Science.gov

Sample records for alachlor acetochlor metolachlor

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

    USGS Publications Warehouse

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

    1999-01-01

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

  2. Biodegradation of the acetanilide herbicides alachlor, metolachlor, and propachlor.

    PubMed

    Stamper, D M; Tuovinen, O H

    1998-01-01

    Alachlor, metolachlor, and propachlor are detoxified in biological systems by the formation of glutathione-acetanilide conjugates. This conjugation is mediated by glutathione-S-transferase, which is present in microorganisms, plants, and mammals. Other organic sulfides and inorganic sulfide also react through a nucleophilic attack on the 2-chloro group of acetanilide herbicides, but the products are only partially characterized. Sorption in soils and sediments is an important factor controlling the migration and bioavailability of these herbicides, while microbial degradation is the most important factor in determining their overall fate in the environment. The biodegradation of alachlor and metolachlor is proposed to be only partial and primarily cometabolic, and the ring cleavage seems to be slow or insignificant. Propachlor biodegradation has been reported to proceed to substantial (> 50%) mineralization of the ring structure. Reductive dechlorination may be one of the initial breakdown mechanisms under anaerobic conditions. Aerobic and anaerobic transformation products vary in their polarity and therefore in soil binding coefficient. A catabolic pathway for chloroacetanilide herbicides has not been presented in the literature because of the lack of mineralization data under defined cultural conditions.

  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. 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.

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

    PubMed

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

    2010-01-01

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

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

    USGS Publications Warehouse

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

    2002-01-01

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

  8. 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.

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

    USGS Publications Warehouse

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

    1998-01-01

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

  10. Acetochlor

    Integrated Risk Information System (IRIS)

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

  11. 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.

  12. 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

  13. 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...

  14. 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

  15. 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.

  16. Occurrence and transport of acetochlor in streams of the Mississippi River Basin

    USGS Publications Warehouse

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

    1999-01-01

    The herbicide acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6- methylphenyl) acetamide] was first used on corn (Zea mays L.) in the USA during the growing season of 1994. By 1996, it was the third most heavily used corn herbicide in the midwestern USA. During the growing season of 1997, 78% of 375 samples collected at 32 stream sites in the Mississippi River Basin contained detectable concentrations of acetochlor. However, concentrations in only 2% of the samples exceeded 2 ??g/L, the maximum annual average concentration allowable in public water supplies derived primarily from surface water. The largest acetochlor concentrations were detected in streams draining basins in parts of Illinois, Indiana, and Iowa. The median concentration of acetochlor in streams was about 10% that of atrazine (6- chloro-N-ethyl-N-isopropyl-1,3,5-triazine-2,4-diamine), about 25% that of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide], about 50% that of cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5- triazin-2-yl]amino]-2-methylpropionitrile], and about threefold that of alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide]. Load estimates indicate that, during the growing season of 1997, agricultural subbasins draining areas of Illinois, Indiana, and Iowa contributed about 37000 kg, or 74%, of the 50 000 kg of acetochlor measured in streams of the Mississippi River Basin.

  17. Water Quality Conditions at Tributary Projects in the Omaha District: 2006 Annual Report

    DTIC Science & Technology

    2007-12-01

    pesticide scan (GCMS) includes: acetochlor, alachlor, atrazine, benfluralin, butylate, chlorpyrifos , cyanazine, cycloate, EPTC, hexazinone...Immunoassay analysis. **** The pesticide scan (GCMS) includes: acetochlor, alachlor, atrazine, benfluralin, butylate, chlorpyrifos , cyanazine...alachlor, atrazine, benfluralin, butylate, chlorpyrifos , cyanazine, cycloate, EPTC, hexazinone, isopropalin, metribuzin, metolachlor, molinate, oxadiazon

  18. Phytoremediation of metolachlor by transgenic rice plants expressing human CYP2B6.

    PubMed

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

    2005-11-16

    We introduced the human cytochrome P450 gene CYP2B6 into rice plants (Oryza sativa L. cv. Nipponbare), and the CYP2B6-expressing rice plants became more tolerant to various herbicides than nontransgenic Nipponbare rice plants. In particular, CYP2B6 rice plants grown in soil showed tolerance to the chloroacetanilide herbicides alachlor and metolachlor. We evaluated the degradation of metolachlor by CYP2B6 rice plants to confirm the metabolic activity of the introduced CYP2B6. Although both CYP2B6 and nontransgenic Nipponbare rice plants could decrease the amount of metolachlor in plant tissue and culture medium, CYP2B6 rice plants could remove much greater amounts. In a greenhouse, the ability of CYP2B6 rice plants to remove metolachlor was confirmed in large-scale experiments, in which these plants appeared able to decrease residual quantities of metolachlor in water and soil.

  19. Improving alachlor biodegradability by ferrate oxidation.

    PubMed

    Zhu, Jian-Hang; Yan, Xi-Luan; Liu, Ye; Zhang, Bao

    2006-07-31

    Alachlor can be recalcitrant when present at high concentrations in wastewater. Ferrate oxidation was used as a pretreatment to improve its biodegradability and was evaluated by monitoring alachlor elimination and removal of COD(Cr) (chemical oxygen demand determined by potassium dichromate) during the oxidation process up to a value compatible with biological treatment. Ferrate oxidation resulted in elimination of alachlor followed by degradation of its intermediates. High pH suppressed alachlor removal and COD(Cr) removal due to the low redox potential of ferrate ions. Although alachlor can be totally eliminated within 10 min under optimized conditions (alachlor, 40 mg l(-1); ferrate:alachlor molar ratio, 2; and pH 7.0), its complete mineralization cannot be achieved by ferrate oxidation alone. Alachlor solution treated by ferrate for 10 min inhibited an up-flow biotreatment with activated sludge. The biodegradability of ferrate-pretreated solution improved when the treatment was increased to 20 min, at the point of which BOD(5)/COD(Cr) ratio of the treated solution was increased to 0.87 from 0.35 after 10 min treatment. Under optimized conditions, ferrate oxidation for 20 min resulted in total elimination of alachlor, partial removal of COD(Cr) and the ferrate-treated solution could be effectively treated by the up-flow activated sludge process.

  20. Comparative toxicity of racemic metolachlor and S-metolachlor to Chlorella pyrenoidosa.

    PubMed

    Liu, Huijun; Xiong, Mingyu

    2009-06-28

    The toxicity of the chiral herbicides rac-metolachlor and S-metolachlor to Chlorella pyrenoidosa was determined and compared in this study, based on four different test endpoints: the growth inhibition rate, the chlorophyll a and chlorophyll b concentration, the catalase activity, and the ultrastructural morphology of cells. The 24, 48, 72, and 96h EC(50) values of rac-metolachlor were 0.196, 0.241, 0.177 and 0.152mgL(-1), respectively; these values were higher than those of S-metolachlor, which were 0.116, 0.106, 0.081 and 0.068mgL(-1), respectively. This indicates that S-metolachlor was more toxic to C. pyrenoidosa than rac-metolachlor. The Chla and Chlb concentration of C. pyrenoidosa treated by rac-metolachlor was higher than that treated by S-metolachlor. In general, the catalase activity of C. pyrenoidosa treated by S-metolachlor was higher than that exposed to rac-metolachlor, and catalase activity was inhibited at high concentrations of both herbicides. The ultrastructural morphology of cells grown in the two herbicides was observed by transmission electron microscopy. The cell wall separated from the cell membrane, accumulated starch granules were observed in the chloroplast, and some lipid droplets and unknown electron-opaque deposits were also observed in the cytoplasm. The mechanism of the toxicity of rac- and S-metolachlor toxicity to C. pyrenoidosa was explored, and the enantioselective toxicity of rac- and S-metolachlor to C. pyrenoidosa was determined. These results will help to develop an understanding of the biologically mediated environmental processes of rac- and S-metolachlor.

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

    PubMed

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

    2016-09-09

    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.

  2. Enantioselectivity of racemic metolachlor and S-metolachlor in maize seedlings.

    PubMed

    Xie, Fei; Liu, Hui J; Cai, Wei D

    2010-11-01

    Chiral herbicides may have enantioselective effects on plants. In this study, we assessed and compared the enantioselectivity of the chiral herbicides rac-metolachlor and S-metolachlor to maize seedlings. The superoxide dismutase activity (SOD) activity of roots and stem leaves treated by rac-metolachlor was 1.38 and 1.99 times that of roots and stem leaves treated by S-metolachlor. The peroxidase activity (POD) activity of roots and stem leaves was 1.48 and 2.79 times that of roots and stem leaves treated by S-metolachlor, respectively, while the catalase activity (CAT) activity was 4.77 and 8.37 times greater, respectively. The Hill reaction activity of leaves treated by rac-metolachlor were 1.45, 1.33, and 1.14 times those treated by S-metolachlor with treatments of 18.6, 37.2, and 74.4 μM. The differences observed between treatments of rac- and S-metolachlor were significant. Significant differences in maize seedling morphology were also observed between rac- and S-metolachlor treatments. The degradation rate of S-metolachlor in roots was greater than that of rac-metolachlor. The half-lives of rac- and S-metolachlor were 80.6 and 60.3 h at 18.6 μM; 119.5 and 90 h at 37.2 μM; and 169 and 164.8 h at 74.4 μM, respectively. Using the liquid chromatography-mass spectrometry method, hydroxymetolachlor, deschlorometolachlor and deschlorometolachlor propanol were considered to be possible metabolites. We determined the enantioselective toxicity of rac- and S-metolachlor to maize and speculated on the proposed metabolic pathway of metolachlor in maize roots. These results will help to develop an understanding of the proper application of rac- and S-metolachlor in crops, and give some information for environmental safety evaluation of rac- and S-metolachlor.

  3. 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.

  4. The acetochlor registration partnership: prospective ground water monitoring program.

    PubMed

    Newcombe, Andrew C; Gustafson, David I; Fuhrman, John D; van Wesenbeeck, Ian J; Simmons, Nick D; Klein, Andrew J; Travis, Kim Z; Harradine, Kevin J

    2005-01-01

    The Acetochlor Registration Partnership conducted a prospective ground water (PGW) monitoring program to investigate acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide] transport to ground water at eight sites. The distribution of soil textures among these sites was weighted toward coarser soil types, while also including finer-textured soils that dominate most corn (Zea mays L.)-growing areas of the United States. Each site consisted of a 1.2-ha test plot adjacent to a 0.2-ha control plot. Suction lysimeters and monitoring wells were installed at multiple depths within each test and control plot to sample soil-pore water and near-surface ground water. Irrigation was applied to each site during the growing season to ensure water input of 110 to 200% of average historical rainfall. Acetochlor dissipated rapidly from surface soils at all sites with a DT(50) (time for 50% of the initial residues to dissipate) of only 3 to 9 d, but leaching was not an important loss mechanism, with only 0.25% of the 15,312 soil-pore water and ground water samples analyzed containing parent acetochlor at or above 0.05 microg L(-1). However, quantifiable residues of a soil degradation product, acetochlor ethanesulfonic acid, were more common, with approximately 16% of water samples containing concentrations at or above 1.0 microg L(-1). A second soil degradation product, acetochlor oxanilic acid, was present at concentrations at or above 1.0 microg L(-1) in only 0.15% of water samples analyzed. The acetochlor PGW program demonstrated that acetochlor lacks the potential to leach to ground water at detectable concentrations, and when applied in accordance with label restrictions, is unlikely to move to ground water at concentrations hazardous to human health.

  5. Thyroid endocrine disruption of acetochlor on zebrafish (Danio rerio) larvae.

    PubMed

    Yang, Mei; Hu, Jingjin; Li, Shuying; Ma, Youning; Gui, Wenjun; Zhu, Guonian

    2016-06-01

    The herbicide acetochlor is widely used and detected in the environment and biota, and has been suspected to disrupt the thyroid endocrine system, but underlying mechanisms have not yet been clarified. In the present study, zebrafish larvae (7 days post-fertilization) were exposed to a series concentration of acetochlor (0, 1, 3, 10, 30, 100 and 300 µg l(-1) ) within a 14-day window until 21 days post-fertilization. Thyroid hormones and mRNA expression profiles of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were analyzed. Exposure to the positive control, 3,5,3'-triiodothyronine (T3 ), altered the mRNA expression, suggesting that the HPT axis in the critical window of zebrafish responded to chemical exposure and could be used to evaluate the effects of chemicals on the thyroid endocrine system. The mRNA expressions of genes involved in thyroid hormone synthesis (tshβ, slc5a5 and tpo) were upregulated significantly with acetochlor treatment, which might be responsible for the increased thyroxine concentrations. The downregulation of genes related to thyroid hormone metabolism (dio1 and ugt1ab) and transport (ttr) in zebrafish larvae exposed to acetochlor might further explain the increased thyroxine levels and decreased T3 levels. The mRNA expression of the thyroid hormone receptor (trα) was also upregulated upon acetochlor exposure. Results suggested that acetochlor altered mRNA expression of the HPT axis-related genes and changed the whole body thyroid hormone levels in zebrafish larvae. It demonstrated that acetochlor could cause endocrine disruption of the thyroid system by simulating the biological activity of T3 . Copyright © 2015 John Wiley & Sons, Ltd.

  6. 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...

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

    USGS Publications Warehouse

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

    1996-01-01

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

  8. Impact of acetochlor on ammonia-oxidizing bacteria in microcosm soils.

    PubMed

    Li, Xinyu; Zhang, Huiwen; Wu, Minna; Su, Zhencheng; Zhang, Chenggang

    2008-01-01

    Acetochlor is an increasingly used herbicide on corn in North China. Currently, the effect of acetochlor on soil ammonia-oxidizing bacteria (AOB) communities is not well documented. Here, we studied the diversity and community composition of AOB in soil amended with three concentrations of acetochlor (50, 150, 250 mg/kg) and the control (0 mg acetochlor/kg soil) in a microcosm experiment by PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and the phylogenetic analysis of excised DGGE bands. DGGE profiles showed that acetochlor had a stimulating effect on AOB at the early stage after acetochlor amended, and the order of intensity and duration is medium-acetochlor amended samples (AM) > low-acetochlor amended samples (AL) > high-acetochlor amended samples (AH). At the end of 60 d microcosm, acetochlor had a negative effect on the diversity of AOB. Cluster analysis of DGGE profiles showed that acetochlor had a greater effect on the community structure of AOB on day 60 than on day 1. The phylogenetic analysis revealed that all the sequences of excised DGGE bands were closely related to members of the genus Nitrosospira and formed two separate subclusters designated as subcluster 1 and subcluster 2 affiliated respectively with clusters 3 and 4 in Nitrosospira as defined by Stephen. Some dominant AOB had a change from subcluster 2 to subcluster 1 with the incubation. The results showed that acetochlor had an effect on the AOB on a long-term basis and the chronic effect of acetochlor should be paid more attention in future.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-09-01

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

  11. 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...

  12. 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...

  13. 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...

  14. 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...

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

    PubMed Central

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

    1996-01-01

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

  16. Field dissipation of acetochlor in two New Zealand soils at two application rates.

    PubMed

    Ma, Qingli; Rahman, Anis; Holland, Patrick T; James, Trevor K; McNaughton, Don E

    2004-01-01

    The persistence of pesticides in soils has both economic and environmental significance and is often used as a key parameter in pesticide risk assessment. Persistence of acetochlor [2'-ethyl-6'-methyl-N-(ethoxymethyl)-2-chloroacetylanilide] in two New Zealand field soils was measured over two years and the data were used to identify models that adequately describe acetochlor persistence in the field. Acetochlor was sprayed onto six fallow plots (3 x 9 m each) at each site at the recommended rate (2.5 kg a.i. ha(-1)) and at twice that rate. Acetochlor concentrations were measured in soil cores. Simple first-order kinetics (Model 1) adequately described acetochlor persistence in Hamilton clay loam soil (Humic Hapludull, Illuvial Spadic) at the high application rate, but overestimated it at the low application rate. A quadratic model (Model 2), a first-order double-exponential model (Model 3), a first-order biphasic model (Model 4), or a two-compartment model (Model 5) better described acetochlor persistence at the low application rate. The time for 50% (DT50) and 90% (DT90) of initial acetochlor loss was approximately 9 and 56 d, and 18 and 63 d at low and high application rates, respectively. The more complex Models 2 through 5 also better described the biphasic dissipation of acetochlor in Horotiu sandy loam soil (Typic Orthic Allophanic) than Model 1, with Model 1 significantly underestimating acetochlor concentrations on the day of application at both application rates. The DT50 and DT90 values were 5 and 29 d and 7 and 31 d at low and high application rates, respectively. Overall, application rate significantly affected the DT50 and DT90 values in the Hamilton soil, but not in the Horotiu soil. Faster acetochlor loss in the Horotiu soil possibly resulted from the higher soil organic carbon content that retained more acetochlor near the soil surface where higher temperature and photolysis accelerated the loss.

  17. Near-infrared spectroscopy study for determination of adsorbed acetochlor in the organic and inorganic bentonites.

    PubMed

    Tomić, Zorica P; Ašanin, Darko; Đurović, Rada; Đorđević, Aleksandar; Makreski, Petre

    2012-12-01

    NIR spectroscopy is used to determine acetochlor herbicide adsorption on Na-montmorillonite (NaP) and organically modified montmorillonite (NaOM). Both montmorillonites NIR spectra shows bands at 7061 and 6791 cm(-1). Organo-montmorillonite is characterised by two emphasized bands at 5871 and 5667 cm(-1) that are attributed to the fundamental overtones of the mid-IR bands at 2916 and 2850 cm(-1). Bands at 6017 and 6013 cm(-1) are attributed to acetochlor adsorbed to organo-montmorillonite and Na-montmorillonite, which is confirmed by X-ray powder diffraction (XRPD). Greater quantity of acetochlor is adsorbed to organo-clays compared to non-modified montmorillonite. Acetochlor poses high risk to environmental contamination. Organo-clays are the most useful for removing acetochlor from water and soil.

  18. 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

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

    PubMed

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

    2001-11-01

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

  20. 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...

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

    PubMed

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

    2012-02-01

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

  2. Temperature dependence of Henry's law constants of metolachlor and diazinon.

    PubMed

    Feigenbrugel, Valérie; Le Calvé, Stéphane; Mirabel, Philippe

    2004-10-01

    A dynamic system based on the water/air equilibrium at the interface within the length of a microporous tube has been used to determine experimentally the Henry's law constants (HLC) of two pesticides: metolachlor and diazinon. The measurements were conducted over the temperature range 283-301 K. At 293 K, HLCs values are (42.6+/-2.8) x 10(3) (in units of M atm(-1)) for metolachlor and (3.0+/-0.3)x10(3) for diazinon. The obtained data were used to derive the following Arrhenius expressions: HLC=(3.0+/-0.4) x 10(-11) exp((10,200+/-1,000)/T) for metolachlor and (7.2+/-0.5) x 10(-15) exp((11,900+/-700)/T) for diazinon. At a cumulus cloud temperature of 283 K, the fractions of metolachlor and diazinon in the atmospheric aqueous phase are about 57% and 11% respectively. In order to evaluate the impact of a cloud on the atmospheric chemistry of both studied pesticides, we compare also their atmospheric lifetimes under clear sky (tau(gas)), and cloudy conditions (tau(multiphase)). The calculated multiphase lifetimes (in units of hours) are significantly lower than those in gas phase at a cumulus temperature of 283 K (in parentheses): metolachlor, 0.4 (2.9); diazinon, 1.9 (5.0).

  3. Adsorption of phenthoate and acetochlor from water by clays and organoclays.

    PubMed

    Liao, Min; Xie, Xiao-Mei

    2004-01-01

    Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltrimethylammonium bromide (DTAB), and cetylpyridinium chloride (CPC) were studied. The adsorption equilibrium data points were fitted to Freundlich isotherm equations. The adsorption of phenthoate and acetochlor were significantly enhanced by surfactant treatment of the clays. The amount of both pesticides adsorbed per unit mass of organoclay followed the order of TTA-kaolin < TTA-montmorillonite < TTA-bentonite, which is inconsistent with the organic carbon content of the clays. The removal efficiency of organomontmorillonite to treat acetochlor is in the order of CP (C16)-montmorillonite > TTA (C14)-montmorillonite > DTA (C12)-montmorillonite. Phenthoate is adsorbed to greater extent than acetochlor by each adsorbent, which may be due to the higher hydrophobicity of phenthoate, indicating considerable hydrophobic interaction between adsorbent/adsorbate systems.

  4. [Toxicity effects of Rac- and S-metolachlor on two algaes].

    PubMed

    Cai, Wei-Dan; Liu, Hui-Jun; Fang, Zhi-Guo

    2012-02-01

    The enantioselective toxicity of the chiral herbicides Rac- and S-metolachlor to Scenedesmus obliquus and Chlorella vulgaris was determined, and the effect of humic acid was studied by using acute toxicity testing method. The results indicated that the toxicity of Rac- and S-metolachlor increased with increasing concentration and exposure time. The EC(50, 96 h) ratio of Rac-metolachlor to S-metolachlor was 2.25 for C. vulgaris and 1.81 for S. obliquus, indicating that S-metolachlor had higher effect on two algaes, and S. obliquus was more sensitive to Rac- and S-metolachlor. Linear correlation between toxicity on S. obliquus and C. vulgaris was observed. The toxicity of Rac- and S-metolachlor changed with humic acid, with more significant change was observed in S-metolachlor (P<0.05).

  5. Storm flow export of metolachlor from a coastal plain watershed.

    PubMed

    Watts, D W; Novak, J M; Johnson, M H; Stone, K C

    2000-03-01

    During an 18-month (1994-1995) survey of the surface water in an Atlantic Coastal Plain watershed, metolachlor was most frequently detected during storm flow events. Therefore, a sampling procedure, focused on storm flow, was implemented in June of 1996. During 1996, three tropical cyclones made landfall within 150 km of the watershed. These storms, as well as several summer thunderstorms, produced six distinct storm flow events within the watershed. Metolachlor was detected leaving the watershed during each event. In early September, Hurricane Fran produced the largest storm flow event and accounted for the majority of the metolachlor exports. During the storm event triggered by Hurricane Fran, the highest daily average flow (7.5 m2 s-1) and highest concentration (5.1 micrograms L-1) ever measured at the watershed outlet were recorded. Storm flow exports leaving the watershed represented 0.1 g ha-1 or about 0.04% of active ingredient applied.

  6. Enantioselective binding interaction of the metolachlor pesticide enatiomers with bovine serum albumin - A spectroscopic analysis study

    NASA Astrophysics Data System (ADS)

    Ni, Yongnian; Zhang, Fangyuan; Kokot, Serge

    2012-11-01

    Enantioselective binding interaction of the pesticides, metolachlor (RAC-metolachlor) and its S-enantiomer (S-metolachlor), with bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorption spectroscopy. Both RAC- and S-metolachlors quenched the intrinsic fluorescence of BSA via a static mechanism, and various binding parameters indicated that electrostatic forces were involved in the binding of both of these compounds. Site marker competitive experiments demonstrated that S-metolachlor bound to site I of BSA, while R-metolachlor bound to site II, indicating the importance of enantiomeric factors for binding site selection. Further experiments showed that S-metolachlor had a higher binding affinity to BSA than R-metolachlor. The obtained spectral data were resolved with use of the multivariate curve resolution-alternating least squares method (MCR-ALS), and the extracted concentration profiles of the reacting species in the interaction were obtained. These profiles indicated that S-metolachlor was the main active constituent of RAC-metolachlor for binding with BSA, and these findings have significant implications in providing an explanation why S-metolachlor is the preferred herbicide in practice than RAC-metolachlor.

  7. 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...

  8. 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...

  9. 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...

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

    PubMed

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

    2001-01-01

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

  11. 77 FR 48902 - S-Metolachlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... physical, chemical, and fate/transport characteristics of S-metolachlor. Further information regarding EPA... Model/Exposure Analysis Modeling System (PRZM/ EXAMS) Screening Concentration in Ground Water (SCI-GROW... chemical residue in or on a food) only if EPA determines that the tolerance is ``safe.'' Section...

  12. 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 ...

  13. 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…

  14. 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.

  15. 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.

  16. 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...

  17. Single and joint stress of acetochlor and Pb on three agricultural crops in northeast China.

    PubMed

    Chao, Lei; Zhou, Qi-xing; Chen, Su; Cui, Shuang; Wang, Mei-e

    2007-01-01

    In order to evaluate ecological risk of agrochemicals in agricultural environment, single and joint toxic effects of an important herbicide and a typical heavy metal on root elongation of crops were investigated. Seeds of the three crops including wheat (Triticum aestivum), Chinese cabbage (Brassica pekimensis) and soybean (Glycine max) as the main crops in northeast China were exposed to acetochlor as a herbicide and lead (Pb) as a heavy metal using the pot-culture method, and meadow brown soil as one of the main soils distributed in northeast China was applied in the investigation. The results indicated that the interactive effects of the two pollutants on root elongation of the three crops were very complicated although they had markedly significant (P < 0.01) linear interrelationships based on the regression analyses. When the concentration of added Pb2+ reached 200 mg/kg, acetochlor and Pb had an antagonistic effect on the inhibition of root elongation of the three crops. However, acetochlor and Pb had significantly (P < 0.05) synergic effects on the inhibition of root elongation when concentration of added Pb2+ was up to 1000 mg/kg. At the low concentration of added Pb, joint toxicity of acetochlor and Pb was more dependent on the concentration of Pb. Among the three crops, wheat was the most sensitive to the toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.

  18. 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.

  19. Effect of chiral differences of metolachlor and its (S)-isomer on their toxicity to earthworms.

    PubMed

    Xu, Dongmei; Wen, Yuezhong; Wang, Kaixiong

    2010-11-01

    The effects of (Rac)-metolachlor and (S)-metolachlor on the avoidance behavior, bodyweight change and in vivo enzyme activity of earthworms (Eisenia foetida) were determined and compared in this study. The effects of (Rac)-metolachlor on the enzyme activities of E. foetida and bodyweight were more significant than those of (S)-metolachlor at the same concentrations. In the short term (2 d, 7 d), (S)-metolachlor had faster effects on cellulase and catalase activities of E. foetida. However, in the relatively long term (14 d, 28 d), (Rac)-metolachlor had higher toxic effects on cellulase and catalase activities. The inter-group difference between (Rac)-metolachlor and (S)-metolachlor on E. foetida enzyme activities was the most significant for catalase, and the least significant for cellulase. The test of avoidance behavior shows that earthworms are more sensitive to the stimulation of (Rac)-metolachlor than to that of (S)-metolachlor. The results will help to develop an understanding of the biologically mediated environmental processes of these two herbicides.

  20. [Influence of the coexistence of Zn2+ on the enantioselective toxicity of metolachlor to Scenedesmus obliquus].

    PubMed

    Hu, Xiao-Na; Zhang, Shu-Xian; Chen, Cai-Dong; Liu, Hui-Jun

    2014-01-01

    To evaluate the enantioselective toxicity of chiral pesticide coexisting with heavy metal, the enantioselective toxicity of Rac-, S-metolachlor alone and coexisting with Zn2+ on Scenedesmus obliquus was studied by using standard toxic testing method. The results showed that the trend of the enantioselective toxicity of Rac- and S-metolachlor coexisting with Zn2+ was similar to that of Rac- and S-metolachlor alone. The growth inhibition rate of Scenedesmus obliquus was decreased by the coexistence of Zn2+ with high concentrations of metolachlor. The inhibition rates with 0.30 mg x L(-1) Rac- and S-metolachlor alone at 24 h were 49.61% and 59.73%, and in the coexistence of Zn2+ the values were 38.41% and 42.52%, respectively. The enantioselective toxicity of Rac- and S-metolachlor was expanded and the toxicity of S-metolachlor increased greater than that of Rac-metolachlor. The coexistence of Zn2+ showed partial increase in toxicity of metolachlor in low concentrations, while there was antagonistic effect in high content of metolachlor. The trend of Chlorophyll content of Scenedesmus obliquus at 96 h was in accordance with the growth inhibition.

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

    USGS Publications Warehouse

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

    1994-01-01

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

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

    SciTech Connect

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

    1994-03-01

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

  3. 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.

  4. 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

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

    PubMed

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

    2004-04-05

    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

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

    PubMed

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

    2010-04-01

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

  7. Modulation of 2,6-dinitrotoluene genotoxicity by alachlor treatment of Fischer 344 rats.

    PubMed

    George, S E; Allison, J C; Brooks, L R; Eischen, B T; Kohan, M J; Warren, S H; King, L C

    1998-01-01

    Due to its widespread use as a preemergent herbicide, alachlor has been detected as a groundwater contaminant. The procarcinogen, 2,6-dinitrotoluene (DNT), a by-product of the munitions industry and a precursor to polyurethane production, is found in the manufacturing waste stream. This study explores the effect of alachlor treatment on the bioactivation of DNT by examining urine mutagenicity, intestinal enzymes, and hepatic DNA adducts to detect changes in metabolism. Five-week-old male rats were treated daily by gavage with 50 mg/kg of alachlor for up to 5 weeks while control animals received an equal volume of peanut oil. At 1, 3, and 5 weeks following the initial alachlor dose, animals were administered p.o. 75 mg/kg DNT or DMSO. Urine was collected for 24 hr in metabolism cages. Following incubation with sulfatase and beta-glucuronidase, urines were individually concentrated by C-18 solid phase extraction, dried under N2, and prepared for bioassay in Salmonella typhimurium strain TA98 with and without metabolic activation. Urine from peanut oil- and alachlor-treated rots was not mutagenic. Even though calf thymus DNA-alachlor adducts formed in vitro, no hepatic DNA adducts were detected in vivo in these two treatment groups. Interestingly, a significant increase in excretion of mutagenic urine from DNT-treated rats was observed following 3 weeks of alachlor treatment in the absence of S9 (690 +/- 130 vs. 339 +/- 28 revertants/ml) which corresponded to increased DNT-related hepatic DNA adduct formation (5.90 +/- 0.88 adducts/10(8) nucleotides vs. 10.56 x +/- 0.59 adducts/10(8) nucleotides [relative adduct level (RAL)]). Elevation in the production of mutagenic urine from control and treated animals was linked to increases in intestinal nitroreductase and beta-glucuronidase activities; however, the only significant alachlor-related effects were an increase in small intestinal 1-week beta-glucuronidase and 5-week dehydrochlorinase activities. The increased urine

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

    USGS Publications Warehouse

    Crawford, Charles G.

