mL or less of organic solvent by PFE. PMID:10995321

  9. HYPOTHYROIDISM AND PESTICIDE USE AMONG MALE PRIVATE PESTICIDE APPLICATORS IN THE AGRICULTURAL HEALTH STUDY

    PubMed Central

    Goldner, Whitney S.; Sandler, Dale P.; Yu, Fang; Shostrom, Valerie; Hoppin, Jane A.; Kamel, Freya; LeVan, Tricia D.

    2013-01-01

    Objective Evaluate the association between thyroid disease and use of insecticides, herbicides, fumigants/fungicides in male applicators in the Agricultural Health Study. Methods We examined the association between use of 50 specific pesticides and self-reported hypothyroidism, hyperthyroidism, and ‘other’ thyroid disease among 22,246 male pesticide applicators. Results There was increased odds of hypothyroidism with ever-use of the herbicides 2,4-D, 2,4,5-T, 2,4,5-TP, alachlor, dicamba, and petroleum oil. Hypothyroidism was also associated with ever-use of eight insecticides: organochlorines chlordane, DDT, heptachlor, lindane, and toxaphene; organophosphates diazinon and malathion; and the carbamate carbofuran. Exposure-response analysis showed increasing odds with increasing level of exposure for the herbicides alachlor and 2,4-D, and the insecticides aldrin, chlordane, DDT, lindane, and parathion. Conclusions There is an association between hypothyroidism and specific herbicides and insecticides in male applicators, similar to previous results for spouses. PMID:24064777

  10. Herbicide sorption to fine particulate matter suspended downwind of agricultural operations: field and laboratory investigations.

    PubMed

    Clymo, Amelia S; Shin, Jin Young; Holmen, Britt A

    2005-01-15

    Tillage-induced erosion of herbicides bound to airborne soil particles has not been quantified as a mechanism for offsite herbicide transport. This study quantifies the release of two preemergent herbicides, metolachlor and pendimethalin, to the atmosphere as gas- and particle-phase species during soil incorporation operations. Fine particulate matter (PM2.5) and gas-phase samples were collected at three sampling heights during herbicide disking into the soil in Davis, CA, in May 2000 and May 2001 using filter/PUF sampling. Quartz fiber filters (QFFs) were used in May 2000, and Teflon membrane filters (TMFs) were used in May 2001. The field data were combined with laboratory filter/PUF partitioning experiments to account for adsorption to the filter surfaces and quantify the mass of PM2.5-bound herbicides in the field samples. Laboratory results indicate a significant adsorption of metolachlor, but not pendimethalin, to the quartz filter surfaces. Metolachlor partitioning to PM2.5 collected on TMF filters resulted in corrected PM2.5 field partition coefficient values, Kp,corr = Cp/Cg, of approximately 10(-3.5) m3/microg, indicating its preference for the gas phase. Pendimethalin exhibited more semivolatile behavior,with Kp,corr values that ranged from 10(-3) to 10(-1) m3/ microg and increased with sampling height and distance downwind of the operation. An increase in pendimethalin enrichment at a height of 5 m suggests winnowing of finer, more sorptive soil components with corresponding higher transport potential. Pendimethalin was enriched in the PM2.5 samples by up to a factor of 250 compared to the field soil, indicating thatfurther research on the processes controlling the generation of PM-bound herbicides during agricultural operations is warranted to enable prediction of off-site mass fluxes by this mechanism. PMID:15707040

  11. Bioremediation of pesticide wastes in soil using two plant species, Kochia Scoparia and Brassica Napus

    SciTech Connect

    Kruger, E.L.; Anderson, T.A.; Coats, J.R.

    1995-12-31

    Radiotracer studies were conducted to determine the fate of atrazine and metolachlor, applied as a mixture, in soils taken from pesticide-contaminated sites. Samples taken from nonvegetated areas and from the rhizosphere of Kochia scoparia were treated with {sup 14}C-atrazine and unlabeled metolachlor (50 {mu}g/g each) and incubated for 30, 60 or 135 d. A mass balance of the {sup 14}C applied revealed significant differences between the two soil types in soil bound residues, {sup 14}CO{sub 2}, and the extractable organic fraction (p<0.05). After 135-d incubation, 28% of the applied {sup 14}C was mineralized in Kochia rhizosphere soil, compared to 4% in soil taken from a nonvegetated area. A greater amount of {sup 14}C was extractable from the nonvegetated soil compared to the rhizosphere soil (64% and 22%, respectively). The half-life of atrazine based on extractable {sup 14}C-atrazine was 193 d in nonvegetated soil and 50 d in Kochia rhizosphere soil. Additional subsamples of nonvegetated soils treated with a mixture of {sup 14}C-atrazine and metolachlor were allowed to age for 135 d, and then were either planted with Brassica napus, Kochia scoparia, or left unvegetated. Incubations were carried out in enclosed chambers under controlled conditions. After 30 additional days, a subset of samples was extracted and analyzed using thin-layer chromatography, soil and plant combustion, and liquid scintillation spectroscopy. The percent of applied {sup 14}C-atrazine remaining as atrazine in soil which was nonvegetated, or planted with Brassica napus or Kochia scoparia was 9.3, 6.5, and 4.2%, respectively. Combustion of plants revealed that 11% of the applied radioactivity was taken up in Kochia scoparia, while less than 1% was taken up in Brassica napus plants. The potential for vegetation to aid in bioremediating pesticide wastes in soil is promising.

  12. Nitrate and Pesticide Transport From Tile-Drained Fields in the Willamette Valley, Oregon

    NASA Astrophysics Data System (ADS)

    Warren, K. L.; Rupp, D. E.; Selker, J. S.; Dragila, M. I.; Peachey, R. E.

    2002-12-01

    Tile drainage affects the hydrology and thus the solute transport on agricultural fields by increasing the volume of water that drains from the subsurface. Previous NAWQA studies have shown elevated nitrate levels in wells and high detection frequencies for selected pesticides in Willamette Valley streams. As a substantial area of Willamette Valley agricultural land is tile-drained, it is important to determine the role of tile drains in surface water and ground water pollution. Four fields in the Willamette Valley were instrumented to monitor tile effluent for two winter seasons. On two fields, surface runoff was also monitored for the second season. Field areas ranged from 3 to 30 acres and were cropped in grass, corn, or a grass/corn rotation. Tile effluent nitrate concentrations frequently exceeded 10 ppm on some fields. Flow-weighted averages for each field were 0.87 ppm and 1.36 ppm for two established grass fields, and 8.1 ppm and 14.4 ppm for grass fields that had recently grown corn. Mass losses ranged from 1.15%-6.45% of the applied nitrate through the tile drains. Diuron, Metolachlor, and Chlorpyrifos were tested in selected surface runoff and tile effluent samples. On one field, Metolachlor concentrations were similar in the tile drains and surface runoff. Concentrations in both sources were 10 times lower than the drinking water advisory for Metolachlor. In a second field, Chlorpyrifos concentrations were two orders of magnitude lower than drinking water advisories in both sources. On the same field, Diuron concentrations were significantly higher in the surface runoff than in the tile effluent. Diuron concentrations were 1-2 orders of magnitude higher during the first precipitation events after application in the surface runoff. On a third field, Diuron was at least 10 times lower than drinking water advisories in the tile effluent, with the highest concentrations found in samples collected within 21 days of pesticide application.

  13. Pesticide and Nitrate-N Behavior in Groundwater Within a Riparian Wetland

    NASA Astrophysics Data System (ADS)

    Rice, C. P.; Bialek, K.; Angier, J. T.; McCarty, G. W.

    2002-05-01

    Information regarding the behavior and fate of agrochemicals in groundwater within riparian ecosystems is essential in order to assess the overall function of riparian systems at contaminant removal. This study included analysis of pesticides and nutrients in groundwater from a first-order riparian wetland that borders a conventionally farmed cornfield. Vertical depth profiles of groundwater were analyzed for agricultural chemicals. Samples were obtained from piezometers nested at various depths in different locations throughout the riparian wetland. Some of the nests were in areas with little or no visible groundwater seepage to the surface, others were placed in zones of active groundwater emergence (upwelling) onto the land surface (within zones of continuous surface saturation). In those profiles where upwelling was low, there was a clear demarcation in nitrate-N and oxygen contents at depth (between 135 and 175 cm) within the piezometer nests. This same horizon also coincided with the region where atrazine and atrazine degradate (desethyl- and desisopropyl-atrazine) concentrations substantially diminished. Another herbicide, metolachlor, and degradates (metolachlor ethane sulfonic acid and metolachlor oxanilic acid), showed only a slight reduction in concentrations over this zone and maintained a fairly uniform concentration over the vertical profile. Vertical depth profiles in areas where upwelling was high did not show significant variations in herbicide residues; e.g., the concentrations throughout the profile were similar to the levels measured at the deepest zone within the underlying aquifer. Processes leading to these differences were preferential degradation and sorption. This spatial disparity was reflected in the surface water, with implications for the overall contaminant-mitigating properties of the riparian system.

  14. Short-term effects of herbicides on primary productivity of periphyton in lotic environments.

    PubMed

    Day, K E

    1993-06-01

    : Freshwater algae are quite sensitive to herbicides that enter running water ecosystems through direct application, aerial drift, and/or watershed run-off. However, due to a lack of suitable methodologies, few studies examine the effects of such contamination on naturally occurring attached algal communities under field conditions (i. e., exposure regimes using pulsed doses or brief episodes of peak concentrations to simulate surface run-off during storm events). This paper describes a method for determining the acute short-term effects of four herbicides (hexazinone, atrazine, tebuthiuron and metolachlor) on the net primary productivity (NPP) of periphytic algae in the field using a portable bankside incubator; NPP was measured by monitoring changes in oxygen production (mg O2 per m(2)) upper surface of rock substrate per h and mg O2 h per mg chlorophyll using the light-dark technique. All herbicides with photosynthetic inhibition as a mode of action significantly reduced NPP. The lowest observed effect concentrations (LOECs) for the herbicides were 43 μg hexazinone l(-1), 109 μg atrazine l(-1) and 137 μg tebuthiuron l(-1). The no observed effect concentrations (NOECs) for these chemicals were <43 μg hexazinone l(-1), 93 μg atrazine l(-1) and 52 μg tebuthiuron l(-1). Metolachlor did not significantly reduce NPP at the concentrations that were tested (range 19.6-274 μg l(-1)). However, community respiration (which included respiration by invertebrates) was significantly reduced at the highest metolachlor concentration (274 μg l(-1)). Community respiration was not significantly affected by any concentration of the other three herbicides used. PMID:24201554

  15. Agricultural chemicals in Iowa's ground water, 1982-95: What are the trends?

    USGS Publications Warehouse

    Koplin, Dana W.; Hallberg, George; Sneck-Fahrer, D. A.; Libra, Robert

    1997-01-01

    The Iowa Department of Natural Resources. Geological Survey Bureau: the University of Iowa Hygienic Laboratory; and the U.S. Geological Survey (USGS) have been working together to address this question. As part of the Iowa Ground-Water Monitoring Program (IGWM). water samples have been collected from selected Iowa municipal wells since 1982. An examination of this data identified two trends: (1) concentrations of atrazine in Iowa's ground water generally were decreasing over time, and (2) concentrations of metolachlor generally were increasing. Continuing ground-water sampling can determine if these trends represent long-term changes in chemical concentrations.

  16. Herbicides in streams. Midwestern United States

    USGS Publications Warehouse

    Goolsby, Donald A.; Thurman, E. Michael; Kolpin, Dana W.

    1991-01-01

    Results from a 2-year study of 149 streams geographically distributed across the corn-producing region of 10 midwestern States show that detectable concentrations of herbicides persist year round in most streams. Some herbicides exceeded proposed maximum contaminant levels for drinking water for periods of several weeks to several months following application. Atrazine was the most frequently detected and most persistent herbicide measured, followed by desethylatrazine and metolachlor. The seasonal distribution of atrazine indicates that aquifers contributing base flow to many of the streams are contaminated with herbicides.

  17. Transport of agricultural chemicals in surface flow, tileflow, and streamflow of Walnut Creek Watershed near Ames, Iowa, April 1991-September 1993

    USGS Publications Warehouse

    Soenksen, P.J.

    1996-01-01

    Chemical loss ratios indicated differences in the transport characteristics of the three subwatersheds. The downstream subwatershed, which has steeper terrain, a more-developed natural drainage system, and fewer tiles than the two upland subwatersheds, had the largest loss rates for all three chemicals 206 percent for nitrate as nitrogen (October 1992-September 1993) and 20 percent for atrazine and 2.9 percent for metolachlor (April-September 1993). For May-July 1993, when most of the herbicides were transported, the downstream subwatershed also had the largest cumulative unit discharge and the largest streamflow-to-precipitation ratios.

  18. Modelling the dissipation and leaching of two herbicides in decomposing mulch of crop residues

    NASA Astrophysics Data System (ADS)

    Aslam, Sohaib; Iqbal, Akhtar; Lafolie, François; Recous, Sylvie; Benoit, Pierre; Garnier, Patricia

    2013-04-01

    Conservation agricultural practices are increasingly adopted because of ecosystem services such as conservation of soil and water resources. These farming systems are characterized mainly by the presence of mulch made of residues of harvested or cover crops on soil surface. The mulch can intercept and retain applied pesticides depending on pesticide molecule and rainfall timing. The pesticide wash-off from mulch is considered a key process in pesticide fate and can have effects on degradation and transport processes. This work highlights a modelling approach to study the pesticide wash-off from mulch residues and their further transport in soil under two rainfall regimes. Transformation and leaching of two herbicides, s-metolachlor and glyphosate, was studied and simulated by Pastis-mulch model. A pesticide module describing pesticide degradation in mulch and soil was coupled to a transport model including a mulch module. The model was tested to simulate the pesticide dissipation, wash-off from mulch and further leaching in soil. Pesticide degradation parameters in mulch were estimated from incubation experiments with 14C-labelled molecules in small cylinders. The model was then tested using the data obtained through a soil column experiment (reconstructed soil cores :15 cm diameter x 35 cm depth), a mulch of Zea mais + Doliquos lablab and with two treatments varied by water regimes: i) frequent rain (temperate, twice a week) with week intensity (6 mm/hr); and ii) occasional rain (tropical, twice a month) with stronger intensity (20 mm/hr). Columns were incubated at 20 °C for 84 days to monitor soil water, C, N and pesticide dynamics. Model successfully simulated the experimental data of pesticide dissipation in mulch residues. Results showed that the rain regime affected more S-metolachlor than glyphosate behavior. The simulated results indicated also that the dynamics in mulch of the two molecules differed according to the rain treatment. Glyphosate showed a

  19. Simulation of stream discharge and transport of nitrate and selected herbicides in the Mississippi River Basin

    USGS Publications Warehouse

    Broshears, R.E.; Clark, G.M.; Jobson, H.E.

    2001-01-01

    Stream discharge and the transport of nitrate, atrazine, and metolachlor in the Mississippi River Basin were simulated using the DAFLOW/BLTM hydrologic model. The simulated domain for stream discharge included river reaches downstream from the following stations in the National Stream Quality Accounting Network: Mississippi River at Clinton, IA; Missouri River at Hermann, MO: Ohio River at Grand Chain, IL: And Arkansas River at Little Rock, AR. Coefficients of hydraulic geometry were calibrated using data from water year 1996; the model was validated by favourable simulation of observed discharges in water years 1992-1994. The transport of nitrate, atrazine, and metolachlor was simulated downstream from the Mississippi River at Thebes, IL, and the Ohio River at Grand Chain. Simulated concentrations compared favourably with observed concentrations at Baton Rouge, LA. Development of this model is a preliminary step in gaining a more quantitative understanding of the sources and fate of nutrients and pesticides delivered from the Mississippi River Basin to the Gulf of Mexico.

  20. Simulation of stream discharge and transport of nitrate and selected herbicides in the Mississippi River Basin

    NASA Astrophysics Data System (ADS)

    Broshears, Robert E.; Clark, Gregory M.; Jobson, Harvey E.

    2001-05-01

    Stream discharge and the transport of nitrate, atrazine, and metolachlor in the Mississippi River Basin were simulated using the DAFLOW/BLTM hydrologic model. The simulated domain for stream discharge included river reaches downstream from the following stations in the National Stream Quality Accounting Network: Mississippi River at Clinton, IA; Missouri River at Hermann, MO; Ohio River at Grand Chain, IL; and Arkansas River at Little Rock, AR. Coefficients of hydraulic geometry were calibrated using data from water year 1996; the model was validated by favourable simulation of observed discharges in water years 1992-1994. The transport of nitrate, atrazine, and metolachlor was simulated downstream from the Mississippi River at Thebes, IL, and the Ohio River at Grand Chain. Simulated concentrations compared favourably with observed concentrations at Baton Rouge, LA. Development of this model is a preliminary step in gaining a more quantitative understanding of the sources and fate of nutrients and pesticides delivered from the Mississippi River Basin to the Gulf of Mexico. Published in 2001 by John Wiley & Sons, Ltd.

  1. Effects of aging herbicide mixtures on soil respiration and plant survival in soils from a pesticide-contaminated site

    SciTech Connect

    Kruger, E.L.; Anhalt, J.C.; Anderson, T.A.

    1996-10-01

    Three herbicides, atrazine, metolachlor, and pendimethalin, were applied individually and in all possible combinations to soil taken from a pesticide-contaminated site in Iowa. The rate of application for each chemical was 50 {mu}g/g, representative of contamination problems at mixing and loading areas of agrochemical dealer sites. Treated soils were incubated at 24{degrees}C in the dark for 0, 21, and 63 d, and soil moisture tension was maintained at -33 kPa. Soil respiration was measured daily by using an infrared gas analyzer for 10 d at the end of each incubation period. Subsamples of treated soils were used in plant germination and survival studies. Concentrations of each herbicide were determined by gas chromatography at day 0, 21, and 63. Soil respiration was elevated for the first 6 d immediately following treatment, and then declined to very low levels. At the end of day 21 and 63, soil respiration remained at very low levels. The half-lives for atrazine, metolachlor, and pendimethalin individually in soil or in combination with one and/or the other herbicide will be reported. The results of germination and survival studies with kochia, giant foxtail, birdsfoot trefoil, crown vetch, and soybean will also be reported.

  2. Active and passive sampling for the assessment of hydrophilic organic contaminants in a river basin-ecotoxicological risk assessment.

    PubMed

    Terzopoulou, Evangelia; Voutsa, Dimitra

    2016-03-01

    This study presents a complementary approach for the evaluation of water quality in a river basin by employing active and passive sampling. Thirty-eight hydrophilic organic compounds (HpOCs) (organohalogen herbicides, organophosphorous pesticides, carbamate, triazine, urea, pharmaceuticals, phenols, and industrial chemicals) were studied in grab water samples and in passive samplers POCIS collected along Strymonas River, Northern Greece, at three sampling campaigns during the year 2013. Almost all the target compounds were detected at the periods of high rainfall intensity and/or low flow rate. The most frequently detected compounds were aminocarb, carbaryl, chlorfenviphos, chloropropham, 2,4-D, diflubenzuron, diuron, isoproturon, metolachlor, and salicylic acid. Bisphenol A and nonylphenol were also occasionally detected. The use of POCIS allowed the detection of more micropollutants than active sampling. Low discrepancy between the concentrations obtained from both samplings was observed, at least for compounds with >50 % detection frequency; thus, POCIS could be a valuable tool for the selection and monitoring of the most relevant HpOCs in the river basin. Results showed relatively low risk from the presence of HpOCs; however, the potential risk associated with micropollutants such as carbaryl, dinoseb, diuron, fenthion, isoproturon, metolachlor, nonylphenol, and salicylic acid should not be neglected. PMID:26573318

  3. Bioremediation of soils impacted by chlorinated pesticides/herbicides and nitroaromatics

    SciTech Connect

    Fisher, D.R.; Seech, A.G.; Bucens, P.G.

    1995-12-31

    Chlorinated pesticide and herbicide manufacturing and application, coupled with the long natural half-lives of these compounds, has resulted in many incidents of soil contamination throughout the world. Soils impacted by nitroaromatics such as 2,4,6-trinitrotoluene (TNT), due largely to past military activities, are also common. The potential environmental and human health risks are spawning development of various technologies to remediate these impacted soils. Bench-scale microcosm studies using four North American soils, containing (1) Metolachlor, (2) 2,4-D and 2,4,5-T, (3) chlorinated pesticides (including DDT, DDD, DDE and toxaphene) and (4) TNT, were conducted. The most effective approach involved successive establishment of anoxic and oxic conditions in the soil. The anoxic/oxic cycling process, controlled by the addition of Daramend organic amendments and other agents, enhances reductive decomposition of soil contaminants (in the anoxic phase) and contaminant mineralization (in the oxic phase). Substantial reductions in contaminant concentrations have been observed. Metolachlor concentrations have been reduced from 139 to 4 mg/kg, p,p-DDT from 684 to 2 mg/kg, toxaphene from 1,045 to 244 mg/kg and TNT from 7,200 to 19 mg/kg, all in under 190 days. A patent on this technology has been granted.

  4. Pesticides in surface water, bed sediment, and ground water adjacent to commercial cranberry bogs, Lac du Flambeau Reservation, Vilas County, Wisconsin

    USGS Publications Warehouse

    Saad, David A.

    2005-01-01

    In samples from the Trout River, which is used as a source of water to maintain lake levels in the Corn Lakes, the only pesticides detected were the non-targeted compounds atrazine and deethyl atrazine, indicating it was not a source of targeted compounds detected in the Corn Lakes. Only two pesticides (chlorpyrifos and metolachlor) were detected in bed-sediment samples collected from the lakes; chlorpyrifos from Little Trout Lake and metolachlor from the Corn Lakes. Four pesticides (the targeted compounds napropamide and norflurazon and the non-targeted compounds atrazine and deethyl atrazine) were detected in ground-water samples from two of four sampled monitor wells. The highest ground-water concentrations (up to 0.14 ?g/L napropamide and 0.56 ?g/L norflurazon) were measured in samples from the monitoring well located directly downgradient from the Corn Lakes and commercial cranberry operations. No pesticides were detected in samples from the reference well located upgradient from the Corn Lakes and cranberry operations. Further study is needed to identify additional pesticides as well as chronic effects on aquatic organisms to determine whether cranberry-related pesticides affect the lake ecosystems of the Lac du Flambeau Reservation.

  5. Leaching of the Neonicotinoids Thiamethoxam and Imidacloprid from Sugar Beet Seed Dressings to Subsurface Tile Drains.

    PubMed

    Wettstein, Felix E; Kasteel, Roy; Garcia Delgado, Maria F; Hanke, Irene; Huntscha, Sebastian; Balmer, Marianne E; Poiger, Thomas; Bucheli, Thomas D

    2016-08-24

    Pesticide transport from seed dressings toward subsurface tile drains is still poorly understood. We monitored the neonicotinoid insecticides imidacloprid and thiamethoxam from sugar beet seed dressings in flow-proportional drainage water samples, together with spray applications of bromide and the herbicide S-metolachlor in spring and the fungicides epoxiconazole and kresoxim-methyl in summer. Event-driven, high first concentration maxima up to 2830 and 1290 ng/L for thiamethoxam and imidacloprid, respectively, were followed by an extended period of tailing and suggested preferential flow. Nevertheless, mass recoveries declined in agreement with the degradation and sorption properties collated in the groundwater ubiquity score, following the order bromide (4.9%), thiamethoxam (1.2%), imidacloprid (0.48%), kresoxim-methyl acid (0.17%), S-metolachlor (0.032%), epoxiconazole (0.013%), and kresoxim-methyl (0.003%), and indicated increased leaching from seed dressings compared to spray applications. Measured concentrations and mass recoveries indicate that subsurface tile drains contribute to surface water contamination with neonicotinoids from seed dressings. PMID:27529118

  6. Model prediction uncertainty of bromide and pesticides transport in laboratory column

    NASA Astrophysics Data System (ADS)

    Dusek, Jaromir; Dohnal, Michal; Snehota, Michal; Sobotkova, Martina; Ray, Chittaranjan; Vogel, Tomas

    2016-04-01

    Knowledge of transport parameters of reactive solutes such as pesticides is a prerequisite for reliable predictions of their fate and transport in soil porous systems. Water flow and transport of bromide tracer and five pesticides (atrazine, imazaquin, sulfometuron methyl, S-metolachlor, and imidacloprid) through an undisturbed soil column of tropical Oxisol were analyzed using a one-dimensional numerical model. Laboratory column leaching experiment with three flow interruptions was conducted. The applied numerical model is based on Richards' equation for solving water flow and the advection-dispersion equation for solving solute transport. A global optimization method was used to evaluate the model's sensitivity to transport parameters and the uncertainty of model predictions. Within the Monte Carlo modeling framework, multiple forward simulations searching through the parametric space, were executed to describe the observed breakthrough curves. All pesticides were found to be relatively mobile. Experimental data indicated significant non-conservative behavior of bromide tracer. All pesticides, with the exception of imidacloprid, were found less persistent. Three of the five pesticides (atrazine, sulfometuron methyl, and S-metolachlor) were better described by the linear kinetic sorption model, while the breakthrough curves of imazaquin and imidacloprid were more appropriately approximated using nonlinear instantaneous sorption. Sensitivity analysis suggested that the model is most sensitive to sorption distribution coefficient. The prediction limits contained most of the measured points of the experimental breakthrough curves, indicating adequate model concept and model structure for the description of transport processes in the soil column under study.

  7. Soil surface colonization by phototrophic indigenous organisms, in two contrasted soils treated by formulated maize herbicide mixtures.

    PubMed

    Joly, Pierre; Misson, Benjamin; Perrière, Fanny; Bonnemoy, Frédérique; Joly, Muriel; Donnadieu-Bernard, Florence; Aguer, Jean-Pierre; Bohatier, Jacques; Mallet, Clarisse

    2014-11-01

    Soil phototrophic microorganisms, contributors to soil health and food webs, share their particular metabolism with plants. Current agricultural practices employ mixtures of pesticides to ensure the crops yields and can potentially impair these non-target organisms. However despite this environmental reality, studies dealing the susceptibility of phototrophic microorganisms to pesticide mixtures are scarce. We designed a 3 months microcosm study to assess the ecotoxicity of realistic herbicide mixtures of formulated S-metolachlor (Dual Gold Safeneur(®)), mesotrione (Callisto(®)) and nicosulfuron (Milagro(®)) on phototrophic communities of two soils (Limagne vertisol and Versailles luvisol). The soils presented different colonizing communities, with diatoms and chlorophyceae dominating communities in Limagne soil and cyanobacteria and bryophyta communities in Versailles soil. The results highlighted the strong impairment of Dual Gold Safeneur(®) treated microcosms on the biomass and the composition of both soil phototrophic communities, with no resilience after a delay of 3 months. This study also excluded any significant mixture effect on these organisms for Callisto(®) and Milagro(®) herbicides. We strongly recommend carrying on extensive soil studies on S-metolachlor and its commercial formulations, in order to reconsider its use from an ecotoxicological point of view. PMID:25129149

  8. Dissolved pesticide concentrations in the Sacramento-San Joaquin Delta and Grizzly Bay, California, 2011-12

    USGS Publications Warehouse

    Orlando, James L.; McWayne, Megan; Sanders, Corey; Hladik, Michelle

    2013-01-01

    Surface-water samples were collected from sites within the Sacramento-San Joaquin Delta and Grizzly Bay, California, during the spring in 2011 and 2012, and they were analyzed by the U.S. Geological Survey for a suite of 99 current-use pesticides and pesticide degradates. Samples were collected and analyzed as part of a collaborative project studying the occurrence and characteristics of phytoplankton in the San Francisco Estuary. Samples were analyzed by two separate laboratory methods employing gas chromatography/mass spectrometry or liquid chromatography with tandem mass spectrometry. Method detection limits ranged from 0.9 to 10.5 nanograms per liter (ng/L). Eighteen pesticides were detected in samples collected during 2011, and the most frequently detected compounds were the herbicides clomazone, diuron, hexazinone and metolachlor, and the diuron degradates 3,4-dichloroaniline and N-(3,4-dichlorophenyl)-N’-methylurea (DCPMU). Concentrations for all compounds were less than 75 ng/L, except for the rice herbicide clomazone and the fungicide tetraconazole, which had maximum concentrations of 535 and 511 ng/L, respectively. In samples collected in 2012, a total of 16 pesticides were detected. The most frequently detected compounds were the fungicides azoxystrobin and boscalid and the herbicides diuron, hexazinone, metolachlor, and simazine. Maximum concentrations for all compounds detected in 2012 were less than 75 ng/L, except for the fungicide azoxystrobin and the herbicides hexazinone and simazine, which were detected at up to 188, 134, and 140 ng/L, respectively.

  9. 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

  10. Phytotoxicity of four herbicides on Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii.

    PubMed

    Pan, Huiyun; Li, Xiaolu; Xu, Xiaohua; Gao, Shixiang

    2009-01-01

    The physiological effects of 4 herbicides (butachlor, quinclorac, bensulfuron-methyl and atrazine) on 3 submerged macrophytes (Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii) were tested in laboratory. The variables of the relative growth rate and the photosynthetic pigment content showed that all of the tested herbicides affected the growth of the plants obviously, even at the lowest concentration (0.0001 mg/L). Except for the C. demersum treated with quinclorac at 0.005 and 0.01 mg/L, the relative growth rates of the plants were inhibited significantly (p < 0.01). Statistical analysis of chlorophyll a (Chl-a) contents was carried out with both the t-test and one-way ANOVA to determine the difference between the treatment and control. The results showed that Chl-a contents of the plants in all treatment groups were affected by herbicides significantly, except for the C. demersum treated with bensulfuron-methyl at 0.0005 mg/L. The decrease in Chl-a content was positively correlated to the dosage of the herbicides in most treatment groups. It was suggested that herbicides in water bodies might potentially affect the growth of aquatic macrophytes. Since the Chl-a content of submerged macrophytes responded to the stress of herbicides sensitively and directly, it could be used as a biomaker in environmental monitoring or in the ecological risk assessment of herbicide contamination. PMID:19634441

  11. Identification of pesticide varieties by testing microalgae using Visible/Near Infrared Hyperspectral Imaging technology.

    PubMed

    Shao, Yongni; Jiang, Linjun; Zhou, Hong; Pan, Jian; He, Yong

    2016-01-01

    In our study, the feasibility of using visible/near infrared hyperspectral imaging technology to detect the changes of the internal components of Chlorella pyrenoidosa so as to determine the varieties of pesticides (such as butachlor, atrazine and glyphosate) at three concentrations (0.6 mg/L, 3 mg/L, 15 mg/L) was investigated. Three models (partial least squares discriminant analysis combined with full wavelengths, FW-PLSDA; partial least squares discriminant analysis combined with competitive adaptive reweighted sampling algorithm, CARS-PLSDA; linear discrimination analysis combined with regression coefficients, RC-LDA) were built by the hyperspectral data of Chlorella pyrenoidosa to find which model can produce the most optimal result. The RC-LDA model, which achieved an average correct classification rate of 97.0% was more superior than FW-PLSDA (72.2%) and CARS-PLSDA (84.0%), and it proved that visible/near infrared hyperspectral imaging could be a rapid and reliable technique to identify pesticide varieties. It also proved that microalgae can be a very promising medium to indicate characteristics of pesticides. PMID:27071456

  12. Ecological risk assessment of herbicides in Japan: Integrating spatiotemporal variation in exposure and effects using a multimedia model and algal density dynamics models.

    PubMed

    Hayashi, Takehiko I; Imaizumi, Yoshitaka; Yokomizo, Hiroyuki; Tatarazako, Norihisa; Suzuki, Noriyuki

    2016-01-01

    Application of herbicides to paddy fields in Japan has strong seasonality, and their environmental concentrations exhibit clear spatiotemporal variation. The authors developed an approach that combines a multimedia environmental exposure model (Grid-Catchment Integrated Modeling System) and density dynamics models for algae. This approach enabled assessment of ecological risk when the exposure concentration shows spatiotemporal variation. First, risk maps of 5 herbicides (pretilachlor, butachlor, simetryn, mefenacet, and esprocarb) were created from the spatial predictions of environmental concentrations and 50% inhibitory concentrations of the herbicides. Simulations of algal density dynamics at high-risk sites were then conducted by incorporating the predicted temporal dynamics of the environmental concentration of each herbicide at the sites. The results suggested that the risk of pretilachlor was clearly the highest of the 5 herbicides, in terms of both the spatial distributions and the temporal durations. The present study highlights the importance of integrating exposure models and effect models to clarify spatial and temporal risk and to develop management plans for chemical exposure that shows high spatiotemporal variation. PMID:26183805

  13. Ternary toxicological interactions of insecticides, herbicides, and a heavy metal on the earthworm Eisenia fetida.

    PubMed

    Wang, Yanhua; Chen, Chen; Qian, Yongzhong; Zhao, Xueping; Wang, Qiang

    2015-03-01

    The combined toxicities of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor), and a heavy metal (cadmium) have been examined using the acute toxicity test on the earthworm. With a concentration of 2.75 mg/kg being lethal for 50% of the organisms, imidacloprid exhibited the highest acute toxicity toward the earthworm Eisenia fetida. Toxicological interactions of these chemicals in ternary mixtures were studied using the combination-index (CI) equation method. Twenty-one ternary mixtures exhibited various interactive effects, in which 11 combinations showed synergistic effects, four led to dual synergistic/additive behaviors, one exhibited an additive effect, and five showed increasing antagonism within the entire range of effects. The CI method was compared with the classical models of concentration addition and independent action, and it was found that the CI method could accurately predict combined toxicity of the chemicals studied. The predicted synergism in the majority of the mixtures, especially at low-effect levels, might have implications in the real terrestrial environment. PMID:25463238

  14. The synergistic toxicity of the multiple chemical mixtures: implications for risk assessment in the terrestrial environment.

    PubMed

    Chen, Chen; Wang, Yanhua; Qian, Yongzhong; Zhao, Xueping; Wang, Qiang

    2015-04-01

    The combined toxicity of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor) and a heavy metal (cadmium) has been examined with the earthworm acute toxicity test. Toxicological interactions of these chemicals in four, five, six, seven, and eight-component mixtures were studied using the combination-index (CI) equation method. In four-component and five-component mixtures, the synergistic effects predominated at lower effect levels, while the patterns of interactions found in six, seven, and eight-component mixtures displayed synergism. The λ-CY+IMI+BUT+ATR+CPF+PHO combination displayed the most strongly synergistic interaction, with CI values ranging from 0.09 to 0.15. The nature of the interaction changes with the effect level and the relevance of synergistic effects increase with the complexity of the mixture. The CI method was compared with the classical models of concentration addition (CA) and independent action (IA) and we found that the CI method could accurately predict the combined toxicity. The predicted synergism resulted from co-existence of the pesticides and the heavy metal especially at low effect levels may have important implications in risk assessment for the real terrestrial environment. PMID:25667058

  15. Identification of pesticide varieties by testing microalgae using Visible/Near Infrared Hyperspectral Imaging technology

    PubMed Central

    Shao, Yongni; Jiang, Linjun; Zhou, Hong; Pan, Jian; He, Yong

    2016-01-01

    In our study, the feasibility of using visible/near infrared hyperspectral imaging technology to detect the changes of the internal components of Chlorella pyrenoidosa so as to determine the varieties of pesticides (such as butachlor, atrazine and glyphosate) at three concentrations (0.6 mg/L, 3 mg/L, 15 mg/L) was investigated. Three models (partial least squares discriminant analysis combined with full wavelengths, FW-PLSDA; partial least squares discriminant analysis combined with competitive adaptive reweighted sampling algorithm, CARS-PLSDA; linear discrimination analysis combined with regression coefficients, RC-LDA) were built by the hyperspectral data of Chlorella pyrenoidosa to find which model can produce the most optimal result. The RC-LDA model, which achieved an average correct classification rate of 97.0% was more superior than FW-PLSDA (72.2%) and CARS-PLSDA (84.0%), and it proved that visible/near infrared hyperspectral imaging could be a rapid and reliable technique to identify pesticide varieties. It also proved that microalgae can be a very promising medium to indicate characteristics of pesticides. PMID:27071456

  16. Identification of pesticide varieties by testing microalgae using Visible/Near Infrared Hyperspectral Imaging technology

    NASA Astrophysics Data System (ADS)

    Shao, Yongni; Jiang, Linjun; Zhou, Hong; Pan, Jian; He, Yong

    2016-04-01

    In our study, the feasibility of using visible/near infrared hyperspectral imaging technology to detect the changes of the internal components of Chlorella pyrenoidosa so as to determine the varieties of pesticides (such as butachlor, atrazine and glyphosate) at three concentrations (0.6 mg/L, 3 mg/L, 15 mg/L) was investigated. Three models (partial least squares discriminant analysis combined with full wavelengths, FW-PLSDA; partial least squares discriminant analysis combined with competitive adaptive reweighted sampling algorithm, CARS-PLSDA; linear discrimination analysis combined with regression coefficients, RC-LDA) were built by the hyperspectral data of Chlorella pyrenoidosa to find which model can produce the most optimal result. The RC-LDA model, which achieved an average correct classification rate of 97.0% was more superior than FW-PLSDA (72.2%) and CARS-PLSDA (84.0%), and it proved that visible/near infrared hyperspectral imaging could be a rapid and reliable technique to identify pesticide varieties. It also proved that microalgae can be a very promising medium to indicate characteristics of pesticides.