    1997-01-01

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

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

    USGS Publications Warehouse

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

    2000-01-01

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

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

    SciTech Connect

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

    1992-01-01

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

  11. 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

  12. 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...

  13. 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...

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

    PubMed

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

    2014-03-01

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

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

    USGS Publications Warehouse

    Clark, Gregory M.; Goolsby, Donald 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.

  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. Spectral characterization and chiral interactions of plant microsomal cytochrome P450 with metolachlor and herbicide safeners.

    PubMed

    Liu, Huijun

    2010-01-01

    The content and spectral characteristics of cytochrome P450 (Cyt P450) and cytochrome b(5) (Cyt b(5)) extracted from shoots of etiolated maize and rice seedlings were studied by using ultraviolet (UV) difference spectrophotometry. The results showed that fenclorim, rac-metolachlor and S-metolachlor may induce the same P450 isoenzyme with lambda(max) at 453 nm, while naphthalic anhydride (NA) induced another one with lambda(max) at 447 nm. The microsomal Cyt P450 and Cyt b(5) content of maize seedlings was higher than that of rice, and the Cyt b(5) content was higher than that of Cyt P450. Maize and rice microsomal Cyt P450 and Cyt b(5) were induced at different levels by the four chemicals, with the order as follows: NA > fenclorim > rac-metolachlor > S-metolachlor with p < 0.05. When induced by NA, fenclorim, rac-metolachlor and S-metolachlor, the maize Cyt P450 content was, respectively, 5.63-, 3.30-, 3.02- and 2.48-fold that of the control, the rice Cyt P450 content was 8.54-, 2.20-, 1.91- and 1.33-fold that of the control, the maize Cyt b(5) content was 9.89-, 5.49-, 4.69- and 3.40-fold that of the control, and the rice Cyt b(5) content was 7.76-, 4.56-, 2.60- and 1.82-fold that of the control. An enantio-difference existed when rac- and S-metolachlor combined with plant Cyt P450. The interaction of microsomal Cyt P450 with S-metolachlor is higher than that with rac-metolachlor, which may be one of the reasons why S-metolachlor is superior at killing weeds compared with rac-metolachlor. These results will help to develop an understanding of the tolerance for and selectivity of rac- and S-metolachlor.

  18. An evaluation of the carcinogenic potential of the herbicide alachlor to man.

    PubMed

    Heydens, W F; Wilson, A G; Kier, L D; Lau, H; Thake, D C; Martens, M A

    1999-06-01

    Chronic bioassays have revealed that alachlor caused nasal, thyroid, and stomach tumours in rats but was not carcinogenic in mice. Significant increases in thyroid and stomach tumours were observed only at doses that exceeded the maximum tolerated dose (MTD). While nasal tumours were found at doses below the MTD, they were small and benign in nature. This publication describes the work undertaken by Monsanto to understand the carcinogenic mode of action of alachlor in the rat and to investigate the relevance to humans. The genetic toxicity of alachlor has been investigated in an extensive battery of in vitro and in vivo test systems. In addition, target-specific mutagenicity tests, such as the COMET assay and DNA binding in nasal tissue, were carried out to investigate any possible in-situ genotoxic action. The weight-of-evidence analysis of all available data clearly demonstrates that alachlor exerts its carcinogenicity in the rat by non-genotoxic mechanisms. In the rat, alachlor is initially metabolised primarily in the liver through the P-450 pathway and by glutathione conjugation. The glutathione conjugates and their metabolites undergo enterohepatic circulation with further metabolism in the gastrointestinal tract, liver, and then nasal tissue where they can be converted to a diethyliminoquinone metabolite (DEIQ). This electrophilic species binds to the cysteine moiety of proteins leading to cell damage and increased cell turnover. When comparisons of in vitro nasal metabolic capability were made, the rat's capacity to form DEIQ from precursor metabolites was 38 times greater than for the mouse, 30-fold higher than monkey, and 751 times greater than that of humans. This data is consistent with the results of studies showing in vivo formation of DEIQ-protein adducts in the nasal tissue of rats but not mice or monkeys. The lack of DEIQ nasal adducts in mice is consistent with the lack of nasal tumours in that species. When the differences between rat and humans

  19. Comparative responses of sperm cells and embryos of Pacific oyster (Crassostrea gigas) to exposure to metolachlor and its degradation products.

    PubMed

    Mai, Huong; Gonzalez, Patrice; Pardon, Patrick; Tapie, Nathalie; Budzinski, Hélène; Cachot, Jérôme; Morin, Bénédicte

    2014-02-01

    Metolachlor is one of the most intensively used chloroacetanilide herbicides in agriculture. Consequently, it has been frequently detected in coastal waters as well as its major degradation products, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA) which are encountered at higher concentrations than metolachlor. Although a few studies of metolachlor toxicity have been conducted on marine organisms, little is known about the environmental toxicity of metolachlor degradation products. In this study, the deleterious effects of metolachlor and its degradation products on spermatozoa and embryos of Crassostrea gigas have been compared using biomarkers of developmental defects, DNA damage and gene transcription levels. After 24h exposure, significant increases in the percentage of abnormal D-larvae and DNA damage were observed from 0.01 μg L(-1) for S-metolachlor and 0.1 μg L(-1) for MESA and MOA. Results showed that S-metolachlor was more embryotoxic and genotoxic than its degradation products. Oyster sperm was also very sensitive to metolachlor exposure and followed the pattern: metolachlor (0.01 μg L(-1))>MOA (0.1 μg L(-1))>MESA (1 μg L(-1)). Metolachlor and MESA mainly triggered variations in the transcription level of genes encoding proteins involved in oxidative stress responses (mitochondrial superoxide dismutase and catalase). Overall, no significant variation in transcription levels could be detected in C. gigas embryos exposed to MOA. This study demonstrates that metolachlor and its main degradation products have the potential to impact several steps of oyster development and therefore recruitment in coastal areas exposed to chronic inputs of pesticides.

  20. 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.

  1. 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.

  2. [Prolonged convulsion after intoxication of alachlor herbicide (Lasso): a case report].

    PubMed

    Naito, Hiromichi; Nagae, Masaharu; Okahara, Shuji; Maeyama, Hiroki; Okada, Daisuke; Hagioka, Shingo; Morimoto, Naoki

    2011-03-01

    We experienced a case of alachlor herbicide (Lasso) intoxication. A 57-year-old man was transported to our hospital by ambulance after ingesting 450 mL of Lasso. He was unconscious and had difficulty in breathing. Gastric lavage was performed after tracheal intubation and the patient was placed on mechanical ventilation. Activated charcoal and laxative were administrated. Even after admission, disturbance of consciousness persisted. He had liver and kidney disorders but these did not progress to multiple organ failure. He experienced convulsions from day 4 and was administered anticonvulsants. Convulsion was intractable and needed long-term treatment. His general condition improved until discharge. He was weaned from mechanical ventilation and recovered consciousness, but he still displayed tremors. The herbicide (Lasso) is a combination of alachlor and monochlorobenzene. Studies have shown that alachlor is neurotoxic and monochlorobenzene accumulates in the brain. In case of intoxication with the herbicide Lasso, treatment is required for ameliorating neurotoxic effects and intractable convulsion as well as liver and kidney disorders, gastrointestinal mucosal damage, hematopoietic disorder, and acute circulatory failure.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Degradation of alachlor in natural and sludge-amended soils, studied by gas and liquid chromatography coupled to mass spectrometry (GC-MS and HPLC-MS).

    PubMed

    Rodríguez-Cruz, Sonia; Lacorte, Silvia

    2005-11-30

    Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] is an herbicide used worldwide. The relative rates of disappearance of alachlor, the formation kinetics of alachlor ethane sulfonic acid (ESA), and the formation of other degradation products in two different soils (a soil with natural organic matter and a sludge-amended soil) has been studied. For such a purpose, soil samples were spiked with alachlor at 2.5 mg kg(-1), concentration generally applied in agricultural soils, and were submitted to sunlight, simulating natural field conditions. Extracts were analyzed by GC-MS and HPLC-MS in scan mode. A good correlation was observed between both techniques, and HPLC-MS allowed the determination of two eluting peaks corresponding to the two stereoisomeric forms of alachlor ESA. Degradation of alachlor in the two soils followed first-order kinetics. Half-life in the natural soil was 4.2 +/- 0.1 days, and half-life in the sludge-amended soil was 5.8 +/- 0.8 days. The higher half-life observed in the sludge-amended soil was attributed to the higher sorption of alachlor to this soil compared to the natural soil. The degradation of alachlor in both soils gave rise to the production of alachlor ESA. Its concentration increased during the incubation period, and after 27 days, its concentration was about 0.59 mg kg(-1) in the natural soil and 0.37 mg kg(-1) in the sludge-amended soil. The other two alachlor transformation products were identified using GC-MS, and the abundance of these degradation products increased while alachlor was degraded.

  8. Enhanced retention of linuron, alachlor and metalaxyl in sandy soil columns intercalated with wood barriers.

    PubMed

    Rodríguez-Cruz, M S; Ordax, J M; Arienzo, M; Sánchez-Martín, M J

    2011-03-01

    A study has been made of the effect a reactive barrier made of pine (softwood) or oak (hardwood) wood intercalated in a sandy soil column has on the retention of linuron, alachlor and metalaxyl (pesticides with contrasting physicochemical characteristics). The leaching of pesticides has been carried out under a saturated flow regime and breakthrough curves (BTCs) have been obtained at flow rates of 1 m Lmin(-1) (all pesticides) and 3 m Lmin(-1) (linuron). The cumulative curves in the unmodified soil indicate a leaching of pesticides >80% of the total amount of compound added. After barrier intercalation, linuron leaching decreases significantly and a modification of the leaching kinetics of alachlor and metalaxyl has been observed. The theoretical R factors increased ∼2.6-3.3, 1.2-1.6-fold, and 1.4-1.7-fold and the concentration of the maximum peak decreased ∼6-12-fold, 2-4-fold and 1.2-2-fold for linuron, alachlor and metalaxyl, respectively. When considering the three pesticides, significant correlations have been found between the theoretical retardation factor (R) and the pore volume corresponding to the maximum peaks of the BTCs (r=0.77; p<0.05) or the total volume leached (r=-0.78; p<0.05). The results reveal the efficacy of reactive wood barriers to decrease the leaching of pesticides from point sources of pollution depends on the type of wood, the hydrophobicity of the pesticide and the adopted water flow rate. Pine was more effective than oak in decreasing the leaching of hydrophobic pesticide linuron or in decreasing the maximum peak concentration of the less hydrophobic pesticides in soils. Efficacy of these wood barriers was limited for the least hydrophobic pesticide metalaxyl.

  9. Indirect photolysis promoted by natural and engineered wetland water constituents: processes leading to alachlor degradation.

    PubMed

    Miller, Penney L; Chin, Yu-Ping

    2005-06-15

    Wetland surface waters that received drainage from agricultural fields were probed for constituents that would promote the photodegradation of agriculture herbicides. Alachlor proved to be a good chemical probe for examining indirect photolysis due to its lack of reactivity by either direct photolysis or dark reaction pathways and its ubiquity as an agricultural herbicide. Water samples were taken from natural (Old Woman Creek) and engineered wetlands in Ohio that receive copious amounts of agricultural runoff. Possible photosensitizers including dissolved organic matter (DOM), iron, and nitrate were measured in the samples. In alkaline waters (pH > 7.8), the photochemical degradation of alachlor became important only in the presence of high nitrate levels (approximately equal to 1 mM). In pH-adjusted (approximately 4) samples, the observed degradation rate coefficient increased 3-18 times of that measured at the natural pH. Methanol quenching experiments and kinetics modeling suggest that hydroxyl radical is the principal reactant. The promotion of the reaction at the lower pH was apparently related to the activation of the photochemical pathways associated with the DOM and possibly iron-DOM complexes. The rate coefficients measured for the photodegradation of alachlor in reconstituted DOM isolates (cation-exchanged material with very low iron levels) were similar in magnitude to those measured in natural waters containing low amounts of nitrate and high amounts of DOM. Moreover, these reactions also exhibited a pH dependency. Thus, these results suggest that DOM plays a role in promoting an indirect photolytic mechanism that is highly pH dependent.

  10. 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

  11. 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.

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

    PubMed

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

    2012-01-01

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

  13. Fungicide dissipation and impact on metolachlor aerobic soil degradation and soil microbial dynamics.

    PubMed

    White, Paul M; Potter, Thomas L; Culbreath, Albert K

    2010-02-15

    Pesticides are typically applied as mixtures and or sequentially to soil and plants 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 communities. Thus there is a potential to impact soil processes responsible for herbicide degradation. This may change herbicide efficacy and environmental fate characteristics. Our study objective was to determine the effects of 4 peanut fungicides, chlorothalonil (2,4,5,6-tetrachloro-1,3-benzenedicarbonitrile), tebuconazole (alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), flutriafol (alpha-(2-fluorophenyl)-alpha-(4-fluorophenyl)-1H-1,2,4-triazole-1-ethanol), and cyproconazole (alpha-(4-chlorophenyl)-alpha-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol) on the dissipation kinetics of the herbicide, metolachlor (2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide), and on the soil microbial community. This was done through laboratory incubation of field treated soil. Chlorothalonil significantly reduced metolachlor soil dissipation as compared to the non-treated control or soil treated with the other fungicides. Metolachlor DT(50) was 99 days for chlorothalonil-treated soil and 56, 45, 53, and 46 days for control, tebuconazole, flutriafol, and cyproconazole-treated soils, respectively. Significant reductions in predominant metolachlor metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOA), produced by oxidation of glutathione-metolachlor conjugates were also observed in chlorothalonil-treated soil. This suggested that the fungicide impacted soil glutathione-S-transferase (GST) activity. Fungicide DT(50) was 27-80 days but impacts on the soil microbial community as indicated by lipid biomarker analysis were minimal. Overall study results indicated that

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

    USGS Publications Warehouse

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

    2000-01-01

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

  15. [Experimental poisoning of carp fingerlings (Cyprinus carpio L.) with the herbicidal preparation, lasagrin (alachlor)].

    PubMed

    Doĭcheva, L A

    1978-01-01

    The acute intoxication of K1 carp (Cyprinus carpio L.) with the herbicide preparation lassagrin (alachlor) was studied under experimental conditions in a laboratory. Used were a total of 360 young carps of 10 g each, measuring 9-10 cm. The experiments were carried out in 30-1 glass aquariums that were preliminary filled with water that was adequately heated and deprived of chlorine at pH = 6.9, T0C = 18-20 degrees C, O2 = 10.4 mg/1; hardness = 1.5 German degrees. The preparation was directly placed in the aquariums in eleven concentrations. The following characteristic symptoms of intoxication were established: higher irritability of the nervous system with superactivity, lack of coordination and orientation, depression in later hours, loss of sight, disturbed pigmentation. No morphologic changes were found at necropsy. Determined was the concentration at which 50% of the test material died at the 96th hour of exposure: LC50/TLm/=4.67 mg, the interval of dependability at 95% probability being 4.04-5.30. Both toxicometry data and intoxication symptoms with the use of lassagrin (alachlor, lasso) made it reasonable to believe that the preparation could be referred to poisons having resorptive action so far as carps are concerned.

  16. Simultaneous screening of herbicide degradation byproducts in water treatment plants using high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Cheng, Xiaoliang; Shi, Honglan; Adams, Craig D; Timmons, Terry; Ma, Yinfa

    2010-04-28

    Currently, herbicides are widely used in various combinations at many stages of cultivation and during postharvest storage. There are increasing concerns about the public health impact of herbicide degradation byproducts that may be present in water bodies used either as drinking water or for recreational purposes. This work investigated the sulfonic acid and oxanilic acid degradation products of metolachlor, alachlor, acetochlor, and propachlor in a variety of water bodies. The objective was to develop a fast, accurate, and easy method for quantitative analysis of herbicide degradation products using liquid chromatography with tandem mass spectrometry without solid phase extraction, but performing levels of detection lower than those obtained in previous studies with solid phase extraction. This research also screened 68 water samples, both untreated source water and treated water, from 34 water treatment plants in Missouri. Finally, it examined seasonal trends in levels of those degradation products by collecting and testing samples monthly. This highly sensitive method can analyze these degradation products to low ng/L levels. The method limit of quantification ranges from 0.04 to 0.05 ppb for each analyte; and quantitative analyses show a precision with RSDs of around 0.6% to 3% in treated water and 2% to 19% in untreated source water. Concentrations of alachlor ESA, acetochlor OA, metolachlor OA, and metolachlor ESA were detected from the Missouri River and the Mississippi River water bodies in summer time. Occurrences of these compounds in treated water samples are all lower than those in the untreated source water samples.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Sytnyk, Svitlana; Wiche, Oliver

    2016-04-01

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

  19. 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. 

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

    PubMed

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

    2011-11-30

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

  2. 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...

  3. 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...

  4. 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.

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

    PubMed

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

    2006-03-01

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

  6. 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...

  7. 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...

  8. Effectiveness of Integrated Best Management Practices on Mitigation of Atrazine and Metolachlor in an Agricultural Lake Watershed.

    PubMed

    Lizotte, Richard; Locke, Martin; Bingner, Ronald; Steinriede, R Wade; Smith, Sammie

    2017-04-01

    The study examined the influence of land-use (cropping patterns) and integrated agricultural best management practices (BMPs) on spring herbicide levels in an agricultural watershed. Atrazine and metolachlor were applied for weed control during spring of 1998-2002, 2005, and 2007-2013. Watershed-wide mass of applied herbicides ranged from 12.7 to 209.2 g atrazine and 10.9-302.2 g metolachlor with greatest application during 1998, 2009-2010 (atrazine) and 2007-2013 (metolachlor). Spring herbicide concentrations in Beasley Lake water ranged from below detection to 3.54 μg atrazine/L and 3.01 μg metolachlor/L. Multiple linear regression analyses with cropping patterns, BMPs, rainfall and time as independent variables, showed atrazine applications were associated with increases in cotton acreage and quail buffer, while metolachlor applications increased over time. Multiple linear regressions showed lake atrazine concentrations were associated with conservation tillage, rainfall, and corn, while lake metolachlor concentrations were associated with the cumulative metolachlor application and sediment retention pond installation.

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

    PubMed

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

    2014-11-15

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

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

    PubMed

    Potter, Thomas L; Gerstl, Zev; White, Paul W; Cutts, George S; Webster, Theodore M; Truman, Clint C; Strickland, Timothy C; Bosch, David D

    2010-10-13

    Use of genetically modified cultivars resistant to the herbicide glyphosate (N-phosphonomethylglycine) is strongly associated with conservation-tillage (CsT) management for maize ( Zea mays L.), soybean ( Glycine max L.), and cotton ( Gossypium hirsutum L.) cultivation. Due to the emergence of glyphosate-resistant weed biotypes, alternate weed management practices are needed to sustain CsT use. This work focused on metolachlor use (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide) in a CsT system. The fate and efficacy of granular and emulsifiable concentrate (EC) formulations or an EC surrogate were compared for CsT cotton production in the Atlantic Coastal Plain region of southern Georgia (USA). The granular formulation, a clay-alginate polymer, was produced in the authors' laboratory; EC was a commercial product. In field and laboratory dissipations the granular metolachlor exhibited 8-fold greater soil persistence. Rainfall simulation runoff assessments indicated that use of the granular formulation in a common CsT system, strip-tillage (ST), may reduce metolachlor runoff loss when compared to conventional tillage (CT) management or when EC formulations are used in the ST system. Metolachlor leaching assessments using field-deployed lysimeters showed some tillage (ST > CT) and formulation (EC > granular) differences. Overall leaching was generally small when compared to runoff loss. Finally, greenhouse bioassays showed control of two weed species with the granular was greater than or equal to that of the EC formulation; however, the granular formulation suppressed cotton growth to a greater extent. In sum, this metolachlor granular formulation has advantages for CsT cotton production; however, additional research is needed to assess impacts on crop injury.

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

    PubMed

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

    2005-07-15

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

  12. 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.

  13. Ascorbate-Promoted Surface Iron Cycle for Efficient Heterogeneous Fenton Alachlor Degradation with Hematite Nanocrystals.

    PubMed

    Huang, Xiaopeng; Hou, Xiaojing; Jia, Falong; Song, Fahui; Zhao, Jincai; Zhang, Lizhi

    2017-03-15

    This study reports the H2O2 activation with different hematite nanocrystals and ascorbate ions for the herbicide alachlor degradation at pH 5. We found that hematite nanoplates (HNPs) exposed with {001} facets exhibited better catalytic performance than hematite nanocubes (HNCs) exposed with {012} facets, which was attributed to the formation of inner-sphere iron-ascorbate complexes on the hematite facets. The 3-fold undercoordination Fe cations of {001} facet favors the formation of inner-sphere iron-ascorbate complexes, while the 5-fold undercoordination Fe cations of {012} facet has stereo-hindrance effect, disfavoring the complex formation. The surface area normalized alachlor degradation rate constant (23.3 × 10(-4) min(-1) L m(-2)) of HNPs-ascorbate Fenton system was about 2.6 times that (9.1 × 10(-4) min(-1) L m(-2)) of HNCs-ascorbate counterpart. Meanwhile, the 89.0% of dechlorination and 30.0% of denitrification in the HNPs-ascorbate Fenton system were also significantly higher than those (60.9% and 13.1%) of the HNCs-ascorbate one. More importantly, the reductive dissolution of hematite by ascorbate was strongly coupled with the subsequent H2O2 decomposition by surface bound ferrous ions through surface iron cycle on the hematite facets in the hematite-ascorbate Fenton systems. This coupling could significantly inhibit the conversion of surface bound ferrous ions to dissolved ones, and thus account for the stability of hematite nanocrystals. This work sheds light on the internal relationship between iron geochemical cycling and contaminants degradation, and also inspires us to utilize surface iron cycle of widely existent hematite for environmental remediation.

  14. Influence of herbicide structure, clay acidity, and humic acid coating on acetanilide herbicide adsorption on homoionic clays.

    PubMed

    Liu, Weiping; Gan, Jianying; Yates, Scott R

    2002-07-03

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite was studied by coupling batch equilibration and FT-IR analysis. Adsorption decreased in the order metolachlor > acetochlor > alachlor > propachlor on Ca(2+)- or Mg(2+)-saturated clays and in the order metolachlor > alachlor > acetachlor > propachlor on Al(3+)- or Fe(3+)-saturated clays. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in bonding. For the same herbicide, adsorption of alachlor, acetachlor, and metolachlor on clay followed the order Ca(2+) approximately Mg(2+) < Al(3+) < or = Fe(3+), which coincided with the increasing acidity of homoionic clays. Adsorption of propachlor, however, showed an opposite dependence, suggesting a different governing interaction. In clay and humic acid mixtures, herbicide adsorption was less than that expected from independent additive adsorption by the individual constituents, and the deviation was dependent on the clay-to-humic acid ratio, with the greatest deviation consistently occurring at a 60:40 clay-to-humic acid ratio.

  15. 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.

  16. GC-ECD analysis of S-metolachlor (Dual Gold) in cotton plant and soil in trial field.

    PubMed

    Cao, Pengying; Liu, Fengmao; Wang, Suli; Wang, Yuhong; Han, Lijun

    2008-08-01

    The analytical method of S-metolachlor residue and its degradation in cotton and soil in trial field were investigated. S-metolachlor EC (96% w/w) was applied as pre-emergence at dosages of 1,500 and 2,250 ml ha(-1) 3 days after sowing of the cottonseeds in the field. The soil and the plant samples were collected at different intervals and the residues of S-metolachlor were analyzed by GC-ECD. The results showed that the degradation of S-metolachlor in cotton leaves in Beijing and Nanjing coincides with C = 0.1113e(-0.1050t) and C = 0.1177e(-0.1580t), respectively; the half-lives were about 6.6 and 4.4 days. The degradation of S-metolachlor in soil in Beijing and Nanjing coincides with C = 1.0621e(-0.0475) (t), and C = 0.9212e(-0.0548) (t), respectively; the half-lives were about 14.6 and 12.6 days,. At harvest time, the S-metolachlor in cotton seeds and soil samples were detected by GC-ECD and confirmed by GC/MS. The results showed that the residues in cottonseeds were lower than the USA EPA's maximum residue limit of 0.1 mg kg(-1) in cottonseed. It could be considered as safe to human beings and environment.

  17. Influence of chemical treatments on glutathione S-transferases of maize with activity towards metolachlor and cinnamic acid.

    PubMed

    Cottingham, C K; Hatzios, K K; Meredith, S

    1998-01-01

    The subcellular distribution of glutathione S-transferase (GST) activity extracted from shoots of 3-day-old etiolated seedlings of maize (Zea mays L., Northrup-King 9283 hybrid) and the induction of soluble and membrane-bound GST activity by the safener benoxacor, the herbicide metolachlor and their combination (CGA-180937) were investigated. GST activity extracted from maize shoots was detected in both cytosolic and microsomal fractions and utilized 1-chloro-2,4-dinitrobenzene (CDNB), metolachlor, and trans-cinnamic acid (CA) as substrates. Soluble GST activity extracted from maize shoots was greater than microsomal with CDNB or metolachlor as substrate. Membrane-bound GST activity was greater than soluble with cinnamic acid as substrate. Washing the microsomal preparations from maize shoots with Triton X-100 increased GST(CA) activity. Pretreatment with the safener benoxacor or a formulated combination of the herbicide metolachlor with benoxacor induced soluble GST(CDNB), GST(metolachlor) and GST(CA) activities in maize shoots. Benoxacor and CGA-180937 induced also membrane-bound GST(CDNB) and GST(CA) activities in maize shoots, but did not affect membrane-bound GST(metolachlor) activity. These results confirm that maize contains multiple GST isozymes that differ in their substrate specificity and inducibility by safeners or other chemicals.

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

    PubMed

    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-1-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. Treatments 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 day to 0.38 day and showed similar rates in the aquaria and the outdoor systems. The second phase of the chlorpyrifis loss pattern was slower (18-20 days) in all the treatments except for the low herbicide treatment in the outdoor test, where it was 3.4 days. Compared to the outdoor system, herbicide losses were much slower in the aquaria, e.g., 150 days for atrazine and 55 days for metolachlor, and no appreciable loss of herbicide was apparent in the high-treated aquaria. In the outdoor systems, the half-lives for the low herbicide treatment were 27 days and 12 days, respectively, for atrazine and metolachlor, and 48 and 20 days, respectively for the high herbicide-treated pond. Very low levels of CIAT (6-amino-2-chloro-4-iso-propylamino- s-triazine) and CEAT (2-chloro-4-ethylamino-6-ethylamino- s-triazine), degradation products of atrazine, were observed in the outdoor studies.

  19. Biochar characteristics produced from rice husks and their sorption properties for the acetanilide herbicide metolachlor.

    PubMed

    Wei, Lan; Huang, Yufen; Li, Yanliang; Huang, Lianxi; Mar, Nyo Nyo; Huang, Qing; Liu, Zhongzhen

    2017-02-01

    Rice husk biochar (RHBC) was prepared for use as adsorbents for the herbicide metolachlor. The characteristics and sorption properties of metolachlor adsorbed by the RHBC prepared at different pyrolysis temperatures were determined by analysis of physico-chemical characteristics, Fourier transform infrared spectroscopy (FTIR), Boehm titration, scanning electron microscopy (SEM), and thermodynamics and kinetics adsorption. With increasing pyrolysis temperature, the RHBC surface area greatly increased (from 2.57 to 53.08 m(2) g(-1)). RHBC produced at the highest temperature (750 °C) had the greatest surface area; SEM also showed the formation of a porous surface on RH-750 biochar. The sorption capacity of RHBC also increased significantly with increasing pyrolysis temperature and was characterized by the Freundlich constant K f for the adsorption capacity increasing from 125.17-269.46 (pyrolysis at 300 °C) to 339.94-765.24 (pyrolysis at 750 °C). The results indicated that the surface area and pore diameter of RHBC produced with high pyrolysis temperature (i.e., 750 °C) had the greatest impact on the adsorption of metolachlor. The FTIR, Boehm titration, and SEM analysis showed that the greatest number of surface groups were on RHBC produced at the lowest temperature (300 °C). The biochars produced at different pyrolysis temperatures had different mechanisms of adsorbing metolachlor, which exhibited a transition from hydrogen bonds dominant at low pyrolytic temperature to pore-filling dominant at higher pyrolytic temperature.

  20. 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.

  1. 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.

  2. Effect of controlled release formulations of diuron and alachlor herbicides on the biochemical activity of agricultural soils.

    PubMed

    Tejada, Manuel; Morillo, Esmeralda; Gómez, Isidoro; Madrid, Fernando; Undabeytia, Tomás

    2017-01-15

    The use of pesticides in agriculture is essential because it reduces the economic losses caused by pests, improving crop yields. In spite of the growing number of studies concerning the development and application of controlled release formulations (CRFs) of pesticides in agricultural soils, there are no studies about the effects of such formulations on the biochemical properties. In this paper the dissipation of diuron and alachlor in three agricultural soils for 127days, applied either as commercial or CRFs, was determined as well as their concomitant effects on soil biochemical properties. Dehydrogenase, urease, β-glucosidase and phosphatase activities were measured thought the experimental period. The application of alachlor as CRF increases its half-life time in soils, whereas no differences were noticed between diuron formulations due to its slower degradation, which takes longer than its release from the CRF. At the end of the incubation period, the enzymatic activities were the same after the use of diuron either as commercial or CRF, recovering the soil previous status. For alachlor formulations, no differences in enzymatic activities were again observed between both formulations, but their levels in soils were enhanced. Therefore, the use of these CRFs does not adversely affect the soil biochemical properties.