  17. Effects of sampling strategies on estimates of annual mean herbicide concentrations in midwestern rivers

    USGS Publications Warehouse

    Battaglin, W.A.; Hay, L.E.

    1996-01-01

    The effects of 10 sampling strategies on estimates of annual mean concentrations of the herbicides atrazine, alachlor, and cyanazine in selected midwestern rivers were tested. The accuracy of the strategies was computed by comparing time-weighted annual mean herbicide concentrations calculated from water samples collected from 17 locations on midwestern rivers, with simulated annual mean concentrations calculated for each sampling strategy, using Monte Carlo simulations. Monthly sampling was the most accurate strategy tested. The U.S. Environmental Protection Agency requires quarterly sampling for municipalities using surface water as a source of drinking water. Due to the seasonality of herbicide occurrence and transport, quarterly sampling underestimates annual mean herbicide concentrations in over 40% of the simulations. Three of the strategies tested showed that, relative to quarterly sampling, a more accurate representation of annual mean concentrations could be obtained by sampling more frequently during spring and early summer runoff and assuming zero herbicide concentration during late summer and winter months.

  18. Are Streams in Agricultural and Urban Areas Contaminated by Pesticides?

    USGS Publications Warehouse

    Kimbrough, R.A.

    1995-01-01

    To answer this question, a study of pesticides in streams in a small agricultural area and a small urban area in Colorado was conducted in 1993 by the U.S. Geological Survey (USGS) as part of the National Water-Quality Assessment (NAWQA) program. The results indicate that pesticides are present in streams, and both agricultural and urban areas are probable sources of the contamination. In the agricultural area, 30 pesticides were detected and in the urban area, 26 pesticides were detected at least once during the thirteen month study. In the agricultural area, the herbicides alachlor (two samples) and cyanazine (four samples) and the insecticide diazinon (one sample) were the only pesticides that exceeded the U.S. Environmental Protection Agency's maximum contaminant levels (MCLs) or health advisory levels (HALs) for drinking water. No pesticides exceeded MCLs or HALs in the urban area.

  19. Organomineral Interactions and Herbicide Sorption in Brazilian Tropical and Subtropical Oxisols under No-Tillage.

    PubMed

    Bonfleur, Eloana J; Kookana, Rai S; Tornisielo, Valdemar L; Regitano, Jussara B

    2016-05-25

    We evaluated the effects of the soil organic matter (SOM) composition, distribution between soil aggregates size, and their interactions with the mineral phase on herbicide sorption (alachlor, bentazon, and imazethapyr) in tropical and subtropical Oxisols under no-till systems (NT). Using soil physical fractionation approach, sorption experiments were performed on whole soils and their aggregates. SOM chemistry was assessed by CP/MAS (13)C NMR. The lower sorption observed in tropical soils was attributed to the greater blockage of SOM sorption sites than in subtropical soils. When these sites were exposed upon physical fractionation, sorption of the three herbicides in tropical soils increased, especially for imazethapyr. High amounts of poorly crystallized sesquioxides in these soils may have contributed to masking of sorption sites, indicating that organomineral interactions may lead to blockage of sorption sites on SOM in tropical soils. PMID:26666375

  20. Movement of pesticides and nutrients into tile drainage water. Final report, 22 September 1985-22 September 1988

    SciTech Connect

    Van Scoyoc, G.E.; Kladivko, E.J.

    1989-01-01

    Concern about contamination of surface and ground water by agricultural chemicals has increased in the last five years. The objectives of this study were to determine field-scale pesticide and nutrient losses to tile drains over a 3-year period on a low-organic-matter, poorly structured silt loam soil under typical agricultural management practices. A tile-drainage spacing study was instrumented to measure water outflow rates and to continuously collect tile outflow samples on a flow-proportional basis. Two replicates of 3 tile spacings (5, 10, and 20 m) were included in the study. Water samples were analyzed for all applied pesticides (atrazine, cyanazine, alachlor, carbofuran, terbufos, and chlorpyrifos) as well as major nutrients (N,P,K) and sediment.

  1. Pesticide distributions in surface water: The distribution of pesticide concentrations at two study sites points to herbicides that may affect management of public water supplies

    USGS Publications Warehouse

    Stamer, J.K.; Wieczorek, M.E.

    1996-01-01

    Distributions of concentrations of 46 pesticides were documented from May 1992 through March 1994 for Maple Creek near Nickerson, Neb., and Platte River at Louisville, Neb. As their source of public water supplies, Lincoln and the western part of Omaha withdraw groundwater from the adjacent alluvium near the Platte River site, which is hydraulically connected to the Platte River. Organonitrogen herbicides dominated the pesticide distributions at each site. Variations in the distributions of pesticides at the two sites partly reflect differences in land use and land management practices. Diazinon, an insecticide used in urban areas, was commonly detected at the Platte River site but not at the Maple Creek site. Of the 46 pesticides analyzed at the Platte River site, the herbicides atrazine and alachlor were more likely to exceed their respective maximum contaminant levels of 3.0 and 2.0 pg/L; cyanazine was more likely to exceed the health advisory level of 1.0 ??g/L.

  2. Performance of different work clothing types for reducing skin exposure to pesticides during open field treatment.

    PubMed

    Protano, Carmela; Guidotti, Maurizio; Vitali, Matteo

    2009-07-01

    The aim of this study was to estimate the performance of different work clothing types for reducing skin exposure to five pesticides (azinphos-methyl, terbutylazine, alachlor, dimethoate, and dicamba) in field distribution by tractor equipped with boom sprayer. Performance was assessed by measuring the penetration factors of different types of work clothing. The results show that the protection offered by personal protective equipment (PPE) was always >97%, whereas the performance of cotton garments ranged from 84.1% to 92.5%. The different cotton garments differed significantly in their permeability, and the upper part of the body was the anatomical region showing the greatest values of the penetration factors. These results confirm the necessity of using PPE properly to minimise dermal exposure to pesticides. PMID:19424648

  3. Ascorbic acid/Fe@Fe2O3: A highly efficient combined Fenton reagent to remove organic contaminants.

    PubMed

    Hou, Xiaojing; Huang, Xiaopeng; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

    2016-06-01

    In this study, we demonstrate that the combination of ascorbic acid and Fe@Fe2O3 core-shell nanowires (AA/Fe@Fe2O3) offers a highly efficient Fenton reagent. This combined Fenton reagent exhibited extremely high activity on the decomposition of H2O2 to produce OH for the degradation of various organic contaminants, including rhodamine B, methylene blue, alachlor, atrazine, siduron, lincomycin, and chloroamphenicol. The contaminant degradation constants in the AA/Fe@Fe2O3/H2O2 Fenton systems were 38-53 times higher than those in the conventional homogeneous Fenton system (Fe(II)/H2O2) at pH 3.8. Moreover, the OH generation rate constant in the AA/Fe@Fe2O3/H2O2 Fenton system was 1-3 orders of magnitudes greater than those of heterogeneous Fenton systems developed with other iron-containing materials (α-FeOOH, α-Fe2O3, FeOCl, and so on). The high activity of AA/Fe@Fe2O3 was attributed to the effective Fe(III)/Fe(II) cycle and the iron-ascorbate complex formation to stabilize ferrous ions with desirable and steady concentrations. During the AA/Fe@Fe2O3/H2O2 Fenton process, ascorbic acid served as a reducing and complexing reagent, enabling the reuse of Fe@Fe2O3 nanowires. We systematically investigated the alachlor and ascorbic acid degradation and found that they could be effectively degraded in the AA/Fe@Fe2O3/H2O2 system, accompanying with 100% of dechlorination and 92% of denitrification. This study sheds light on the importance of Fe(III)/Fe(II) cycle for the design of high efficient Fenton system and provides an alternative pathway for the organic contaminants removal. PMID:26921510

  4. Amidase activity in soils. IV. Effects of trace elements and pesticides

    SciTech Connect

    Frankenberger, W.T., Jr.; Tabatabai, M.A.

    1981-11-01

    Amidase was recently detected in soils, and this study was carried out to assess the effects of 21 trace elements, 12 herbicides, 2 fungicides, and 2 insecticides on the activity of this enzyme. Results showed that most of the trace elements and pesticides studied inhibited amidase activity in soils. The degree of inhibition varied among the soils used. When the trace elements were compared by using 5 ..mu..mol/g of soil, the average inhibition of amidase in three soils showed that Ag(I), Hg(I), As(III), and Se(IV) were the most effective inhibitors, but only Ag(I) and As(III) showed average inhibition > 50%. The least effective inhibitors (average inhibition < 3%) included Cu(I), Ba(II), Cu(II), Fe(II), Ni(II), Al(III), Fe(III), Ti(IV), V(IV), As(V), Mo(VI), and W(VI). Other elements that inhibited amidase activity in soils were Cd(II), Co(II), Mn(II), Pb(II), Sn(II), Zn(II), B(III), and Cr(III). Enzyme kinetic studies showed that As(III) was a competitive inhibitor of amidase, whereas Ag(I), Hg(II), and Se(IV) were noncompetitive inhibitors. When the pesticides studied were compared by using 10 ..mu..g of active ingredient per gram of soil, the average inhibition of amidase in three soils ranged from 2% with dinitroamine, EPTC plus R-25788, and captan to 10% with butylate. Other pesticides that inhibited amidase activity in soils were atrazine, naptalam, chloramben, dicamba, cyanazine, 2,4-D, alachlor, paraquat, trifluralin, maneb, diazinon, and malathion. The inhibition of amidase by diazinon, alachlor, and butylate followed noncompetitive kinetics.

  5. Pesticide Use and Relative Leukocyte Telomere Length in the Agricultural Health Study.

    PubMed

    Andreotti, Gabriella; Hoppin, Jane A; Hou, Lifang; Koutros, Stella; Gadalla, Shahinaz M; Savage, Sharon A; Lubin, Jay; Blair, Aaron; Hoxha, Mirjam; Baccarelli, Andrea; Sandler, Dale; Alavanja, Michael; Beane Freeman, Laura E

    2015-01-01

    Some studies suggest that telomere length (TL) may be influenced by environmental exposures, including pesticides. We examined associations between occupational pesticide use reported at three time points and relative telomere length (RTL) in the Agricultural Health Study (AHS), a prospective cohort study of pesticide applicators in Iowa and North Carolina. RTL was measured by qPCR using leukocyte DNA from 568 cancer-free male AHS participants aged 31-94 years with blood samples collected between 2006 and 2008. Self-reported information, including pesticide use, was collected at three time points: enrollment (1993-1997) and two follow-up questionnaires (1998-2003, 2005-2008). For each pesticide, we evaluated cumulative use (using data from all three questionnaires), and more recent use (using data from the last follow-up questionnaire). Multivariable linear regression was used to examine the associations between pesticide use (ever, lifetime days, intensity-weighted lifetime days (lifetime days*intensity score)) and RTL, adjusting for age at blood draw and use of other pesticides. Of the 57 pesticides evaluated with cumulative use, increasing lifetime days of 2,4-D (p-trend=0.001), diazinon (p-trend=0.002), and butylate (p-trend=0.01) were significantly associated with shorter RTL, while increasing lifetime days of alachlor was significantly associated with longer RTL (p-trend=0.03). Only the association with 2,4-D was significant after adjustment for multiple comparisons. Of the 40 pesticides evaluated for recent use, malathion was associated with shorter RTL (p=0.03), and alachlor with longer RTL (p=0.03). Our findings suggest that leukocyte TL may be impacted by cumulative use and recent use of certain pesticides. PMID:26196902

  6. Pesticide Use and Relative Leukocyte Telomere Length in the Agricultural Health Study

    PubMed Central

    Andreotti, Gabriella; Hoppin, Jane A.; Hou, Lifang; Koutros, Stella; Gadalla, Shahinaz M.; Savage, Sharon A.; Lubin, Jay; Blair, Aaron; Hoxha, Mirjam; Baccarelli, Andrea; Sandler, Dale; Alavanja, Michael; Beane Freeman, Laura E.

    2015-01-01

    Some studies suggest that telomere length (TL) may be influenced by environmental exposures, including pesticides. We examined associations between occupational pesticide use reported at three time points and relative telomere length (RTL) in the Agricultural Health Study (AHS), a prospective cohort study of pesticide applicators in Iowa and North Carolina. RTL was measured by qPCR using leukocyte DNA from 568 cancer-free male AHS participants aged 31-94 years with blood samples collected between 2006 and 2008. Self-reported information, including pesticide use, was collected at three time points: enrollment (1993-1997) and two follow-up questionnaires (1998-2003, 2005-2008). For each pesticide, we evaluated cumulative use (using data from all three questionnaires), and more recent use (using data from the last follow-up questionnaire). Multivariable linear regression was used to examine the associations between pesticide use (ever, lifetime days, intensity-weighted lifetime days (lifetime days*intensity score)) and RTL, adjusting for age at blood draw and use of other pesticides. Of the 57 pesticides evaluated with cumulative use, increasing lifetime days of 2,4-D (p-trend=0.001), diazinon (p-trend=0.002), and butylate (p-trend=0.01) were significantly associated with shorter RTL, while increasing lifetime days of alachlor was significantly associated with longer RTL (p-trend=0.03). Only the association with 2,4-D was significant after adjustment for multiple comparisons. Of the 40 pesticides evaluated for recent use, malathion was associated with shorter RTL (p=0.03), and alachlor with longer RTL (p=0.03). Our findings suggest that leukocyte TL may be impacted by cumulative use and recent use of certain pesticides. PMID:26196902

  7. Agricultural chemicals in alluvial aquifers in Missouri after the 1993 flood

    USGS Publications Warehouse

    Heimann, D.C.; Richards, J.M.; Wilkison, D.H.

    1997-01-01

    Intense rains produced flooding during the spring and summer of 1993 over much of the midwestern USA including many agricultural areas of Missouri. Because of potential contamination from floodwater, an investigation was conducted to determine the changes in concentrations of agricultural chemicals in water samples from alluvial wells in Missouri after the flood. Water samples from 80 alluvial wells with historical data were collected in March, July, and November 1994, and analyzed for dissolved herbicides, herbicide metabolites, and nitrate (NO3). There were no statistically significant differences in the distribution of alachlor ((2,chloro-2'-6'-diethyl-N-[methoxymethyl]acetanilide), atrazine (2-chloro- 4-ethylamino-6-isopropylamino-1, 3, 5 triazine), and nitrate concentrations between pre- and postflood samples (?? = 0.05). The detection frequency of alachlor and atrazine in postflood samples was generally lower than the frequency in preflood samples. Analyses of agricultural chemicals in water samples from an intensely sampled well field indicate significant differences between the distribution of dissolved P concentrations in pre- and postflood samples (?? = 0.05). However, no significant differences were detected between the pre- and postflood distributions of NO3 or ammonia concentrations. Because of the numerous sources of temporal variability and the relatively short record of water-quality data for the study wells, a cause-and-effect relation between changes in agricultural chemical concentrations and a single factor of the 1993 flood is difficult to determine. Based on the results of this study, the 1993 flood did not cause widespread or long-term significant changes in concentrations of agricultural chemicals in water from alluvial aquifers in Missouri.

  8. Impact of grassed waterways and compost filter socks on the quality of surface runoff from corn fields.

    PubMed

    Shipitalo, Martin J; Bonta, James V; Dayton, Elizabeth A; Owens, Lloyd B

    2010-01-01

    Surface runoff from cropland frequently has high concentrations of nutrients and herbicides, particularly in the first few events after application. Grassed waterways can control erosion while transmitting this runoff offsite, but are generally ineffective in removing dissolved agrochemicals. In this study, we routed runoff from one tilled (0.67 ha) and one no-till watershed (0.79 ha) planted to corn (Zea mays L.) into parallel, 30-m-long grassed waterways. Two 46-cm-diam. filter socks filled with composted bark and wood chips were placed 7.5 m apart in the upper half of one waterway and in the lower half of the other waterway to determine if they decreased concentrations of sediment and dissolved chemicals. Automated samplers were used to obtain samples above and below the treated segments of the waterways for two crop years. The filter socks had no significant effect (P alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] (18%) concentrations for the tilled watersheds, but this was insufficient to reduce alachlor concentrations to acceptable levels. PMID:20400596

  9. Interlaboratory comparison of extraction efficiency of pesticides from surface and laboratory water using solid-phase extraction disks.

    PubMed

    Senseman, Scott A; Mueller, Thomas C; Riley, Melissa B; Wauchope, R Don; Clegg, Chris; Young, Roddy W; Southwick, Lloyd M; Moye, H Anson; Dumas, Jose A; Mersie, Wondi; Mattice, John D; Leidy, Ross B

    2003-06-18

    A continuation of an earlier interlaboratory comparison was conducted (1) to assess solid-phase extraction (SPE) using Empore disks to extract atrazine, bromacil, metolachlor, and chlorpyrifos from various water sources accompanied by different sample shipping and quantitative techniques and (2) to compare quantitative results of individual laboratories with results of one common laboratory. Three replicates of a composite surface water (SW) sample were fortified with the analytes along with three replicates of deionized water (DW). A nonfortified DW sample and a nonfortified SW sample were also extracted. All samples were extracted using Empore C(18) disks. After extraction, part of the samples were eluted and analyzed in-house. Duplicate samples were evaporated in a 2-mL vial, shipped dry to a central laboratory (SDC), redissolved, and analyzed. Overall, samples analyzed in-house had higher recoveries than SDC samples. Laboratory x analysis type and laboratory x water source interactions were significant for all four compounds. Seven laboratories participated in this interlaboratory comparison program. No differences in atrazine recoveries were observed from in-house samples analyzed by laboratories A, B, D, and G compared with the recovery of SDC samples. In-house atrazine recoveries from laboratories C and F were higher when compared with recovery from SDC samples. However, laboratory E had lower recoveries from in-house samples compared with SDC samples. For each laboratory, lower recoveries were observed for chlorpyrifos from the SDC samples compared with samples analyzed in-house. Bromacil recovery was <65% at two of the seven laboratories in the study. Bromacil recoveries for the remaining laboratories were >75%. Three laboratories showed no differences in metolachlor recovery; two laboratories had higher recoveries for samples analyzed in-house, and two other laboratories showed higher metolachlor recovery for SDC samples. Laboratory G had a higher

  10. 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

  11. Seasonal changes in concentrations of dissolved pesticides and organic carbon in the Sacramento-San Joaquin delta, California, 1994-1996

    USGS Publications Warehouse

    Orlando, James L.; Kuivila, Kathryn M.