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

    USGS Publications Warehouse

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

    2002-01-01

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

  4. Isolation and identification of the metolachlor stereoisomers using high-performance liquid chromatography, polarimetric measurements, and enantioselective gas chromatography.

    PubMed

    Müller, M D; Poiger, T; Buser, H

    2001-01-01

    Because of the presence of two chiral elements (an asymmetrically substituted carbon and a chiral axis), the herbicide metolachlor consists of four stereoisomers stable at ambient temperature with aSS-, aRS-, aSR-, and aRR-configurations (aSS, the isomer with aS,1'S-configuration, etc.). Metolachlor, initially introduced into the market as the racemic product containing all four stereoisomers, is currently being replaced worldwide by S-metolachlor, the product enantiomerically enriched with the herbicidally active 1'S-isomers (aSS, aRS). The isomer-specific analysis of metolachlor requires not only enantioselective ("chiral") analytical techniques but also suitable reference compounds. In this study, two of the four metolachlor isomers were isolated from rac-metolachlor in enantio- (ee > 98%) and diastereomerically pure forms by a combination of achiral and chiral high-performance liquid chromatography (HPLC). The two isomers were identified as the aSS- and the aRR-isomers by polarimetric measurements, in reference to previous data. The two isomers were then thermally equilibrated to 1:1 mixtures of the aSS/aRS and aRR/aSR diastereomers, respectively, so that analytical data of all four metolachlor isomers became available; they were then used to identify these isomers in technical products by chiral high-resolution gas chromatography (HRGC). The kinetics of the thermally induced interconversion of the atropisomers was studied and the consequences, such as for GC analysis, are discussed. A comparison of on-column and split/splitless injection indicated that the latter technique results in significant isomerization prior to separation and, therefore, cannot be used for accurate isomer analysis.

  5. 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

  6. 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.

  7. 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.

  8. Dechlorination of chloroacetanilide herbicides by plant growth regulator sodium bisulfite.

    PubMed

    Bian, Haitao; Chen, Jingwen; Cai, Xiyun; Liu, Ping; Wang, Ying; Huang, Liping; Qiao, Xianliang; Hao, Ce

    2009-08-01

    Chloroacetanilide herbicides are frequently detected in groundwater and surface waters, and pose high risks to aquatic biota. In this study, sodium bisulfite (NaHSO(3)), a plant growth regulator used in China, was used to remove three chloroacetanilide herbicides including alachlor, acetochlor and S-metolachlor. These herbicides were rapidly dechlorinated by NaHSO(3) in neutral conditions. The dechlorination was accelerated with increasing pH, temperature and NaHSO(3) concentrations. Kinetic analysis and mass spectrum identification revealed that the reaction followed S(N)2 nucleophilic substitution, in which the chlorine was replaced by the reactive specie sulfite. Alachlor and its isomer acetochlor had similar reaction rates, whereas they were more readily transformed than S-metolachlor that had larger steric hindrance and weaker electrophilicity. The transformation products were chloroacetanilide ethane sulfonic acids (ESAs), which were also encountered as major metabolites of these herbicides in natural environment via common metabolic pathways and were less toxic to green algae compared to the parent herbicides. These results indicate that NaHSO(3) can accelerate transformation of chloroacetanilide herbicides to the less toxic transformation products by nucleophilic substitution and dechlorination in aquatic environment. NaHSO(3) can be potentially used for the removal of chloroacetanilide herbicides from wastewater effluent, spill sites and accidental discharge.

  9. 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.

  10. Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water.

    PubMed

    Souissi, Yasmine; Bouchonnet, Stéphane; Bourcier, Sophie; Kusk, Kresten Ole; Sablier, Michel; Andersen, Henrik Rasmus

    2013-08-01

    The widespread occurrence of chlorinated herbicides and their degradation products in the aquatic environment raises health and environmental concerns. As a consequence pesticides, and to a lesser degree their degradation products, are monitored by authorities both in surface waters and drinking waters. In this study the formation of degradation products from ultraviolet (UV) treatment of the three chloroacetamide herbicides acetochlor, alachlor and metolachlor and their biological effects were investigated. UV treatment is mainly used for disinfection in water and wastewater treatments. First, the chemical structures of the main UV-degradation products were identified using gas chromatography coupled with mass spectrometry and liquid chromatography-mass spectrometry. The main transformation reactions were dechlorination, mono- and multi-hydroxylation and cyclizations. The ecotoxicity of the mixed photoproducts formed by UV-treatment until 90% of the original pesticide was converted was compared to the toxicity of chloroacetamides using the green alga Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the marine bacteria Vibrio fischeri as test organisms. UV-treatment of alachlor and metolachlor increased the toxicity compared to the parent compounds while an equal toxicity was found for photolysis products of acetochlor. This suggests that toxic photodegradation products are generated from chloroacetamides under UV-treatment. An important perspective of this finding is that the photolysis products are at least as toxic as the parent compounds.

  11. Historical review (1983-1992) surface water monitoring for the herbicide metolachlor in midwestern rivers and lakes

    SciTech Connect

    Tierney, D.P.; Newby, L.C.

    1995-12-01

    Metolachlor monitoring data from six studies involving 84 rivers, streams and lakes at 106 locations in the central and southeastern United States in 15 states were summarized. These studies cover a ten-year period (1983-1992). The surface water bodies were chosen because most drained agricultural watersheds with a hi-story of metolachlor use. Metolachlor was detected in 57% of 6,125 samples. Only one sample exceeded the 100 ppb lifetime drinking water health advisory level, while 71% of all samples were below 1.0 ppb and 87% were below 5.0 ppb; less than 1.0% of the samples exceeded 30.0 ppb. Spring mean values for all sites and years ranged from non-detectable to 15.63 ppb. Annual means at all locations were below 5.0 ppb, while 76.9% were below 1.00 ppb and 14.5% had non-detectable residues. Metolachlor individual, spring and annual mean concentrations in the 84 surface water bodies were compared to the EPA drinking water Health Advisories (HAL). None of the spring and annual mean concentrations exceeded the lifetime metolachlor HAL of 100 ppb. The concentrations measured in rivers, streams, lakes and reservoirs and presented in this report are not expected to pose any acute or chronic health risks to populations who are using these waters.

  12. Occurrence, distribution, and loads of selected pesticides in streams in the Lake Erie-Lake St. Clair basin, 1996-98

    USGS Publications Warehouse

    Frey, Jeffrey W.

    2001-01-01

    Loads and yields of selected pesticides were calculated. The highest loads calculated were those for atrazine and metolachlor in the Maumee River at Waterville, Ohio, with 47,000 and 44,000 pounds per year, respectively. Of the row-crop basins, either the St. Joseph River near Newville, Ind., or the Auglaize River near Fort Jennings, Ohio, had the highest yields for the herbicides acetochlor, alachlor, atrazine, cyanazine, metolachlor, and simazine. The Cuyahoga River at Cleveland, Ohio, had the highest yields for diazinon and prometon?pesticides that typically are applied heavily in urban areas. The percentage of the applied atrazine that was calculated in the stream was determined for each basin in 1997. The export of atrazine ranged from 0.10 percent at the River Raisin near2 Manchester, Mich., to 10.6 percent at the St. Joseph River near Newville, Ind.

  13. The phenotype of grape leaves caused by acetochlor or fluoroglycofen, and effects of latter herbicide on grape leaves.

    PubMed

    Tan, Wei; Liang, Ting; Li, Qingliang; Du, Yuanpeng; Zhai, Heng

    2014-09-01

    Fluoroglycofen and acetochlor are two different herbicides used in vineyards to eradicate weeds. This present study first characterized the effects of these chemicals on phenotype of grape leaves. Results showed that acetochlor caused the middle- and upper-node grape leaves become yellow at 60th day after treatment, while fluoroglycofen caused the ones became dark green. Then the effects of fluoroglycofen on photosynthetic pigments and chloroplast ultrastructure were characterized. Results showed that fluoroglycofen increased the chlorophyll and carotenoid contents by different extent in different node leaves, while it did not affect the net photosynthesis rate significantly. Chloroplast ultrastructure analysis showed that the gap between thylakoids layers in few chloroplasts of middle-node leaves increased, which was also observed in ones of upper-node leaves; the number and size of chloroplast increased. Analysis on the deformed leaves of grapevines treated with 375 g ai ha(-1) fluoroglycofen showed that the starch grain per cell was much more and larger than that in the same size control leaves; the dark green and yellow parts had more or fewer chloroplast than the control, respectively, but both with more grana per chloroplast and less layers per granum. Chloroplasts went larger and round. Taken together, these results suggested that fluoroglycofen caused the grape leaves become dark green, which might be associated with the changes of chloroplast; the growth inhibition in the second year might be due to accumulation of starch.

  14. 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.

  15. 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.

  16. Monitoring stereoselective degradation of metolachlor in a constructed wetland: use of statistically valid enantiomeric and diastereomeric fractions as opposed to ratios.

    PubMed

    Aboul Eish, Mohamed Y Z; Wells, Martha J M

    2008-03-01

    Environmentally contaminated aqueous samples are examined for evidence of stereoselective degradation of metolachlor. The unique chemical structure of metolachlor, a chloroacetamide herbicide, consists of four stereoisomers due to axial and/or C-chirality. The degradation of metolachlor is monitored over time in agricultural runoff water that is applied to a subsurface flow constructed wetland. Metolachlor stereoisomers are isolated from aqueous samples by achiral reversed-phase solid-phase extraction and analyzed by normal-phase high-performance liquid chromatography using a chiral stationary phase. The analyses of 64 post-application samples, collected over a period of four weeks, are reported. The samples are filtered (0.45 microm) prior to analysis and thereby represent metolachlor in solution and/or associated with dissolved organic carbon. Sixteen samples demonstrate total racemic metolachlor concentrations greater than 10 ppb. Of these 16 samples, one sample is determined statistically to demonstrate enantioselective degradation. Significant contributions made by this study include the evaluation of stereoselectivity based on mathematically derived fractions, rather than ratios, and statistical evaluation of precision establishing the variability resulting from chromatographic processes versus metabolic processes. The research demonstrates that distribution of metolachlor between the solid phase composed of chemical and/or biological particulates and the aqueous phase is not primarily stereoselective, and that stereoselectively enriched metolachlor does not dominate in the aqueous phase.

  17. A novel function of sanshools: the alleviation of injury from metolachlor in rice seedlings.

    PubMed

    Tang, Xinke; Zhou, Xiaomao; Wu, Jing; Li, Jingbo; Bai, Lianyang

    2014-03-01

    Szechuan peppers are extensively used as a spice and in traditional medicine in Asia, primarily because of its active compounds, sanshools (S). However, there is only limited mention in agriculture, and there are no papers reporting its use as an herbicide safener. In this study, we provide the first evidence that S can effectively alleviate rice-seedling injury from metolachlor (M). We observed that the M-treated (0.25 μM) rice seedlings, which were 56.0%, 66.0%, and 57.0% of the non-treated control in shoot height, root length, and fresh biomass, respectively, were recovered by S to 93.1%, 97.6%, and 94.8%, respectively. The emergence rate was enhanced to over 80% in the M+S treatment, whereas it was below 60% in the M treatment. This M+S mixture elevated the rice-seedling root activity to higher than 87.0% of the value for the non-treated control. The activity of glutathione transferases in the combined treatments approximately doubles that of the M treatment and quadruples that of the non-treated controls. This effect was positively correlated with the induced expression of OsGSTU3. Our results suggest that S may represent a new group of safeners and enable the possibility of using these compounds for improving plant production or protecting rice from the phytotoxicity of metolachlor.

  18. 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

  19. Stability of isoproturon, bentazone, terbuthylazine and alachlor in natural groundwater, surface water and soil water samples stored under laboratory conditions.

    PubMed

    Mouvet, C; Jeannot, R; Riolland, H; Maciag, C

    1997-09-01

    The stability of isoproturon, bentazone, terbuthylazine and alachlor was investigated in groundwater (GrW), surface water (SuW) and soil water from the unsaturated zone (SoW). Samples fortified with a low spiking level (LSL) of about 0.3-0.5 microgram/L and a high spiking level (HSL) of about 0.9-1.3 micrograms/L were stored for 1, 2, 14 (GrW) and 30 days (SuW and SoW) at 4 degrees C in amber glass bottles without biological inhibition. The initial pesticide concentration played a significant role, the lowest concentrations being the least stable for all pesticides. Nevertheless, after 14 days of storage, no concentration had decreased significantly compared to day 0 values, except for bentazone LSL in the GrW and SuW. Significant losses of alachlor were observed only after 30 days. Terbuthylazine and isoproturon were stable for 30 days, except for a slight loss of terbuthylazine HSL in the SoW. The very poor recovery of bentazone from the SoW gave poor results for interpretation. Overall, the stability of the molecules was highest in the GrW and lowest in the SoW. For SoW, the variability of triplicate determinations at a given storage time was, in some cases, as great as the changes in mean concentrations observed over the total 30 day storage period.

  20. 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.

  1. 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 ...

  2. 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.

  3. 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...

  4. Enantioselective induction of a glutathione-S-transferase, a glutathione transporter and an ABC transporter in maize by Metolachlor and its (S)-isomer.

    PubMed

    Pang, Sen; Ran, Zhaojin; Liu, Zhiqian; Song, Xiaoyu; Duan, Liusheng; Li, Xuefeng; Wang, Chengju

    2012-01-01

    The metabolism of chiral herbicides in plants remains poorly understood. Glutathione conjugation reactions are one of the principal mechanisms that plants utilize to detoxify xenobiotics. The induction by rac- and S-metolachlor of the expression of three genes, ZmGST27, ZmGT1 and ZmMRP1, encoding respectively a glutathione-S-transferase, a glutathione transporter and an ATP-binding cassette (ABC) transporter was studied in maize. The results demonstrate that the inducing effect of rac- and S-metolachlor on the expression of ZmGST27 and ZmGT1 is comparable. However, the inducing effect of rac-metolachlor on ZmMRP1 expression is more pronounced than that of S-metolachlor. Furthermore, vanadate, an ABC transporter inhibitor, could greatly reduce the difference in herbicidal activity between rac- and S-metolachlor. These results suggest that the ABC transporters may preferentially transport conjugates of rac-metolachlor, leading to a faster metabolism of the latter. Through comparing the expression of ZmGST27, ZmMRP1 and ZmGT1 after treatment by rac- and S-metolachlor, we provide novel insights into the metabolic processes of chiral herbicides in plants.

  5. Enantioselective Induction of a Glutathione-S-Transferase, a Glutathione Transporter and an ABC Transporter in Maize by Metolachlor and Its (S)-Isomer

    PubMed Central

    Liu, Zhiqian; Song, Xiaoyu; Duan, Liusheng; Li, Xuefeng; Wang, Chengju

    2012-01-01

    The metabolism of chiral herbicides in plants remains poorly understood. Glutathione conjugation reactions are one of the principal mechanisms that plants utilize to detoxify xenobiotics. The induction by rac- and S-metolachlor of the expression of three genes, ZmGST27, ZmGT1 and ZmMRP1, encoding respectively a glutathione-S-transferase, a glutathione transporter and an ATP-binding cassette (ABC) transporter was studied in maize. The results demonstrate that the inducing effect of rac- and S-metolachlor on the expression of ZmGST27 and ZmGT1 is comparable. However, the inducing effect of rac-metolachlor on ZmMRP1 expression is more pronounced than that of S-metolachlor. Furthermore, vanadate, an ABC transporter inhibitor, could greatly reduce the difference in herbicidal activity between rac- and S-metolachlor. These results suggest that the ABC transporters may preferentially transport conjugates of rac-metolachlor, leading to a faster metabolism of the latter. Through comparing the expression of ZmGST27, ZmMRP1 and ZmGT1 after treatment by rac- and S-metolachlor, we provide novel insights into the metabolic processes of chiral herbicides in plants. PMID:23144728

  6. 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

  7. 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.

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

    PubMed

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

    2009-02-25

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

  9. Determination of the 1'S and 1'R diastereomers of metolachlor and S-metolachlor in water by chiral liquid chromatography-mass spectrometry/mass spectrometry (LC/MS/MS).

    PubMed

    Kabler, A Kent; Chen, Sunmao

    2006-08-23

    An enantioselective method for the separation and quantification of the diastereomer pairs of metolachlor and S-metolachlor in surface and ground waters is presented. Samples are purified and concentrated using a C18 (octadecyl silica) solid-phase extraction (SPE) procedure and analyzed by chiral column liquid chromatography-mass spectrometry/mass spectrometry (LC/MS/MS) interfaced with either atmospheric pressure chemical ionization (APcI) or atmospheric pressure photoionization (APPI) sources. The overall mean percent procedural recoveries (percent relative standard deviations) are 89% (10.6%) for surface water and 80% (9.1%) for ground water. The method limit of quantitation (LOQ) is 0.10 ppb. The method validation was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160.

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

    USGS Publications Warehouse

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

    2007-01-01

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

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

    PubMed

    Lizotte, Richard E; Knight, Scott S; Shields, F Douglas; Bryant, Charles T

    2009-12-01

    We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a pesticide mixture of atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first 2 h of amendment at the upstream amendment site but not at any time at the downstream site. H. azteca survival varied spatially and temporally in conjunction with measured pesticide mixture concentrations. Hyalella azteca 96 h survival pesticide mixture effects concentrations ranges were 10.214–11.997, 5.822–6.658, 0.650–0.817, and 0.030–0.048 μg L−1 for atrazine, metolachlor, fipronil, and fipronil-sulfone, respectively.

  12. 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).

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

    PubMed

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

    2016-02-01

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

  14. Buffer strip effect on terbuthylazine, desethyl-terbuthylazine and S-metolachlor runoff from maize fields in Northern Italy.

    PubMed

    Milan, Marco; Vidotto, Francesco; Piano, Serenella; Negre, Michèle; Ferrero, Aldo

    2013-01-01

    The effectiveness of a 6 m wide vegetative buffer strip for reducing runoff of S-metolachlor, terbuthylazine and desethyl-terbuthylazine was studied in 2007-2008 in Northern Italy. Two cultivated fields, with and without the buffer strip, were compared. Residues of the chemicals were investigated in runoff water collected after runoff events and their dissipation in the soil was studied. The highest concentration of the chemicals in water occurred in samples collected from the unbuffered field at the first runoff events. Losses of terbuthylazine and S-metolachlor in runoff waters were particularly high in 2007 (2.6% and 0.9% of the amount applied, respectively). Soil half-life of terbuthylazine and S-metolachlor ranged between 12.1 and 8.9 days and 16 and 7 days, respectively. The presence of desethyl-terbuthylazine was related to parent compound degradation. The buffer strip allowed an important reduction of chemical content in water (> 90%), in particular during the first runoff events.

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

    USGS Publications Warehouse

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

    1995-01-01

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

  16. Effect of soil moisture on the release of alachlor from alginate-based controlled-release formulations.

    PubMed

    Nasser, Ahmed; Mingelgrin, Uri; Gerstl, Zev

    2008-02-27

    The release of alachlor from controlled-release formulations (CRFs) based on alginate-montmorillonite matrices into aqueous polyethylene glycol (PEG) solutions of different concentrations and into a soil at different moisture contents was studied. In distilled water and in PEG-containing solutions displaying -0.1 MPa potential and up, the beads imbibe water and swell. The ensuing increase in weight is about 5%, and the increase in the bead's diameter is about 10%. At water potentials of -0.5 MPa and lower, loss of weight and shrinkage of the beads were observed. The changes in weight and diameter of the alginate-clay beads incubated in a Hamra loamy sand soil at 26.5% moisture content (w/w; -0.18 MPa) were similar to those observed in PEG solutions of >-0.5 MPa moisture potential. The weight and diameter losses observed in the drier soils (12.0 and 7.1% water content; -0.49 and -1.11 MPa) were similar to those in the more concentrated PEG solutions. A decrease in the rate of release of the active ingredient from the beads into soil was observed as the water potential decreased (drier soils). The release of the active ingredient from the investigated CRFs displayed a linear relationship to the square root of time, suggesting a diffusion-controlled-release rate. Data extracted from this relationship enabled the formulation of a mathematical model that correlates rate of release to water content.

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

    PubMed Central

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

    2016-01-01

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

  18. 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

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

    PubMed

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

    2008-02-27

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

  20. Adsorption of chloroacetanilide herbicides on soil and its components. III. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays.

    PubMed

    Liu, Wei-ping; Fang, Zhuo; Liu, Hui-jun; Yang, Wei-chun

    2002-04-01

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca(2+)-, Mg(2+)-, Al(3+)- and Fe(3+)-saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor > acetolachlor > alachlor > propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg2+ < Ca2+ < Al3+ < or = Fe3+ which coincided with the increasing acidity of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.

  1. 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 ...

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

    USGS Publications Warehouse

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

    2009-01-01

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

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

    USGS Publications Warehouse

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

    2001-01-01

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

  4. 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 ...

  5. Environmental concentrations of irgarol, diuron and S-metolachlor induce deleterious effects on gametes and embryos of the Pacific oyster, Crassostrea gigas.

    PubMed

    Mai, Huong; Morin, Bénédicte; Pardon, Patrick; Gonzalez, Patrice; Budzinski, Hélène; Cachot, Jérôme

    2013-08-01

    Irgarol and diuron are the most representative "organic booster biocides" that replace organotin compounds in antifouling paints, and metolachlor is one of the most extensively used chloroacetamide herbicides in agriculture. The toxicity of S-metolachlor, irgarol and diuron was evaluated in Pacific oyster (Crassostrea gigas) gametes or embryos exposed to concentrations of pesticides ranging from 0.1× to 1000×, with 1× corresponding to environmental concentrations of the three studied pesticides in Arcachon Bay (France). Exposures were performed on (1) spermatozoa alone (2) oocytes alone and (3) both spermatozoa and oocytes, and adverse effects on fertilization success and offspring development were recorded. The results showed that the fertilizing capacity of spermatozoa was significantly affected after gamete exposure to pesticide concentrations as low as 1× of irgarol and diuron and 10× of metolachlor. The offspring obtained from pesticide-exposed spermatozoa displayed a dose-dependent increase in developmental abnormalities. In contrast, treating oocytes with pesticide concentrations up to 10× did not alter fertilization rate and offspring quality. However, a significant decline in fertilization success and increase in abnormal D-larvae prevalence were observed at higher concentrations 10× (0.1 μg L(-1)) for S-metolachlor and 100× for irgarol (1.0 μg L(-1)) and diuron (4.0 μg L(-1)). Irgarol, diuron and S-metolachlor also induced a dose-dependent increase in abnormal D-larvae prevalence when freshly fertilized embryos were treated with pesticide concentrations as low as concentration of 1× (0.01 μg L(-1) for irgarol or S-metolachlor, and 0.04 μg L(-1) for diuron). The two bioassays on C. gigas spermatozoa and embryos displayed similar sensitivities to the studied pesticides while oocytes were less sensitive. Diuron, irgarol and S-metolachlor induced spermiotoxicity and embryotoxicity at environmentally relevant concentrations and therefore might be

  6. 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.

  7. Sorption-desorption of alachlor and linuron in a semiarid soil as influenced by organic matter properties after 16 years of periodic inputs.

    PubMed

    Dorado, José; López-Fando, Cristina; Zancada, María-Cristina; Almendros, Gonzalo

    2005-06-29

    The effect of management practices on soil potential for regulating the residual concentration of pesticides was examined in samples from a Calcic Haploxeralf in Toledo (central Spain). Sorption-desorption of alachlor and linuron was found to depend on inputs of lignocelullosic wastes or cattle manure for the past 16 years. For a given herbicide, the soil sorption capacity (K(f)) follows the order control < crop residues < manure, which is consistent with the organic C content in the soil samples. Some structural characteristics of the soil humic acid as revealed by visible and infrared spectroscopies and analytical pyrolysis were useful to forecast the sorption-desorption intensity. Simple and multiple linear correlation analyses illustrate enhanced sorption of alachlor and linuron in soil plots where slightly altered soil organic matter accumulated (positive correlations with the intensity of infrared lignin signature band and with the methoxyphenol yields after pyrolysis of the humic acids and negative correlation with the aromaticity as pointed out by the optical density at 465 nm). Linuron showed a preference for soils with humic acids of low molecular weight and low degree of internal cross-linking, as inferred from the positive correlation with the ratio between optical densities at 465 and 665 nm. Under the conditions of the present experiment, agricultural practices including organic amendments seem to have a beneficial effect in the control of leaching and sorption of pesticides.

  8. Major herbicides in ground water: results from the National Water-Quality Assessment.

    PubMed

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

    2001-01-01

    To improve understanding of the factors affecting pesticide occurrence in ground water, patterns of detection were examined for selected herbicides, based primarily on results from the National Water-Quality Assessment (NAWQA) program. The NAWQA data were derived from 2,227 sites (wells and springs) sampled in 20 major hydrologic basins across the USA from 1993 to 1995. Results are presented for six high-use herbicides--atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), cyanazine (2-[4-chloro-6-ethylamino-1,3,5triazin-2-yl]amino]-2-methylpropionitrile), simazine (2-chloro-4,6-bis-[ethylamino]-s-triazine), alachlor (2-chloro-N-[2,6-diethylphenyl]-N-[methoxymethyl]acetamide), acetochlor (2-chloro-N-[ethoxymethyl]-N-[2-ethyl-6-methylphenyl]acetamide), and metolachlor (2-chloro-N-[2-ethyl-6-methylphenyl]-N-[2-methoxylethyl]acetamide)--as well as for prometon (2,4-bis[isopropylamino]-6-methoxy-s-triazine), a nonagricultural herbicide detected frequently during the study. Concentrations were <1 microg L(-1) at 98% of the sites with detections, but exceeded drinking-water criteria (for atrazine) at two sites. In urban areas, frequencies of detection (at or above 0.01 microg L(-1)) of atrazine, cyanazine, simazine, alachlor, and metolachlor in shallow ground water were positively correlated with their nonagricultural use nationwide (P < 0.05). Among different agricultural areas, frequencies of detection were positively correlated with nearby agricultural use for atrazine, cyanazine, alachlor, and metolachlor, but not simazine. Multivariate analysis demonstrated that for these five herbicides, frequencies of detection beneath agricultural areas were positively correlated with their agricultural use and persistence in aerobic soil. Acetochlor, an agricultural herbicide first registered in 1994 for use in the USA, was detected in shallow ground water by 1995, consistent with previous field-scale studies indicating that some pesticides may be detected in ground

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

    USGS Publications Warehouse

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

    2001-01-01

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

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

    USGS Publications Warehouse

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

    1996-01-01

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

  11. 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.

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

    PubMed

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

    2006-04-19

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

  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.

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

    USGS Publications Warehouse

    Fogarty, Lisa R.; Duris, Joseph W.

    2007-01-01

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

  15. Effects of common-use pesticides on developmental and reproductive processes in Daphnia.

    PubMed

    Kashian, Donna R; Dodson, Stanley I

    2002-06-01

    Daphnia magna were evaluated for use as a screen for pesticides that have been demonstrated to have estrogenic (o'p'-DDT, di-n-butyl phthalate, toxaphene), anti-androgenic (p'p-DDE, linuron), thyroid (acetochlor, alachlor, metribuzin), insulin (amitraz) or lutenizing hormone (2,4-D) activity in vertebrates, and to establish daphnid sensitivity to these compounds. Pesticides with unknown effects on vertebrate endocrine systems (chlorosulfuran, cyanazine, diflubenzuron, metolachlor, and diquat) were also evaluated. Compounds were assayed for six days at environmentally relevant concentrations ranging from 0.001 to 100 mirog/L, using female Daphnia and their offspring. Sublethal endpoints included offspring sex (sex determination), clutch size (fecundity), and adult size (growth rate). Toxaphene was the only compound that affected sexual differentiation, increasing male production. Daphnia fecundity declined with exposure to toxaphene, and daphnid growth rates were reduced by acetochlor exposure. Diflubenzuron, o'p'-DDT, and p'p-DDE significantly reduced Daphnia survival. No correlation existed between affected reproductive or developmental processes and specific endocrine systems or subsystems. Results from this study indicate that Daphnia make a good screen for assessing potential environmental impacts but are not a useful indicator of pesticide hormonal activity in vertebrates. This assay consistently detected sublethal but ecologically relevant effects of these pesticides on Daphnia at environmentally relevant concentrations typically below their listed EC50 value.

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

    USGS Publications Warehouse

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

    2009-01-01

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

  17. 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

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

    PubMed

    Baran, Nicole; Gourcy, Laurence

    2013-11-01

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

  19. Photocatalysis of S-metolachlor in aqueous suspension of magnetic cerium-doped mTiO2 core-shell under simulated solar light.

    PubMed

    Mermana, J; Sutthivaiyakit, P; Blaise, C; Gagné, F; Charnsethikul, S; Kidkhunthod, P; Sutthivaiyakit, S

    2017-02-01

    Magnetic cerium-doped mesoporous titanium dioxide was synthesized by combining sol-gel method and calcination using tetrabutanate and ammonium cerium nitrate as precursors and Pluronic P123 as a template coating on iron oxide covered with carbon in ethanol. The magnetic Ce-doped catalyst showed only anatase structure with a slight increase in lattice parameters compared to the undoped catalyst. The Ce LIII-edge X-ray absorption near-edge spectroscopy (XANES) spectra showed Ce(3+), and the cerium substitution doping into titanium dioxide was proposed. Degradation of S-metolachlor in aqueous magnetic photocatalyst suspension followed (pseudo) first-order kinetics in the presence of 0.5 g L(-1) of γ-Fe2O3@C@0.16 mol% Ce-mTiO2 with a half-life of 55.18 ± 1.63 min. Fifteen degradation products were identified, and their transformation routes of the photocatalytic degradation were then proposed. Complementary toxicity assessment of the treated S-metolachlor solution was undertaken with Environment Canada's algal microplate assay measuring growth inhibition (72-h IC50) in the freshwater chlorophyte Pseudokirchneriella subcapitata. This test method revealed a significant decrease in toxicity (1.7-fold reduction after 180 min of irradiation treatment), thereby confirming that the by-products formed following photocatalysis would be less harmful from an environmental point of view. Photocatalytic degradation of S-metolachlor thus appears to hold promise as a cost-effective treatment technology to diminish the presence of this herbicide in aquatic systems.

  20. 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

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

    NASA Astrophysics Data System (ADS)

    Kinney, Chad A.; Mosier, Arvin R.; Ferrer, Imma; Furlong, Edward T.; Mandernack, Kevin W.

    2004-03-01

    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

  3. 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.

  4. Atmospheric Transport and Deposition of Agricultural Chemicals

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Analysis of the chloroacetanilide herbicides in water using SPME with CAR/PDMS and GC/ECD.

    PubMed

    Hwang, Ying-Ming; Wong, Yih-Gang; Ho, Wu-Hsiung

    2005-01-01

    The solid-phase microextraction (SPME) technique using a 75 mm film of carboxen/polydimethylsiloxane was applied to the analysis of chloroacetanilide herbicides (acetochlor, alachlor, butachlor, metolachlor, and propachlor) residues. The feasibility of SPME with gas chromatography electron capture detection analysis has been evaluated. The effects of experimental parameters such as magnetic stirring, salt addition, humic acid addition, pH value, and extraction time, as well as desorption temperature and time, were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The inhibition of humic acid to the extraction of chloroacetanilide herbicides was observed. A standard addition method for calibration was recommended to reduce deviations caused by matrix interferences. The proposed method provided a simple and rapid analytical procedure for chloroacetanilide herbicides in water with limits of detection 0.002-0.065 microg/L for deionized water, and 0.005-0.22 microg/L for farm water. The relative standard deviations (n = 5) for analyses of farm water were 7-20% for 5 [corrected] microg/L chloroacetanilide herbicides. This application was illustrated by the analysis of sample collected from farm water in the Chung-hwa area, Taiwan.

  10. Simultaneous quantification of acetanilide herbicides and their oxanilic and sulfonic acid metabolites in natural waters.

    PubMed

    Heberle, S A; Aga, D S; Hany, R; Müller, S R

    2000-02-15

    This paper describes a procedure for simultaneous enrichment, separation, and quantification of acetanilide herbicides and their major ionic oxanilic acid (OXA) and ethanesulfonic acid (ESA) metabolites in groundwater and surface water using Carbopack B as a solid-phase extraction (SPE) material. The analytes adsorbed on Carbopack B were eluted selectively from the solid phase in three fractions containing the parent compounds (PCs), their OXA metabolites, and their ESA metabolites, respectively. The complete separation of the three compound classes allowed the analysis of the neutral PCs (acetochlor, alachlor, and metolachlor) and their methylated OXA metabolites by gas chromatography/mass spectrometry. The ESA compounds were analyzed by high-performance liquid chromatography with UV detection. The use of Carbopack B resulted in good recoveries of the polar metabolites even from large sample volumes (1 L). Absolute recoveries from spiked surface and groundwater samples ranged between 76 and 100% for the PCs, between 41 and 91% for the OXAs, and between 47 and 96% for the ESAs. The maximum standard deviation of the absolute recoveries was 12%. The method detection limits are between 1 and 8 ng/L for the PCs, between 1 and 7 ng/L for the OXAs, and between 10 and 90 ng/L for the ESAs.

  11. 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.

  12. Determination of triazine and chloroacetanilide herbicides in soils by microwave-assisted extraction (MAE) coupled to gas chromatographic analysis with either GC-NPD or GC-MS.

    PubMed

    Vryzas, Zisis; Papadopoulou-Mourkidou, Euphemia

    2002-08-28

    A simple and rapid method based on microwave-assisted extraction (MAE) coupled to gas chromatographic analysis was developed for the analysis of triazine (atrazine, cyanazine, metribuzine, simazine and deethylatrazine, and deisopropylatrazine) and chloroacetanilide (acetochlor, alachlor, and metolachlor) herbicide residues in soils. Soil samples are processed by MAE for 5 min at 80 degrees C in the presence of acetonitrile (20 mL/sample). Mean recovery values of most solutes are >80% in the 10 to 500 microg/kg fortification range with respective RSDs (relative standard deviations) < 20%. The limits of quantification (LOQ) and limits of detection (LOD) are 10 and 1 to 5 microg/kg, respectively. The method was validated with two types of soils containing 1.5 and 3.0% organic matter content, respectively; no statistically significant differences were found between solute recovery values from the two types of soils. The solute mean recovery values from freshly spiked (24 h aging) and spiked samples stored refrigerated for one week before processed were also not statistically different. Residue levels determined in field weathered soils were higher when soils were processed by MAE than with a comparison method based on flask-shaking of soil suspensions overnight. Extracts were analyzed by a gas chromatographic system equipped either with a thermionic (GC-NPD) or a mass spectrometric detector (GC-MS).

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Iridium-imine and -amine complexes relevant to the (S)-metolachlor process: structures, exchange kinetics, and C-H activation by Iri causing racemization.

    PubMed

    Dorta, Romano; Broggini, Diego; Kissner, Reinhard; Togni, Antonio

    2004-09-20

    Iridium complexes of DMA-imine [2,6-dimethylphenyl-1'-methyl-2'-methoxyethylimine, 1 a) and (R)-DMA-amine [(1'R)-2,6-dimethylphenyl-1'-methyl-2'-methoxyethylamine, 2 a] that are relevant to the catalytic imine hydrogenation step of the Syngenta (S)-Metolachlor process were synthesized: metathetical exchange of [Ir2Cl2(cod)2] (cod=1,5-cyclooctadiene) with [Ag(1 a)2]BF4 and [Ag((R)-2 a)2]BF4 afforded [Ir(cod)(kappa2- -1 a)]BF4 (11) and [Ir(cod)(kappa2-(R)-2 a)]BF4 ((R)-19)), respectively. These complexes were then used in stopped-flow experiments to study the displacement of amine 2 a from complex 19 by imine 1 a to form the imine complex 11, thus modeling the product/substrate exchange step in the catalytic cycle. The data suggest a two-step associative mechanism characterized by k1=(2.6+/-0.3) x 10(2) M(-1) s(-1) and k2=(4.3+/-0.6) x 10(-2) s(-1) with the respective activation energies EA1=(7.5+/-0.6) kJ mol(-1) and EA2=(37+/-3) kJ mol(-1). Furthermore, complex 11 reacted with H2O to afford the hydrolysis product [Ir(cod)(eta(6-)-2,6-dimethylaniline)]BF4 (12), and with I2 to liberate quantitatively the DMA-iminium salt 14. On the other hand, the chiral amine complex (R)-19 formed the optically inactive eta6-bound compound [Ir(cod)(eta6-rac-2 a)]BF4 (rac-18) upon dissolution in THF at room temperature, presumably via intramolecular C-H activation. This racemization was found to be a two-step event with k'1=9.0 x 10(-4) s(-1) and k2=2.89 x 10(-5) s(-1), featuring an optically active intermediate prior to sp3 C-H activation. Compounds 11, 12, rac-18, and (R)-19 were structurally characterized by single-crystal X-ray analyses.

  18. 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

  19. 78 FR 13264 - Acetochlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    .... Monsanto Company requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA). DATES.... In two developmental toxicity studies in rats, fetal effects (increased early resorptions, post... (mortality, clinical signs of toxicity, and decreased maternal body weight gain). In two rabbit...

  20. 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.

  1. 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.

  2. 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

  3. Mechanisms to Detoxify Selected Organic Contaminants in Higher Plants and Microbes, and Their Potential Use in Landscape Management

    DTIC Science & Technology

    2004-10-01

    Phanerochaete chrisosporium Phanerochaete sordida Phellinus werii Polyporus versicolor Pleurotus ostreatus This strain degrades ~50% DDT in 30 days... substrate , was also identified in potato cells (Edwards and Owen, 1989). Conjugation with glutathione is characteristic of chloroacetamide herbicides (Le...xenobiotic conjugation with glutathione, had a three times higher activity when alachlor was used as a substrate than with metolachlor (O’Connel et al

  4. 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.

  5. Adsorption mechanism of chloroacetanilide herbicides to modified montmorillonite.

    PubMed

    El-Nahhal, Yasser

    2003-09-01

    This study was undertaken to characterize the adsorption mechanism of alachlor and metolachlor on montmorillonite modified with cationic surfactants. Adsorbed amounts of cationic surfactant on montmorillonite surfaces were determined by CNHSO analyzer. Equilibrium concentrations of alachlor and metolachlor were determined by GC and adsorption results were fit to a linear regression equation. The slope of the isotherms (Kd) was normalized to the fraction of organic carbon on montmorillonite complexes to produce corresponding Koc. Adsorption of surfactants fit very well to Langmuir equation. Increased basal spacing indicates that surfactant molecules could penetrate through the interlayer spacing and arrange themselves in different ways. Equilibrium data of alachlor and metolachlor suggest that adsorption may occur via physical or chemical bonds. Koc values of alachlor or metolachlor decreased as the fraction of the organic carbon increased in montmorillonite complexes indicating independent adsorption process. Changes of the molar free energy of the adsorption reactions were in the range of physical adsorption, indicating that adsorption reactions are spontaneous and the molecules either adsorb on the surface or penetrate into the inter-layers of montmorillonite-surfactant complex. Careful investigation of the adsorption data suggests that interaction may occur via the active groups such as carbonyl group (-C=O), anilidic (C-N) group and/or phenyl rings. This information may provide better understanding on adsorption mechanism and be useful in designing ecologically acceptable herbicide formulations.

  6. 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 ...

  7. Environmental Quality: Environmental Protection and Enhancement

    DTIC Science & Technology

    2002-01-17

    MTBE (20) Alachlor ESA (36) Lead- 210 (9) Nitrobenzene (21) 1,2-diphenylhydrazine (37) Polonium - 210 (10) Terbacil (22) Diazinon (11) Acetochlor (23... asbestos management, radon reduction, pollution prevention, environmental restoration, environmental quality technology, automated environmental...37 Complaint management • 7–4, page 37 Noise assessment • 7–5, page 38 Technical assistance • 7–6, page 39 Chapter 8 Asbestos Management, page 43

  8. Sparingly soluble pesticide dissolved in ionic liquid aqueous.

    PubMed

    Fan, Tengfei; Wu, Xuemin; Peng, Qingrong

    2014-10-02

    Ionic liquids may be considered as "environment-friendly solvents" for sparingly soluble pesticides. In this study, a series of aqueous ionic liquids (ILs) with different cations and different anions was used as environment-friendly alternative to harmful organic solvents sparingly dissolved in soluble pesticides (metolachlor, acetochlor, clethodim, thiamethoxam, and prochloraz). The aggregation behavior of aqueous ILs was investigated through surface tension measurement. Minimum area per IL molecule (Amin) values from the surface tension measurement showed that alkyl chain length and the halide anions strongly affect the aggregation behavior of ILs and the solubilization of pesticides. The solubility of metolachlor, acetochlor, clethodim, thiamethoxam, nitenpyram, and prochloraz in aqueous ILs increased. More importantly, the solubility of prochloraz in [C10mim][I] became 5771-fold higher than that in pure water. The substantially enhanced solubility of the above pesticides proved that aqueous ILs are promising environment-friendly solvents for pesticides that are commercially processed in emulsifiable concentrate (EC) formulation.

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

    USGS Publications Warehouse

    King, Robin B.

    2003-01-01

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

  10. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  11. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  12. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  13. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  14. 40 CFR 180.470 - Acetochlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  15. 40 CFR 180.249 - Alachlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... per million Animal feed, nongrass, group 18, forage 1.4 Animal feed, nongrass, group 18, hay 1.2 Grain..., 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...

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

    USGS Publications Warehouse

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

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

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

  18. 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.

  19. Comparative metabolism and elimination of acetanilide compounds by rat.

    PubMed

    Davison, K L; Larsen, G L; Feil, V J

    1994-10-01

    1. 14C-labelled propachlor, alachlor, butachlor, metolachlor, methoxypropachlor and some of their mercapturic acid pathway metabolites (MAP) were given to rat either by gavage or by perfusion into a renal artery. MAP metabolites were isolated from bile and urine. 2. Rat gavaged with propachlor and methoxypropachlor eliminated 14C mostly in urine, whereas rat gavaged with alachlor, butachlor and metolachlor eliminated 14C about equally divided between urine and faeces. When bile ducts were cannulated, the gavaged rat eliminated most of the 14C in bile for all compounds. The amount of 14C in bile from the propachlor-gavaged rat was less than that for the other acetanilides, with the difference being in the urine. 3. The mercapturic acid metabolites 2-methylsulphinyl-N-(1-methylhydroxyethyl)-N-phenylacetam ide and 2-methylsulphinyl-N-(1-methylmethoxyethyl)-N-phenylacetam ide were isolated from the urine and bile of the methoxypropachlor-gavaged rat. 4. Bile was the major route for 14C elimination when MAP metabolites of alachlor, butachlor and metolachlor were perfused into a renal artery. Urine was the major route for 14C elimination when MAP metabolites of propachlor and methoxypropachlor were perfused. Mercapturic acid conjugates were major metabolites in bile and urine when MAP metabolites were perfused. 5. We conclude that alkyl groups on the phenyl portion of the acetanilide causes biliary elimination to be favoured over urinary elimination.

  20. 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).

  1. Enantioseparation of four amide herbicide stereoisomers using high-performance liquid chromatography.

    PubMed

    Xie, Jingqian; Zhao, Lu; Liu, Kai; Guo, Fangjie; Liu, Weiping

    2016-11-04

    The chirality of herbicides has been the focus of research. However, there is little information on the enantioseparation of amide herbicides with different chiral elements. In this study, the need for different chiral stationary phases (CSPs), mobile phases, temperatures and flow rates for the separation of napropamide, acetochlor and propisochlor was discussed in detail and compared to metolachlor. Resolution of C-chiral enantiomers was easier than that of axial-chiral enantiomers. Metolachlor and acetochlor could achieve baseline separation only on AY-H and AS-H columns, respectively. Propisochlor had satisfactory separations on OD-H and AS-H columns. Napropamide was separated on OJ-H, AY-H and AS-H columns. Both the structures of the compounds and CSPs and the interactions between them played significant roles in the enantioseparations. Molecule dockings were also used to elucidate the separation mechanisms. C-chiral enantiomers had perfect symmetry in their optical properties, whereas the axial-chiral enantiomers did not. The elution order for napropamide, acetochlor and propisochlor, with a single chiral location, was R- prior to S-. These results were the first that compare the enantioseparations of four amide herbicides with different chirality, and they provided the absolute configurations for the herbicides. The paper also illustrated certain mechanisms for enantioseparations.

  2. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....04 Milk 0.02 Nut, tree, group 14 0.10 Okra 0.50 Peanut 0.20 Peanut, hay 20 Peanut, meal 0.40 Potato 0... and liver 0.04 Leaf petioles, subgroup 4B 0.10 Melon, subgroup 9A 0.10 Milk 0.02 Okra 0.10 Onion,...

  3. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., meat 0.02 Horse, meat byproducts, except kidney and liver 0.04 Milk 0.02 Nut, tree, group 14 0.10 Okra... and liver 0.04 Leaf petioles, subgroup 4B 0.10 Melon, subgroup 9A 0.10 Milk 0.02 Okra 0.10 Onion,...

  4. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....04 Milk 0.02 Nut, tree, group 14 0.10 Okra 0.50 Peanut 0.20 Peanut, hay 20 Peanut, meal 0.40 Potato 0....04 Leaf petioles, subgroup 4B 0.10 Melon, subgroup 9A 0.10 Milk 0.02 Okra 0.10 Onion, bulb,...

  5. 40 CFR 180.368 - Metolachlor; tolerances for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., meat 0.02 Horse, meat byproducts, except kidney and liver 0.04 Milk 0.02 Nut, tree, group 14 0.10 Okra... and liver 0.04 Leaf petioles, subgroup 4B 0.10 Melon, subgroup 9A 0.10 Milk 0.02 Okra 0.10 Onion,...

  6. 75 FR 56897 - S-metolachlor; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-17

    ...); cucumber, okra, sesame seed, and sorghum sweet, at 0.1 ppm; Brassica, leafy greens, subgroup 5B, and turnip... at 0.13 ppm, leafy Brassica greens, subgroup 5B at 1.8 ppm, melon subgroup 9B at 0.10 ppm, okra at 0... Carrot, roots 0.40 * * * * * Cucumber 0.13 * * * * * Melon, subgroup 9A 0.10 * * * * * Okra 0.10...

  7. 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...

  8. 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.

  9. [Study on the reaction mechanism of chloroacetanilide herbicides with urease using fluorescence spectrum and high-performance liquid chromatography].

    PubMed

    Liu, Hui-jun; Zhan, Xiu-Ming; Li, Ke-bin; Liu, Wei-ping

    2005-03-01

    The relationship between excess thermodynamic function and binding to urease of four chloroacetanilide herbicides was studied using high-performance liquid chromatography and fluorescence spectrum. The linear relationship between the composition of mobile phase of RP-HPLC and the capacity factor of chloroacetanilide herbicides has been obtained. The excess thermodynamic enthalpy (deltaH* ) of acetochlor, pretilachlor, butachlor and metolachlor was determined, and the binding constant K and the number of binding sites with urease were calculated. The relationship between excess thermodynamic function and the binding constant K was suggested.

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

    PubMed

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

    2011-11-30

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

  11. 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

  12. 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.

  13. Glutathione conjugation and contaminant transformation

    USGS Publications Warehouse

    Field, Jennifer A.; Thurman, E.M.

    1996-01-01

    The recent identification of a novel sulfonated metabolite of alachlor in groundwater and metolachlor in soil is likely the result of glutathione conjugation. Glutathione conjugation is an important biochemical reaction that leads, in the case of alachlor, to the formation of a rather difficult to detect, water-soluble, and therefore highly mobile, sulfonated metabolite. Research from weed science, toxicology, and biochemistry is discussed to support the hypothesis that glutathione conjugation is a potentially important detoxification pathway carried out by aquatic and terrestrial plants and soil microorganisms. A brief review of the biochemical basis for glutathione conjugation is presented. We recommend that multidisciplinary research focus on the occurrence and expression of glutathione and its attendant enzymes in plants and microorganisms, relationships between electrophilic substrate structure and enzyme activity, and the potential exploitation of plants and microorganisms that are competent in glutathione conjugation for phytoremediation and bioremediation.

  14. 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.

  15. 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

  16. Temporal trends of selected agricultural chemicals in Iowa's groundwater, 1982-1995: Are things getting better?

    USGS Publications Warehouse

    Kolpin, D.W.; Sneck-Fahrer, D.; Hallberg, G.R.; Libra, R.D.

    1997-01-01

    Since 1982, the Iowa Groundwater Monitoring (IGWM) Program has been used to sample untreated groundwater from Iowa municipal wells for selected agricultural chemicals. This long-term database was used to determine if concentrations of select agricultural chemicals in groundwater have changed with time. Nitrate, alachlor [2-chloro-2′-6′-diethyl-N-(methoxymethyl)-acetanilide], atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile)], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] were selected for this temporal analysis of the data. Conclusive temporal changes in frequency of detection and median chemical concentrations were found only for atrazine (decrease) and metolachlor (increase). The greatest temporal chemical changes occurred in the shallowest wells and in alluvial aquifers—both relating to groups of wells generally having the youngest groundwater age. The temporal patterns found for atrazine and metolachlor are consistent with their patterns of chemical use and/or application rates and are suggestive of a causal relation. Only continued data collection, however, will indicate if the trends in chemical concentrations described here represent long-term temporal patterns or only short-term changes in groundwater. No definitive answers could be made in regards to the question of overall improvements in groundwater quality with respect to agricultural chemical contamination and time, due to the inherent problems with the simplistic measurement of overall severity (summation of alachlor + atrazine + cyanazine + metolachlor concentrations) examined for this study. To adequately determine if there is an actual decreasing trend in the overall severity of contamination (improving groundwater quality), the collection of additional water-chemistry data and the investigation of other measures of severity are needed.

  17. 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

  18. 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

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

    USGS Publications Warehouse

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

    2007-01-01

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

  20. 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,

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

    EPA Science Inventory

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

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

    USGS Publications Warehouse

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

    1993-01-01

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

  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.

  4. 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.

  5. Characterization of acetanilide herbicides degrading bacteria isolated from tea garden soil.

    PubMed

    Wang, Yei-Shung; Liu, Jian-Chang; Chen, Wen-Ching; Yen, Jui-Hung

    2008-04-01

    Three different green manures were added to the tea garden soils separately and incubated for 40 days. After, incubation, acetanilide herbicides alachlor and metolachlor were spiked into the soils, separately, followed by the isolation of bacteria in each soil at designed intervals. Several bacterial strains were isolated from the soils and identified as Bacillus silvestris, B. niacini, B. pseudomycoides, B. cereus, B. thuringiensis, B. simplex, B. megaterium, and two other Bacillus sp. (Met1 and Met2). Three unique strains with different morphologies were chosen for further investigation. They were B. megaterium, B. niacini, and B. silvestris. The isolated herbicide-degrading bacteria showed optimal performance among three incubation temperatures of 30 degrees C and the best activity in the 10 to 50 microg/ml concentration of the herbicide. Each bacterial strain was able to degrade more than one kind of test herbicides. After incubation for 119 days, B. cereus showed the highest activity to degrade alachlor and propachlor, and B. thuringiensis to degrade metolachlor.

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

    USGS Publications Warehouse

    Ator, Scott; Denver, Judith M.

    2012-01-01

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

  7. 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.

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

    USGS Publications Warehouse

    Perry, C.A.

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

  10. 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

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  13. Nitrapyrin in streams: The first study documenting off-field transport of a nitrogen stabilizer compound

    USGS Publications Warehouse

    Woodward, Emily; Hladik, Michelle; Kolpin, Dana W.

    2016-01-01

    Nitrapyrin is a bactericide that is co-applied with fertilizer to prevent nitrification and enhance corn yields. While there have been studies of the environmental fate of nitrapyrin, there is no documentation of its off-field transport to streams. In 2016, 59 water samples from 11 streams across Iowa were analyzed for nitrapyrin and its degradate, 6-chloropicolinic acid (6-CPA), along with three widely used herbicides, acetochlor, atrazine, and metolachlor. Nitrapyrin was detected in seven streams (39% of water samples) with concentrations ranging from 12 to 240 ng/L; 6-CPA was never detected. The herbicides were ubiquitously detected (100% of samples, 28–16000 ng/L). Higher nitrapyrin concentrations in streams were associated with rainfall events following spring fertilizer applications. Nitrapyrin persisted in streams for up to 5 weeks. These results highlight the need for more research focused on the environmental fate and transport of nitrapyrin and the potential toxicity this compound could have on nontarget organisms.

  14. Novel chromatographic separation and carbon solid-phase extraction of acetanilide herbicide degradation products.

    PubMed

    Shoemaker, Jody A

    2002-01-01

    One acetamide and 5 acetanilide herbicides are currently registered for use in the United States. Over the past several years, ethanesulfonic acid (ESA) and oxanilic acid (OA) degradation products of these acetanilide/acetamide herbicides have been found in U.S. ground waters and surface waters. Alachlor ESA and other acetanilide degradation products are listed on the U.S. Environmental Protection Agency's (EPA) 1998 Drinking Water Contaminant Candidate List. Consequently, EPA is interested in obtaining national occurrence data for these contaminants in drinking water. EPA currently does not have a method for determining these acetanilide degradation products in drinking water; therefore, a research method is being developed using liquid chromatography/negative ion electrospray/mass spectrometry with solid-phase extraction (SPE). A novel chromatographic separation of the acetochlor/alachlor ESA and OA structural isomers was developed which uses an ammonium acetate-methanol gradient combined with heating the analytical column to 70 degrees C. Twelve acetanilide degradates were extracted by SPE from 100 mL water samples using carbon cartridges with mean recoveries >90% and relative standard deviations < or =16%.

  15. 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; Boehlke, Adam R.; Fishman, Neil S.; Battaglin, William A.; Kuivila, Kathryn

    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.

  16. Reduction in metolachlor and degradates concentrations in shallow groundwater through cover crop use

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pesticide use during crop production has the potential to adversely impact groundwater quality. In southern Florida climatic and hydrogeologic conditions and agronomic practices indicate that contamination risks are high. In the current study soil dissipation of the widely used herbicide, metolachlo...

  17. 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...

  18. 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...

  19. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. 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...

  2. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. 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.

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

    USGS Publications Warehouse

    Fenelon, Joseph M.; Moore, Rhett C.

    1996-01-01

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

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

    USGS Publications Warehouse

    Ryberg, Karen R.; Gilliom, Robert J.

    2015-01-01

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

  11. 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.

  12. 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

  13. 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

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

    USGS Publications Warehouse

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

    2007-01-01

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

  15. 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.

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

    USGS Publications Warehouse

    Stamer, J.K.

    1996-01-01

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

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

    USGS Publications Warehouse

    Woodside, Michael D.; Ruhl, Kelly E.

    2001-01-01

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

  18. 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.

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

    USGS Publications Warehouse

    Pereira, W.E.

    1990-01-01

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

  20. 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

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

    USGS Publications Warehouse

    Hickman, R. Edward

    2004-01-01

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

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

    EPA Science Inventory

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

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

    USGS Publications Warehouse

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

    2006-01-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

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

  6. Fast analysis of high-energy compounds and agricultural chemicals in water with desorption electrospray ionization mass spectrometry.

    PubMed

    Mulligan, Christopher C; MacMillan, Denise K; Noll, Robert J; Cooks, R Graham

    2007-01-01

    Novel sampling and detection methods using desorption electrospray ionization (DESI) are examined in the detection of explosives (RDX, TNT, HMX, and TNB) and agricultural chemicals (atrazine, alachlor and acetochlor) from aqueous matrices and authentic contaminated groundwater samples. DESI allows analysis of solid and liquid compounds directly from surfaces of interest with little or no sample preparation. Significant savings in analysis time and sample preparation are realized. The methods investigated here include (i) immediate analysis of filter paper wetted with contaminated water samples without further sample preparation, (ii) rapid liquid-liquid extraction (LLE), and (iii) analyte extraction from contaminated groundwater samples on-site using solid-phase extraction (SPE) membranes, followed by direct DESI analysis of the membrane. The wetted filter paper experiment demonstrates the maximum sample throughput for DESI analysis of aqueous matrices but has inadequate sensitivity for some of these analytes. Both the LLE and the SPE methods have adequate sensitivity. The resulting SPE membranes and/or small volume solvent extracts produced in these experiments are readily transported to off-site facilities for direct analysis by DESI. This realizes a significant reduction in the costs of sample shipping compared with those for typical liter-sized samples of groundwater. Total analysis times for these preliminary DESI analyses are comparable with or shorter than those for GC/MS and limits of detection approach environmental action levels for these compounds while maintaining a modest relative standard deviation. Tandem mass spectrometric data is used to provide additional specificity as needed.

  7. Ultrasound-assisted extraction and solid-phase extraction for the simultaneous determination of five amide herbicides in fish samples by gas chromatography with electron capture detection.

    PubMed

    Qu, Zhipeng; Bai, Xiuzhi; Zhang, Ting; Yang, Zhaoguang

    2017-03-01

    An efficient sample extraction and clean-up method was developed for simultaneous determination of five amide herbicides (alachlor, acetochlor, propisochlor, metazachlor, and butachlor) in fish samples. The protocol consisted of ultrasound-assisted solvent extraction and solid-phase extraction clean-up. In detail, aliquots of homogenized fish flesh were thoroughly mixed with 20 mL of n-hexane and then extracted with ultrasonication for 40 min. Each sample was centrifuged and the supernatant was collected for the subsequent clean-up. For the sample preparation, the above supernatant was processed with a C18 column with 3 mL of dichloromethane/n-hexane (1:1, v/v) as the eluant. Then the samples were analyzed by gas chromatography with electron capture detection. The correlation coefficients of the five calibration curves were 0.9976-0.9998 (n = 3). The limits of detection (S/N = 3, n = 11) and limits of quantification (S/N = 10, n = 11) were 0.19-0.42 and 0.63-1.39 μg/kg, respectively. The recoveries of this method were 71.2-92.6% with good precision (<4.7% relative standard deviations, n = 6). The developed method was successfully applied to monitor the five amide herbicides in fish samples collected from different cities.

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

    USGS Publications Warehouse

    Sullivan, Daniel J.; Richards, Kevin D.

    1996-01-01

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

  9. 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

  10. 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

  11. Seasonal Variation in the Measurement of Urinary Pesticide Metabolites among Latino Farmworkers in Eastern North Carolina

    PubMed Central

    Arcury, Thomas A.; Grzywacz, Joseph G.; Isom, Scott; Whalley, Lara E.; Vallejos, Quirina M.; Chen, Haiying; Galván, Leonardo; Barr, Dana B.; Quandt, Sara A.

    2009-01-01

    This analysis describes the detection of urinary pesticide metabolites for Latino farmworkers across the agricultural season. Two hundred and eighty four farmworkers were recruited from 44 camps in eastern North Carolina in 2007. Data were collected at one month intervals for a total of 939 data points. The OP insecticide metabolites 3,5,6-trichloropyridinol (46.2%), malathion dicarboxylic acid (27.7%), and para-nitrophenol (97.4%); the pyrethroid metabolite 3-phenoxybenzoic acid (56.4%); and the herbicides 2,4-D (68.1%), acetochlor (29.2%), and metolachlor (16.9%) were found in sizable percentages of the samples. The percentage of farmworkers for whom metabolites were detected varied across the agricultural season. None of the farmworker characteristics were significantly associated with the detection of any pesticide metabolite. Seasonality overrides the effects of other farmworker characteristics in predicting detection of pesticide urinary metabolites. Future research needs to collect multiple exposure measures at frequent intervals over an extended period to characterize factors associated with exposure. PMID:19886344

  12. 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.