    2006-01-01

    The Sacramento-San Joaquin Delta (Delta) of California is an ecologically rich and hydrologically complex region that receives runoff from nearly one-quarter of the state. Water-quality studies of surface water in the region have found dissolved pesticides in winter storm runoff at concentrations toxic to some aquatic invertebrates. However, scientists have little information on pesticide concentrations in the Delta on a seasonal timescale or the importance of pesticide contributions from within-Delta sources. Consequently, the U.S. Geological Survey conducted a study from 1994 to 1996 during which water samples were collected seasonally from 31 sites located within the Delta and on major tributaries to the Delta. Water samples were analyzed for 20 current-use pesticides and dissolved organic carbon. During the study, 11 current-use pesticides were detected; maximum concentrations ranging from 17 ng/L (for trifluralin) to 1,160 ng/L (for metolachlor). The highest concentrations of five pesticides (carbaryl, carbofuran, metolachlor, molinate, and simazine) were greater than 900 ng/L. The greatest number of pesticides was detected in the summer of 1994, whereas the least number were detected in the winter of 1994. The herbicides metolachlor and simazine were the most frequently detected pesticides and were detected in five of the six sampling seasons. The herbicides molinate and EPTC were detected only during the three summer sampling seasons. A comparison of pesticides detected during the spring and summer of 1995 showed some seasonal variability. Comparison of the three summer seasons sampled showed that a larger number of pesticides were detected, and with generally higher maximum concentrations, in 1994 than in 1995 or 1996. Dissolved organic carbon (DOC) concentrations ranged, over the course of the study, from 1.4 mg/L to 10.4 mg/L, and had a median concentration of 3.8 mg/L. On a seasonal basis, the lowest maximum DOC concentrations occurred during the summer

  12. Water-Quality Data for Pharmaceuticals and Other Organic Wastewater Contaminants in Ground Water and in Untreated Drinking Water Sources in the United States, 2000-01

    USGS Publications Warehouse

    Barnes, Kimberlee K.; Kolpin, Dana W.; Focazio, Michael J.; Furlong, Edward T.; Meyer, Michael T.; Zaugg, Steven D.; Haack, Sheridan K.; Barber, Larry B.; Thurman, E. Michael

    2008-01-01

    The five most frequently detected compounds in samples collected from ambient ground-water sites are N,N-diethyltoluamide (35 percent, insect repellant), bisphenol A (30 percent, plasticizer), tri(2-chloroethy) phosphate (30 percent, fire retardant), sulfamethoxazole (23 percent, veterinary and human antibiotic), and 4-octylphenol monoethoxylate (19 percent, detergent metabolite). The five most frequently detected organic wastewater contaminants in samples of untreated drinking water from surface-water sources are cholesterol (59 percent, natural sterol), metolachlor (53 percent, herbicide), cotinine (51 percent, nicotine metabolite), β-sitosterol (37 percent, natural plant sterol), and 1,7-dimethylxanthine (27 percent, caffeine metabolite). The five most frequently detected organic wastewater contaminants in samples of untreated drinking water from ground-water sources are tetrachloroethylene (24 percent, solvent), carbamazepine (20 percent, pharmaceutical), bisphenol A (20 percent, plasticizer), 1,7-dimethylxanthine (16 percent, caffeine metabolite), and tri(2-chloroethyl) phosphate (12 percent, fire retardant).

  13. Occurrence and Distribution of Pesticides in the St. Lucie River Watershed, South-Central Florida, 2000-01, Based on Enzyme-Linked Immunosorbent Assay (ELISA) Screening

    USGS Publications Warehouse

    Lietz, A.C.

    2003-01-01

    , respectively. The highest median triazine concentration was found in the cropland/pastureland area. Chloroacetanilide concentra-tions ranged from highest to lowest in the citrus, integrated, urban/built-up, and cropland/pastureland areas, respectively. Chlorophenoxy compound concentrations ranged from highest to lowest in the urban/built-up, integrated, citrus, and cropland/pastureland areas, respectively. The maximum concentrations of triazines, chloroacetanilides, and chlorophenoxy compounds were 0.63, 1.0, and 14 micrograms per liter, respectively. Organophosphate was detected once at an integrated site at a concentration of 0.20 microgram per liter. Currently, the U.S. Environmental Protection Agency has no aquatic life guidelines for atrazine and metolachlor. However, assuming that all triazine and metolachlor concentrations from ELISA and gas chromatography/mass spectrometry (GC/MS) analyses were the result of atrazine and metolachlor detections, no concentrations exceeded the Canadian aquatic life guidelines for atrazine and metolachlor. One organophosphate detection (0.2 microgram per liter) did exceed the U.S. Environmental Protection Agency aquatic life guideline for chlorpyrifos. The deethylatrazine/atrazine ratio (DAR) is an important indicator of atrazine transport in the environment. The DAR ranged from 0.25 to 0.33, indicating that postapplication runoff was the most likely source of atrazine to the environment at the time of sampling. Deisopropylatrazine is a metabolite of atrazine and structurally similar compounds, such as simazine and cyanazine. The deisopropylatrazine/deethylatrazine ratio (D2R) is an indicator of nonpoint sources of deisopropylatrazine to the environment. The ratio ranged from 1 to 3 in this study, indicating simazine was an important source of deisopropylatrazine to the environment at the time of sampling, as opposed to atrazine alone. Confirmation analyses by GC/MS for triazines detected by ELISA indicated t

  14. Biosurfactant-enhanced soil bioremediation

    SciTech Connect

    Kosaric, N.; Lu, G.; Velikonja, J.

    1995-12-01

    Bioremediation of soil contaminated with organic chemicals is a viable alternative method for clean-up and remedy of hazardous waste sites. The final objective in this approach is to convert the parent toxicant into a readily biodegradable product which is harmless to human health and/or the environment. Biodegradation of hydrocarbons in soil can also efficiently be enhanced by addition or in-situ production of biosufactants. It was generally observed that the degradation time was shortened and particularly the adaptation time for the microbes. More data from our laboratories showed that chlorinated aromatic compounds, such as 2,4-dichlorophenol, a herbicide Metolachlor, as well as naphthalene are degraded faster and more completely when selected biosurfactants are added to the soil. More recent data demonstrated an enhanced biodegradation of heavy hydrocarbons in petrochemical sludges, and in contaminated oil when biosurfactants were present or were added prior to the biodegradation process.

  15. Pesticide residues in groundwater in The Netherlands: state of observations and future directions of research.

    PubMed

    Loch, J P; Verdam, B

    1989-01-01

    In the first stage of a programme of sampling and analysis for pesticide residues in groundwater in The Netherlands, the upper groundwater below four vulnerable soils was analysed for nearly 2,5 years in eight sampling rounds. Of 18 compounds analysed, including some metabolites, 1,3-dichloropropene, aldicarb, ethoprophos dinoseb, metamitron, atrazine, desethyl- and desisopropylatrazine, metolachlor and ethylenethioureum were repeatedly detected in the groundwater in concentrations above 0.1 micrograms.dm-3, the limit for pesticides in drinking water set by the EC. These observations were made below fields with potatoe-, maize- and bulb flower culture, all on low-humic to moderately humic sandy soils. No residues were found below a cracked light clay on a sandy subsoil. On the locations sampled evidence was found for complete in situ removal in the upper groundwater of 1,3-dichloropropene, high persistence of aldicarb residues and partial in situ degradation of dinoseb. PMID:2756375

  16. Process design for wastewater treatment: catalytic ozonation of organic pollutants.

    PubMed

    Derrouiche, S; Bourdin, D; Roche, P; Houssais, B; Machinal, C; Coste, M; Restivo, J; Orfão, J J M; Pereira, M F R; Marco, Y; Garcia-Bordeje, E

    2013-01-01

    Emerging micropollutants have been recently the target of interest for their potential harmful effects in the environment and their resistance to conventional water treatments. Catalytic ozonation is an advanced oxidation process consisting of the formation of highly reactive radicals from the decomposition of ozone promoted by a catalyst. Nanocarbon materials have been shown to be effective catalysts for this process, either in powder form or grown on the surface of a monolithic structure. In this work, carbon nanofibers grown on the surface of a cordierite honeycomb monolith are tested as catalyst for the ozonation of five selected micropollutants: atrazine (ATZ), bezafibrate, erythromycin, metolachlor, and nonylphenol. The process is tested both in laboratorial and real conditions. Later on, ATZ was selected as a target pollutant to further investigate the role of the catalytic material. It is shown that the inclusion of a catalyst improves the mineralization degree compared to single ozonation. PMID:24056437

  17. Spatial, seasonal and vertical distributions of currently-used pesticides in the marine boundary layer of the North Sea

    NASA Astrophysics Data System (ADS)

    Mai, Carolin; Theobald, Norbert; Lammel, Gerhard; Hühnerfuss, Heinrich

    2013-08-01

    Pesticides are transported beyond source regions and reach coastal waters and shelf seas. 23 representatives of six chemical classes of currently-used pesticides (CUPs) were simultaneously quantified in the marine boundary layer and the surface seawater of the German Bight and the central North Sea in 2009 and 2010.Terbuthylazine, metolachlor, metazachlor, pendimethalin and trifluralin exhibited the highest concentrations, seasonally highly variable. Advection of contaminated air from land and subsequent atmospheric deposition was shown to contribute to surface seawater contamination significantly, in particular in regions beyond riverine input and during the main seasons of application in agriculture. Deposition was most significant for the seasonal and spatial distributions of pendimethalin and trifluralin. Atrazine and simazine levels in the air are lower than 1-2 decades ago.

  18. Stream-water chemistry, nutrients, and pesticides in Town Brook, a headwater stream of the Cannonsville Reservoir Watershed, Delaware County, New York, 1999

    USGS Publications Warehouse

    McHale, Michael R.; Phillips, Patrick J.

    2001-01-01

    metabolites (degradation products) were detected in the samples. Four compounds (metolachlor, atrazine, metolachlor ESA, and metolachlor OA) were detected in concentrations greater than 1 micrograms per liter (?g/L) in one or more samples. Two of these compounds.the herbicide metabolites metalochlor ESA and metalochlor OA.were detected in concentrations higher than those of the parent compound metolachlor. Only one sample, collected during the July 4 storm, exceeded New York State surface-water-quality standards for any pesticide (simazine); its concentration of 0.53 ?g/L was 0.03 ?g/L higher than the New York State standard (0.50 ?g/L). No concentrations exceeded Federal water-quality standards. Pesticide and metabolite concentrations were as much as 25 times greater during stormflow than during baseflow. Stormflow pesticide concentrations were indicative of a spring 'flushing', in which stream pesticide concentrations are elevated from concentrations typical during the rest of the year during the first few storms after pesticide application. Pesticides and pesticide metabolites were detected in all stormflow samples. These results illustrate the need to include baseflow and stormflow in pesticide sampling routines. The results of this study emphasize the need for (1) baseflow and stormflow sampling to capture the range of nutrient and pesticide concentrations from agricultural watersheds, and (2) research to define the mechanisms of nutrient and pesticide export in agriculutral watersheds.

  19. Spatial and Temporal Variability in Pesticide Exposure Downstream of a Heavily Irrigated Cropping Area: Application of Different Monitoring Techniques.

    PubMed

    O'Brien, Dominique; Lewis, Stephen; Davis, Aaron; Gallen, Christie; Smith, Rachael; Turner, Ryan; Warne, Michael; Turner, Scott; Caswell, Stewart; Mueller, Jochen F; Brodie, Jon

    2016-05-25

    Pesticide exposure threatens many freshwater and estuarine ecosystems around the world. This study examined the temporal and spatial trends of pesticide concentrations in a waterway within an agriculturally developed dry-tropics catchment using a combination of grab and passive sampling methods over a continuous two-year monitoring program. A total of 43 pesticide residues were detected with 7 pesticides exceeding ecologically relevant water quality guidelines/trigger values during the study period and 4 (ametryn, atrazine, diuron, and metolachlor) of these exceeding guidelines for several months. The presence and concentration of the pesticides in the stream coincided with seasonal variability in rainfall, harvest timing/cropping cycle, and management changes. The sampling approach used demonstrates that the application of these complementary sampling techniques (both grab and passive sampling methods) was effective in establishing pesticide usage patterns in upstream locations where application data are unavailable. PMID:26755130

  20. Mississippi oxbow lake sediment quality during an artificial flood.

    PubMed

    Knight, S S; Lizotte, R E; Moore, M T; Smith, S; Shields, F D

    2009-04-01

    Surface sediment quality was assessed during a 35-day artificial flood in a shallow (<1.5 m) oxbow lake along the Coldwater River, Mississippi, using Hyalella azteca 28-day bioassays. Seventeen pesticides were monitored in sediments before, during and after flooding, with increases in atrazine and metolachlor concentrations coinciding with two unexpected storm events, 51 and 56 mm, during and after flooding, respectively. Mean 28-day H. azteca survival was >85% throughout this study. However, growth was affected at three sites during flooding with limited growth recovery after flooding. Patterns in observed growth impairment were associated with changes in atrazine (R(2)=0.524) and fipronil sulfone (R(2)=0.584) concentrations. PMID:19183821

  1. Soil sorption and leaching of active ingredients of Lumax® under mineral or organic fertilization.

    PubMed

    Pinna, Maria Vittoria; Roggero, Pier Paolo; Seddaiu, Giovanna; Pusino, Alba

    2014-09-01

    The study describes the soil sorption of the herbicide Lumax®, composed of S-metolachlor (MTC), terbuthylazine (TBZ), and mesotrione (MST), as influenced by mineral and organic fertilizers. The investigation was performed on a sandy soil of an agricultural area designated as a Nitrate Vulnerable Zone, where mineral and organic fertilizers were applied for many years. Two organic fertilizers, cattle manure and slurry, respectively, and a mineral fertilizer with a nitrification inhibitor, Entec®, were compared. According to the experiments, performed with a batch method, the sorption conformed to Freundlich model. The extent of sorption of Lumax® ingredients was closely related to their octanol-water partition coefficient Kow. The respective desorption was hysteretic. Leaching trials were carried out by using water or solutions of DOM or Entec® as the eluants. Only the elution with the mineral fertilizer promoted the leaching of Lumax® active ingredients. PMID:24997942

  2. Large-scale pesticide monitoring across Great Barrier Reef catchments--Paddock to Reef Integrated Monitoring, Modelling and Reporting Program.

    PubMed

    Smith, Rachael; Middlebrook, Rachael; Turner, Ryan; Huggins, Rae; Vardy, Suzanne; Warne, Michael

    2012-01-01

    The transport and potential toxicity of pesticides in Queensland (QLD) catchments from agricultural areas is a key concern for the Great Barrier Reef (GBR). In 2009, a pesticide monitoring program was established as part of the Australian and QLD Governments' Reef Plan (2009). Samples were collected at eight End of System sites (above the tidal zone) and three sub-catchment sites. At least two pesticides were detected at every site including insecticides, fungicides, herbicides, and the Reef Plan's (2009) five priority photosystem II (PSII) herbicides (diuron, atrazine, hexazinone, tebuthiuron and ametryn). Diuron, atrazine and metolachlor exceeded Australian and New Zealand water quality guideline trigger values (TVs) at eight sites. Accounting for PSII herbicide mixtures increased the estimated toxicity and led to larger exceedances of the TVs at more sites. This study demonstrates the widespread contamination of pesticides, particularly PSII herbicides, across the GBR catchment area which discharges to the GBR. PMID:21920563

  3. Agricultural pesticides and selected degradation products in five tidal regions and the main stem of Chesapeake Bay, USA.

    PubMed

    McConnell, Laura L; Rice, Clifford P; Hapeman, Cathleen J; Drakeford, Leticia; Harman-Fetcho, Jennifer A; Bialek, Krystyna; Fulton, Michael H; Leight, Andrew K; Allen, Gregory

    2007-12-01

    Nutrients, sediment, and toxics from water sources and the surrounding airshed are major problems contributing to poor water quality in many regions of the Chesapeake Bay, an important estuary located in the mid-Atlantic region of the United States. During the early spring of 2000, surface water samples were collected for pesticide analysis from 18 stations spanning the Chesapeake Bay. In a separate effort from July to September of 2004, 61 stations within several tidal regions were characterized with respect to 21 pesticides and 11 of their degradation products. Three regions were located on the agricultural Delmarva Peninsula: The Chester, Nanticoke, and Pocomoke Rivers. Two regions were located on the more urban western shore: The Rhode and South Rivers and the Lower Mobjack Bay, including the Back and Poquoson Rivers. In both studies, herbicides and their degradation products were the most frequently detected chemicals. In 2000, atrazine and metolachlor were found at all 18 stations. In 2004, the highest parent herbicide concentrations were found in the upstream region of Chester River. The highest concentration for any analyte in these studies was for the ethane sulfonic acid of metolachlor (MESA) at 2,900 ng/L in the Nanticoke River. The degradation product MESA also had the greatest concentration of any analyte in the Pocomoke River (2,100 ng/L) and in the Chester River (1,200 ng/L). In the agricultural tributaries, herbicide degradation product concentrations were more strongly correlated with salinity than the parent herbicides. In the two nonagricultural watersheds on the western shore, no gradient in herbicide concentrations was observed, indicating the pesticide source to these areas was water from the Bay main stem. PMID:18020682

  4. Environmental monitoring of selected pesticides and organic chemicals in urban stormwater recycling systems using passive sampling techniques

    NASA Astrophysics Data System (ADS)

    Page, Declan; Miotliński, Konrad; Gonzalez, Dennis; Barry, Karen; Dillon, Peter; Gallen, Christie

    2014-03-01

    Water recycling via aquifers has become a valuable tool to augment urban water supplies in many countries. This study reports the first use of passive samplers for monitoring of organic micropollutants in Managed Aquifer Recharge (MAR). Five different configurations of passive samplers were deployed in a stormwater treatment wetland, groundwater monitoring wells and a recovery tank to capture a range of polar and non-polar micropollutants present in the system. The passive samplers were analysed for a suite of pesticides, polycyclic aromatic hydrocarbons (PAHs) and other chemicals. As a result, 17 pesticides and pesticide degradation products, 5 PAHs and 8 other organic chemicals including flame retardants and fragrances were detected in urban stormwater recharging Aquifer Storage and Recovery (ASR) and an Aquifer Storage Transfer and Recovery (ASTR) system. Of the pesticides detected, diuron, metolachlor and chlorpyrifos were generally detected at the highest concentrations in one or more passive samplers, whereas chlorpyrifos, diuron, metolachlor, simazine, galaxolide and triallate were detected in multiple samplers. Fluorene was the PAH detected at the highest concentration and the flame retardant Tris(1-chloro-2-propyl)phosphate was the chemical detected in the greatest abundance at all sites. The passive samplers showed different efficiencies for capture of micropollutants with the Empore disc samplers giving the most reliable results. The results indicate generally low levels of organic micropollutants in the stormwater, as the contaminants detected were present at very low ng/L levels, generally two to four orders of magnitude below the drinking water guidelines (NHMRC, 2011). The efficiency of attenuation of these organic micropollutants during MAR was difficult to determine due to variations in the source water concentrations. Comparisons were made between different samplers, to give a field-based calibration where existing lab-based calibrations were

  5. Evaluating changes in matrix based, recovery-adjusted concentrations in paired data for pesticides in groundwater

    USGS Publications Warehouse

    Zimmerman, Tammy M.; Breen, Kevin J.