  13. 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

  14. Analysis of substrate specificity of pig CYP2B22 and CYP2C49 towards herbicides by transgenic rice plants.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ozawa, Kenjirou; Ido, Yoshiko; Kojima, Misaki; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-12-01

    We introduced two novel types of pig (Sus scrofa) cytochrome P450, CYP2B22 and CYP2C49, into rice plants (Oryza sativa L. cv. 'Nipponbare') to produce herbicide-tolerant plants and to confirm the metabolic activities of the cytochrome P450 species. In germination tests, both types of transgenic plants showed tolerance to various herbicides with different modes of action. CYP2B22 rice plants showed tolerance towards 12 herbicides including chlortoluron (100 microM), amiprofos-methyl (2.5 microM), pendimethalin (10 microM), metolachlor (2.5 microM), and esprocarb (20 microM). CYP2C49 rice plants showed tolerance towards 13 herbicides, including chlortoluron (100 microM), norflurazon (0.5 microM), amiprofos-methyl (2.5 microM), alachlor (0.8 microM), and isoxaben (1 microM). The herbicide tolerance was considered to reflect the substrate specificity of the introduced P450 species. We used (14)C-labeled metolachlor and norflurazon to confirm the P450 activity in the transgenic rice plants. The herbicides were metabolized more quickly in the transgenic rice plants than in the nontransgenic rice plants. Therefore, CYP2B22 and CYP2C49 rice plants became more tolerant to various herbicides than nontransgenic control plants because of accelerated metabolism of the herbicides by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, these transgenic rice plants may become useful tools for the breeding of herbicide-tolerant crops.

  15. Occurrence, distribution, loads, and yields of selected pesticides in the Little River basin, Kentucky, 2003-04

    USGS Publications Warehouse

    Crain, Angela S.

    2006-01-01

    Water resources in the Little River Basin are potentially vulnerable to applications of pesticides associated with both agricultural and nonagricultural activities, because much of the basin is characterized by karst topography. Concerns about water quality resulting from pesticide use in karst areas and lack of data on concentrations of pesticides in surface water led to further investigation of water quality in the Little River Basin, which includes about 600 square miles in Christian and Trigg Counties and a portion of Caldwell County in western Kentucky. Water samples were collected in streams in the Little River Basin, Kentucky during 2003-04 as part of a study conducted in cooperation with the Kentucky Department of Agriculture. The objectives of the study were to assess the occurrence and distribution of pesticides, to evaluate the spatial and seasonal variability of pesticides, and to evaluate loads and yields of selected pesticides in the basin. A total of 91 water samples was collected at 4 fixed-network sites from March through November 2003 and from February through November 2004. An additional 20 samples were collected at 5 synoptic-network sites within the same period. Twenty-four pesticides were detected of the 127 pesticides analyzed in the stream samples. Of the 24 detected pesticides, 15 were herbicides, 7 were insecticides, and 2 were fungicides. The most commonly detected pesticides-atrazine, simazine, metolachlor, and acetochlor-were those most heavily used on crops during the study. Atrazine and simazine were detected in 100 percent of all surface-water samples, and metolachlor and acetochlor were detected in more than 45 percent. The pesticide degradate, deethylatrazine, was detected in 100 percent of the samples. Only one nonagricultural herbicide, prometon, was detected in more than 50 percent of the samples. Diazinon, the most commonly detected insecticide, was found in 25 percent of all samples and was found at all sites except Casey

  16. Pesticide concentrations in wetlands on the Lake Traverse Indian Reservation, South and North Dakota, July 2015

    USGS Publications Warehouse

    Carter, Janet M.; Thompson, Ryan F.

    2016-05-04

    During July 2015, water samples were collected from 18 wetlands on the Lake Traverse Indian Reservation in northeastern South Dakota and southeastern North Dakota and analyzed for physical properties and 54 pesticides. This study by the U.S. Geological Survey in cooperation with the Sisseton-Wahpeton Oyate was designed to provide an update on pesticide concentrations of the same 18 wetlands that were sampled for a reconnaissance-level assessment during July 2006. The purpose of this report is to present the results of the assessment of pesticide concentrations in selected Lake Traverse Indian Reservation wetlands during July 2015 and provide a comparison of pesticide concentrations between 2006 and 2015.Of the 54 pesticides that were analyzed for in the samples collected during July 2015, 47 pesticides were not detected in any samples. Seven pesticides—2-chloro-4-isopropylamino-6-amino-s-triazine (CIAT); 2,4–D; acetachlor; atrazine; glyphosate; metolachlor; and prometon—were detected in the 2015 samples with estimated concentrations or concentrations greater than the laboratory reporting level, and most pesticides were detected at low concentrations in only a few samples. Samples from all wetlands contained at least one detected pesticide. The maximum number of pesticides detected in a wetland sample was six, and the median number of pesticides detected was three.The most commonly detected pesticides in the 2015 samples were atrazine and the atrazine degradate CIAT (also known as deethylatrazine), which were detected in 14 and 13 of the wetlands sampled, respectively. Glyphosate was detected in samples from 11 wetlands, and metolachlor was detected in samples from 10 wetlands. The other detected pesticides were 2,4–D (4 wetlands), acetochlor (3 wetlands), and prometon (1 wetland).The same pesticides that were detected in the 2006 samples were detected in the 2015 samples, with the exception of simazine, which was detected only in one sample in 2006

  17. Regional patterns of pesticide concentrations in surface waters of New York in 1997

    USGS Publications Warehouse

    Phillips, P.J.; Eckhardt, D.A.; Freehafer, D.A.; Wall, G.R.; Ingleston, H.H.

    2002-01-01

    The predominant mixtures of pesticides found in New York surface waters consist of five principal components. First, herbicides commonly used on corn (atrazine, metolachlor, alachlor, cyanazine) and a herbicide degradate (deethylatrazine) were positively correlated to a corn-herbicide component, and watersheds with the highest corn-herbicide component scores were those in which large amounts of row crops are grown. Second, two insecticides (diazinon and carbaryl) and one herbicide (prometon) widely used in urban and residential settings were positively correlated to an urban/residential component. Watersheds with the highest urban/residential component scores were those with large amounts of urban and residential land use. A third component was related to two herbicides (EPTC and cyanazine) used on dry beans and corn, the fourth to an herbicide (simazine) and an insecticide (carbaryl) commonly used in orchards and vineyards, and the fifth to an herbicide (DCPA). Results of this study indicate that this approach can be used to: (1) identify common mixtures of pesticides in surface waters, (2) relate these mixtures to land use and pesticide applications, and (3) indicate regions where these mixtures of pesticides are commonly found.

  18. 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.

  19. 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.

  20. 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).

  1. A field study to compare performance of stainless steel research monitoring wells with existing on-farm drinking water wells in measuring pesticide and nitrate concentrations.

    PubMed

    Smith, C N; Payne, W R; Pope, J D; Winkie, J H; Parrish, R S

    1999-02-01

    Existing drinking water wells are widely used for the collection of ground water samples to evaluate chemical contamination. A well comparison study was conducted to compare pesticide and nitrate-N data from specially designed stainless steel research monitoring wells with data from nearby existing on-farm drinking water wells. Results could help to determine whether adequate information concerning ground water contamination can be obtained from existing drinking water wells for use in making pollutant control decisions. The study was conducted during 1993-1994 in the Little Coharie Watershed, a 158 square mile area located in the coastal plain of eastern North Carolina. Statistical analysis indicated that research monitoring wells provided a greater probability of detecting pesticides in ground water than existing on-farm wells. Atrazine was the most frequently detected pesticide found in all wells, followed in order by fluometuron, carbofuran, metolachlor, alachlor, carbaryl, butylate, chlorothalonil, linuron and simazine. Ninety-seven percent of all wells had observed concentrations of nitrate-N, ranging from 0.1 to 30.1 mg/L. There was not a significant difference between research wells and existing wells for monitoring nitrate-N. Based on results of this study, existing drinking water wells can be used for monitoring nitrate; however, specialized stainless steel monitoring wells should be used for monitoring pesticides in ground water.

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

    USGS Publications Warehouse

    Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Hughes, Jane S.; Biddinger, Gregory R.; Mones, Eugene

    1995-01-01

    We determined net photosynthesis and respiration rates for sago pondweed (potamogeton pectinatus) exposed to various concentrations of 11 herbicides widely used in Maryland during the past decade. Net photosynthesis and respiration were determined by measuring changes in the. oxygen content of solutions containing dilutions of technical grade herbicides. At 20-22? C and 58 umol/m2/sec of photosynthetically active radiation (PAR), oxygen production of undosed plants averaged 0.72-2.03 mg/g fresh wt/h. Respiration rates of undosed plants averaged 0.46-0.60 mg O2/g fresh wt/h. Nominal herbicide concentrations (ng/L) that reduced net photosynthesis by 5O percent (IC5O) were: metribuzin, 8; atrazine, 29; cyanazine, 32; linuron, 70; simazine, 164; and paraquat, 240. IC5O values for 2,4-D, acifluorfen, glyphosate and metolachlor exceeded the maximum test concentration of 10,000 ng/L. The IC5O value for alachlor was estimated to be between 1,000 and 10,000 ng/L. None of the herbicides tested had a significant effect on dark respiration.

  3. Mineralization of the s-triazine ring of atrazine by stable bacterial mixed cultures.

    PubMed Central

    Mandelbaum, R T; Wackett, L P; Allan, D L

    1993-01-01

    Enrichment cultures containing atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) at a concentration of 100 ppm (0.46 mM) as a sole nitrogen source were obtained from soils exposed to repeated spills of atrazine, alachlor, and metolachlor. Bacterial growth occurred concomitantly with formation of metabolites from atrazine and subsequent biosynthesis of protein. When ring-labeled [14C]atrazine was used, 80% or more of the s-triazine ring carbon atoms were liberated as 14CO2. Hydroxyatrazine may be an intermediate in the atrazine mineralization pathway. More than 200 pure cultures isolated from the enrichment cultures failed to utilize atrazine as a nitrogen source. Mixing pure cultures restored atrazine-mineralizing activity. Repeated transfer of the mixed cultures led to increased rates of atrazine metabolism. The rate of atrazine degradation, even at the elevated concentrations used, far exceeded the rates previously reported in soils, waters, and mixed and pure cultures of bacteria. PMID:8328795

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

    PubMed

    Foster, Gregory D; Miller, Cherie V; Huff, Thomas B; Roberts, Eldon

    2003-07-01

    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.

  5. 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.

  6. Simultaneous removal of pesticides from water by rice husk ash: batch and column studies.

    PubMed

    Saha, Ajoy; Gajbhiye, V T; Gupta, Suman; Kumar, Rajesh; Ghosh, Rakesh Kumar

    2014-11-01

    The present study evaluated rice husk ash (RHA) as an adsorbent for simultaneous removal of a mixture of seven different pesticides (alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, and p,p'-DDT) and two metabolites (p,p'-DDE and endosulfan sulfate) from water. The adsorbent RHA was prepared in the laboratory and characterized by techniques such as X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectrometry. Adsorption kinetics were well described by the pseudo-second-order kinetic model. The Freundlich isotherm model fitted the equilibrium data better than the Langmuir model, and the maximum sorption capacity varied from 0.078 to 0.166 mg/g. The column elution studies showed that 10 L of mixed pesticide-contaminated water (0.05 mg/L) can be treated with only 10 g of RHA at a removal efficiency of 90%. The results implied that RHA can be used as a low-cost, easily available, and efficient adsorbent for the simultaneous removal of pesticides from contaminated water.

  7. Evaluation of herbicides for use in transplanting leucaena leucocephala and prosopis alba on semi-arid lands without irrigation

    SciTech Connect

    Felker, P.; Smith, D.; Smith, M.; Bingham, R.L.; Reyes, I.

    1984-01-01

    Five herbicides were applied to plots at 2 rates in April 1982, and 3-month old seedlings planted 2 days later. Basal diameter was measured after 110 days and converted to dry weight using published equations. Percent weed cover was recorded 45, 75, and 105 days after planting. All herbicides increased survival over untreated controls. The greatest biomass production of both species was obtained with oryzalin treatment at 2.8 kg/ha active ingredient, which increased production 4-5X compared with control plots. Oryzalin was second to napropamide (2.24 kg/ha active ingredient) in grass control and equal to oxyfluorfen (1.12 kg/ha active ingredient) in forb control, oxyfluorfen at this rate also gave the second best biomass production. Oryzalin increased survival from 71 to 87% for Leucaena and from 81-94% for Prosopis, and is considered to be the best herbicide tested, followed by oxyfluorfen and metolachlor. Alachlor was considered to be too short-lived and napropamide too expensive.

  8. 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. 

  9. 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.

  10. Characterization of two Arabidopsis thaliana glutathione S-transferases.

    PubMed

    Nutricati, Eliana; Miceli, Antonio; Blando, Federica; De Bellis, Luigi

    2006-09-01

    Glutathione S-transferases (GST) are multifunctional proteins encoded by a large gene family, divided on the basis of sequence identity into phi, tau, theta, zeta and lambda classes. The phi and tau classes are present only in plants. GSTs appear to be ubiquitous in plants and are involved in herbicide detoxification and stress response, but little is known about the precise role of GSTs in normal plant physiology and during biotic and abiotic stress response. Two cDNAs representing the two plant classes tau and phi, AtGSTF9 and AtGSTU26, were expressed in vitro and the corresponding proteins were analysed. Both GSTs were able to catalyse a glutathione conjugation to 1-chloro-2,4-dinitrobenzene (CDNB), but they were inactive as transferases towards p-nitrobenzylchloride (pNBC). AtGSTF9 showed activity towards benzyl isothiocyanate (BITC) and an activity as glutathione peroxidase with cumene hydroperoxide (CumHPO). AtGSTU26 was not active as glutathione peroxidase and towards BITC. RT-PCR analysis was used to evaluate the expression of the two genes in response to treatment with herbicides and safeners, chemicals, low and high temperature. Our results reveal that AtGSTU26 is induced by the chloroacetanilide herbicides alachlor and metolachlor and the safener benoxacor, and after exposure to low temperatures. In contrast, AtGSTF9 seems not to be influenced by the treatments employed.

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

    USGS Publications Warehouse

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

    1999-01-01

    Frequencies of detection at or above 0.01 microgram per liter in shallow ground water beneath agricultural areas during the NAWQA study were significantly correlated with agricultural use in those areas for atrazine, cyanazine, alachlor, and metolachlor (P<0.05; Spearman rank correlations), but not for simazine (P>0.05). In urban areas, overall frequencies of detection of these five herbicides in shallow ground water were positively correlated with their total nonagricultural use nationwide (P=0.026; simple linear correlation). Multivariate statistical analysis indicated that frequencies of detection in shallow ground water beneath agricultural areas were positively correlated with half-lives for transformation in aerobic soil and agricultural use of the compounds (P≤0.0001 for both parameters). Although frequencies of detection were not significantly correlated with their subsurface mobility (Koc; P=0.19) or the median well depths of the sampled networks (P=0.72), the range of Koc values among the five herbicides and the range of well depths were limited.

  12. Investigation of factors affecting terrestrial passive sampling device performance and uptake rates in laboratory chambers

    SciTech Connect

    Johnson, K.A.; Weisskopf, C.P.

    1995-12-31

    A rapid sampling method using passive sampling devices (PSDS) for soil contaminant characterization shows extreme promise. The use of PSDs increases ease and speed of analysis, decreases solvent usage and cost, and minimizes the transport of contaminated soils. Time and cost savings allow a high sampling frequency, providing a more thorough site characterization than traditional methods. The authors have conducted both laboratory and field studies with terrestrial PSDS. Laboratory studies demonstrated the concentration and moisture dependence of sampler uptake and provided an estimate of the optimal field sampling time for soils contaminated with polychlorinated biphenyls (PCBs). These PSDs were also used to accurately estimate PCB concentrations at hazardous waste site where concentrations ranged from 0.01 to 200 ug PCB/g soil. However, PSDs in the field had sampling rates approximately three times greater than in the laboratory. As a result several factors affecting PSD sampling rates and/or performance in laboratory chambers were evaluated. The parameters investigated were soil bulk density or compactness, chamber size and air flow. The chemicals used in these studies included two PCB congeners (52 and 153), three organochlorine pesticides (DDT, dieldrin and methoxychlor), three organophosphate pesticides (chlorpyrifos, diazinon and terbufos) and three herbicides (alachlor, atrazine and metolachlor).

  13. Groundwater pesticide levels and the association with Parkinson disease.

    PubMed

    James, Katherine A; Hall, Deborah A

    2015-01-01

    It is unclear whether exposure to environmentally relevant levels of pesticides in groundwater is associated with an increased risk of Parkinson disease (PD). The purpose of this study was to examine the relationship between PD and pesticide levels in groundwater. This cross-sectional study included 332 971 Medicare beneficiaries, including 4207 prevalent cases of PD from the 2007 Colorado Medicare Beneficiary Database. Residential pesticide levels were estimated from a spatial model based on 286 well water samples with atrazine, simazine, alachlor, and metolachlor measurements. A logistic regression model with known PD risk factors was used to assess the association between residential groundwater pesticide levels and prevalent PD. We found that for every 1.0 µg/L of pesticide in groundwater, the risk of PD increases by 3% (odds ratio = 1.03; 95% confidence interval: 1.02-1.04) while adjusting for age, race/ethnicity, and gender suggesting that higher age-standardized PD prevalence ratios are associated with increasing levels of pesticides in groundwater.

  14. 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.

    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.

  15. 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.

  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. 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.

  18. 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...

  19. Environmental determinants of the urinary concentrations of herbicides during pregnancy: the PELAGIE mother-child cohort (France).

    PubMed

    Chevrier, Cécile; Serrano, Tania; Lecerf, Rémi; Limon, Gwendolina; Petit, Claire; Monfort, Christine; Hubert-Moy, Laurence; Durand, Gaël; Cordier, Sylvaine

    2014-02-01

    Herbicides are generally the most extensively used of the pesticides applied to agricultural crops. However, the literature contains little evidence useful in assessing the potential sources of the general population's exposure to herbicides, including by residential proximity to crops. The objective of this study was to take advantage of data from the PELAGIE mother-child cohort to identify the main determinants of the body burden of exposure to the chloroacetanilide and triazine herbicides commonly used on corn crops in Brittany, France, before 2006. Urine samples from a randomly selected subcohort of women in the first trimester of pregnancy (n=579) were assayed for herbicide metabolites. The residential exposure resulting from proximity to corn crops was assessed with satellite-image-based scores combined with meteorological data. Data on diet, drinking tap water (from the public water supply), occupations, and household herbicide use were collected by questionnaires. Herbicides were quantified in 5.3% to 39.7% of urine samples. Alachlor and acetochlor were found most frequently in the urine of women living in rural areas. The presence of dealkylated triazine metabolites in urine samples was positively associated with residential proximity to corn crops (OR=1.38, 95% CI: 1.05-1.80). Urinary metabolites of both atrazine and dealkylated triazine were correlated with tap water consumption (OR=2.94, 1.09-7.90, and OR=1.82, 1.10-3.03, respectively); hydroxylated triazine metabolites were correlated with fish intake (OR=1.48, 1.09-1.99). This study reinforces previous results that suggest that environmental contamination resulting from agricultural activities may contribute to the general population's exposure to herbicides.

  20. Concentrations of nutrients, pesticides, and suspended sediment in the karst terrane of the Sinking Creek basin, Kentucky, 2004

    USGS Publications Warehouse

    Crain, Angela S.

    2006-01-01

    Water samples were collected in streams and springs in the karst terrane of the Sinking Creek Basin in 2004 as part of study in cooperation with the Kentucky Department of Agriculture. A total of 48 water samples were collected at 7 sites (4 springs, 2 streams, and 1 karst window) from April through November 2004. The karst terrane of the Sinking Creek Basin (also known as Boiling Spring Basin) encompasses about 125 square miles in Breckinridge County and portions of Meade and Hardin Counties in Kentucky. Fourteen pesticides were detected of the 52 pesticides analyzed in the stream and spring samples. Of the 14 detected pesticides, 12 were herbicides and 2 were insecticides. The most commonly detected pesticides?atrazine, simazine, metolachlor, and acetochlor?were those most heavily used on crops during the study. Atrazine was detected in 100 percent of all samples; simazine, metolachlor, and acetochlor were detected in more than 35 percent of all samples. The pesticide-transformation compound, deethylatrazine, was detected in 98 percent of the samples. Only one nonagricultural herbicide, prometon, was detected in more than 30 percent of the samples. Malathion, the most commonly detected insecticide, was found in 4 percent of the samples, which was followed by carbofuran (2 percent). Most of the pesticides were present in low concentrations; however, atrazine was found in springs exceeding the U.S. Environmental Protection Agency?s (USEPA) standards for drinking water. Atrazine exceeded the USEPA?s maximum contaminant level 2 times in 48 detections. Concentrations of nitrate greater than 10 milligrams per liter (mg/L) were not found in water samples from any of the sites. Concentrations of nitrite plus nitrate ranged from 0.21 to 3.9 mg/L at the seven sites. The median concentration of nitrite plus nitrate for all sites sampled was 1.5 mg/L. Concentrations of nitrite plus nitrate generally were higher in the springs than in the main stem of Sinking Creek. Forty

  1. Ground-Water Quality in the Upper Susquehanna River Basin, New York, 2004-05

    USGS Publications Warehouse

    Hetcher-Aguila, Kari K.; Eckhardt, David A.V.

    2006-01-01

    Water samples were collected from 20 production wells and 13 private residential wells throughout the upper Susquehanna River Basin (upstream from the Pennsylvania border) during the fall of 2004 and the spring of 2005 and analyzed to describe the chemical quality of ground water in the upper basin. Wells were selected to represent areas of greatest ground-water use and highest vulnerability to contamination, and to provide a representative sampling from the entire (4,516 square-mile) upper basin. Samples were analyzed for physical properties, nutrients, inorganic constituents, metals, radionuclides, pesticides, volatile organic compounds, and bacteria. The cations that were detected in the highest concentrations were calcium, magnesium, and sodium; the anions that were detected in the greatest concentrations were bicarbonate, chloride, and sulfate. The predominant nutrient was nitrate, the concentrations of which were greater in samples from sand and gravel aquifers than in samples from bedrock. The metals barium, boron, cobalt, copper, and nickel were detected in every sample; the metals with the highest concentrations were barium, boron, iron, manganese, strontium, and lithium. The pesticide compounds detected most frequently were atrazine, deethylatrazine, alachlor ESA, and two degradation products of metolachlor (metolachlor ESA and metolachlor OA); the compounds detected in highest concentration were metolachlor ESA and OA. Volatile organic compounds were detected in 11 samples, and concentrations of 3 of these compounds exceeded 1 microgram per liter (?g/L). Methyl tert-butyl ether (MTBE), a gasollline additive, was not detected in any sample. Several analytes were found in concentrations that exceeded Federal and New York State water-quality standards, which are typically identical. Chloride concentrations exceeded the U.S. Environmental Protection Agency (USEPA) Secondary Maximum Contaminant Level (SMCL) of 250 milligrams per liter (mg/L) in two samples

  2. 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

  3. Identifying sources of emerging organic contaminants in a mixed use watershed using principal components analysis.

    PubMed

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

    2014-01-01

    Principal components analysis (PCA) was used to identify sources of emerging organic contaminants in the Zumbro River watershed in Southeastern Minnesota. Two main principal components (PCs) were identified, which together explained more than 50% of the variance in the data. Principal Component 1 (PC1) was attributed to urban wastewater-derived sources, including municipal wastewater and residential septic tank effluents, while Principal Component 2 (PC2) was attributed to agricultural sources. The variances of the concentrations of cotinine, DEET and the prescription drugs carbamazepine, erythromycin and sulfamethoxazole were best explained by PC1, while the variances of the concentrations of the agricultural pesticides atrazine, metolachlor and acetochlor were best explained by PC2. Mixed use compounds carbaryl, iprodione and daidzein did not specifically group with either PC1 or PC2. Furthermore, despite the fact that caffeine and acetaminophen have been historically associated with human use, they could not be attributed to a single dominant land use category (e.g., urban/residential or agricultural). Contributions from septic systems did not clarify the source for these two compounds, suggesting that additional sources, such as runoff from biosolid-amended soils, may exist. Based on these results, PCA may be a useful way to broadly categorize the sources of new and previously uncharacterized emerging contaminants or may help to clarify transport pathways in a given area. Acetaminophen and caffeine were not ideal markers for urban/residential contamination sources in the study area and may need to be reconsidered as such in other areas as well.

  4. Metabolic pathway involved in 2-methyl-6-ethylaniline degradation by Sphingobium sp. strain MEA3-1 and cloning of the novel flavin-dependent monooxygenase system meaBA.

    PubMed

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei; Cui, Zhongli

    2015-12-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02' in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase.

  5. Streamflow and water-quality characteristics of the Ottawa River and selected tributaries in Allen, Hardin, and Putnam Counties, Ohio

    USGS Publications Warehouse

    Shaffer, Kimberly

    2003-01-01

    Streamflow and water-quality measurements were made on the Ottawa River and selected tributaries between 1999 to 2002. Ten sets of streamflow measurements were made at an index station on the Auglaize River at Fort Jennings (station 04186500) and at 19 other sites along the Ottawa River and selected tributaries. These data were collected to relate daily mean streamflow at the Auglaize River at Fort Jennings and the instantaneous streamflow at each of the other 19 sites. Two sets of water-quality samples were collected and 4 or 5 dissolved-oxygen measurements were made at the 19 sites. Water samples were collected during periods of potential stress on the aquatic communities, once during low flow and once during a runoff event that occurred after recent land application of pesticides. The first set of water-quality samples was analyzed for groups of nutrients, major ions and trace elements, and physical properties, whereas the second set was analyzed for nutrients, pesticides, and physical properties. With regard to nutrients and physical properties, median values of specific conductance, pH, dissolved oxygen, alkalinity, and orthophosphate were higher during low flow than during the runoff event. In contrast, the median concentrations of total phosphorus, ammonia nitrogen, nitrite plus nitrate nitrogen, and ammonia plus organic nitrogen were higher during the runoff event than during low flow. Orthophosphate, total phosphorus, and dissolved-oxygen concentrations all had wider ranges during the low-flow sampling than the runoff-event sampling. Of the 25 major ions and trace elements analyzed for, 15 were detected in all 18 samples, and 10 were detected infrequently or not detected at all. The runoff samples were analyzed for 48 pesticides, 18 of which were detected in one or more samples and 30 of which were not detected. Of the 18 pesticides detected, 13 were detected in 5 or more samples. Five pesticides?acetochlor, atrazine, deethylatrazine, metolachlor, and

  6. Herbicides and herbicide degradates in shallow groundwater and the Cedar River near a municipal well field, Cedar Rapids, Iowa

    USGS Publications Warehouse

    Boyd, R.A.

    2000-01-01

    Water samples were collected near a Cedar Rapids, Iowa municipal well field from June 1998 to August 1998 and analyzed for selected triazine and acetanilide herbicides and degradates. The purpose of the study was to evaluate the occurrence of herbicides and herbicide degradates in the well field during a period following springtime application of herbicides to upstream cropland. The well field is in an alluvial aquifer adjacent to the Cedar River. Parent herbicide concentrations generally were greatest in June, and decreased in July and August. Atrazine was most frequently detected and occurred at the greatest concentrations; acetochlor, cyanazine and metolachlor also were detected, but at lesser concentrations than atrazine. Triazine degradate concentrations were relatively small (<0.50 ??g/l) and generally decreased from June to August. Although the rate of groundwater movement is relatively fast (approx. 1 m per day) in the alluvial aquifer near the Cedar River, deethylatrazine (DEA) to atrazine ratios in groundwater samples collected near the Cedar River indicate that atrazine and DEA probably are gradually transported into the alluvial aquifer from the Cedar River. Deisopropylatrazine (DIA) to DEA ratios in water samples indicate most DIA in the Cedar River and alluvial aquifer is produced by atrazine degradation, although some could be from cyanazine degradation. Acetanilide degradates were detected more frequently and at greater concentrations than their corresponding parent herbicides. Ethanesulfonic-acid (ESA) degradates comprised at least 80% of the total acetanilide-degradate concentrations in samples collected from the Cedar River and alluvial aquifer in June, July and August; oxanilic acid degradates comprised less than 20% of the total concentrations. ESA-degradate concentrations generally were smallest in June and greater in July and August. Acetanilide degradate concentrations in groundwater adjacent to the Cedar River indicate acetanilide

  7. Gene Expression and Microscopic Analysis of Arabidopsis Exposed to Chloroacetanilide Herbicides and Explosive Compounds. A Phytoremediation Approach1

    PubMed Central

    Mezzari, Melissa P.; Walters, Katherine; Jelínkova, Marcela; Shih, Ming-Che; Just, Craig L.; Schnoor, Jerald L.

    2005-01-01

    Understanding the function of detoxifying enzymes in plants toward xenobiotics is of major importance for phytoremediation applications. In this work, Arabidopsis (Arabidopsis thaliana; ecotype Columbia) seedlings were exposed to 0.6 mm acetochlor (AOC), 2 mm metolachlor (MOC), 0.6 mm 2,4,6-trinitrotoluene (TNT), and 0.3 mm hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). In vivo glutathione (GSH) conjugation reactions of AOC, MOC, RDX, and TNT were studied in root cells using a multiphoton microscope. In situ labeling with monochlorobimane, used as a competitive compound for conjugation reactions with GSH, confirmed that AOC and MOC are conjugated in Arabidopsis cells. Reverse transcription-PCR established the expression profile of glutathione S-transferases (GSTs) and nitroreductases enzymes. Genes selected for this study were AtGSTF2, AtGSTU1, AtGSTU24, and two isoforms of 12-oxophytodienoate reductase (OPR1 and OPR2). The five transcripts tested were induced by all treatments, but RDX resulted in low induction. The mRNA level of AtGSTU24 showed substantial increase for all chemicals (23-fold induction for AOC, 18-fold for MOC, 5-fold for RDX, and 40-fold for TNT). It appears that GSTs are also involved in the conjugation reactions with metabolites of TNT, and to a lesser extent with RDX. Results indicate that OPR2 is involved in plant metabolism of TNT (11-fold induction), and in oxidative stress when exposed to AOC (7-fold), MOC (9-fold), and RDX (2-fold). This study comprises gene expression analysis of Arabidopsis exposed to RDX and AOC, which are considered significant environmental contaminants, and demonstrates the importance of microscopy methods for phytoremediation investigations. PMID:15923336

  8. Metabolic Pathway Involved in 2-Methyl-6-Ethylaniline Degradation by Sphingobium sp. Strain MEA3-1 and Cloning of the Novel Flavin-Dependent Monooxygenase System meaBA

    PubMed Central

    Dong, Weiliang; Chen, Qiongzhen; Hou, Ying; Li, Shuhuan; Zhuang, Kai; Huang, Fei; Zhou, Jie; Li, Zhoukun; Wang, Jue; Fu, Lei; Zhang, Zhengguang; Huang, Yan; Wang, Fei

    2015-01-01

    2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor. Sphingobium sp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02′ in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation with meaBA in MEA3-1Mut and heterologous expression in Pseudomonas putida strain KT2440 resulted in the production of an active MEHQ monooxygenase. PMID:26386060

  9. Pesticide Urinary Metabolite Levels of Children in Eastern North Carolina Farmworker Households

    PubMed Central

    Arcury, Thomas A.; Grzywacz, Joseph G.; Barr, Dana B.; Tapia, Janeth; Chen, Haiying; Quandt, Sara A.

    2007-01-01

    Background In this investigation we documented the pesticide urinary metabolite levels of farmworker children in North Carolina, determined the number of different metabolites detected for each child, and delineated risk factors associated with the number of metabolites. Methods Urine samples were collected from 60 Latino farmworker children 1–6 years of age (34 female, 26 male). Interviews were completed by their mothers in Spanish. We analyzed urine samples for 14 pesticide metabolites, including the organophosphate pesticides chlorpyrifos, coumaphos, diazinon, isazaphos, malathion, pirimiphos, and parathion and its methyl counterpart; a common metabolite of at least 18 pyrethroid insecticides; the repellent DEET; and the herbicides 2,4,5-trichlorphenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, acetochlor, atrazine, and metolachlor. Predictors included measures of paraoccupational, residential, and environmental exposure, child characteristics, and mother characteristics. Results Thirteen metabolites were present in the urine samples. Organophosphate pesticide metabolites were detected in a substantial proportion of children, particularly metabolites of parathion/methyl parathion (90.0%; geometric mean 1.00 μg/L), chlorpyrifos/chlorpyrifos methyl (83.3%; geometric mean 1.92 μg/L), and diazinon (55.0%; geometric mean 10.56 μg/L). The number of metabolites detected ranged from 0 to 7, with a mode of 4 detected (28.3%). Boys, children living in rented housing, and children with mothers working part-time had more metabolites detected. Conclusions Children in farmworker homes experience multiple sources of pesticide exposure. Pesticides may remain in their environments for long periods. Environmental and occupational health changes are needed to address these exposures. Research is needed with more precise measures of exposure and on the health effects of concurrent exposure to multiple pesticides. PMID:17687456

  10. Concentration of selected sulfonylurea, sulfonamide, and imidazolinone herbicides, other pesticides, and nutrients in 71 streams, 5 reservoir outflows, and 25 wells in the Midwestern United States, 1998

    USGS Publications Warehouse

    Battaglin, William A.; Furlong, Edward T.; Burkhardt, Mark R.

    2001-01-01

    Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are recently developed herbicides that function by inhibiting the action of a key plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but crop and non-crop plants demonstrate a wide range in sensitivity to SUs, SAs, and IMIs, with over a 10,000-fold difference in observed toxicity levels for some compounds. SUs, SAs, and IMIs are applied either pre- or post-emergence to crops commonly at 1/50th or less of the rate of other herbicides. Little is known about their occurrence, fate, or transport in surface water or ground water in the United States. To obtain information on the occurrence of SU, SA, and IMI herbicides in the Midwestern United States, 214 water samples were collected from 76 surface-water and 25 ground-water sites in 1998. These samples were analyzed for 16 SU, SA, and IMI herbicides by using highperformance liquid chromatography/mass spectrometry. Samples also were analyzed for 46 pesticides and pesticide degradation products and 13 herbicides and 10 herbicide degradates. At least 1 of the 16 SUs, SAs, or IMIs was detected at or above the method reporting limit of 0.010 microgram per liter (ug/L) in 83 percent of 133 stream samples. Imazethapyr was detected most frequently (69 percent of samples), followed by flumetsulam (65 percent of samples) and nicosulfuron (53 percent of samples). At least one SU, SA, or IMI herbicide was detected at or above the method reporting limit in 6 of 8 reservoir samples and 5 of 25 ground-water samples. SU, SA, and IMI herbicides occurred less frequently and at a fraction (often 1/50th or less) of the concentrations of other herbicides such as atrazine. Acetochlor, atrazine, cyanazine, and metolachlor were all detected in 95 percent or more of 136 stream samples.

  11. Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action.

    PubMed

    Wang, Ning; Ivey, Christopher D; Ingersoll, Christopher G; Brumbaugh, William G; Alvarez, David; Hammer, Edward J; Bauer, Candice R; Augspurger, Tom; Raimondo, Sandy; Barnhart, M Christopher

    2017-03-01

    Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r(2)  = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In

  12. A pesticide monitoring survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment.

    PubMed

    Papadakis, Emmaluel N; Vryzas, Zisis; Kotopoulou, Athena; Kintzikoglou, Katerina; Makris, Konstantinos C; Papadopoulou-Mourkidou, Euphemia

    2015-06-01

    A pesticide monitoring study covering the main rivers and lakes of Northern Greece (Macedonia, Thrace and Thessaly) was undertaken. A total of 416 samples were collected over a 1.5-year sampling period (September 1999- February 2001) from six rivers and ten lakes. The water samples were analyzed with an off-line solid phase extraction technique coupled with a gas chromatography ion trap mass spectrometer using an analytical method for 147 pesticides and their metabolites, including organochlorines, organophosphates, triazines, chloroacetanilides, pyrethroids, carbamates, phthalimides and other pesticides (herbicides, insecticides and fungicides). Based on the pesticide survey results, a human health carcinogenic and non-carcinogenic risk assessment was conducted for adults and children. Ecotoxicological risk assessment was also conducted using default endpoint values and the risk quotient method. Results showed that the herbicides metolachlor, prometryn, alachlor and molinate, were the most frequently detected pesticides (29%, 12.5%, 12.5% and 10%, respectively). They also exhibited the highest concentration values, often exceeding 1 μg/L. Chlorpyrifos ethyl was the most frequently detected insecticide (7%). Seasonal variations in measured pesticide concentrations were observed in all rivers and lakes. The highest concentrations were recorded during May-June period, right after pesticide application. Concentrations of six pesticides were above the maximum allowable limit of 0.1 μg/L set for drinking water. Alachlor, atrazine and a-HCH showed unacceptable carcinogenic risk estimates (4.5E-06, 4.6E-06 and 1.3E-04, respectively). Annual average concentrations of chlorpyriphos ethyl (0.031 μg L), dicofol (0.01 μg/L), dieldrin (0.02 μg/L) and endosulfan a (0.065 μg/L) exceeded the EU environmental quality standards. The risk quotient estimates for the insecticides chorpyrifos ethyl, diazinon and parathion methyl and herbicide prometryn were above acceptable risk

  13. Acute sensitivity of a broad range of freshwater mussels to chemicals with different modes of toxic action

    USGS Publications Warehouse

    Wang, Ning; Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Alvarez, David; Hammer, Edward J.; Bauer, Candice R.; Augspurger, Tom; Raimondo, Sandy; Barnhart, M.Christopher

    2017-01-01

    Freshwater mussels, one of the most imperiled groups of animals in the world, are generally underrepresented in toxicity databases used for the development of ambient water quality criteria and other environmental guidance values. Acute 96-h toxicity tests were conducted to evaluate the sensitivity of 5 species of juvenile mussels from 2 families and 4 tribes to 10 chemicals (ammonia, metals, major ions, and organic compounds) and to screen 10 additional chemicals (mainly organic compounds) with a commonly tested mussel species, fatmucket (Lampsilis siliquoidea). In the multi-species study, median effect concentrations (EC50s) among the 5 species differed by a factor of ≤2 for chloride, potassium, sulfate, and zinc; a factor of ≤5 for ammonia, chromium, copper, and nickel; and factors of 6 and 12 for metolachlor and alachlor, respectively, indicating that mussels representing different families or tribes had similar sensitivity to most of the tested chemicals, regardless of modes of action. There was a strong linear relationship between EC50s for fatmucket and the other 4 mussel species across the 10 chemicals (r2 = 0.97, slope close to 1.0), indicating that fatmucket was similar to other mussel species; thus, this commonly tested species can be a good surrogate for protecting other mussels in acute exposures. The sensitivity of juvenile fatmucket among different populations or cultured from larvae of wild adults and captive-cultured adults was also similar in acute exposures to copper or chloride, indicating captive-cultured adult mussels can reliably be used to reproduce juveniles for toxicity testing. In compiled databases for all freshwater species, 1 or more mussel species were among the 4 most sensitive species for alachlor, ammonia, chloride, potassium, sulfate, copper, nickel, and zinc; therefore, the development of water quality criteria and other environmental guidance values for these chemicals should reflect the sensitivity of mussels. In

  14. 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

  15. Lifetime Pesticide Use and Telomere Shortening among Male Pesticide Applicators in the Agricultural Health Study

    PubMed Central

    Hou, Lifang; Andreotti, Gabriella; Baccarelli, Andrea A.; Savage, Sharon; Hoppin, Jane A.; Sandler, Dale P.; Barker, Joseph; Zhu, Zhong-Zheng; Hoxha, Mirjam; Dioni, Laura; Zhang, Xiao; Koutros, Stella; Freeman, Laura E. Beane

    2013-01-01

    Background: Telomere length (TL) in surrogate tissues may be influenced by environmental exposures. Objective: We aimed to determine whether lifetime pesticides use is associated with buccal cell TL. Methods: We examined buccal cell TL in relation to lifetime use of 48 pesticides for 1,234 cancer-free white male pesticide applicators in the Agricultural Health Study (AHS), a prospective cohort study of 57,310 licensed pesticide applicators. Participants provided detailed information on lifetime use of 50 pesticides at enrollment (1993–1997). Buccal cells were collected from 1999 to 2006. Relative telomere length (RTL) was measured using quantitative real-time polymerase chain reaction. We used linear regression modeling to evaluate the associations between specific pesticides and the logarithm of RTL, adjusting for age at buccal cell collection, state of residence, applicator license type, chewing tobacco use, and total lifetime days of all pesticide use. Results: The mean RTL for participants decreased significantly in association with increased lifetime days of pesticide use for alachlor (p = 0.002), 2,4-dichlorophenoxyacetic acid (2,4-D; p = 0.004), metolachlor (p = 0.01), trifluralin (p = 0.05), permethrin (for animal application) (p = 0.02), and toxaphene (p = 0.04). A similar pattern of RTL shortening was observed with the metric lifetime intensity-weighted days of pesticide use. For dichlorodiphenyltrichloroethane (DDT), we observed significant RTL shortening for lifetime intensity-weighted days (p = 0.04), but not for lifetime days of DDT use (p = 0.08). No significant RTL lengthening was observed for any pesticide. Conclusion: Seven pesticides previously associated with cancer risk in the epidemiologic literature were inversely associated with RTL in buccal cell DNA among cancer-free pesticide applicators. Replication of these findings is needed because we cannot rule out chance or fully rule out bias. PMID:23774483

  16. Removal of mixed pesticides from aqueous solutions using organoclays: evaluation of equilibrium and kinetic model.

    PubMed

    Saha, Ajoy; Ahammed Shabeer Tp; Gajbhiye, V T; Gupta, Suman; Kumar, Rajesh

    2013-07-01

    Removal of mixed pesticides, namely alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, p,p'-DDT and two metabolites p,p'-DDE and endosulfan sulphate from aqueous solution by batch adsorption onto three commercial organo-modified montmorillonite clays [modified with octadecylamine (ODA-M), modified with dimethyl- dialkylamine (DMDA-M) and modified with octadecylamine and aminopropyltriethoxysilane (ODAAPS-M)] were investigated. Effect of process variables, mainly contact time and initial concentration of mixed pesticides, on adsorption phenomenon were evaluated. To understand the adsorption kinetic pseudo-first-order and pseudo-second-order models were tested. The pseudo-second-order model provided the best fit for explaining adsorption kinetics, on the basis of high correlation coefficient (r) and normalized percent deviation values. The adsorption equilibrium was explained by the Freundlich isotherm (r = 0.951-0.992). High values (0.17-0.52 mg g⁻¹) of Freundlich constant (K(f)) indicated higher affinity of pesticides towards all three organoclays, as a result of hydrophobic interaction between the adsorbent/adsorbate systems. Pesticides with high octanol-water partition coefficient (K(ow)) and low water solubility showed faster adsorption with higher K(f) values as compared to the pesticides with low K(ow) and high water solubility. The order of organoclays for removal efficiency of mixed pesticide was ODAAPS-M > DMDA-M > ODA-M. These findings may find application to decontaminate or treat mixed pesticide contaminated industrial/agricultural waste waters.

  17. Pesticides in Streams in Central Nebraska

    USGS Publications Warehouse

    Stamer, J.K.; Wieczorek, Michael

    1995-01-01

    Contamination of surface and ground water from non-point sources is a national issue. Examples of nonpoint-source contaminants from agricultural activities are pesticides, which include fungicides, herbicides, and insecticides; sediment; nutrients (nitrogen and phosphorus); and fecal bacteria. Of these contaminants, pesticides receive the most attention because of the potential toxicity to aquatic life and to humans. Most farmers use pesticides to increase crop yields and values. Herbicides prevent or inhibit the growth of weeds that compete for nutrients and moisture needed by the crops. Herbicides are applied before, during, or following planting. In addition to agricultural use, herbicides are used in urban areas, often in larger rates of application, for weed control such as among rights-of-way. Alachlor, atrazine, cyanazine, and metolachlor, which are referred to as organonitrogen herbicides, were the four most commonly applied herbicides (1991) in the Central Nebraska Basins (CNB). These herbicides are used for corn, sorghum, and soybean production. Atrazine was the most extensively applied pesticide (1991) in central Nebraska. Insecticides are used to protect the crop seeds in storage prior to planting and also to protect the plants from destruction once the seeds have germinated. Like herbicides, insecticides are also used in urban areas to protect lawns, trees, and ornamentals. Many of the 46 pesticides shown in the table have either a Maximum Contaminant Level (MCL) of Health Advisory Level (HAL) established by the U.S. Environmental Protection Agency (USEPA) for public water supplies. The purposes of this Fact Sheet are to (1) to provide water-utility managers, water-resources planners and managers, and State regulators an improved understanding of the distributions of concentrations of pesticides in streams and their relation to respective drinking-water regulations or criteria, and (2) to describe concentrations of pesticides in streams draining a

  18. Occurrence of pesticides in transboundary aquifers of North-eastern Greece.

    PubMed

    Vryzas, Zisis; Papadakis, Emmanuel N; Vassiliou, George; Papadopoulou-Mourkidou, Euphemia

    2012-12-15

    A five-year groundwater monitoring program undertaken in Evros (north-east Greece), showed a diversification in the levels of pesticide residues detected in adjacent transboundary aquifers. During the first two years 37 wells, including irrigation, drinking water and artesian wells were monitored while the next three years the survey was focused on the 11 most contaminated wells. The presence of pesticide residues was also monitored in the phreatic horizon (shallow groundwater) of four experimental boreholes drilled in the respective margins of four fields. Among the compounds found alachlor, metolachlor, atrazine, desethylatrazine (DEA), desisopropylatrazine (DIA) and caffeine were constantly detected. Pesticide concentrations were much lower (up to 1.54 μg/L) in the water of the monitored drinking water wells (deep groundwater aquifers) compared to those found in the phreatic horizon (experimental boreholes) of the respective areas (up to 5.20 μg/L). DEA to atrazine concentration ratios (DAR) determined for the phreatic horizon of the three boreholes and respective wells were lower than 1, indicating that preferential flow was the cause of the fast downward movement of atrazine to the phreatic horizon. In contrast the DAR for the fourth borehole and the adjacent well were greater than 1 indicating the absence of preferential flow of atrazine. Catabolic processes of the soil converted atrazine to DEA which is more mobile than atrazine itself through chromatographic (darcian) flow. This differential behavior of pesticides in adjacent aquifers (3 km) was further investigated by determining the apparent age of water in the two wells. The apparent age of the water present in the first aquifer was 21.7 years whereas the apparent age of that in the second aquifer was approximately 1.2 years. The faster replenishing rate of the latter is an indication that this aquifer is very vulnerable to contamination with pollutants present in the infiltrated soil water.

  19. 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.

  20. Relationships between land uses and rainwater quality in a southcentral Pennsylvania watershed

    USGS Publications Warehouse

    Shertzer, R.H.; Hall, D.W.; Steffy, S.A.; Kime, R.A.

    1998-01-01

    Spatial and temporal variability in rainfall concentrations of nutrients, major ions, and herbicides was monitored at 7 locations in or near the Conodoguinet Creek watershed in southcentral Pennsylvania from 1991-1993. Results were used to (1) compare precipitation quality in forested, agricultural and urban areas, and (2) assess the practicality of using volunteer citizen monitoring in such a study. As indicated in previous studies, sulfate and nitrogen concentrations in precipitation were linked to sample pH. Concentrations of major ions in precipitation appeared to relate more to regional influences rather than local influences. However, concentrations of herbicides in precipitation may have been influenced by both regional and local use which caused compounds like atrazine, deethylatrazine, propazine, simazine, metolachlor, alachlor, ametryn, and prometon to be present in detectable concentrations in rainfall. Seasonality was evident in nitrogen, sulfate, pH, and herbicide data and was suggested in calcium, iron, manganese, magnesium, orthophosphate, and chloride data. Agricultural weed control activities were probably responsible for the seasonal pattern in pesticide data which peaked in May and June. Tropical storm Danielle may have caused the apparent seasonal patterns for the other nine parameters. This storm did not follow the typical west to east movement pattern and consequently produced rainfall of relative high quality. A variety of quality assurance checks indicated that trained volunteer citizen monitors were successful participants in this intensive and extensive scientific study, collecting good quality samples in a timely manner. Without this kind of volunteer help, it is extremely difficult to complete studies that require sampling in response to natural events such as rainfall.

  1. Pesticides in shallow groundwater in the Delmarva Peninsula

    USGS Publications Warehouse

    Koterba, M.T.; Banks, W.S.L.; Shedlock, R.J.

    1993-01-01

    A regional study of the areal and depth distribution of pesticides in shallow groundwater in the Delmarva Peninsula of Delaware, Maryland, and Virginia was done to (i) relate the pesticides detected to landscape and shallow subsurface features, and (ii) evaluate aquifer vulnerability and the potential contamination of drinking-water supplies. Water samples collected at 100 wells from 1988 to 1990 were analyzed for concentrations of 36 pesticides, four metabolites, and other constituents. The most commonly detected residues were atrazine, cyanazine, simazine, alachlor, metolachlor, and dicamba. Concentrations were low; few exceeded 3 ??g L-1. Most detections correlate with the intensive use of these herbicides in three widely distributed and commonly rotated crops-corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and small grain-particularly if grown in well- drained soils. Most detections occurred in samples collected from shallow wells screened within 10 m of the overlying water table. The shallow depth distribution of most residues is consistent with their suspected history of use (ca. 20 yr), and patterns in shallow groundwater flow in the surficial aquifer in the study area. The areal and depth distributions of detectable residues in groundwater did not correlate with a vulnerability index, nor any of the component scores developed to estimate that index using the DRASTIC method. The shallow depth of most detections also indicates why few samples from water-supply wells in this study had measurable concentrations of pesticides; most supply wells are deeper than 10 m below the water table. The low number of contaminated samples from supply wells implies that deep groundwater currently (1992) used for drinking generally does not contain detectable pesticide residues.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Water-quality assessment of the Kentucky River basin, Kentucky; results of investigations of surface-water quality, 1987-90

    USGS Publications Warehouse

    Haag, K.H.; Garcia, Rene; Jarrett, G.L.; Porter, S.D.

    1995-01-01

    The U.S. Geological Survey investigated the water quality of the Kentucky River Basin in Kentucky as part of the National Water-Quality Assessment program. Data collected during 1987-90 were used to describe the spatial and temporal variability of water-quality constituents including metals and trace elements, nutrients, sediments, pesticides, dissolved oxygen, and fecal-coliform bacteria. Oil-production activities were the source of barium, bromide, chloride, magnesium, and sodium in several watersheds. High concentrations of aluminum, iron, and zinc were related to surface mining in the Eastern Coal Field Region. High concentrations of lead and zinc occurred in streambed sediments in urban areas, whereas concentrations of arsenic, strontium, and uranium were associated with natural geologic sources. Concentrations of phosphorus were significantly correlated with urban and agricultural land use. The high phosphorus content of Bluegrass Region soils was an important source of phosphorus in streams. At many sites in urban areas, most of the stream nitrogen load was attributable to wastewater-treatment-plant effluent. Average suspended-sediment concentrations were positively correlated with discharge. There was a downward trend in suspended-sediment concentrations downstream in the Kentucky River main stem during the study. The most frequently detected herbicides in water samples were atrazine, 2,4-D, alachlor, metolachlor, and dicamba. Diazinon, malathion, and parathion were the most frequently detected organophosphate insecticides in water samples. Detectable concentrations of aldrin, chlordane, DDT, DDE, dieldrin, endrin, endosulfan, heptachlor, and lindane were found in streambed-sediment samples. Dissolved-oxygen concentrations were sometimes below the minimum concentration needed to sustain aquatic life. At some sites, high concentrations of fecal-indicator bacteria were found and water samples did not meet sanitary water-quality criteria.

  7. Combination of a pesticide exposure and a bacterial challenge: in vivo effects on immune response of Pacific oyster, Crassostrea gigas (Thunberg).

    PubMed

    Gagnaire, Beatrice; Gay, Melanie; Huvet, Arnaud; Daniel, Jean-Yves; Saulnier, Denis; Renault, Tristan

    2007-08-15

    To assess the impact of pollution induced by pesticides on Pacific oyster, Crassostrea gigas, health in France, in vivo effects of combined pesticide exposure and bacterial challenge on cell activities and gene expression in hemocytes were tested using flow cytometry and real-time PCR. As a first step, an in vivo model of experimental contamination was developed. Pacific oysters were exposed to a mixture of eight pesticides (atrazine, glyphosate, alachlor, metolachlor, fosetyl-alumimium, terbuthylazine, diuron and carbaryl) at environmentally relevant concentrations over a 7-day period. Hemocyte parameters (cell mortality, enzyme activities and phagocytosis) were monitored using flow cytometry and gene expression was evaluated by real-time PCR (RT-PCR). The expression of 19 genes involved in C. gigas hemocyte functions was characterized using RT-PCR. After 7 days of exposure, phagocytosis was significantly reduced and the 19 selected genes were down-regulated in treated animals. As a second step, the experimental contamination method previously developed was used to study interactions between pesticide exposure and bacterial challenge by intramuscular injection of two Vibrio splendidus-related pathogenic strains. Oyster mortality and expression of 10 of the 19 selected genes were followed 4 and 24h post-injection. Oyster mortality was higher in pesticide-treated oysters compared to untreated oysters after the bacterial challenge. Gene expression was up-regulated in pesticide-treated oysters compared to untreated oysters after the bacterial challenge. We hypothesize that gene over-expression due to an interaction between pesticides and bacteria could lead to an injury of host tissues, resulting in higher mortality rates. In conclusion, this study is the first to show effects of pesticides at environmentally relevant concentrations on C. gigas hemocytes and to hypothesize that pesticides modulate the immune response to a bacterial challenge in oysters.

  8. Herbicide safener-binding protein of maize. Purification, cloning, and expression of an encoding cDNA.

    PubMed

    Scott-Craig, J S; Casida, J E; Poduje, L; Walton, J D

    1998-03-01

    Dichloroacetamide safeners protect maize (Zea mays L.) against injury from chloroacetanilide and thiocarbamate herbicides. Etiolated maize seedlings have a high-affinity cytosolic-binding site for the safener [3H](R,S)-3-dichloroacetyl-2,2,5-trimethyl-1, 3-oxazol-idine ([3H]Saf), and this safener-binding activity (SafBA) is competitively inhibited by the herbicides. The safener-binding protein (SafBP), purified to homogeneity, has a relative molecular weight of 39,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an isoelectric point of 5.5. Antiserum raised against purified SafBP specifically recognizes a 39-kD protein in etiolated maize and sorghum (Sorghum bicolor L.), which have SafBA, but not in etiolated wheat (Triticum aestivum L.), oat (Avena sativa L.), barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), or Arabidopsis, which lack SafBA. SafBP is most abundant in the coleoptile and scarcest in the leaves, consistent with the distribution of SafBA. SBP1, a cDNA encoding SafBP, was cloned using polymerase chain reaction primers based on purified proteolytic peptides. Extracts of Escherichia coli cells expressing SBP1 have strong [3H]Saf binding, which, like binding to the native maize protein, is competitively inhibited by the safener dichlormid and the herbicides S-ethyl dipropylthiocarbamate, alachlor, and metolachlor. SBP1 is predicted to encode a phenolic O-methyltransferase, but SafBP does not O-methylate catechol or caffeic acid. The acquisition of its encoding gene opens experimental approaches for the evaluation of the role of SafBP in response to the relevant safeners and herbicides.

  9. Quality of water from public-supply wells in principal aquifers of Illinois, 1984-87

    USGS Publications Warehouse

    Voelker, David C.

    1989-01-01

    The quality of water from public-supply wells that tap the principal aquifers in Illinois are summarized. Water quality data collected during the study included inorganic and volatile organic constituents in 2,756 samples and soluble organic constituents in 330 samples from 2,080 public supply wells. Water quality differs among the aquifers as well as within each aquifer. Groundwater quality generally is suitable for most domestic uses; however, concentrations of iron, dissolved solids , and manganese commonly exceed the States 's general-use and public--and food-processing water supply standards. Water from some wells also contains concentrations of barium, chloride, fluoride, and sulfates that exceed those State standards. Most of these conditions are considered to be the result of natural processes. Volatile organic compounds occurred in more than 300 of the 2,756 samples collected. The sand and gravel aquifers generally are the most susceptible to human-induced contamination; 172 of the 1,047 samples from these aquifers indicate the presence of at least one volatile organic compound. Soluble organic compounds analyzed for included more than 30 pesticides, herbicides, and polychlorinated biphenyls (PCB's). Of the 330 wells sampled, water from only 8 wells had quantifiable concentrations of soluble organic compounds. Water from five wells contained metolachlor, atrazine, alachlor, cyanazine, and metribuzin. Water from three wells contained detectable levels of PCB's. The presence of these soluble organics appears to be limited to wells located near sources of potential contamination. Soluble organic compounds were detected only in wells located near sources of potential contamination. Soluble organic compounds were detected only in wells open to the sand and gravel aquifers. (USGS)

  10. Spatial and temporal distribution of pesticide air concentrations in Canadian agricultural regions

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Tuduri, Ludovic; Harner, Tom; Blanchard, Pierrette; Waite, Don; Poissant, Laurier; Murphy, Clair; Belzer, Wayne; Aulagnier, Fabien; Li, Yi-Fan; Sverko, Ed

    The Canadian Pesticide Air Sampling Campaign was initiated in 2003 to assess atmospheric levels of pesticides, especially currently used pesticides (CUPs) in agricultural regions across Canada. In the first campaign during the spring to summer of 2003, over 40 pesticides were detected. The spatial and temporal distribution of pesticides in the Canadian atmosphere was shown to reflect the pesticide usage in each region. Several herbicides including triallate, bromoxynil, MCPA, 2,4-D, dicamba, trifluralin and ethalfluralin were detected at highest levels at Bratt's Lake, SK in the prairie region. Strong relationships between air concentrations and dry depositions were observed at this site. Although no application occurred in the Canadian Prairies in 2003, high air concentrations of lindane ( γ-hexachlorocyclohexane) were still observed at Bratt's Lake and Hafford, SK. Two fungicides (chlorothalonil and metalaxyl) and two insecticides (endosulfan and carbofuran) were measured at highest levels at Kensington, PEI. Maximum concentrations of chlorpyrifos and metolachlor were found at St. Anicet, QC. The southern Ontario site, Egbert showed highest concentration of alachlor. Malathion was detected at the highest level at the west coast site, Abbotsford, BC. In case of legacy chlorinated insecticides, high concentrations of DDT, DDE and dieldrin were detected in British Columbia while α-HCH and HCB were found to be fairly uniform across the country. Chlordane was detected in Ontario, Québec and Prince Edward Island. This study demonstrates that the sources for the observed atmospheric occurrence of pesticides include local current pesticide application, volatilization of pesticide residues from soil and atmospheric transport. In many instances, these data represent the first measurements for certain pesticides in a given part of Canada.

  11. Pesticide use and risk of end-stage renal disease among licensed pesticide applicators in the Agricultural Health Study

    PubMed Central

    Lebov, Jill F.; Engel, Lawrence S.; Richardson, David; Hogan, Susan L.; Hoppin, Jane A.; Sandler, Dale P.