    2012-01-01

    Pesticide concentration data for waters from selected carbonate-rock aquifers in agricultural areas of Pennsylvania were collected in 1993–2009 for occurrence and distribution assessments. A set of 30 wells was visited once in 1993–1995 and again in 2008–2009 to assess concentration changes. The data include censored matched pairs (nondetections of a compound in one or both samples of a pair). A potentially improved approach for assessing concentration changes is presented where (i) concentrations are adjusted with models of matrix-spike recovery and (ii) area-wide temporal change is tested by use of the paired Prentice-Wilcoxon (PPW) statistical test. The PPW results for atrazine, simazine, metolachlor, prometon, and an atrazine degradate, deethylatrazine (DEA), are compared using recovery-adjusted and unadjusted concentrations. Results for adjusted compared with unadjusted concentrations in 2008–2009 compared with 1993–1995 were similar for atrazine and simazine (significant decrease; 95% confidence level) and metolachlor (no change) but differed for DEA (adjusted, decrease; unadjusted, increase) and prometon (adjusted, decrease; unadjusted, no change). The PPW results were different on recovery-adjusted compared with unadjusted concentrations. Not accounting for variability in recovery can mask a true change, misidentify a change when no true change exists, or assign a direction opposite of the true change in concentration that resulted from matrix influences on extraction and laboratory method performance. However, matrix-based models of recovery derived from a laboratory performance dataset from multiple studies for national assessment, as used herein, rather than time- and study-specific recoveries may introduce uncertainty in recovery adjustments for individual samples that should be considered in assessing change.

  6. Transport of bromide and pesticides through an undisturbed soil column: a modeling study with global optimization analysis.

    PubMed

    Dusek, Jaromir; Dohnal, Michal; Snehota, Michal; Sobotkova, Martina; Ray, Chittaranjan; Vogel, Tomas

    2015-01-01

    The fate of pesticides in tropical soils is still not understood as well as it is for soils in temperate regions. In this study, water flow and transport of bromide tracer and five pesticides (atrazine, imazaquin, sulfometuron methyl, S-metolachlor, and imidacloprid) through an undisturbed soil column of tropical Oxisol were analyzed using a one-dimensional numerical model. The numerical model is based on Richards' equation for solving water flow, and the advection-dispersion equation for solving solute transport. Data from a laboratory column leaching experiment were used in the uncertainty analysis using a global optimization methodology to evaluate the model's sensitivity to transport parameters. All pesticides were found to be relatively mobile (sorption distribution coefficients lower than 2 cm(3) g(-1)). Experimental data indicated significant non-conservative behavior of bromide tracer. All pesticides, with the exception of imidacloprid, were found less persistent (degradation half-lives smaller than 45 days). Three of the five pesticides (atrazine, sulfometuron methyl, and S-metolachlor) were better described by the linear kinetic sorption model, while the breakthrough curves of imazaquin and imidacloprid were more appropriately approximated using nonlinear instantaneous sorption. Sensitivity analysis suggested that the model is most sensitive to sorption distribution coefficient. The prediction limits contained most of the measured points of the experimental breakthrough curves, indicating adequate model concept and model structure for the description of transport processes in the soil column under study. Uncertainty analysis using a physically-based Monte Carlo modeling of pesticide fate and transport provides useful information for the evaluation of chemical leaching in Hawaii soils. PMID:25703186

  7. Environmental monitoring of selected pesticides and organic chemicals in urban stormwater recycling systems using passive sampling techniques.

    PubMed

    Page, Declan; Miotliński, Konrad; Gonzalez, Dennis; Barry, Karen; Dillon, Peter; Gallen, Christie

    2014-03-01

    Water recycling via aquifers has become a valuable tool to augment urban water supplies in many countries. This study reports the first use of passive samplers for monitoring of organic micropollutants in Managed Aquifer Recharge (MAR). Five different configurations of passive samplers were deployed in a stormwater treatment wetland, groundwater monitoring wells and a recovery tank to capture a range of polar and non-polar micropollutants present in the system. The passive samplers were analysed for a suite of pesticides, polycyclic aromatic hydrocarbons (PAHs) and other chemicals. As a result, 17 pesticides and pesticide degradation products, 5 PAHs and 8 other organic chemicals including flame retardants and fragrances were detected in urban stormwater recharging Aquifer Storage and Recovery (ASR) and an Aquifer Storage Transfer and Recovery (ASTR) system. Of the pesticides detected, diuron, metolachlor and chlorpyrifos were generally detected at the highest concentrations in one or more passive samplers, whereas chlorpyrifos, diuron, metolachlor, simazine, galaxolide and triallate were detected in multiple samplers. Fluorene was the PAH detected at the highest concentration and the flame retardant Tris(1-chloro-2-propyl)phosphate was the chemical detected in the greatest abundance at all sites. The passive samplers showed different efficiencies for capture of micropollutants with the Empore disc samplers giving the most reliable results. The results indicate generally low levels of organic micropollutants in the stormwater, as the contaminants detected were present at very low ng/L levels, generally two to four orders of magnitude below the drinking water guidelines (NHMRC, 2011). The efficiency of attenuation of these organic micropollutants during MAR was difficult to determine due to variations in the source water concentrations. Comparisons were made between different samplers, to give a field-based calibration where existing lab-based calibrations were

  8. Calibration of a passive sampling device for time-integrated sampling of hydrophilic herbicides in aquatic environments.

    PubMed

    Tran, Anh T K; Hyne, Ross V; Doble, P

    2007-03-01

    Two types of solid-phase materials, a styrenedivinylbenzene copolymer sorbent (embedded in a SDB-XC Empore disk) and a styrenedivinylbenzene copolymer sorbent modified with sulfonic acid functional groups (embedded in a SDB-RPS Empore disk), were compared as a receiving phase in a passive sampling device for monitoring polar pesticides. The SDB-XC Empore disk was selected for further evaluation, overlayed with either a polysulfone or a polyethersulfone diffusion membrane. The target herbicides included five nonionized herbicides (simazine, atrazine, diuron, clomazone, and metolachlor) and four phenoxy acid herbicides (dicamba, (2,4-dichlorophenoxy)acetic acid [2,4-D], (4-chloro-2-methylphenoxy)acetic acid [MCPA], and triclopyr) with log octanol/water partition coefficient (log K(OW)) values of less than three in water. Uptake of these herbicides generally was higher into a device constructed of a SDB-XC Empore disk as a receiving phase covered with a polyethersulfone membrane compared to a similar device covered with a polysulfone membrane. Using the device with a SDB-XC Empore disk covered with a polyethersulfone membrane, linear uptake of simazine, atrazine, diuron, clomazone, and metolachlor was observed for up to 21 d, and daily sampling rates of the herbicides from water in a laboratory flow-through system were determined. The uptake rate of each nonionized herbicide by the Empore disk-based passive sampler was linearly proportional to its concentration in the water, and the sampling rate was independent of the water concentrations over the 21-d period. Uptake of the phenoxy acid herbicides (2,4-D, MCPA, and triclopyr) obeyed first-order kinetics and rapidly reached equilibrium in the passive sampler after approximately 12 d of exposure. The Empore disk-based passive sampler displayed isotropic kinetics, with a release half-life for triclopyr of approximately 6 d. PMID:17373506

  9. Community air monitoring for pesticides-part 2: multiresidue determination of pesticides in air by gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.

    PubMed

    Hengel, Matt; Lee, P

    2014-03-01

    Two multiresidue methods were developed to determine pesticides in air collected in California. Pesticides were trapped using XAD-4 resin and extracted with ethyl acetate. Based on an analytical method from the University of California Davis Trace Analytical Laboratory, pesticides were detected by analyzing the extract by gas chromatography-mass spectrometry (GC-MS) to determine chlorothalonil, chlorthal-dimethyl, cycloate, dicloran, dicofol, EPTC, ethalfluralin, iprodione, mefenoxam, metolachlor, PCNB, permethrin, pronamide, simazine, trifluralin, and vinclozolin. A GC with a flame photometric detector was used to determine chlorpyrifos, chlorpyrifos oxon, diazinon, diazinon oxon, dimethoate, dimethoate oxon, fonophos, fonophos oxon, malathion, malathion oxon, naled, and oxydemeton. Trapping efficiencies ranged from 78 to 92 % for low level (0.5 μg) and 37-104 % for high level (50 and 100 μg) recoveries. Little to no degradation of compounds occurred over 31 days; recoveries ranged from 78 to 113 %. In the California Department of Food and Agriculture (CDFA) method, pesticides were detected by analyzing the extract by GC-MS to determine chlorothalonil, chlorpyrifos, cypermethrin, dichlorvos, dicofol, endosulfan 1, endosulfan sulfate, oxyfluorfen, permethrin, propargite, and trifluralin. A liquid chromatograph coupled to a MS was used to determine azinphos-methyl, chloropyrifos oxon, DEF, diazinon, diazinon oxon, dimethoate, dimethoate oxon, diuron, EPTC, malathion, malathion oxon, metolachlor, molinate, norflurazon, oryzalin, phosmet, propanil, simazine and thiobencarb. Trapping efficiencies for compounds determined by the CDFA method ranged from 10 to 113, 22 to 114, and 56 to 132 % for 10, 5, and 2 μg spikes, respectively. Storage tests yielded 70-170 % recovery for up to 28 days. These multiresidue methods represent flexible, sensitive, accurate, and cost-effective ways to determine residues of various pesticides in ambient air. PMID:24370860

  10. Transport of bromide and pesticides through an undisturbed soil column: A modeling study with global optimization analysis

    NASA Astrophysics Data System (ADS)

    Dusek, Jaromir; Dohnal, Michal; Snehota, Michal; Sobotkova, Martina; Ray, Chittaranjan; Vogel, Tomas

    2015-04-01

    The fate of pesticides in tropical soils is still not understood as well as it is for soils in temperate regions. In this study, water flow and transport of bromide tracer and five pesticides (atrazine, imazaquin, sulfometuron methyl, S-metolachlor, and imidacloprid) through an undisturbed soil column of tropical Oxisol were analyzed using a one-dimensional numerical model. The numerical model is based on Richards' equation for solving water flow, and the advection-dispersion equation for solving solute transport. Data from a laboratory column leaching experiment were used in the uncertainty analysis using a global optimization methodology to evaluate the model's sensitivity to transport parameters. All pesticides were found to be relatively mobile (sorption distribution coefficients lower than 2 cm3 g- 1). Experimental data indicated significant non-conservative behavior of bromide tracer. All pesticides, with the exception of imidacloprid, were found less persistent (degradation half-lives smaller than 45 days). Three of the five pesticides (atrazine, sulfometuron methyl, and S-metolachlor) were better described by the linear kinetic sorption model, while the breakthrough curves of imazaquin and imidacloprid were more appropriately approximated using nonlinear instantaneous sorption. Sensitivity analysis suggested that the model is most sensitive to sorption distribution coefficient. The prediction limits contained most of the measured points of the experimental breakthrough curves, indicating adequate model concept and model structure for the description of transport processes in the soil column under study. Uncertainty analysis using a physically-based Monte Carlo modeling of pesticide fate and transport provides useful information for the evaluation of chemical leaching in Hawaii soils.

  11. 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

  12. Effect of vegetative filter strips on herbicide runoff under various types of rainfall.

    PubMed

    Otto, Stefan; Cardinali, Alessandra; Marotta, Ester; Paradisi, Cristina; Zanin, Giuseppe

    2012-06-01

    Narrow vegetative filter strips proved to effectively reduce herbicide runoff from cultivated fields mainly due to the ability of vegetation to delay surface runoff, promote infiltration and adsorb herbicides. A field trial was conducted from 2007 to 2009 in north-east Italy in order to evaluate the effectiveness of various types of vegetative filter strips to reduce spring-summer runoff of the herbicides mesotrione, metolachlor and terbuthylazine, widely used in maize, and to evaluate the effect of the rainfall characteristics on the runoff volume and concentration. Results show that without vegetative filter strip the herbicide load that reaches the surface water is about 5-6 g ha(-1)year(-1) for metolachlor and terbuthylazine (i.e. 0.5-0.9% of the applied rate), confirming that runoff from flat fields as in the Po Valley can have a minor effect on the water quality, and that most of the risk is posed by a few, or even just one extreme rainfall event with a return period of about 25-27 years, causing runoff with a maximum concentration of 64-77 μg L(-1). Mesotrione instead showed rapid soil disappearance and was observed at a concentration of 1.0-3.8 μg L(-1) only after one extreme (artificial) rainfall. Vegetative filter strips of any type are generally effective and can reduce herbicide runoff by 80-88%. Their effectiveness is steady even under severe rainfall conditions, and this supports their implementation in an environmental regulatory scheme at a catchment or regional scale. PMID:22463948

  13. Pesticides in storm runoff from agricultural and urban areas in the Tuolumne River basin in the vicinity of Modesto, California

    USGS Publications Warehouse

    Kratzer, Charles R.

    1998-01-01

    The occurrence, concentrations, and loads of dissolved pesticides in storm runoff were compared for two contrasting land uses in the Tuolumne River Basin, California, during two different winter storms: agricultural areas (February 1994) and the Modesto urban area (February 1995). Both storms followed the main application period of pesticides on dormant almond orchards. Eight samples of runoff from agricultural areas were collected from a Tuolumne River site, and 10 samples of runoff from urban areas were collected from five storm drains. All samples were analyzed for 46 pesticides. Six pesticides were detected in runoff from agricultural areas, and 15 pesticides were detected in runoff from urban areas. Chlorpyrifos, diazinon, dacthal (DCPA), metolachlor, and simazine were detected in almost every sample. Median concentrations were higher in the runoff from urban areas for all pesticides except napropamide and simazine. The greater occurrence and concentrations in storm drains is partly attributed to dilution of agricultural runoff by nonstorm base-flow in the Tuolumne River and by storm runoff from nonagricultural and nonurban land. In most cases, the occurrence and relative concentrations of pesticides found in storm runoff from agricultural and urban areas were related to reported pesticide application. Pesticide concentrations in runoff from agricultural areas were more variable during the storm hydrograph than were concentrations in runoff from urban areas. All peak pesticide concentrations in runoff from agricultural areas occurred during the rising limb of the storm hydrograph, whereas peak concentrations in the storm drains occurred at varying times during the storm hydrograph. Transport of pesticides from agricultural areas during the February 1994 storm exceeded transport from urban areas during the February 1995 storm for chlorpyrifos, diazinon, metolachlor, napropamide, and simazine. Transport of DCPA was about the same from agricultural and urban

  14. Application of herbicides is likely to reduce greenhouse gas (N2O and CH4) emissions from rice-wheat cropping systems

    NASA Astrophysics Data System (ADS)

    Jiang, Jingyan; Chen, Linmei; Sun, Qing; Sang, Mengmeng; Huang, Yao

    2015-04-01

    Herbicides have been widely used to control weeds in croplands; however, their effects on greenhouse gas emissions remain unclear. The effects of three wheat herbicides (acetochlor, AC; tribenuron-methyl, TBM; fenoxaprop-p-ethyl, FE) and two rice herbicides (butachlor, BC; bensulfuron-methyl, BSM) on N2O and CH4 emissions were investigated in this study. In the wheat growing season, applications of AC and FE + TBM significantly reduced N2O emissions by 31% compared with no herbicide use (p = 0.001). In the rice growing season, the application of BC significantly reduced CH4 emissions by 58% (p = 0.022), and BSM significantly reduced N2O emissions by 27% (p = 0.040); however, no significant difference among treatments with regard to the aggregate emissions of N2O and CH4 in the CO2 equivalent for the 100-year horizon was observed (p > 0.05). Relative to control plots, which were not treated with herbicides, the combined application of the herbicides FE and TBM in the wheat season led to a significant decrease in greenhouse gas intensity (GHGI) by ∼41% (p = 0.002), and the application of BC together with BSM reduced GHGI by 22% in the rice season, although this reduction was not statistically significant (p = 0.158). Further investigation suggested that the inhibitory effect of herbicides on N2O emissions in the wheat field could be ascribed to low soil ammonium nitrogen and less abundance of denitrifying bacteria. The inhibitory effects of separate applications of BC on CH4 emissions in rice fields, in contrast, were linked to high soil nitrate nitrogen and urease activity.

  15. Pesticide management and their residues in sediments and surface and drinking water in the Mekong Delta, Vietnam.

    PubMed

    Toan, Pham Van; Sebesvari, Zita; Bläsing, Melanie; Rosendahl, Ingrid; Renaud, Fabrice G

    2013-05-01

    Public concern in Vietnam is increasing with respect to pesticide pollution of the environment and of drinking water resources. While established monitoring programs in the Mekong Delta (MD) focus on the analysis of organochlorines and some organophosphates, the environmental concentrations of more recently used pesticides such as carbamates, pyrethroides, and triazoles are not monitored. In the present study, household level pesticide use and management was therefore surveyed and combined with a one year environmental monitoring program of thirteen relevant pesticides (buprofezin, butachlor, cypermethrin, α-endosulfan, β-endosulfan, endosulfan-sulfate, fenobucarb, fipronil, isoprothiolane, pretilachlor, profenofos, propanil, and propiconazole) in surface water, soil, and sediment samples. The surveys showed that household level pesticide management remains suboptimal in the Mekong Delta. As a consequence, a wide range of pesticide residues were present in water, soil, and sediments throughout the monitoring period. Maximum concentrations recorded were up to 11.24 μg l(-1) in water for isoprothiolane and up to 521 μg kg(-1) dm in sediment for buprofezin. Annual average concentrations ranged up to 3.34 μg l(-1) in water and up to 135 μg kg(-1) dm in sediment, both for isoprothiolane. Occurrence of pesticides in the environment throughout the year and co-occurrence of several pesticides in the samples indicate a considerable chronic exposure of biota and humans to pesticides. This has a high relevance in the delta as water for drinking is often extracted from canals and rivers by rural households (GSO, 2005, and own surveys). The treatment used by the households for preparing surface water prior to consumption (flocculation followed by boiling) is insufficient for the removal of the studied pesticides and boiling can actually increase the concentration of non-volatile pollutants. PMID:23500396

  16. Nonpoint-source pollutant discharges of the three major tributaries to Reelfoot Lake, west Tennessee, October 1987-September 1989

    USGS Publications Warehouse

    Lewis, Michael E.; Garrett, Jerry W.; Hoos, Anne B.