    2017-01-01

    Objectives Experimental studies suggest a relationship between pesticide exposure and renal impairment, but epidemiological evidence is limited. We evaluated the association between exposure to 41 specific pesticides and end-stage renal disease (ESRD) incidence in the Agricultural Health Study (AHS), a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. Methods Via linkage to the United States Renal Data System, we identified 320 ESRD cases diagnosed between enrollment (1993-1997) and December 2011 among 55,580 male licensed pesticide applicators. Participants provided pesticide use information via self-administered questionnaires. Lifetime pesticide use was defined as the product of duration and frequency of use and then modified by an intensity factor to account for differences in pesticide application practices. Cox proportional hazards models, adjusted for age and state, were used to estimate associations between ESRD and: 1) ordinal categories of intensity-weighted lifetime use of 41 pesticides, 2) poisoning and high-level pesticide exposures, and 3) pesticide exposure resulting in a medical visit or hospitalization. Results Positive exposure-response trends were observed for the herbicides alachlor, atrazine, metolachlor, paraquat, and pendimethalin, and the insecticide chlordane. More than one medical visit due to pesticide use (HR = 2.13; 95% CI: 1.17, 3.89) and hospitalization due to pesticide use (HR = 3.05; 95% CI: 1.67, 5.58) were significantly associated with ESRD. Conclusions Our findings support an association between ESRD and chronic exposure to specific pesticides and suggest pesticide exposures resulting in medical visits may increase the risk of ESRD. PMID:26177651

  12. Fate and transport of pesticides in the ground water systems of southwest Georgia, 1993-2005

    USGS Publications Warehouse

    Dalton, M.S.; Frick, E.A.

    2008-01-01

    Modern agricultural practices in the United States have resulted in nearly unrivaled efficiency and productivity. Unfortunately, there is also the potential for release of these compounds to the environment and consequent adverse affects on wildlife and human populations. Since 1993, the National Water-Quality Assessment (NAWQA) program of the U.S. Geological Survey has evaluated water quality in agricultural areas to address these concerns. The objective of this study is to evaluate trends in pesticide concentrations from 1993-2005 in the surficial and Upper Floridan aquifers of southwest Georgia using pesticide and pesticide degradate data collected for the NAWQA program. There were six compounds - five herbicides and one degradate - that were detected in more than 20% of samples: atrazine, deethylatrazine (DEA), metolachlor, alachlor, floumeturon, and tebuthiuron. Of the 128 wells sampled during the study, only eight wells had pesticide concentrations that either increased (7) or decreased (1) on a decadal time scale. Most of the significant trends were increasing concentrations of pesticides in older water; median pesticide concentrations did not differ between the surficial and Upper Floridan aquifers from 1993 and 2005. Deethylatrazine, in the Upper Floridan aquifer, was the only compound that had a significant change (increase) in concentration during the study. The limited number of wells with increases in pesticide concentrations suggest that ground-water sources of these compounds are not increasing in concentration over the time scale represented in this study. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  13. Hydrogeology, herbicides and nutrients in ground water and springs, and relation of water quality to land use and agricultural practices near Carlisle, Pennsylvania

    USGS Publications Warehouse

    Hippe, D.J.; Witt, E. C.; Giovannitti, R.M.

    1994-01-01

    Discharge and water-quality data collected in two adjacent karst-spring basins in Cumberland County, Pa., from May 1990 through April 1991 were used to (1) describe the hydrogeology of the area; (2) determine the concentrations of selected herbicides, herbicide-soil metabolites, and nutrients in water from wells and discharges from springs, (3) determine herbicide and nutrient discharges from springs; and (4) determine the relation of ground-water quality to land use and agricultural practices in the spring basins. The study area is underlain by a regolith-mantled carbonate-rock aquifer system. Agricultural land, forest, and residential land are the principal land uses. Herbicides are applied primarily to cornfields. Cyanazine, atrazine, metolachlor, and alachlor account for about 90 percent of the documented herbicide use on cropland. Daily mean discharge of Alexanders and Mount Rock Springs was 3.8 and 3.7 cubic feet per second, and total discharge was 1,390 and 1,370 cubic feet per second-days. Increases in discharge were related to individual periods of precipitation, but maximum flow rates lagged precipitation periods by 2 to 5 days. The recharge area to each spring is estimated to be 2.8 square miles. Atrazine was the only herbicide in common use that was detected in discharges from springs. Atrazine and the atrazine soil-metabolite deethylatrazine (DEA) were detected in spring discharges for the duration of the study. Changes in atrazine and DEA concentrations in the discharges from springs were minimal, and no flush of herbicides from the springs followed application. Temporal variation in constituent discharges was related mostly to changes in spring flow; the largest daily constituent discharges coincided with periods of increased spring flow during the winter and early spring. Atrazine and DEA discharged from Alexanders Spring and Mount Rock Spring were about 0.5 and 0.6 percent of the estimated annual atrazine use on row crops in their respective

  14. Water-quality assessment of the Albemarle-Pamlico drainage basin, North Carolina and Virginia; characterization of suspended sediment, nutrients, and pesticides

    USGS Publications Warehouse

    Harned, Douglas; McMahon, Gerard; Spruill, T.B.; Woodside, M.D.

    1995-01-01

    The 28,000-square-mile Albemarle-Pamlico drainage basin includes the Roanoke, Dan, Chowan Tar, and Neuse Rivers. The basin extends through four physiographic provinces in North Carolina and Virginia-Valley and Ridge, Blue Ridge, Piedmont and Coastal Plain. The spatial and temporal trends in ground-water and riverine water quality in the study area were characterized by using readily available data sources The primary data sources that were used included the U.S. Geological Survey's National Water Data Storage and Retrieval System (WATSTORE) database, the U.S. Environmental Protection Agency's Storage and Retrieval System (STORET) database, and results of a few investigations of pesticide occurrence. The principal water-quality constituents examined were suspended sediment, nutrients, and pesticides. The data examined generally spanned the period from 1950 to 1993. The only significant trends in suspended sediment were detected at three Chowan River tributary sites which showed long-term decreases. Suspended- and total-solids concentrations have decreased throughout the Albemarle-Pamlico drainage basin. The decreases are probably a result of (1) construction of new lakes and ponds in the basin, which trap solids, (2) improved agricultural soil management, and (3) improved wastewater treatment. Nutrient point sources are much less than nonpoint nutrient sources at the eight NASQAN basins examined for nutrient loads. The greatest nitrogen inputs are associated with crop fertilizer and biological nitrogen fixation by soybeans and peanuts, whereas atmospheric and animal-related nitrogen inputs are comparable in magnitude. The largest phosphorus inputs are associated with animal wastes. The most commonly detected pesticides in surface water in the STORET database were atrazine and aldrin.Intensive organonitrogen herbicide sampling of Chicod Creek in 1992 showed seasonal variations in pesticide concentration. The most commonly detected herbicides were atrazine, alachlor

  15. Analysis and occurrence of selected medium to highly polar pesticides in groundwater of Catalonia (NE Spain): An approach based on on-line solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry detection

    NASA Astrophysics Data System (ADS)

    Postigo, Cristina; López de Alda, Maria José; Barceló, Damià; Ginebreda, Antoni; Garrido, Teresa; Fraile, Josep

    2010-03-01

    SummaryThe present work describes an automated methodology based on on-line solid phase extraction-liquid chromatography-electrospray-tandem mass spectrometry (on-line SPE-LC-ESI-MS/MS) for the determination of 22 medium to highly polar pesticides in groundwater, and its application to the analysis of 133 samples collected from different aquifers of Catalonia (NE Spain), in areas where agricultural practice is significant. Sample preconcentration was performed by passing 5 mL of the sample through PLRPs cartridges (for analysis of 16 pesticides measured in the positive ionization mode) and through Hysphere-Resin GP cartridges (for analysis of six pesticides measured in the negative ionization mode). Further LC-MS/MS determination was performed in the selected reaction monitoring (SRM) mode, by recording two SRM transitions per compound, thus obtaining four identification points. The methodology developed allows the determination of the target compounds at the pg or low ng L -1 level with satisfactory precision (relative standard deviations lower than 16%) and accuracy (recovery percentages higher than 75%) and is well suited for routine monitoring. Its application to various groundwater samples from Catalonia has revealed simazine, diuron and atrazine (present in more than 70% of the samples) as the most ubiquitous compounds. Approximately 16% of the samples investigated had individual pesticides levels above 100 ng L -1 and 7% presented total pesticides levels above 500 ng L -1. Concentrations higher than 100 ng L -1 were found for all triazines studied but cyanazine, the phenylureas diuron, linuron and chlortoluron, the target chloroacetanilides alachlor and metolachlor, and the organophosphate dimethoate in a few samples. Three and eight out of the 16 investigated groundwater bodies presented total pesticide levels exceeding the EU quality standards in terms of individual and total pesticide concentrations, 100 and 500 ng L -1, respectively.

  16. Removal of Pesticides and Inorganic Contaminants in Anaerobic and Aerobic Biological Contactors

    EPA Science Inventory

    This presentation contains data on the removal of pesticides (acetochlor, clethodim, dicrotophos), ammonia, nitrate, bromate and perchlorate through aerobic and anaerobic biological treatment processes.

  17. 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...

  18. 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

  19. Hydrogeology and Water Quality of the Pepacton Reservoir Watershed in Southeastern New York. Part 3. Responses of Stream Base-Flow Chemistry to Hydrogeologic Factors and Nonpoint-Sources of Contamination

    USGS Publications Warehouse

    Heisig, Paul M.; Phillips, Patrick J.

    2004-01-01

    -water quality, and stream base-flow water quality. Chloride and sodium, which are relatively conservative constituents, showed strong linear relations with annual estimates of road-salt application during all four sampling periods. Nonconservative constituents, such as the nutrients nitrate and orthophosphate, showed linear relations with manure production rate among farmed basins, but only at specific times of the year because of losses through biologic activity. Nitrate showed the strongest relation in winter because losses to biological activity were at a minimum. Orthophosphate showed the strongest relation in early summer, when hydrologic and chemical conditions appear to favor release from sediments. Atmospheric nitrogen deposition is an additional source of nitrogen that can be released from mature or stressed forested basins. Detections of herbicides (atrazine, metolachlor, simazine) and herbicide degradates ( Metolachlor ESA, alachlor ESA, deethylatrazine) in base flow were closely correlated with subbasins in which corn was grown during the study. Atrazine was detected at the farmed index site only in early summer, after application and two rain storms. This detection corresponded to the peak orthophosphate concentration. In contrast, metolachlor ESA was detected in nearly all farmedindex- subbasin samples and peaked in late summer, when percent base-flow contributions from farmed valley-bottom areas were likely highest. The implications of this study are that seasonal and more frequent base-flow surveys of water chemistry from small stream basins can help refine the understanding of local hydrogeologic systems and define the effects of nonpointsource contamination on base-flow water quality. The concentration of most nonpoint sources in valley-bottom or lower-hillside areas helped indicate the relative contributions of water from hillside and valley-bottom areas at different times of year. The positive correlations between the intensity of nonpoint-

  20. Summary of and factors affecting pesticide concentrations in streams and shallow wells of the lower Susquehanna River basin, Pennsylvania and Maryland, 1993-95

    USGS Publications Warehouse

    Hainly, Robert A.; Zimmerman, Tammy M.; Loper, Connie A.; Lindsey, Bruce D.

    2001-01-01

    This report presents the detection frequency of 83 analyzed pesticides, describes the concentrations of those pesticides measured in water from streams and shallow wells, and presents conceptual models of the major factors affecting seasonal and areal patterns of pesticide concentrations in water from streams and shallow wells in the Lower Susquehanna River Basin. Seasonal and areal patterns of pesticide concentrations were observed in 577 samples and nearly 40,000 pesticide analyses collected from 155 stream sites and 169 shallow wells from 1993 to 1995. For this study, shallow wells were defined as those generally less than 200 feet deep. The most commonly detected pesticides were agricultural herbicides?atrazine, metolachlor, simazine, prometon, alachlor, and cyanazine. Atrazine and metolachlor are the two most-used agricultural pesticides in the Lower Susquehanna River Basin. Atrazine was detected in 92 percent of all the samples and in 98 percent of the stream samples. Metolachlor was detected in 83 percent of all the samples and in 95 percent of the stream samples. Nearly half of all the analyzed pesticides were not detected in any sample. Of the 45 pesticides that were detected at least once, the median concentrations of 39 of the pesticides were less than the detection limit for the individual compounds, indicating that for at least 50 percent of the samples collected, those pesticides were not detected. Only 10 (less than 0.025 percent) of the measured concentrations exceeded any established drinking-water standards; 25 concentrations exceeded 2 mg/L (micrograms per liter) and 55 concentrations exceeded 1 mg/L. None of the elevated concentrations were measured in samples collected from streams that are used for public drinking-water supplies, and 8 of the 10 were measured in storm-affected samples. The timing and rate of agricultural pesticide applications affect the seasonal and areal concentration patterns of atrazine, simazine, chlorpyrifos, and

  1. 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

  2. Glyphosate, other herbicides, and transformation products in Midwestern streams, 2002

    USGS Publications Warehouse

    Battaglin, W.A.; Kolpin, D.W.; Scribner, E.A.; Kuivila, K.M.; Sandstrom, M.W.

    2005-01-01

    The use of glyphosate has increased rapidly, and there is limited understanding of its environmental fate. The objective of this study was to document the occurrence of glyphosate and the transformation product aminomethylphosphonic acid (AMPA) in Midwestern streams and to compare their occurrence with that of more commonly measured herbicides such as acetochlor, atrazine, and metolachlor. Water samples were collected at sites on 51 streams in nine Midwestern states in 2002 during three runoff events: after the application of pre-emergence herbicides, after the application of post-emergence herbicides, and during harvest season. All samples were analyzed for glyphosate and 20 other herbicides using gas chromatography/mass spectrometry or high performance liquid chromatography/mass spectrometry. The frequency of glyphosate and AMPA detection, range of concentrations in runoff samples, and ratios of AMPA to glyphosate concentrations did not vary throughout the growing season as substantially as for other herbicides like atrazine, probably because of different seasonal use patterns. Glyphosate was detected at or above 0.1 μg/1 in 35 percent of pre-emergence, 40 percent of post-emergence, and 31 percent of harvest season samples, with a maximum concentration of 8.7 μg/1. AMPA was detected at or above 0.1 μg/1 in 53 percent of pre-emergence, 83 percent of post-emergence, and 73 percent of harvest season samples, with a maximum concentration of 3.6 μg/1. Glyphosate was not detected at a concentration at or above the U.S. Environmental Protection Agency's maximum contamination level (MCL) of 700 μg/1 in any sample. Atrazine was detected at or above 0.1 μg/1 in 94 percent of pre-emergence, 96 percent of post-emergence, and 57 percent of harvest season samples, with a maximum concentration of 55 μg/1. Atrazine was detected at or above its MCL (3 μg/1) in 57 percent of pre-emergence and 33 percent of post-emergence samples

  3. Glyphasate, other herbicides, and transformation products in midwestern streams, 2002

    USGS Publications Warehouse

    Battaglin, William A.; Koplin, Dana W.; Scribner, Elizabeth A.; Kuivila, Kathryn; Sandstrom, Mark W.

    2005-01-01

    The use of glyphosate has increased rapidly, and there is limited understanding of its environmental fate. The objective of this study was to document the occurrence of glyphosate and the transformation product aminomethylphosphonic acid (AMPA) in Midwestern streams and to compare their occurrence with that of more commonly measured herbicides such as acetochlor, atrazine, and metolachlor. Water samples were collected at sites on 51 streams in nine Midwestern states in 2002 during three runoff events: after the application of pre-emergence herbicides, after the application of post-emergence herbicides, and during harvest season. All samples were analyzed for glyphosate and 20 other herbicides using gas chromatography/mass spectrometry or high performance liquid chromatography/mass spectrometry. The frequency of glyphosate and AMPA detection, range of concentrations in runoff samples, and ratios of AMPA to glyphosate concentrations did not vary throughout the growing season as substantially as for other herbicides like atrazine, probably because of different seasonal use patterns. Glyphosate was detected at or above 0.1 μg/1 in 35 percent of pre-emergence, 40 percent of post-emergence, and 31 percent of harvest season samples, with a maximum concentration of 8.7 μg/1. AMPA was detected at or above 0.1 μg/1 in 53 percent of pre-emergence, 83 percent of post-emergence, and 73 percent of harvest season samples, with a maximum concentration of 3.6 μg/1. Glyphosate was not detected at a concentration at or above the U.S. Environmental Protection Agency's maximum contamination level (MCL) of 700 μg/1 in any sample. Atrazine was detected at or above 0.1 μg/1 in 94 percent of pre-emergence, 96 percent of post-emergence, and 57 percent of harvest season samples, with a maximum concentration of 55 μg/1. Atrazine was detected at or above its MCL (3 μg/1) in 57 percent of pre-emergence and 33 percent of post-emergence samples.

  4. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    NASA Astrophysics Data System (ADS)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  5. Seasonal exposures to triazine and other pesticides in surface waters in the western Highveld corn-production region in South Africa

    USGS Publications Warehouse

    Du Preez, L.H.; Jansen Van Rensburg, P.J.; Jooste, A.M.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G.; Solomon, K.R.

    2005-01-01

    The objective of this study was to characterize concentrations of atrazine, terbuthylazine, and other pesticides in amphibian habitats in surface waters of a corn-production area of the western Highveld region (North-West Province) of South Africa. The study was conducted from November 2001 to June 2002, coinciding with the corn-production season. Pesticide residues were measured at regular intervals in surface water from eight ponds, three in a non-corn-growing area (NCGA) and five within the corn-growing area (CGA). Measured atrazine concentrations differed significantly among sites and between samples. In the five CGA sites, the maximum atrazine concentrations measured during the study ranged from 1.2 to 9.3 ??g/L. Although no atrazine was recorded as being applied in the catchment of the three NCGA sites, maximum concentrations from 0.39 to 0.84 ??g/L were measured during the study, possibly as a result of atmospheric transport. Maximum measured concentrations of terbuthylazine ranged from 1.22 to 2.1 ??g/L in the NCGA sites and from 1.04 to 4.1 ??g/L in the CGA sites. The source of terbuthylazine in the NCGA sites may have been in use other than in corn. The triazine degradation products, deisopropylatrazine (DIA) and deethylatrazine (DEA) and diaminochlorotriazine (DACT) were also found in water from both the CGA and NCGA sites. Concentrations of DIA were ??? 1 ??g/L throughout the season, while DEA concentrations were mostly 2 ??g/L in some locations. Concentrations of DACT were highly variable (LOD to 8 ??g/L) both before and after planting and application, suggesting that they resulted from historical use of triazines in the area. Other herbicides such as simazine and acetochlor were only detected infrequently and pesticides such as S-metolachlor, cypermethrin, monocrotophos, and terbuphos, known to be used in the CGA, were not detected in any of the samples. Because of dilution by higher than normal rainfall in the study period, these concentrations may

  6. Compound-specific stable isotope analysis of herbicides in stream water: a combined monitoring and modeling approach to assess pollutant degradation at catchment scale

    NASA Astrophysics Data System (ADS)

    Lutz, Stefanie; Van der Velde, Ype; Elsayed, Omniea; Imfeld, Gwenael; Lefrancq, Marie; Payraudeau, Sylvain; Van Breukelen, Boris

    2014-05-01

    Compound-specific stable isotope analysis (CSIA) measures the isotopic composition of a compound, i.e. the relative abundance of light and heavy stable isotopes of an element contained in the compound (e.g. 12C and 13C). As degradation processes may induce a change in isotopic composition (i.e. isotope fractionation), CSIA allows distinguishing degradation from non-destructive processes such as dilution or sorption. CSIA can be combined with model-assisted interpretation to evaluate degradation of contaminants in the environment. Although CSIA methods have also been developed for diffuse pollutants such as pesticides and nitrate, they have not yet been continuously applied in monitoring of diffuse pollution in surface water. Results of a virtual experiment of isotope fractionation at hillslope scale have suggested that CSIA qualifies as a feasible and useful complement to concentration measurements of diffuse pollutants (Lutz et al., 2013). We now present the first continuously measured concentration and carbon CSIA data of herbicides from a 49-ha agricultural catchment (Alsace, France). Stream concentrations of two chloroacetanilide herbicides, i.e. S-metolachlor and acetochlor, were highest (65 μg/L) following an extreme rainfall event in the first month after herbicide application, and subsequently decreased to background concentration level (0.1 μg/L). This decrease was accompanied by an increase of more than 2 ‰ in carbon isotope ratios, which was also observed in surface runoff samples from a plot experiment in the study catchment. The increase of carbon isotope ratios over time indicates the occurrence of herbicide degradation during transport to the stream, and thus demonstrates the advantage of CSIA over pesticide concentration measurements only. Despite providing evidence of herbicide degradation, the field CSIA data do not allow for a comprehensive characterization of herbicide sources, fate and transport in the study catchment. Therefore, we

  7. Contributing recharge areas, groundwater travel time, and groundwater water quality of the Missouri River alluvial aquifer near the City of Independence, Missouri, well field, 1997-2008

    USGS Publications Warehouse

    Kelly, Brian P.

    2011-01-01

    recharge area (CRA) of the Independence well field. Statistical summaries and the spatial and temporal variability of water quality in the Missouri River alluvial aquifer near the Independence well field were characterized from analyses of 598 water samples. Water-quality constituent groups include dissolved oxygen and physical properties, nutrients, major ions and trace elements, wastewater indicator compounds, fuel compounds, and total benzene, toluene, ethylbenzene, and xylene (BTEX), alachlor, and atrazine. The Missouri Secondary Maximum Contaminant Level (SMCL) for iron was exceeded in almost all monitoring wells. The Missouri Maximum Contaminant Level (MCL) for arsenic was exceeded 32 times in samples from monitoring wells. The MCL for barium was exceeded five times in samples from one monitoring well. The SMCL for manganese was exceeded 160 times in samples from all monitoring wells and the combined well-field sample. The most frequently detected wastewater indicator compounds were N,N-diethyl-meta-toluamide (DEET), phenol, caffeine, and metolachlor. The most frequently detected fuel compounds were toluene and benzene. Alachlor was detected in 22 samples and atrazine was detected in 37 samples and the combined well-field sample. The MCL for atrazine was exceeded in one sample from one monitoring well. Samples from monitoring wells with median concentrations of total inorganic nitrogen larger than 1 milligram per liter (mg/L) are located near agricultural land and may indicate that agricultural land practices are the source of nitrogen to groundwater. Largest median values of specific conductance; total inorganic nitrogen; dissolved calcium, magnesium, sodium, iron, arsenic, manganese, bicarbonate, and sulfate and detections of wastewater indicator compounds generally were in water samples from monitoring wells with CRAs that intersect the south bank of the Missouri River. Zones of higher specific conductance were located just upstream from the Independen

  8. 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

  9. Relation of pesticide concentrations to season, streamflow, and land use in seven New Jersey streams

    USGS Publications Warehouse

    Reiser, Robert G.

    1999-01-01

    The presence and variability of pesticides in seven New Jersey streams was documented by analyzing 146 samples collected from the streams from April 1996 through June 1998. The samples were analyzed for 85 pesticides, including 50 herbicides, 28 insecticides, and 7 degradation products, at method detection limits that ranged from 0.001 to 0.018 μg/L (micrograms per liter). Pesticides were frequently detected; however, concentrations were generally low. The pesticides most frequently detected were atrazine, in 97 percent of the samples; prometon, 96 percent; metolachlor, 95 percent; desethyl-atrazine, 91 percent; simazine, 88 percent; diazinon, 58 percent; alachlor, 56 percent; and carbaryl, 54 percent. Detection frequencies were highest during the growing season (April-September). At least one pesticide was detected in all but one of these samples, and 49 percent of the samples contained 9 or more pesticides. The numbers of pesticides detected at a given site ranged from 13 to 29. Ten pesticides were detected at concentrations that exceeded established water-quality criteria. Thirty-one of these detections were in samples collected during the growing season and one during the nongrowing season. The pesticides that exceeded the U.S. Environmental Protection Agency (USEPA) maximum contaminant level for drinking water were atrazine, which exceeded 3 μg/L in four samples, and alachlor, 2 μg/L in two samples. Cyanazine exceeded the USEPA liftime health advisory level (HAL) of 1 μg/L in two samples. These eight detections occurred during runoff shortly after spring pesticide applications and represent a potential threat to municipal water supplies in the Raritan River basin. Concentrations of chlorpyrifos, chlorthalonil, diazinon, ethyl-parathion, and methyl-azinphos exceeded the chronic life criteria for the protection of aquatic life (ACQR) in 20 samples at four sites during the growing season. Dieldrin was detected in four samples and DDE in two samples at

  10. Nutrients, suspended sediment, and pesticides in water of the Red River of the North Basin, Minnesota and North Dakota, 1990-2004

    USGS Publications Warehouse

    Christensen, V.G.

    2007-01-01

    Nutrient, suspended sediment, and pesticide data from 1990 through 2004 in the Red River of the North Basin were compiled, summarized, and compared to historical data. Streamflow varied widely throughout the basin during the 1990-2004 study period. For 19 of 22 streamflow sites, median annual streamflow during the study period exceeded the long-term average streamflow. High streamflow can have a substantial effect on water quality. In water samples from selected surface-water sites, nitrite plus nitrate concentrations ranged from less than 0.005 to 7.7 milligrams per liter; total Kjeldahl nitrogen concentrations ranged from 0.1 to 7.5 milligrams per liter; total phosphorus concentrations ranged from less than 0.005 to 4.14 milligrams per liter; and dissolved phosphorus concentrations ranged from 0.003 to 4.13 milligrams per liter. Surface-water samples from the Pembina River basin generally had higher nitrite plus nitrate, total phosphorus, and suspended sediment concentrations compared to samples from other Red River Basin sites. Historical data from 1970 through 1990 showed relatively high nitrite plus nitrate and suspended sediment concentrations in samples from some Pembina River sites; in contrast to the 1990-2004 period, total phosphorus concentrations from the 1970-90 period generally were highest at Red River of the North sites. Nitrate concentrations in ground-water samples for the 1990-2004 period were highest in Sheridan County, North Dakota and Marshall and Otter Tail Counties in Minnesota. Concentrations of nitrate in ground water in Marshall and Otter Tail Counties corresponded to relatively high reported fertilizer applications during 2002; however, Sheridan County did not have the high fertilizer applications in 2002 compared to other North Dakota and Minnesota counties. The most frequently detected pesticides or pesticide metabolites were 2, 4-D, bentazon, de-ethylatrazine, metolachlor, picloram, and triallate in surface water and alachlor

  11. Acute sensitivity of the vernal pool fairy shrimp, Branchinecta lynchi (Anostraca; Branchinectidae), and surrogate species to 10 chemicals.

    PubMed

    Ivey, Chris D; Besser, John M; Ingersoll, Chris G; Wang, Ning; Rogers, D Christopher; Raimondo, Sandy; Bauer, Candice R; Hammer, Edward J

    2017-03-01

    Vernal pool fairy shrimp, Branchinecta lynchi, (Branchiopoda; Anostraca) and other fairy shrimp species have been listed as threatened or endangered under the US Endangered Species Act. Because few data exist about the sensitivity of Branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. A series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (B. lynchi, Branchinecta lindahli, and Thamnocephalus platyurus) and 10 chemicals with varying modes of toxic action: ammonia, potassium, chloride, sulfate, chromium(VI), copper, nickel, zinc, alachlor, and metolachlor. The same chemicals were tested in 48-h tests with other branchiopods (the cladocerans Daphnia magna and Ceriodaphnia dubia) and an amphipod (Hyalella azteca), and in 96-h tests with snails (Physa gyrina and Lymnaea stagnalis). Median effect concentrations (EC50s) for B. lynchi were strongly correlated (r(2 ) = 0.975) with EC50s for the commercially available fairy shrimp species T. platyurus for most chemicals tested. Comparison of EC50s for fairy shrimp and EC50s for invertebrate taxa tested concurrently and with other published toxicity data indicated that fairy shrimp were relatively sensitive to potassium and several trace metals compared with other invertebrate taxa, although cladocerans, amphipods, and mussels had similar broad toxicant sensitivity. Interspecies correlation estimation models for predicting toxicity to fairy shrimp from surrogate species indicated that models with cladocerans and freshwater mussels as surrogates produced the best predictions of the sensitivity of fairy shrimp to contaminants. The results of these studies indicate that fairy shrimp are relatively sensitive to a range of toxicants, but Endangered Species Act-listed fairy shrimp of the genus Branchinecta were not consistently more sensitive than other fairy shrimp taxa. Environ Toxicol

  12. 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

  13. Ground-Water Quality Beneath Irrigated Cropland of the Northern and Southern High Plains Aquifer, Nebraska and Texas, 2003-04

    USGS Publications Warehouse

    Stanton, Jennifer S.; Fahlquist, Lynne

    2006-01-01

    A study of the quality of ground water beneath irrigated cropland was completed for the northern and southern High Plains aquifer. Ground-water samples were collected from 30 water-table monitoring wells in the northern agricultural land-use (NAL) study area in Nebraska in 2004 and 29 water-table monitoring wells in the southern agricultural land-use (SAL) study area in Texas in 2003. The two study areas represented different agricultural and hydrogeologic settings. The primary crops grown in the NAL study area were corn and soybeans, and the primary crop in the SAL study area was cotton. Overall, pesticide and fertilizer application rates were larger in the NAL study area. Also, precipitation and recharge rates were greater in the NAL study area, and depths to water and evapotranspiration rates were greater in the SAL study area. Ground-water quality beneath irrigated cropland was different in the two study areas. Nitrate concentrations were larger and pesticide detections were more frequent in the NAL study area. Nitrate concentrations in NAL samples ranged from 1.96 to 106 mg/L (milligrams per liter) as nitrogen, with a median concentration of 10.6 mg/L. Water in 73 percent of NAL samples had at least one pesticide or pesticide degradate detected. Most of the pesticide compounds detected (atrazine, alachlor, metolachlor, simazine, and degradates of those pesticides) are applied to corn and soybean fields. Nitrate concentrations in SAL samples ranged from 0.96 to 21.6 mg/L, with a median of 4.12 mg/L. Water in 24 percent of SAL samples had at least one pesticide or pesticide degradate detected. The pesticide compounds detected were deethylatrazine (a degradate of atrazine and propazine), propazine, fluometuron, and tebuthiuron. Most of the pesticides detected are applied to cotton fields. Dissolved-solids concentrations were larger in the SAL area and were positively correlated with both nitrate and chloride concentrations, suggesting a combination of human and

  14. Analysis of polar organic contaminants in surface water of the northern Adriatic Sea by solid-phase extraction followed by ultrahigh-pressure liquid chromatography-QTRAP® MS using a hybrid triple-quadrupole linear ion trap instrument.