    1992-01-01

    runof/ Significant diflerences in the mean concentrations of nutrients in runoff were defined between the active agricultural months (April through September) and the inactive months (October through March). Storm-runofS samples were analyzed for II selected triazine herbicides. Alachlor and atrazine were the most commonly detected herbicides. Thirty-two percent of the samples contained detectable levels of alachlor and 93 percent of the samples contained detectable levels of atrazine. Ninety percent of the samples collected during the active agricultural months contained detectable leveki of alachlor and all 29 samples contained detectable levels of atrazine. Sixteen samples exceeded lifetime health-advisory levels for atrazine in drinking water (3 micrograms per liter); two samples collected from the April IS, 1988, storm at North Reelfoot Creek and South Reelfoot Creek contained 42 and 57 micrograms per liter of atrazine, respectively. Concentrations of the other nine triazine herbicides were generally less than the level of detection (0.1 microgram per liter).

  17. Assessment of herbicide leaching risk in two tropical soils of Reunion Island (France).

    PubMed

    Bernard, H; Chabalier, P F; Chopart, J L; Legube, B; Vauclin, M

    2005-01-01

    Application of organic chemicals to a newly irrigated sugarcane (Saccharum officinarum L.) area located in the semiarid western part of Reunion Island has prompted local regulatory agencies to determine their potential to contaminate ground water resources. For that purpose, simple indices known as the ground water ubiquity score (Gustafson index, GUS), the retardation factor (RF), the attenuation factor (AF), and the log-transformed attenuation factor (AFT) were employed to assess the potential leaching of five herbicides in two soil types. The herbicides were alachlor [2-chloro-2',6'-diethyl-N-(methoxy-methy) acetanilide], atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine], diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], 2,4-D [(2,4-dichlorophenoxy) acetic-acid], and triclopyr [((3,5,6-trichloro-2-pyridyl)oxy) acetic-acid]. The soil types were Vertic (BV) and Andepts (BA) Inceptisols, which are present throughout the Saint-Gilles study area on Reunion Island. To calculate the indices, herbicide sorption (K(oc)) and dissipation (half-life, DT50) properties were determined from controlled batch experiments. Water fluxes below the root zone were estimated by a capacity-based model driven by a rainfall frequency analysis performed on a 13-yr data series. The results show a lower risk of herbicide leaching than in temperate regions due to the tropical conditions of the study area. Higher temperatures and the presence of highly adsorbent soils may explain smaller DT50 and higher K(oc) values than those reported in literature concerning temperate environments. Based on the RF values, only 2,4-D and triclopyr appear mobile in the BV soil, with all the other herbicides being classified from moderately to very immobile in both soils. The AFT values indicate that the potential leaching of the five herbicides can be considered as unlikely, except during the cyclonic period (about 40 d/yr) when there is a 2.5% probability of recharge rates equal to or

  18. Interaction of environmental chemicals with the estrogen and progesterone receptors from the oviduct of the American alligator.

    PubMed Central

    Vonier, P M; Crain, D A; McLachlan, J A; Guillette, L J; Arnold, S F

    1996-01-01

    Reports of reproductive abnormalities in the American alligator from Lake Apopka, Florida, have been linked to a spill of DDT and other pesticides suspected of having hormonelike activity. To determine whether environmental chemicals had the potential to function as exogenous hormones in the American alligator, we examined the ability of chemicals to bind the estrogen receptor (aER) and progesterone receptor (aPR) in a protein extract prepared from the oviduct of the alligator. In competition binding assays with [3H]17 beta-estradiol, some DDT metabolites showed inhibition of [3H]17 beta-estradiol binding to aER. A combination of DDTs demonstrated an additive decrease in [3H]17 beta-estradiol binding to aER. Modern-use chemicals such as alachlor, trans-nonachlor, endosulfan, and atrazine also competed with [3H]17 beta-estradiol for binding to the aER. To test the effect of chemicals identified in alligator eggs from Lake Apopka on [3H]17 beta-estradiol binding, we mixed these chemicals at concentrations measured in eggs in the competition binding assay. 2,2-bis(4-chlorophenyl)-N-(methoxymethyl)acetamide (p,p'-DDD) and trans-nonachlor, both found in Lake Apopka, interacted with aER, whereas others such as chlordane and toxaphene did not. Surprisingly, combinations of these chemicals decreased [3H]17 beta-estradiol binding in a greater than additive manner. To assess the ability of chemicals to interact with aPR, we performed commpetition binding assays with the synthetic progestin [3H]R5020. Most of the chemicals tested did not reduce [3H]R5020 binding to aPR, whereas endosulfan, alachlor, and kepone inhibited binding. These results provide the first evidence that environmental chemicals bind the aER and aPR from the American alligator, supporting the hypothesis that the reported reproductive abnormalities may be related to the modulation of endocrine-related responses. The findings that combinations of chemicals demonstrated a greater than additive interaction with

  19. Phosphatidylcholine Specific PLC-Induced Dysregulation of Gap Junctions, a Robust Cellular Response to Environmental Toxicants, and Prevention by Resveratrol in a Rat Liver Cell Model

    PubMed Central

    Sovadinova, Iva; Babica, Pavel; Böke, Hatice; Kumar, Esha; Wilke, Andrew; Park, Joon-Suk; Trosko, James E.; Upham, Brad L.

    2015-01-01

    Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. In conclusion: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap

  20. Coupling solid-phase extraction and enzyme-linked immunosorbent assay for ultratrace determination of herbicides in pristine water

    USGS Publications Warehouse

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

    1993-01-01

    Solid-phase extraction (SPE) and enzyme-linked immunosorbent assay (ELISA) were coupled for automated trace analysis of pristine water samples containing 2-chloro-4-ethylamino-6-isopropylamine-s-triazine (atrazine) and 2-chloro-2???,6???-diethyl-N-(methoxymethyl)acetanilide (alachlor). The isolation of the two herbicides on a C18-resin involved the selection of an elution solvent that both removes interfering substances and is compatible with ELISA. Ethyl acetate was selected as the elution solvent followed by a solvent exchange with methanol/water (20/80, % v/v). The SPE-ELISA method has a detection limit of 5.0 ng/L (5 ppt), >90% recovery, and a relative standard deviation of ??10%. The performance of a microtiter plate-based ELISA and a magnetic particle-based ELISA coupled to SPE was also evaluated. Although the sensitivity of the two ELISA methods was comparable, the precision using magnetic particles was improved considerably (??10% versus ??20%) because of the faster reaction kinetics provided by the magnetic particles. Finally, SPE-ELISA and isotope dilution gas chromatography/ mass spectrometry correlated well (correlation coefficient of 0.96) for lake-water samples. The SPE-ELISA method is simple and may have broader applications for the inexpensive automated analysis of other contaminants in water at trace levels.

  1. Plan of study to determine the effect of changes in herbicide use on herbicide concentrations in Midwestern streams, 1989-94

    USGS Publications Warehouse

    Goolsby, Donald A.; Boyer, Laurie L.; Battaglin, William A.

    1994-01-01

    An approach was developed to determine if recent changes in the use of herbicides has affected herbicide concentrations in Midwestern streams. This approach also provides a plan to determine if the abnormally high rainfall and flooding in 1993 has an effect on nitrate concentrations in 1994 in streams that flooded in 1993. The approach involves sampling 53 stream sites, 50 of which were sampled in 1989 and 1990 as part of a reconnaissance to determine the geographic and seasonal distribution of herbicides in 10 Midwestern States. Sites will be sampled twice, once prior to application of herbicides, in March or early April, and once during the first runoff event after application of herbicides. Samples will be analyzed for 11 herbicide and 2 atrazine metabolites by gas chromatography/mass spectrometry. Samples will also be analyzed for ESA (an alachlor metabolite), two cyanazine metabolites, and nutrients. Changes to the manufacturers' label have decreased the maximum recommended application rate for atrazine on com and sorghum by about 50 percent since the 1989-90 study. Conversely, the use of other herbicides, such as cyanazine, has increased by more than 25 percent since 1989. Statistical procedures such as Wilcoxon signed rank tests for paired samples will be used to determine if the distributions of herbicide and nitrate concentrations in 1994 are different from those measured in 1989 and 1990.

  2. The impact of agricultural practices on shallow groundwater in the Bluegrass Region of Kentucky

    SciTech Connect

    Hampson, S.K.; Sendlein, L.V.A. . Dept. of Geological Sciences)

    1993-03-01

    To study the effects of agricultural practices on the groundwater quality of the Inner Bluegrass Region of Kentucky, a large representative row crop and livestock production operation was chosen. Located in southeastern Bourbon County, the study area encompasses a 1,400 acre watershed underlain by limestones and shales of the Ordovician age Lexington Limestone Formation. Sampling and testing of surface water, ephemeral, and perennial spring waters began in the area in October, 1989. At crop and pasture micro-sites within the study area, nests containing porous-cup lysimeters and monitoring wells were installed prior to the 1992 growing season. Samples from the nest locations were analyzed for Nitrate-N, triazines, metolochlor, carbofuran, alachlor, and 2,4-D. While only ten per cent of the total samples from the study area showed triazine or Nitrate-N concentrations in excess of EPA limits, greater than 80 per cent of the samples showed concentrations of triazines above detection limits, and greater than 70 per cent of the samples contained concentrations of Nitrate-N above detection limits. Occurrences of detectable concentrations of triazines and Nitrate-N were more frequent at crop-site nests, than at pasture-site nests. Nests at both the crop and pasture sites indicated dilution of Nitrate-N and triazine concentrations with depth.

  3. Multiresidue method for the quantitation of 20 pesticides in aquatic products.

    PubMed

    Cho, Ha Ra; Park, Jun Seo; Kim, Junghyun; Han, Sang Beom; Choi, Yong Seok

    2015-12-01

    As the consumption of aquatic products increased, the need for regulation of pesticide residues in aquatic products also emerged. Thus, in this study, a scheduled multiple reaction monitoring (sMRM) method employing a novel extraction and purification step based on QuEChERS with EDTA was developed for the simultaneous quantitation of 20 pesticides (alachlor, aldicarb, carbofuran, diazinon, dimethoate, dimethomorph, ethoprophos, ferimzone, fluridone, hexaconazole, iprobenfos, malathion, methidathion, methiocarb, phenthoate, phosalone, phosmet, phosphamidon, pirimicarb, and simazine) in aquatic products. Additionally, the present method was validated in the aspects of specificity, linearity (r ≥ 0.980), sensitivity (the limit of quantitation (LOQ) ≤ 5 ng/g), relative standard deviation, RSD (1.0% ≤ RSD ≤ 19.4%), and recovery (60.1% ≤ recovery ≤ 117.9%). Finally, the validated method was applied for the determination of the 20 pesticide residues in eel and shrimp purchased from local food markets. In the present study, QuEChERS with EDTA was successfully expanded to residual pesticide analysis for the first time. The present method could contribute to the rapid and successful establishment of the positive list system in South Korea. PMID:26466578

  4. Water: pesticides in ground water beneath irrigated farmland in Nebraska, August 1978

    SciTech Connect

    Spalding, R.F.; Junk, G.A.; Richard, J.J.

    1980-09-01

    During the 1978 irrigation season, 14 ground water samples were collected in the Central Platte region of Nebraska, an area known to have high nitrate-nitrogen (NO-N) levels, and analyzed for the presence of 13 pesticide residues. Atrazine levels ranged from 0.06 ..mu..g/liter to 3.12 ..mu..g/liter and were correlated to NO/sub 3/-N concentrations with a coefficient of r = +0.55. Nitrate-nitrogen concentrations were measured as indicators of deep percolation from irrigated lands and ranged from 17.1 mg/liter to 34.3 mg/liter. Alachlor levels ranged from <0.01 ..mu..g/liter to 0.71 ..mu..g/liter. The amounts of 2,4-D were indeterminate because of experimental problems. Levels of the herbicides silvex and EPTC were below the limits of detectability. Levels of the oragnochlorine insecticides endrin, ..gamma..-BHC (lindane), dieldrin, DDT and its primary metabolite DDE, heptachlor and its primary derivative heptachlor epoxide, and methoxychlor were all below the detectable limits of 0.005 and 0.010 ..mu..g/liter.

  5. Pesticides in ground water beneath irrigated farmland in Nebraska, August 1978

    SciTech Connect

    Spalding, R.F.; Junk, G.A.; Richard, J.J.

    1980-09-01

    During the 1978 irrigation season, 14 ground water samples were collected in the Central Platte region of Nebraska, an area known to have high nitrate-nitrogen (NO/sub 3/--N) levels, and analyzed for the presence of 13 pesticide residues. Atrazine levels ranged from 0.06 microgram/liter to 3.12 microgram/liter and were correlated to NO/sub 3/--N concentrations with a coefficient of r . +0.55. Nitrate-nitrogen concentrations were measured as indicators of deep percolation from irrigated lands and ranged from 17.1 mg/liter to 34.3 mg/liter. Alachlor levels ranged from less than 0.01 microgram/liter to 0.71 microgram/liter. The amounts of 2,4-D were indeterminate because of experimental problems. Levels of the herbicides silvex and EPTC were below the limits of detectability. Levels of the organochlorine insecticides endrin, gamma-BHC (lindane), dieldrin, DDT and its primary metabolite DDE, heptachlor and its primary derivative heptachlor epoxide, and methoxychlor were all below the detectable limits of 0.005-0.010 microgram/liter.

  6. Quality of surface water before implementation of a flood-control project in Chaska, Minnesota

    USGS Publications Warehouse

    Tornes, L.H.

    1981-01-01

    Samples were collected for 1 year from East Creek, Chaska Creek, and Courthouse Lake in Chaska, Minnesota, to determine the water quality before implementation of a flood-control project proposed by the U.S. Army Corps of Engineers. The creeks had similar water-quality characteristics. Data indicate that ground water may be the primary source of dissolved solids, sulfate, chloride, and chromium in the creeks. The pesticides alachlor, atrazine, simazine, and 2,4-D were found in water samples from both creeks but were well below the lethal concentrations for fish. Courthouse Lake, a 57-foot-deep stream-trout lake, had a mean summer trophic-state index of 35. Phytoplankton populations varied seasonally, and blue-green algae were predominant only in late summer. The algal-pollution index was highest in late summer, but did not provide evidence of high organic pollution. The apparently successful recovery of Courthouse Lake from past inundations by Minnesota River floodwaters having total phosphorus concentrations as high as 0.66 milligram per liter suggests that the lake, in time, will also recover from the added runoff expected as a result of implementing the flood-control project. The runoff could temporarily raise the total phosphorus concentration in the lake from 0.03 to 0.12 milligram per liter and raise the spring trophic-state index from 49 to 69.

  7. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.

    1991-01-01

    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO[sub 2] to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO[sub 2] is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO[sub 2] into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  8. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.

    1991-12-31

    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO{sub 2} to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO{sub 2} is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO{sub 2} into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  9. Massive immuno multiresidue screening of water pollutants.

    PubMed

    Dobosz, Paulina; Morais, Sergi; Bonet, Emilio; Puchades, Rosa; Maquieira, Ángel

    2015-10-01

    An immuno multiresidue screening assay in microarray format for the determination of complex chemical mixtures at the microgram per liter level, using antibody-functionalized gold nanoparticles, is presented. The analytical method relies on the use of a cocktail of nanogold-labeled specific antibodies, acting as recognition and detection species. The concept of multireside screening is proved by developing a multiplex assay on a compact disk support for the determination of 2-(2,4,5-trichlorophenoxy)propionic acid, 3-phenoxybenozic acid, 4-nitrophenol, alachlor, atrazine, azoxystrobin, chlorpyrifos, diazinon, diuron, endosulfan, fenthion, forchlorfenuron, imidacloprid, malathion, pentachlorophenol, pyraclostrobin, sulfasalazine, and triclosan, achieving detection limits of 0.07, 0.24, 10.9, 0.21, 0.14, 0.11, 0.11, 102, 0.36, 1.8, 1.7, 0.06, 0.08, 5.8, 1.0, 0.39, 0.003, and 12 μg/L, respectively. Due to the selectivity of the antibody-functionalized nanoparticles, the developed screening methodology allows the simultaneous determination of mixtures of water pollutants in a 10-plex configuration. The analytical performances were compared with those of reference chromatographic methods by the analysis of spiked water samples, the sensitivity and recovery results being in good agreement. The presented screening approach directly quantifies the concentration of complex chemical mixtures without sample treatment or preconcentration steps in a total time of 35 min. PMID:26390221

  10. Response of sago pondweed, a submerged aquatic macrophyte, to herbicides in three laboratory culture systems

    USGS Publications Warehouse

    Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Norman, C.M.

    1991-01-01

    The phytotoxicity of atrazine, paraquat, glyphosate, and alachlor to sago pondweed (Potamogeton pectinatus), a submerged aquatic macrophyte, was tested under three types of laboratory culture conditions. In each case, tests were conducted in static systems, the test period was four weeks, and herbicide exposure was chronic, resulting from a single addition of herbicide to the test vessels at the beginning of the test period. The three sets of test conditions employed were(1) axenic cultures in 125-mL flasks containing a nutrient media and sucrose; (2) a microcosm system employing 18.9-L buckets containing a sand, shell, and peat substrate; and (3) an algae-free system employing O.95-L jars containing reconstituted freshwater and a nutrient agar substrate. The primary variable measured was biomass production. Plants grew well in all three test systems, with biomass of untreated plants increasing by a factor of about 5 to 6.5 during the four-week test period. Biomass production in response to herbicide exposure differed significantly among culture systems, which demonstrates the need for a standardized testing protocol for evaluating the effects of toxics on submerged aquatic plants.

  11. Liposome-enhanced immunomigration strips for field screening of toxic chemicals

    SciTech Connect

    Roberts, M.A.; Reeves, S.G.; Siebert, S.T.; Durst, R.A. |

    1995-12-31

    The use of liposomes containing encapsulated dye to provide instantaneous enhancement of signals generated in competitive immunoassays is described for two model analytes of environmental concern, alachlor and PCBs. The application of this strategy to field assays is demonstrated utilizing two complementary assay designs based on immunomigration along a nitrocellulose test strip. The liposome immunocompetition (LIC) assay involves immobilizing antibodies onto a strip and allowing the sample and analyte-tagged, dye-containing liposomes to migrate through this zone. Liposomes passing through without binding, as a result of competition from the sample analyte, are totally bound in an upper collection region, and the degree of color in this region is proportional to the analyte concentration. The liposome immunoaggregation (LIA) assay detects antibody-liposome association in a homogeneous incubation solution into which a test strip is subsequently placed. Antibody-bound aggregates of liposomes are trapped on the porous nitrocellulose test strip at the level of the meniscus, due to mechanisms that will be discussed. However, sample analyte competitively inhibits antibody-liposome association and, therefore, a proportional amount of unbound liposomes will escape entrapment on the nitrocellulose and can then be collected and quantitated in a measurement zone. This latter technique shows enhanced sensitivity, but involves an extra incubation step. Therefore these two techniques may be used interchangeably depending on the sensitivity and time requirements of a particular project. Prototype assay designs are demonstrated here and emerging detection strategies are discussed.

  12. Analysis of selected herbicide metabolites in surface and ground water of the United States

    USGS Publications Warehouse

    Scribner, E.A.; Thurman, E.M.; Zimmerman, L.R.

    2000-01-01

    One of the primary goals of the US Geological Survey (USGS) Laboratory in Lawrence, Kansas, is to develop analytical methods for the analysis of herbicide metabolites in surface and ground water that are vital to the study of herbicide fate and degradation pathways in the environment. Methods to measure metabolite concentrations from three major classes of herbicides - triazine, chloroacetanilide and phenyl-urea - have been developed. Methods for triazine metabolite detection cover nine compounds: six compounds are detected by gas chromatography/mass spectrometry; one is detected by high-performance liquid chromatography with diode-array detection; and eight are detected by liquid chromatography/mass spectrometry. Two metabolites of the chloroacetanilide herbicides - ethane sulfonic acid and oxanilic acid - are detected by high-performance liquid chromatography with diode-array detection and liquid chromatography/mass spectrometry. Alachlor ethane sulfonic acid also has been detected by solid-phase extraction and enzyme-linked immunosorbent assay. Six phenylurea metabolites are all detected by liquid chromatography/mass spectrometry; four of the six metabolites also are detected by gas chromatography/mass spectrometry. Additionally, surveys of herbicides and their metabolites in surface water, ground water, lakes, reservoirs, and rainfall have been conducted through the USGS laboratory in Lawrence. These surveys have been useful in determining herbicide and metabolite occurrence and temporal distribution and have shown that metabolites may be useful in evaluation of non-point-source contamination. Copyright (C) 2000 Elsevier Science B.V.

  13. Aquatic risk assessment of priority and other river basin specific pesticides in surface waters of Mediterranean river basins.

    PubMed

    Silva, Emília; Daam, Michiel A; Cerejeira, Maria José

    2015-09-01

    To meet good chemical and ecological status, Member States are required to monitor priority substances and chemicals identified as substances of concern at European Union and local/river-basin/national level, respectively, in surface water bodies, and to report exceedances of the environmental quality standards (EQSs). Therefore, standards have to be set at national level for river basin specific pollutants. Pesticides used in dominant crops of several agricultural areas within the catchment of Mediterranean river basins ('Mondego', 'Sado' and 'Tejo', Portugal) were selected for monitoring, in addition to the pesticides included in priority lists defined in Europe. From the 29 pesticides and metabolites selected for the study, 20 were detected in surface waters of the river basins, seven of which were priority substances: alachlor, atrazine, chlorfenvinphos, chlorpyrifos, endosulfan, simazine and terbutryn, all of which exceeded their respective EQS values. QSs for other specific pollutants were calculated using different extrapolation techniques (i.e. deterministic or probabilistic) largely based on the method described in view of the Water Framework Directive. Non-acceptable aquatic risks were revealed for molinate, oxadiazon, pendimethalin, propanil, terbuthylazine, and the metabolite desethylatrazine. Implications of these findings for the classification of the ecological status of surface water bodies in Portugal and at the European level are discussed. PMID:26002046

  14. Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

    PubMed Central

    Raina, Renata; Hall, Patricia

    2008-01-01

    A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) with gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode with both electron ionization (EI) and negative-ion chemical ionization (NCI) are presented for over 50 pesticides ranging from organochlorines (OCs), organophosphorus pesticides (OPs) and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin). The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg μL−1 (<100 pg m−3 in air). No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5–10 pg μL−1) along with best confirmation (<25% RSD of ion ratio), while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion). GC-EI/SRM at concentration <100 pg μL−1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1–10 pg μL−1) for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT). PMID:19609395

  15. Pesticides removal in the process of drinking water production.

    PubMed

    Ormad, M P; Miguel, N; Claver, A; Matesanz, J M; Ovelleiro, J L

    2008-03-01

    The aim of this research work was to study the effectiveness of the treatments commonly used in drinking water plants in Spain to degrade 44 pesticides systematically detected in the Ebro River Basin. The pesticides studied are: alachlor, aldrin, ametryn, atrazine, chlorfenvinfos, chlorpyrifos, pp'-DDD, op'-DDE, op'-DDT, pp'-DDT, desethylatrazine, 3,4-dichloroaniline, 4,4'-dichlorobenzophenone, dicofol, dieldrin, dimethoate, diuron, alpha-endosulphan, endosulphan-sulphate, endrin, alpha-HCH, beta-HCH, gamma-HCH, delta-HCH, heptachlor, heptachlor epoxide A, heptachlor epoxide B, hexachlorobenzene, isodrin, 4-isopropylaniline, isoproturon, metholachlor, methoxychlor, molinate, parathion methyl, parathion ethyl, prometon, prometryn, propazine, simazine, terbuthylazine, terbutryn, tetradifon and trifluralin. The techniques applied are: preoxidation by chlorine or ozone, chemical precipitation with aluminium sulphate and activated carbon adsorption. Oxidation by chlorine removes 60% of the studied pesticides, although combining this technique with a coagulation-flocculation-decantation process is more effective. The disadvantage of this treatment is the formation of trihalomethanes. Oxidation by ozone removes 70% of the studied pesticides. Although combination with a subsequent coagulation-flocculation-decantation process does not improve the efficiency of the process, combination with an activated-carbon absorption process gives rise to 90% removal of the studied pesticides. This technique was found to be the most efficient among the techniques studied for degrading the majority of the studied pesticides. PMID:18023468

  16. Chemical stress sensitive luminescent human cells: Molecular biology approach using inducible Drosophila melanogaster hsp22 promoter

    SciTech Connect

    Mandon, C.A.; Diaz, C.; Arrigo, A.-P.; Blum, L.J. . E-mail: Loic.Blum@univ-lyon1.fr

    2005-09-23

    A whole-cell bioassay has been developed for the total toxicity testing of liquid samples. The method is based on the induction of the bioluminescent activity of genetically manipulated mammalian cells. For that purpose, transfection was used to introduce, in HeLa cells, a DNA sensing element that responds to chemical stress agents (heavy metals, genotoxic agents, and endocrine-disrupting chemicals). Such element was designed to direct the expression of a reporting gene (firefly luciferase) through the activation of Drosophila melanogaster hsp22 promoter. A molecular approach was conducted to optimize hsp22 promoter element in order to decrease the background expression level of the reporting gene and to increase the sensitivity of the bioassay for testing endocrine disruptors. As a result, in the presence of 20-100 {mu}M cadmium chloride, a 6-fold increase in luciferase expression was obtained using a specially designed truncated hsp22 promoter construction. The following chemicals known to be found in the polluted samples were tested: CdCl{sub 2}, Cd(NO{sub 3}){sub 2}, NaAsO{sub 2}, alachlore, fentine acetate, thiram, and maneb. The stressing effect of each of them was sensitively detected by the present bioassay in the 0.05-50 {mu}M concentration range.

  17. Light-sensitized decontamination of ground-water hazardous chemicals. Technical report (Final)

    SciTech Connect

    Larson, R.A.; Schlauch, M.B.; Ellis, D.D.; Marley, K.A.; Ju, H.L.

    1988-01-01

    The use of sunlight, oxygen, and dissolved organic compounds active as 'photosensitizers' (substances capable of absorbing sunlight and transforming it into chemically useful forms) is a promising treatment for contaminated waters. Light is absorbed by the sensitizing substance, raising it to a higher energy excited state. Reaction with the excited state substance converts molecular oxygen to a form much more reactive with dissolved compounds. Riboflavin (Vitamin B2), a naturally occurring compound and a known photosensitizer, was investigated for use in this process. A series of kinetic experiments explored its ability to photodegrade several aromatic compounds, phenols and anilines, that are related to some herbicides (such as carbaryl, 2, 4-D, alachlor, atrazine, and trifluralin) commonly found in polluted waters. It was found that riboflavin when added to solutions of phenols or anilines greatly accelerated the rate of their loss in the presence of light. The sensitized photolysis rates increased in the absence of oxygen, suggesting a mechanism involving direct energy or electron transfer between flavin excited states and acceptor molecules. In addition, it was found that some iron salts were very significant promoters of photodestruction of the triazine herbicide, atrazine.

  18. Direct surface analysis of pesticides on soil, leaves, grass, and stainless steel by static secondary ion mass spectrometry

    SciTech Connect

    Ingram, J.C.; Groenewold, G.S.; Appelhans, A.D.; Delmore, J.E.; Olson, J.E.; Miller, D.L.

    1997-02-01

    Direct surface analyses by static secondary ion mass spectrometry (SIMS) were performed for the following pesticides adsorbed on dandelion leaves, grass, soil, and stainless steel samples: alachlor, atrazine, captan, carbofuran, chlorpyrifos, chlorosulfuron, chlorthal-dimethyl, cypermethrin, 2,4-D, diuron, glyphosate, malathion, methomyl, methyl arsonic acid, mocap, norflurazon, oxyfluorfen, paraquat, temik, and trifluralin. The purpose of this study was to evaluate static SIMS as a tool for pesticide analysis, principally for use in screening samples for pesticides. The advantage of direct surface analysis compared with conventional pesticide analysis methods is the elimination of sample pretreatment including extraction, which streamlines the analysis substantially; total analysis time for SIMS analysis was ca. 10 min/sample. Detection of 16 of the 20 pesticides on all four substrates was achieved. Of the remaining four pesticides, only one (trifluralin) was not detected on any of the samples. The minimum detectable quantity was determined for paraquat on soil in order to evaluate the efficacy of using SIMS as a screening tool. Paraquat was detected at 3 pg/mm{sup 2} (c.a. 0.005 monolayers). The results of these studies suggest that SIMS is capable of direct surface detection of a range of pesticides, with low volatility, polar pesticides being the most easily detected. 25 refs., 2 figs., 2 tabs.

  19. Pesticides and their metabolites in selected surface-water public supplies in New York State, 1999

    USGS Publications Warehouse

    Phillips, Patrick J.; Eckhardt, D.A.; Smith, M.A.; Rosenmann, Larry

    2000-01-01

    Sixteen different pesticides or their metabolites (degradations products) where detected in water samples collected in 1999 from three networks of lakes and reservoirs in upstate New York that are sources of public water supply. The networks sampled included the New York City network (10 reservoirs); the Finger Lakes-Great Lakes network (three Finger Lakes and two Great Lakes that supply large and small cities) and the western New York reservoir network (three reservoirs that supply small cities or towns). The concentrations of the compounds detected in the samples generally were low. Only a few of the compounds detected had a concentration exceeding 1 mg/L (microgram per liter), and no compounds detected in the New York City reservoirs network had concentrations exceeding 0.05 mg/L. None of the compounds detected exceeded any Federal or State water-quality standard. Compounds that were most frequently detected, and whose concentrations were highest, were the three herbicides atrazine, metolachlor, and simazine, and two herbicide metabolites (the atrazine metabolite deethylatrazine, and the metolachlor metabolite metolachlor ESA). Most of these compounds, or their parent compounds, are used on corn or other row crops. Median total pesticide and metabolite concentration for each network ranged from less than 0.02 mg/L for the New York City reservoirs network to more than 2 mg/L for the western New York reservoir network; the median for the Finger Lakes.Great Lakes network was about 0.1 mg/L. These differences reflect the amount of agricultural land use within each of the three networks, although other factors can affect pesticide and metabolite concentrations. The watersheds of the New York City reservoirs have the lowest percentage of agricultural land, and those of the western New York reservoirs have the highest. The highest herbicide or herbicide-metabolite concentrations among the New York City reservoirs were in the Cannonsville reservoir, whose watershed has

  20. Dissolved pesticide concentrations entering the Sacramento-San Joaquin Delta from the Sacramento and San Joaquin Rivers, California, 2012-13

    USGS Publications Warehouse

    Orlando, James L.; McWayne, Megan; Sanders, Corey; Hladik, Michelle

    2014-01-01

    Surface-water samples were collected from the Sacramento and San Joaquin Rivers where they enter the Sacramento–San Joaquin Delta, and analyzed by the U.S. Geological Survey for a suite of 99 current-use pesticides and pesticide degradates. Samples were collected twice per month from May 2012 through July 2013 and from May 2012 through April 2013 at the Sacramento River at Freeport, and the San Joaquin River near Vernalis, respectively. Samples were analyzed by two separate laboratory methods by using gas chromatography with mass spectrometry or liquid chromatography with tandem mass spectrometry. Method detection limits ranged from 0.9 to 10.5 nanograms per liter (ng/L). A total of 37 pesticides and degradates were detected in water samples collected during the study (18 herbicides, 11 fungicides, 7 insecticides, and 1 synergist). The most frequently detected pesticides overall were the herbicide hexazinone (detected in 100 percent of the samples); 3,4-dichloroaniline (97 percent), which is a degradate of the herbicides diuron and propanil; the fungicide azoxystrobin (83 percent); and the herbicides diuron (72 percent), simazine (66 percent), and metolachlor (64 percent). Insecticides were rarely detected during the study. Pesticide concentrations varied from below the method detection limits to 984 ng/L (hexazinone). Twenty seven pesticides and (or) degradates were detected in Sacramento River samples, and the average number of pesticides per sample was six. The most frequently detected compounds in these samples were hexazinone (detected in 100 percent of samples), 3,4-dichloroaniline (97 percent), azoxystrobin (88 percent), diuron (56 percent), and simazine (50 percent). Pesticides with the highest detected maximum concentrations in Sacramento River samples included the herbicide clomazone (670 ng/L), azoxystrobin (368 ng/L), 3,4-dichloroaniline (364 ng/L), hexazinone (130 ng/L), and propanil (110 ng/L), and all but hexazinone are primarily associated with

  1. Comparison of three pesticide fate models with respect to the leaching of two herbicides under field conditions in an irrigated maize cropping system.

    PubMed

    Marín-Benito, J M; Pot, V; Alletto, L; Mamy, L; Bedos, C; Barriuso, E; Benoit, P

    2014-11-15

    The ability of three models (PEARL, MACRO and PRZM) to describe the water transfer and leaching of the herbicides S-metolachlor and mesotrione as observed in an irrigated maize monoculture system in Toulouse area (France) was compared. The models were parameterized with field, laboratory and literature data, and pedotransfer functions using equivalent parameterization to better compare the results and the performance of the models. The models were evaluated and compared from soil water pressure, water content and temperature data monitored at 0.2, 0.5 and 1 m depth, together with water percolates and herbicide concentrations measured in a tension plate lysimeter at 1 m depth. Some hydraulic (n, θ(s)) parameters and mesotrione DT50 needed calibration. After calibration, the comparison of the results obtained by the three models indicated that PRZM was not able to simulate properly the water dynamic in the soil profile. On the contrary, PEARL and MACRO simulated generally quite well the observed water pressure head and volumetric water content at the three different depths during wetting periods (e.g. irrigated cropping period) while a poorest performance was obtained for drying periods (fallow period with bare soil and beginning of crop period). Similar water flow dynamics were simulated by PEARL and MACRO in the soil profile although in general, and due to a higher evapotranspiration in MACRO, PEARL simulated a wetter soil than MACRO. For the whole simulated period, the performance of all models to simulate water leaching at 1m depth was poor, with an overestimation of the total water volume measured in the lysimeter (ranging from 2.2 to 6.6 times). By contrast, soil temperature was properly reproduced by the three models. The models were able to simulate the leaching of herbicides at 1m depth in similar appearance time and order of magnitude as field observations. Cumulative observed and simulated mesotrione losses by leaching were consistently higher than the

  2. Towards the field-scale experiments and numerical modeling of pesticides in tropical soils

    NASA Astrophysics Data System (ADS)

    Dusek, J.; Ray, C.; Sanda, M.; Vogel, T.; Green, R.; Loo, B.

    2004-12-01

    Intensive use of pesticides in agriculture inevitably poses an increased threat to groundwater. Recent findings of pesticide residues in selected drinking water wells in Hawaii brings further attention to this problem since the primary source for potable water in Hawaii is groundwater from basal or dike-confined aquifers. A challenging research project was carried out at the University of Hawaii to elucidate potential impacts of selected pesticides on groundwater and to understand pesticide behavior in tropical soils. The major outcome of the project will be a recommendation to the Hawaii Department of Agriculture whether to restrict or approve these pesticide products entering Hawaii's agricultural market. Three sites on Oahu, one on Maui, and one on Kauai were selected for field evaluation of leaching. The soil types on Oahu are Wahiawa Oxisol (Poamoho), Molokai Oxisol (Kunia), and Waialua Vertisol (Waimanalo). The soil at Kula, Maui is an andisol (loam of Kula series) and that at Mana, Kauai is a Vertisol of Malama series. Three herbicides (S-metolachlor, imazaquin, sulfometuron methyl), one fungicide (trifloxystrobin), and one insecticide (imidacloprid) were used in our study. In addition, a commonly used herbicide (atrazine) and potassium bromide tracer were applied as reference chemicals. After spraying, the plots were covered with straw to decrease evaporation from bare soil surface and irrigated with aerial sprinklers for a period of 16 weeks. Disturbed soil samples from various depths were taken at regular intervals for pesticide analysis. Water flow dynamics was monitored with TDR probes and tensiometers installed at three depths. Weather data were acquired simultaneously. In-situ measurements of unsaturated hydraulic conductivity were done using a tension disc infiltrometer. Laboratory experiments of soil-water retention, as well as degradation, sorption, and column displacement experiments for the selected pesticides were conducted. Hence, comprehensive

  3. 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

  4. Pesticides in wells in agricultural and urban areas of the Hudson River basin

    USGS Publications Warehouse

    Phillips, P.J.; Wall, G.R.; Ryan, C.M.

    2000-01-01

    Ground-water samples from four monitoring well networks in the Hudson River basin were analyzed for pesticides (detection limits from 0.001 to 0.018 ??g/L). The most frequent detections were in samples from shallow depths beneath agricultural areas. Concentrations of pesticides in samples from all four networks were generally below 0.10 ??g/L, and the concentration of only one (cyanazine) exceeded any maximum contaminant levels or health advisory levels set by the U.S. Environmental Protection Agency. The well networks represented two land-use and two well-depth categories as follows: 1. agricultural shallow wells - two springs and 14 wells finished less than 15 m below land surface in unconfined unconsolidated aquifers beneath agricultural land, 2. agricultural water-supply-wells - 31 wells finished 1.8 to 120 m below land surface in unconsolidated unconfined aquifers and bedrock aquifers beneath agricultural land 3. urban/residential shallow-wells - 17 wells finished less than 16 m below land surface in unconfined unconsolidated aquifers beneath urban or residential land; and 4. urban/residential water-supply-wells - 25 water-supply or observation wells finished 5 to 113 m below land surface in unconfined, unconsolidated aquifers and bedrock aquifers beneath urban or residential land. Pesticides were detected in 69 percent of the samples from the agricultural shallow wells, in 29 percent of the samples from the agricultural water-supply wells, in no samples from the urban/residential shallow wells, and in 16 percent of the samples from the urban/residential water-supply wells. At least half of the samples from the agricultural shallow-well network contained two herbicides (atrazine and metolachlor) and one herbicide metabolite (deethylatrazine); other pesticides detected in samples from this network included metribuzin, cyanazine, EPTC, and pendimethalin. Samples from the agricultural water-supply wells contained two insecticides (diazinon and malathion), two

  5. Pesticide pollution of multiple drinking water sources in the Mekong Delta, Vietnam: evidence from two provinces.

    PubMed

    Chau, N D G; Sebesvari, Z; Amelung, W; Renaud, F G

    2015-06-01

    Pollution of drinking water sources with agrochemicals is often a major threat to human and ecosystem health in some river deltas, where agricultural production must meet the requirements of national food security or export aspirations. This study was performed to survey the use of different drinking water sources and their pollution with pesticides in order to inform on potential exposure sources to pesticides in rural areas of the Mekong River delta, Vietnam. The field work comprised both household surveys and monitoring of 15 frequently used pesticide active ingredients in different water sources used for drinking (surface water, groundwater, water at public pumping stations, surface water chemically treated at household level, harvested rainwater, and bottled water). Our research also considered the surrounding land use systems as well as the cropping seasons. Improper pesticide storage and waste disposal as well as inadequate personal protection during pesticide handling and application were widespread amongst the interviewed households, with little overall risk awareness for human and environmental health. The results show that despite the local differences in the amount and frequency of pesticides applied, pesticide pollution was ubiquitous. Isoprothiolane (max. concentration 8.49 μg L(-1)), fenobucarb (max. 2.32 μg L(-1)), and fipronil (max. 0.41 μg L(-1)) were detected in almost all analyzed water samples (98 % of all surface samples contained isoprothiolane, for instance). Other pesticides quantified comprised butachlor, pretilachlor, propiconazole, hexaconazole, difenoconazole, cypermethrin, fenoxapro-p-ethyl, tebuconazole, trifloxystrobin, azoxystrobin, quinalphos, and thiamethoxam. Among the studied water sources, concentrations were highest in canal waters. Pesticide concentrations varied with cropping season but did not diminish through the year. Even in harvested rainwater or purchased bottled water, up to 12 different pesticides were detected at

  6. 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.

  7. Urban contribution of pharmaceuticals and other organic wastewater contaminants to streams during differing flow conditions

    USGS Publications Warehouse

    Kolpin, D.W.; Skopec, M.; Meyer, M.T.; Furlong, E.T.; Zaugg, S.D.

    2004-01-01

    During 2001, 76 water samples were collected upstream and downstream of select towns and cities in Iowa during high-, normal- and low-flow conditions to determine the contribution of urban centers to concentrations of pharmaceuticals and other organic wastewater contaminants (OWCs) in streams under varying flow conditions. The towns ranged in population from approximately 2000 to 200 000. Overall, one or more OWCs were detected in 98.7% of the samples collected, with 62 of the 105 compounds being found. The most frequently detected compounds were metolachlor (pesticide), cholesterol (plant and animal sterol), caffeine (stimulant), β-sitosterol (plant sterol) and 1,7-dimethylxanthine (caffeine degradate). The number of OWCs detected decreased as streamflow increased from low- (51 compounds detected) to normal- (28) to high-flow (24) conditions. Antibiotics and other prescription drugs were only frequently detected during low-flow conditions. During low-flow conditions, 15 compounds (out of the 23) and ten compound groups (out of 11) detected in more than 10% of the streams sampled had significantly greater concentrations in samples collected downstream than in those collected upstream of the urban centers. Conversely, no significant differences in the concentrations were found during high-flow conditions. Thus, the urban contribution of OWCs to streams became progressively muted as streamflow increased.

  8. A national reconnaissance for pharmaceuticals and other organic wastewater contaminants in the United States - II) Untreated drinking water sources

    USGS Publications Warehouse

    Focazio, M.J.; Kolpin, D.W.; Barnes, K.K.; Furlong, E.T.; Meyer, M.T.; Zaugg, S.D.; Barber, L.B.; Thurman, M.E.

    2008-01-01

    Sixty-three of the 100 targeted chemicals were detected in at least one water sample. Interestingly, in spite of the low detection levels 60% of the 36 pharmaceuticals (including prescription drugs and antibiotics) analyzed were not detected in any water sample. The five most frequently detected chemicals targeted in surface water were: cholesterol (59%, natural sterol), metolachlor (53%, herbicide), cotinine (51%, nicotine metabolite), β-sitosterol (37%, natural plant sterol), and 1,7-dimethylxanthine (27%, caffeine metabolite); and in ground water: tetrachloroethylene (24%, solvent), carbamazepine (20%, pharmaceutical), bisphenol-A (20%, plasticizer), 1,7-dimethylxanthine (16%, caffeine metabolite), and tri (2-chloroethyl) phosphate (12%, fire retardant). A median of 4 compounds were detected per site indicating that the targeted chemicals generally occur in mixtures (commonly near detection levels) in the environment and likely originate from a variety of animal and human uses and waste sources. These data will help prioritize and determine the need, if any, for future occurrence, fate and transport, and health-effects research for subsets of these chemicals and their degradates most likely to be found in water resources used for drinking water in the United States.

  9. Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid-phase extraction and gas chromatography-electron capture detector.

    PubMed

    Zhang, Yaping; Yang, Jun; Shi, Ronghua; Su, Qingde; Yao, Li; Li, Panpan

    2011-07-01

    A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples. PMID:21656677

  10. Microbial degradation of herbicides.

    PubMed

    Singh, Baljinder; Singh, Kashmir

    2016-03-01

    Herbicides remain the most effective, efficient and economical way to control weeds; and its market continues to grow even with the plethora of generic products. With the development of herbicide-tolerant crops, use of herbicides is increasing around the world that has resulted in severe contamination of the environment. The strategies are now being developed to clean these substances in an economical and eco-friendly manner. In this review, an attempt has been made to pool all the available literature on the biodegradation of key herbicides, clodinafop propargyl, 2,4-dichlorophenoxyacetic acid, atrazine, metolachlor, diuron, glyphosate, imazapyr, pendimethalin and paraquat under the following objectives: (1) to highlight the general characteristic and mode of action, (2) to enlist toxicity in animals, (3) to pool microorganisms capable of degrading herbicides, (4) to discuss the assessment of herbicides degradation by efficient microbes, (5) to highlight biodegradation pathways, (6) to discuss the molecular basis of degradation, (7) to enlist the products of herbicides under degradation process, (8) to highlight the factors effecting biodegradation of herbicides and (9) to discuss the future aspects of herbicides degradation. This review may be useful in developing safer and economic microbiological methods for cleanup of soil and water contaminated with such compounds. PMID:25159042

  11. Comparison of Two Parametric Methods to Estimate Pesticide Mass Loads in California's Central Valley

    USGS Publications Warehouse

    Saleh, D.K.; Lorenz, D.L.; Domagalski, J.L.

    2011-01-01

    Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations. ?? 2010 American Water Resources Association. This article is a US Government work and is in the public domain in the USA.

  12. Comparison of pesticides in eight U.S. urban streams

    USGS Publications Warehouse

    Hoffman, R.S.; Capel, P.D.; Larson, S.J.

    2000-01-01

    Little is known of the occurrence of pesticides in urban streams compared to streams draining agricultural areas. Water samples from eight urban streams from across the United States were analyzed for 75 pesticides and seven transformation products. For six of the eight urban streams, paired agricultural streams were used for comparisons. The herbicides detected most frequently in the urban streams were prometon, simazine, atrazine, tebuthiuron, and metolachlor, and the insecticides detected most frequently were diazinon, carbaryl, chlorpyrifos, and malathion. In contrast to similar-sized agricultural streams, total insecticide concentrations commonly exceeded total herbicide concentrations in these urban streams. In general, the temporal concentration patterns in the urban streams were consistent with the characteristics of the local growing season. The insecticides carbaryl and diazinon exceeded criteria for the protection of aquatic life in many of the urban streams in the spring and summer. When the country as a whole is considered, the estimated mass of herbicides contributed by urban areas to streams is dwarfed by the estimated contribution from agricultural areas, but for insecticides, contributions from urban and agricultural areas may be similar. The results of this study suggest that urban areas should not be overlooked when assessing sources and monitoring the occurrence of pesticides in surface waters.

  13. Comparison of two parametric methods to estimate pesticide mass loads in California's Central Valley

    USGS Publications Warehouse

    Saleh, Dina K.; Lorenz, David L.; Domagalski, Joseph L.

    2011-01-01

    Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations.

  14. Fate of selected pesticides, estrogens, progestogens and volatile organic compounds during artificial aquifer recharge using surface waters.

    PubMed

    Kuster, Marina; Díaz-Cruz, Silvia; Rosell, Mònica; López de Alda, Miren; Barceló, Damià

    2010-05-01

    The artificial recharge of aquifers has become a valuable tool to increase water resources for drinking water production in many countries. In this work a total of 41 organic pollutants belonging to the classes of pesticides, estrogens, progestogens and volatile organic compounds (VOCs) have been monitored in the water from two artificial recharge plants located in Sweden and Denmark. The results from two sampling campaigns performed in each plant indicate good chemical status of the source water, as the contaminants detected were present at very low levels, far from those established in the legislation as maximum admissible concentrations (when existing) and far from those considered as a risk. Thus, of the 17 pesticides investigated, BAM (2,6-dichlorobenzamide), desethylatrazine, simazine, atrazine, terbuthylazine, diuron, metolachlor, and diazinon were the only compounds detected, and total pesticides levels were below 25ng L(-1), respectively. Estrone-3-sulfate was the only estrogen detected, at concentrations lower than 0.5ng L(-1). Progestogens were not found in any sample. Detected VOCs (benzene, toluene, ethylbenzene, and trichloroethylene) were below 0.04microg L(-1). The efficiency of elimination of these organic contaminants was poor as no significant decrease in their concentrations was observed through the recharge process. PMID:20226495

  15. Evaluation of performance reference compounds (PRCs) to monitor emerging polar contaminants by polar organic chemical integrative samplers (POCIS) in rivers.

    PubMed

    Carpinteiro, Inmaculada; Schopfer, Adrien; Estoppey, Nicolas; Fong, Camille; Grandjean, Dominique; de Alencastro, Luiz F

    2016-02-01

    In this work, a method combining polar organic chemical integrative samplers (POCIS) and ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was assessed for the determination of two corrosion inhibitors (benzotriazole and methylbenzotriazole), seven pesticides (atrazine, diuron, isoproturon, linuron, metolachlor, penconazole, terbuthylazine), and four pharmaceuticals (carbamazepine, diclofenac, metformin, sulfamethoxazole) in river water. As a first step, two POCIS sorbents, hydrophilic-lipophilic balance (HLB) and Strata X-CW, were compared. The comparison of the uptake profiles of the studied compounds showed that the HLB sorbent provides better uptake (higher sampled amount and better linearity) than Strata X-CW except for the basic compound metformin. Since the sampling rate (R s) of POCIS depends on environmental factors, seven compounds were evaluated as potential performance reference compounds (PRCs) through kinetic experiments. Deisopropylatrazine-d5 (DIA-d5) and, as far as we know, for the first time 4-methylbenzotriazole-d3 showed suitable desorption. The efficiency of both compounds to correct for the effect of water velocity was shown using a channel system in which POCIS were exposed to 2 and 50 cm s(-1). Finally, POCIS were deployed upstream and downstream of agricultural wine-growing and tree-growing areas in the Lienne River and the Uvrier Canal (Switzerland). The impact of the studied areas on both streams could be demonstrated. PMID:26637214

  16. Off-site movement of pesticide-contaminated fill from agrichemical facilities during the 1993 flooding in Illinois

    USGS Publications Warehouse

    Roy, W.R.; Chou, S.-F.J.; Krapac, I.G.

    1995-01-01

    Twenty retail agrichemical facilities were flooded. There was a concern that pesticide-contaminated road fill at these facilities had been transported into residential areas by the flooding. Forty fill and flood- related sediment samples were collected at six facilities. No significant accumulation of sediments was present at any of the six facilities. At five of the six facilities, it did not appear that road fill had been transported off-site. Pesticides were detected in sediment samples collected off-site adjacent to five of the facilities. Of the 21 samples collected off-site, atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazide) and metolachlor (2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)acet-o-toluidine) were detected in 86 and 81% of the samples, respectively. When compared with on-site concentrations, off-site pesticide concentrations were either at similar levels, or were as much as three orders of magnitude less. The interpretation of the pesticide data was difficult and often inconclusive, because there were no background data on the occurrence and distribution of pesticides at each site before flooding.

  17. Atmospheric concentrations and gas-particle partitions of pesticides: Comparisons between measured and gas-particle partitioning models from source and receptor sites

    NASA Astrophysics Data System (ADS)

    Sadiki, Mustapha; Poissant, Laurier

    Atmospheric concentrations and gas-particles partition were measured for 83 pesticides including organochlorines (OCs), acid herbicides (AHs), neutral herbicides (NHs) and organophosphorus pesticides (OPs). Samples have been collected in June 2005 at two sites, located in Québec, named St. Anicet (agricultural area) and Bay St. François wetland (receptor site). The highest vapor concentration was measured for metolachlor which was 23,600 pg m -3 and 12,200 pg m -3 at St. Anicet and Bay St. François (BSF), respectively. In the particulate phase, MCPA exhibited the highest level (323 pg m -3) at St. Anicet. Gas-particle partitions (GPPs) were also investigated and it was expressed as a function of the fraction of chemical in the particulate phase ( ϕ). The highest average of ϕ was observed for the AHs which were MCPB (75%) and MCPA (50%) at BSF and St. Anicet, respectively. Likewise, the GPPs were estimated by several models, namely Junge-Pankow model, KOA model, and polyparameter linear free energy relationships (ppLFERs). The estimated GPPs were compared to the observed ones and data showed a better correlation at BSF (receptor site) than that at St. Anicet. This suggests a kinetic effect on the GPPs of chemicals.

  18. Organic micropollutants in rivers downstream of the megacity Beijing: sources and mass fluxes in a large-scale wastewater irrigation system.

    PubMed

    Heeb, Florian; Singer, Heinz; Pernet-Coudrier, Benoît; Qi, Weixiao; Liu, Huijuan; Longrée, Philipp; Müller, Beat; Berg, Michael

    2012-08-21

    The Haihe River System (HRS) drains the Chinese megacities Beijing and Tianjin, forming a large-scale irrigation system severely impacted by wastewater-borne pollution. The origin, temporal magnitudes, and annual mass fluxes of a wide range of pharmaceuticals, household chemicals, and pesticides were investigated in the HRS, which drains 70% of the wastewater discharged by 20 million people living in Beijing. Based on Chinese consumption statistics and our initial screening for 268 micropollutants using high-resolution mass spectrometry, 62 compounds were examined in space and time (2009-2010). The median concentrations ranged from 3 ng/L for metolachlor to 1100 ng/L for benzotriazole and sucralose. Concentrations of carbendazim, clarithromycin, diclofenac, and diuron exceed levels of ecotoxicological concern. Mass-flux analyses revealed that pharmaceuticals (5930 kg/year) and most household chemicals (5660 kg/year) originated from urban wastewaters, while the corrosion inhibitor benzotriazole entered the rivers through other pathways. Total pesticide residues amounted to 1550 kg/year. Per capita loads of pharmaceuticals in wastewater were lower than those in Europe, but are expected to increase in the near future. As 95% of the river water is diverted to irrigate agricultural soil, the loads of polar organic micropollutants transported with the water might pose a serious threat to food safety and groundwater quality. PMID:22845779

  19. Reproductive health of bass in the Potomac, U.S.A., drainage: part 2. Seasonal occurrence of persistent and emerging organic contaminants.

    PubMed

    Alvarez, David A; Cranor, Walter L; Perkins, Stephanie D; Schroeder, Vickie L; Iwanowicz, Luke R; Clark, Randal C; Guy, Christopher P; Pinkney, Alfred E; Blazer, Vicki S; Mullican, John E

    2009-05-01

    The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater treatment plant discharges within the watershed. Analysis of the samplers resulted in detection of 84 of 138 targeted chemicals. The agricultural pesticides atrazine and metolachlor had the greatest seasonal changes in water concentrations, with a 3.1- to 91-fold increase in the spring compared with the level in the previous fall. Coinciding with the elevated concentrations of atrazine in the spring were increasing concentrations of the atrazine degradation products desethylatrazine and desisopropylatrazine in the fall following spring and summer application of the parent compound. Other targeted chemicals (organochlorine pesticides, polycyclic aromatic hydrocarbons, and organic wastewater chemicals) did not indicate seasonal changes in occurrence or concentration; however, the overall concentrations and number of chemicals present were greater at the sites downstream of wastewater treatment plant discharges. Several fragrances and flame retardants were identified in these downstream sites, which are characteristic of wastewater effluent and human activities. The bioluminescent yeast estrogen screen in vitro assay of the POCIS extracts indicated the presence of chemicals that were capable of producing an estrogenic response at all sampling sites. PMID:19108592

  20. Biodegradation of organic compounds in vadose zone and aquifer sediments

    SciTech Connect

    Konopka, A.; Turco, R. )

    1991-08-01

    The microbial processes that occur in the subsurface under a typical Midwest agricultural soil were studied. A 26-m bore was installed in November of 1988 at a site of the Purdue University Agronomy Research Center. Aseptic collections of soil materials were made at 17 different depths. Physical analysis indicated that the site contained up to 14 different strata. The site materials were primarily glacial tills with a high carbonate content. The N,P, and organic C contents of sediments tended to decrease with depth. Ambient water content was generally less than the water content, which corresponds to a -0.3-bar equivalent. No pesticides were detected in slurry incubations of up to 128 days. The sorption of atrazine and metolachlor was correlated with the clay content of the sediments. Microbial biomass (determined by direct microscopic count, viable count, and phospholipid assay) in the tills was lower than in either the surface materials or the aquifer located at 25 m. The biodegradation of glucose and phenol occurred rapidly and without a lag in samples from the aquifer capillary fringe, saturated zone, and surface soils. In contrast, lag periods and smaller biodegradation rates were found in the till samples. Subsurface sediments are rich in microbial numbers and activity. The most active strata appear to be transmissive layers in the saturated zone. This implies that the availability of water may limit activity in the profile.