    PubMed

    Loos, Robert; Tavazzi, Simona; Paracchini, Bruno; Canuti, Elisabetta; Weissteiner, Christof

    2013-07-01

    Water-soluble polar organic contaminants are discharged by rivers, cities, and ships into the oceans. Little is known on the fate, pollution effects, and thresholds of toxic chemical mixtures in the marine environment. A new trace analytical method was developed for the multi-compound analysis of polar organic chemical contaminants in marine waters. The method is based on automated solid-phase extraction (SPE) of one-liter water samples followed by ultrahigh-pressure liquid chromatography triple-quadrupole linear ion-trap mass spectrometry (UHPLC-QTRAP(®) MS). Marine water samples from the open Adriatic Sea taken 16 km offshore from Venice (Italy) were analyzed. Method limits of quantification (LOQs) in the low picogram per liter (pg/l) concentration range were achieved. Among the 67 target chemicals analyzed, 45 substances could be detected above the LOQ. The chemicals detected at the highest concentrations were caffeine (up to 367 ng/l), nitrophenol (36 ng/l), 2,4-dinitrophenol (34 ng/l), 5-methyl-1H-benzotriazole (18.5 ng/l), sucralose (11 ng/l), 1H-benzotriazole (9.2 ng/l), terbuthylazine (9 ng/l), alachlor (7.7 ng/l), atrazine-desisopropyl (6.6 ng/l), diethyltoluamide (DEET) (5.0 ng/l), terbuthylazine-desethyl (4.3 ng/l), metolachlor (2.8 ng/l), perfluorooctanoic acid (PFOA) (2.5 ng/l), perfluoropentanoic acid (PFPeA) (2.3 ng/l), linuron (2.3 ng/l), perfluorohexanoic acid (PFHxA) (2.2 ng/l), diuron (2.0 ng/l), perfluorohexane sulfonate (PFHxS) (1.6 ng/l), simazine (1.6 ng/l), atrazine (1.5 ng/l), and perfluorooctane sulfonate (PFOS) (1.3 ng/l). Higher concentrations were detected during summer due to increased levels of tourist activity during this period.

  15. 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

  16. Acute sensitivity of the vernal pool fairy shrimp, Branchinecta lynchi (Anostraca; Branchinectidae), and surrogate species to 10 chemicals

    USGS Publications Warehouse

    Ivey, Chris D.; Besser, John M.; Ingersoll, Christopher G.; Wang, Ning; Rogers, Christopher; Raimondo, Sandy; Bauer, Candice R.; Hammer, Edward J.

    2017-01-01

    Vernal pool fairy shrimp, Branchinecta lynchi, (Branchiopoda; Anostraca) and other fairy shrimp species have been listed as threatened or endangered under the US Endangered Species Act. Because few data exist about the sensitivity of Branchinecta spp. to toxic effects of contaminants, it is difficult to determine whether they are adequately protected by water quality criteria. A series of acute (24-h) lethality/immobilization tests was conducted with 3 species of fairy shrimp (B. lynchi, Branchinecta lindahli, and Thamnocephalus platyurus) and 10 chemicals with varying modes of toxic action: ammonia, potassium, chloride, sulfate, chromium(VI), copper, nickel, zinc, alachlor, and metolachlor. The same chemicals were tested in 48-h tests with other branchiopods (the cladocerans Daphnia magna and Ceriodaphnia dubia) and an amphipod (Hyalella azteca), and in 96-h tests with snails (Physa gyrina and Lymnaea stagnalis). Median effect concentrations (EC50s) for B. lynchi were strongly correlated (r2 = 0.975) with EC50s for the commercially available fairy shrimp species T. platyurus for most chemicals tested. Comparison of EC50s for fairy shrimp and EC50s for invertebrate taxa tested concurrently and with other published toxicity data indicated that fairy shrimp were relatively sensitive to potassium and several trace metals compared with other invertebrate taxa, although cladocerans, amphipods, and mussels had similar broad toxicant sensitivity. Interspecies correlation estimation models for predicting toxicity to fairy shrimp from surrogate species indicated that models with cladocerans and freshwater mussels as surrogates produced the best predictions of the sensitivity of fairy shrimp to contaminants. The results of these studies indicate that fairy shrimp are relatively sensitive to a range of toxicants, but Endangered Species Act-listed fairy shrimp of the genus Branchinecta were not consistently more sensitive than other fairy shrimp taxa. Environ Toxicol Chem

  17. Hydrologic and land-use factors associated with herbicides and nitrate in near-surface aquifers

    USGS Publications Warehouse

    Burkart, Michael R.; Kolpin, Dana W.

    1993-01-01

    Selected herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) metabolites, and NO−3 were examined in near-surface unconsolidated and bedrock aquifers in the midcontinental USA to study the hydrogeologic, spatial, and seasonal distribution of these contaminants. Groundwater samples were collected from 303 wells during the spring and late summer of 1991. At least one herbicide or atrazine metabolite was detected in 24% of the samples collected for herbicide analysis (reporting limit 0.05 µg/L). No herbicide concentration exceeded the USEPA's maximum contaminant level (MCL) or health advisory level. The most frequently detected compound was the at razine metabolite deethylatrazine [2-amino-4-chloro-6-(isopropylamino)-s-triazine] followed by atrazine, deisopropylatrazine [2-amino-4-chloro-6-(ethylamino)-s-triazine], prometon (2,4-bis(isopropylamino)-6-methyoxy-s-triazine), metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1methylethyl)acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], metribuzin [4-amino-6-(tert-butyl)-3-methylthio-as-triazine-5(4H)-one], simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], and cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile]. Nitrite plus nitrate, as nitrogen (N), exceeding 3.0 mg/L (excess NO−3), was found in 29% of the samples, and 6% had −3exceeding the MCL of 10 mg/L. Ammonium as N was detected in excess of 0.01 mg/L in 78% of the samples. A nonlinear increase in the frequency of atrazine detection occurred with decreases in reporting limit. The frequency of atrazine residue detection (atrazine + deethylatrazine + deisopropylatrazine) was 25% greater than for atrazine alone. Herbicide detections and excess NO−3 were notably lacking in the eastern part of the study region where it was estimated that herbicide and fertilizer use were among the largest in the region. Prometon, the second most frequently detected herbicide

  18. 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

  19. Shallow ground-water quality in selected agricultural areas of south-central Georgia, 1994

    USGS Publications Warehouse

    Crandall, C.A.

    1996-01-01

    agricultural activities on ground-water quality. Samples from 30 percent of the wells exceeded the maximum contaminant level (MCL) for nitrate in drinking water (10 mg/L as N). Nitrogen isotope ratios ranged from 2.4 to 9.0 parts per thousand and indicate that most nitrogen in shallow ground water is probably from inorganic fertilizer. In addition, nitrate concentrations were positively correlated (p-values all less than 0.01) with concentrations of some of the major ingredients in fertilizer, such as potassium, calcium, magnesium, manganese, and chloride, and with values of specific conductance. Concentrations of pesticides and volatile organic compounds, detected in samples from 11 wells, were all below the MCLs. Of these constituents, only alachlor, metolachlor, metribuzin, toluene, benzene, and methyl chloride were detected in ground water at concentrations that ranged from 0.01 to 1.0 mg/L (micrograms per liter). Maximum concentrations of 1.0 mg/L of metolachlor and toluene were detected in two wells. Radon concentrations ranged from 530 to 1,400 pCi/L (picocuries per liter), exceeding the proposed MCL of 300 pCi/L in all samples; the median concentration was 1,000 pCi/L.

  20. Relation of Land Use to Streamflow and Water Quality at Selected Sites in the City of Charlotte and Mecklenburg County, North Carolina, 1993-98

    USGS Publications Warehouse

    Bales, Jerad D.; Weaver, J. Curtis; Robinson, Jerald B.

    1999-01-01

    were several times greater than median concentrations in small Piedmont streams but almost an order of magnitude less than total phosphorus concentrations in Charlotte streams during the late 1970's. Bacteria concentrations are not correlated to streamflow. The highest bacteria levels were found in 'first-flush' samples. Higher fecal coliform concentrations were associated with residential land use. Chromium, copper, lead, and zinc occurred at all sites in concentrations that exceeded the North Carolina ambient water-quality standards. The median chromium concentration in the developing basin was more than double the median concentration at any other site. As with chromium, the maximum copper concentration in the developing basin was almost an order of magnitude greater than maximum concentrations at other sites. The highest zinc concentration also occurred in the developing basin. Samples were analyzed for 121 organic compounds and 57 volatile organic compounds. Forty-five organic compounds and seven volatile organic compounds were detected. At least five compounds were detected at all sites, and 15 or more compounds were detected at all sites except two mixed land-use basins. Atrazine, carbaryl, and metolachlor were detected at eight sites, and 90 percent of all samples had measurable amounts of atrazine. About 60 percent of the samples had detectable levels of carbaryl and metolachlor. Diazinon and malathion were measured in samples from seven sites, and methyl parathion, chlorpyrifos, alachlor, and 2,4-D were detected at four or more sites. The fewest compounds were detected in the larger, mixed land-use basins. Residential basins and the developing basin had the greatest number of detections of organic compounds. The pH of wet atmospheric deposition in three Charlotte basins was more variable than the pH measured at a National Atmospheric Deposition Program (NADP)site in Rowan County. Summer pH values were significantly lower than pH meas

  1. IMPROVING STRUCTURE-LINKED ACCESS TO PUBLICLY AVAILABLE CHEMICAL TOXICITY INFORMATION

    EPA Science Inventory

    Hepatotoxicity of the Herbicide Alachlor Associated with Glutathione Depletion, Oxidative Damage and Protein S-Cysteinyl Adduction.

    Toxicity of the herbicide alachlor (2-chloro-2',6'-diethtl-N-[methoxtmethtl]-acetanilide) has been attributed to cytochrome P450-dependent me...

  2. 40 CFR 180.460 - Benoxacor; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances...-metolachlor in or on raw agricultural commodities for which tolerances have been established for...

  3. 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.

  4. 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.

  5. Hydrogeology, Chemical Characteristics, and Transport Processes in the Zone of Contribution of a Public-Supply Well in York, Nebraska

    USGS Publications Warehouse

    Landon, Matthew K.; Clark, Brian R.; McMahon, Peter B.; McGuire, Virginia L.; Turco, Michael J.

    2008-01-01

    aquifers (hereinafter, confined unmixed wells). Delta 18O and delta D values for a minority of wells in the confined aquifers were intermediate between those for the unconfined shallow wells and those for the confined unmixed wells. These intermediate values were consistent with mixing of water from unconfined and confined aquifers (hereinafter, confined mixed wells). Oxidation-reduction conditions were primarily oxic in the unconfined aquifer and variably reducing in the confined aquifers. Trace amounts of volatile organic compounds (VOC), particularly tetrachloroethylene (PCE) and trichloroethylene (TCE), were widely detected in unconfined shallow urban wells and indicated the presence of young urban recharge waters in most confined mixed wells. The presence of degradation products of agricultural pesticides (acetochlor and alachlor) in some confined mixed wells suggests that some fraction of the water in these wells also was the result of recharge in agricultural areas. In the unconfined aquifer, age-tracer data (chlorofluorocarbon and sulfur hexafluoride data, and tritium to helium-3 ratios) fit a piston-flow model, with apparent recharge ages ranging from 7 to 48 years and generally increasing with depth. Age-tracer data for the confined aquifers were consistent with mixing of 'old' water, not containing modern tracers recharged in the last 60 years, and exponentially-mixed 'young' water with modern tracers. Confined unmixed wells contained less than (=) 97% of old water. Confined mixed wells contained >30% young water and mean ages ranged from 12 to 14 years. Median concentrations of nitrate (as nitrogen, hereinafter, nitrate-N) were 17.3 and 16.0 mg/L (milligram per liter) in unconfined shallow urban and agricultural wells, respectively, indicating a range of likely nitrate sources. Septic systems are most numerous near the edge of the urban area and appear to be

  6. 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...

  7. Pesticides in groundwater in the Anacostia River and Rock Creek watersheds in Washington, D.C., 2005 and 2008

    USGS Publications Warehouse

    Koterba, Michael T.; Dieter, Cheryl A.; Miller, Cherie V.

    2010-01-01

    preliminary review of the data collected in 2005 and 2008 indicated that differences in the surficial geology, land use (as a surrogate for pesticide use), and above-average precipitation for most of 2004 through 2008, as well as differences in the number and performance of USGS laboratory methods used, could have led to more pesticides detected in groundwater samples collected in 2008 than in groundwater samples collected in 2005. Thus, although data from both years of collection were used for interpretive analysis, emphasis was placed on the analysis of the data obtained in 2008. The presence of pesticides in shallow groundwater (less than approximately 100 ft (feet), or 30 m (meters), below land surface) indicated at least the upper surficial aquifer in Washington, D.C. was susceptible to contamination. One or more herbicides or insecticides were detected in groundwater samples collected from 50 percent of the shallow wells sampled in 2005, and from 62 percent of the shallow wells sampled in 2008. Differences among types of pesticides in shallow groundwater were apparent. The most frequently detected class of herbicides was the s-triazine compounds-atrazine, simazine, or prometon, or the atrazine-degradate compounds-2-chloro-4-ethylamino-6-amino-s-triazine (desethylatrazine or CIAT) and 2-chloro-4-isopropylamino-6-amino-s-triazine (hydroxyatrazine or OIET). The next most frequently detected classes of herbicides were the chloroacetanilides, including metolachlor and acetochlor, and the ureic herbicides, including diuron (and degradate, 3,4-dichloroaniline), fluometuron, metsulfuron methyl, sulfameturon, bromacil, and tebuthiuron. Insecticides also were detected, but less frequently than herbicides, with one or more insecticides present in groundwater samples from 38 percent of shallow wells sampled in 2008. Detected insecticides included parent or degradate compounds commonly used for either nonspecific or haustellate (sucking) insects, including chlorpyri

  8. Water resources on and near the Nottawaseppi Huron band of Potawatomi indian tribal lands, Calhoun County, Michigan, 2000-03

    USGS Publications Warehouse

    Weaver, T.L.; Healy, D.; Sabin, T.G.

    2005-01-01

    . Atrazine and metolachlor were detected in all samples, and the atrazine degradate deethylatrazine was detected in all samples from Pine Creek and Athens & Indian Creek Drain. Another atrazine degradate (2-hydroxy-atrazine, or OIET) was detected five of the six times that it was included in the analyses. A single sample collected from Athens & Indian Creek Drain in May 2001 had relatively higher concentrations of acetochlor, atrazine, CIAT (deethylatrazine), and diuron than the other sampling sites did during the study. Analysis for various species of mercury was completed on samples collected at Pine Creek and Athens & Indian Creek Drain in July 2003, and results were similar to those typical of unimpaired streams in the Midwest. None of the surface-water sites had major ion, nutrient, or trace-element concentrations that exceeded Michigan Department of Environmental Quality standards for nonpotable surface water.USGS also collected 11 ground-water samples from 7 wells on or adjacent to the traditional reservation in 2003. Two wells were sampled twice, and a single well was sampled three times, in order to document any chemical changes that might have occurred as a result of aquifer recharge, which most typically occurs in late winter to spring in the southern Lower Peninsula of Michigan. Samples were analyzed for 184 pesticides and degradates and caffeine. There were five detections of four pesticides or degradates, but none of the detected chemicals are included in current U.S. Environmental Protection Agency drinking-water standards. The remaining 181 analytes were below laboratory reporting limits.

  9. Interaction of Fensulfothion and Phorate with Preemergence Herbicides on Soybean Parasitic Nematodes

    PubMed Central

    Schmitt, D. P.; Corbin, F. T.

    1981-01-01

    The herbicides alachlor, linuron, vernolate, and metribuzin were applied to plots treated with the nematicide fensulfothion or the insecticide phorate and planted to soybean in two locations in North Carolina. In 1976 treatment with fensulfothion + alachlor or vernolate, phorate + alachlor or metribuzin resulted in greater nematode population densities than no treatment, or treatment with fensulfothion alone, or phorate alone. In 1977 fensulfothion and phorate alone and in combination with the preemergence herbicides effectively controlled Tylenchorhynchus cIaytoni. Late season population resurgence of Heterodera glycines occurred in fensulfothion + alachlor treated plots. Correlation coefficients for H. glycines vs. yield were -0.48 (P = 0.05) and -0.46 (P = 0.05) for 30 and 68 d after planting, respectively. PMID:19300719

  10. 77 FR 67726 - Department of State: State Department Sanctions Information and Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-13

    ... potentially sanctionable. ``Petrochemical products'' includes any aromatic, olefin, and synthesis gas, and any of their derivatives, including ethylene, propylene, butadiene, benzene, toluene, xylene, ammonia..., acrylonitrile butadiene styrene, alachlor, ammonium nitrate, ammonium sulfate, anhydrous ammonia,...

  11. Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July

    USGS Publications Warehouse

    Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.

    2014-01-01

    High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Surface-water-quality assessment of the upper Illinois River Basin in Illinois, Indiana, and Wisconsin; results of investigations through April 1992

    USGS Publications Warehouse

    Schmidt, Arthur R.; Blanchard, Stephen F.

    1997-01-01

    A water-quality assessment of the upper Illinois River Basin (10,949 square miles) was conducted during water years 1987-91. This assessment involved interpretation of available data; 4 years of intensive data collection, including monthly sample collection at eight fixed-monitoring stations in the basin; and synoptic studies of selected water-quality constituents at many sites. The number of exceedances of water-quality criteria for chromium, copper, lead, mercury, silver, and zinc in water was essentially the same at similar stations between 1978-86 and 1987-90. For water and sediment, a large signature for many trace inorganic constituents was observed from the Chicago metropolitan area, mainly from the Des Plaines River Basin and continuing down the Illinois River. Loads of trace inorganic constituents in water were 2-13 times greater from the Chicago metropolitan area than from rural areas in the upper Illinois River Basin. Concentrations of cadmium, mercury, nickel, selenium, and zinc appeared to be relatively enriched in biota in the upper Illinois River Basin compared to other river basins. Biota from some urban sites were enriched with respect to several elements. For example, relatively large concentrations of cadmium, chromium, copper, lead, and nickel were observed in biota from sites in the Chicago River in the metropolitan area and the Calumet River. Results of pesticide sampling in 1988 and 1989 identified the pesticides bromacil, diazinon, malathion, prometon, and simazine as urban related and alachlor, atrazine, cyanazine, metolachlor, and metribuzin as agricultural related. Phenol concentrations never exceeded general-use and secondary-contact water-quality standards of 100 and 300 micrograms per liter, respectively. Pentachlorophenol concentrations observed at the Illinois River at Marseilles, Ill., between 1981 and 1992 decreased beginning in 1987. A breakdown product of the organochlorine pesticide dichloro-diphenyl-trichloroethane (DDT), p

  17. 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

  18. Water Quality in a Wet Meadow, Platte River Valley, Central Nebraska

    USGS Publications Warehouse

    Emmons, Patrick J.

    1996-01-01

    . Atrazine was detected in water from all of the wells sampled in February and June and most of the wells sampled at other times, but only in concentrations of 0.1 to 0.6 micrograms per liter. Concentrations of the other pesticides analyzed, including alachlor, cyanazine, and metolachlor, were at or below the detection limit of 0.05 micrograms per liter. The highest concentrations of nitrate were found in water from the shallow wells (about 15 feet deep). The concentrations of nitrate as nitrogen in water from these wells ranged from 5 to 13 milligrams per liter in June. Concentrations of major cations and anions decreased and their ratios varied with depth. The major cations were calcium and sodium, and the major anions were sulfate and bicarbonate. Water from the shallowest wells was a mixed calcium sodium sulfate type, whereas the deepest alluvial-aquifer water was a calcium sulfate type. The water from the Ogallala Formation was a calcium bicarbonate type. The variability of the groundwater quality reflects seasonal changes in recharge to and evaporation from the alluvial aquifer and rates of movement and mixing within and between the aquifers.

  19. Occurrence and distribution of dissolved pesticides in the San Joaquin River basin, California

    USGS Publications Warehouse

    Panshin, Sandra Yvonne; Dubrovsky, Neil M.; Gronberg, JoAnn M.; Domagalski, Joseph L.

    1998-01-01

    The effects of pesticide application, hydrology, and chemical and physical properties on the occurrence of pesticides in surface water in the San Joaquin River Basin, California, were examined. The study of pesticide occurrence in the highly agricultural San Joaquin?Tulare Basins is part of the National Water-Quality Assessment Program of the U.S. Geological Survey. One hundred forty-three water samples were collected throughout 1993 from sites on the San Joaquin River and three of its tributaries: Orestimba Creek, Salt Slough, and the Merced River. Of the 83 pesticides selected for analysis in this study, 49 different compounds were detected in samples from the four sites and ranged in concentration from less than the detection limit to 20 micrograms per liter. All but one sample contained at least one pesticide, and more than 50 percent of the samples contained seven or more pesticides. Six compounds were detected in more than 50 percent of the samples: four herbicides (dacthal, EPTC, metolachlor, and simazine) and two insecticides (chlorpyrifos and diazinon). None of the measured concentrations exceeded U.S. Environmental Protection Agency drinking water criteria, and many of the measured concentrations were very low. The concentrations of seven pesticides exceeded criteria for the protection of freshwater aquatic life: azinphos-methyl, carbaryl, chlorpyrifos, diazinon, diuron, malathion, and trifluralin. Overall, some criteria for protection of aquatic life were exceeded in a total of 97 samples. Factors affecting the spatial patterns of occurrence of the pesticides in the different subbasins included the pattern of application and hydrology. Seventy percent of pesticides with known application were detected. Overall, 40 different pesticides were detected in Orestimba Creek, 33 in Salt Slough, and 26 in the Merced River. Samples from the Merced River had a relatively low number of detections, despite the high number (35) of pesticides applied, owing to the

  20. Reconnaissance of ground-water quality in the Papio-Missouri River Natural Resources District, eastern Nebraska, July through September 1992

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Ellis, M.J.

    1995-01-01

    A reconnaissance of ground-water quality was conducted in the Papio-Missouri River Natural Resources District of eastern Nebraska. Sixty-one irrigation, municipal, domestic, and industrial wells completed in the principal aquifers--the unconfined Elkhorn, Missouri, and Platte River Valley alluvial aquifers, the upland area alluvial aquifers, and the Dakota aquifer--were selected for water-quality sampling during July, August, and September 1992. Analyses of water samples from the wells included determination of dissolved nitrate as nitrogen and triazine and acetanilide herbicides. Waterquality analyses of a subset of 42 water samples included dissolved solids, major ions, metals, trace elements, and radionuclides. Concentrations of dissolved nitrate as nitrogen in water samples from 2 of 13 wells completed in the upland area alluvial aquifers exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level for drinking water of 10 milligrams per liter. Thirty-nine percent of the dissolved nitrate-as-nitrogen concentrations were less than the detection level of 0.05 milligram per liter. The largest median dissolved nitrate-as-nitrogen concentrations were in water from the upland area alluvial aquifers and the Dakota aquifer. Water from all principal aquifers, except the Dakota aquifer, had detectable concentrations of herbicides. Herbicides detected included alachlor (1 detection), atrazine (13 detections), cyanazine (5 detections), deisopropylatrazine (6 detections), deethylatrazine (9 detections), metolachlor (6 detections), metribuzin (1 detection), prometon (6 detections), and simazine (2 detections). Herbicide concentrations did not exceed U.S. Environmental Protection Agency Maximum Contaminant Levels for drinking water. In areas where the hydraulic gradient favors loss of surface water to ground water, the detection of herbicides in water from wells along the banks of the Platte River indicates that the river could act as a line source of

  1. Water quality and possible sources of nitrate in the Cimarron Terrace Aquifer, Oklahoma, 2003

    USGS Publications Warehouse

    Masoner, Jason R.; Mashburn, Shana L.

    2004-01-01

    Water from the Cimarron terrace aquifer in northwest Oklahoma commonly has nitrate concentrations that exceed the maximum contaminant level of 10 milligrams per liter of nitrite plus nitrate as nitrogen (referred to as nitrate) set by the U.S. Environmental Protection Agency for public drinking water supplies. Starting in July 2003, the U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study in the Cimarron terrace aquifer to assess the water quality and possible sources of nitrate. A qualitative and quantitative approach based on multiple lines of evidence from chemical analysis of nitrate, nitrogen isotopes in nitrate, pesticides (indicative of cropland fertilizer application), and wastewater compounds (indicative of animal or human wastewater) were used to indicate possible sources of nitrate in the Cimarron terrace aquifer. Nitrate was detected in 44 of 45 ground-water samples and had the greatest median concentration (8.03 milligrams per liter) of any nutrient analyzed. Nitrate concentrations ranged from <0.06 to 31.8 milligrams per liter. Seventeen samples had nitrate concentrations exceeding the maximum contaminant level of 10 milligrams per liter. Nitrate concentrations in agricultural areas were significantly greater than nitrate concentrations in grassland areas. Pesticides were detected in 15 of 45 ground-water samples. Atrazine and deethylatrazine, a metabolite of atrazine, were detected most frequently. Deethylatrazine was detected in water samples from 9 wells and atrazine was detected in samples from 8 wells. Tebuthiuron was detected in water samples from 5 wells; metolachlor was detected in samples from 4 wells; prometon was detected in samples from 4 wells; and alachlor was detected in 1 well. None of the detected pesticide concentrations exceeded the maximum contaminant level or health advisory level set by the U.S. Environmental Protection Agency. Wastewater compounds were detected in 28 of

  2. 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.

  3. 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

  4. 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.

  5. Induction of Glutathione S-Transferase Isozymes in Sorghum by Herbicide Antidotes 1

    PubMed Central

    Dean, John V.; Gronwald, John W.; Eberlein, Charlotte V.

    1990-01-01

    Certain chemicals referred to as herbicide antidotes protect sorghum from injury by chloroacetanilide herbicides such as metolachlor. The effect of herbicide antidotes on the glutathione S-transferase isozyme complement of etiolated sorghum (Sorghum bicolor [L.] Moench) shoots was examined. Elution profiles of glutathione S-transferase isozymes from untreated and antidote-treated seedlings were generated by fast protein liquid chromatography utilizing an anion exchange (Mono Q) column. In untreated seedlings, there were two glutathione S-transferase isozymes, a major isozyme which exhibited activity toward 1-chloro-2,4-dinitrobenzene and a minor isozyme which exhibited activity toward metolachlor. Treating sorghum seedlings with various antidotes (flurazole, oxabetrinil, CGA-133205, naphthalic anhydride, dichlormid) resulted in the appearance of four to five additional glutathione S-transferase isozymes (de-pending on the particular antidote) which exhibited activity toward metolachlor as a substrate and little or no activity with 1-chloro-2,4-dinitrobenzene. Treating etiolated sorghum shoots with metolachlor was also found to induce at least four isozymes which exhibited activity toward the herbicide. An increase in glutathione S-transferase activity, measured with metolachlor as substrate, was detected within 4 h after treatment with 30 micromolar oxabetrinil, but 36 hours were required for maximum expression of activity. Addition of either the transcription inhibitor cordycepin or the translation inhibitor cycloheximide inhibited the appearance of glutathione S-transferase activity measured with metolachlor as substrate. The results are consistent with the hypothesis that antidotes confer protection against metolachlor injury in sorghum by inducing the de novo synthesis of glutathione S-transferase isozymes which catalyze the detoxification of the herbicide. PMID:16667299

  6. 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.

  7. 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...

  8. 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 ...

  9. Big Bend Dam/Lake Sharpe Master Plan, Missouri River, South Dakota: Update of Design Memorandum MB-90

    DTIC Science & Technology

    2003-10-01

    be Monitored at Lake Sharpe Deepwater Parameter Near Surface Near Bottom Tailwater Total Suspended Solids X X X Total Kjeldahl Nitrogen X X X...Transparency (Secchi Depth) X X Turbidity X X Profile4 X5 X5 X6 1 One complete pesticide scan in May or June and “Rapid Assay ” for atrazine, alachlor

  10. 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...

  11. 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.; Linder, Gregory L.; Krest, Sherry K.; Sparling, Donald W.; Little, Edward E.

    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.

  12. 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.

  13. Cytotoxicity of sulfurous acid on cell membrane and bioactivity of Nitrosomonas europaea.

    PubMed

    Jiang, Ruiyu; Wang, Mingqing; Xue, Jianliang; Xu, Ning; Hou, Guihua; Zhang, Wubing

    2015-01-01

    Nitrosomonas europaea, an ammonia oxidizing bacterium, was chosen as a research model to study the alteration of cell membrane in the presence of sulfurous acid and biodegradation of acetochlor. Significant changes of the outer cell membrane were observed in the presence of sulfurous acid using scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). The fluorescence polarization has shown a significant decrease in membrane fluidity and the increase of permeability of cell membrane. Lysozyme experiment show the cell becomes easily influenced by substance in medium. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) measurements show considerable amount of Ca(2+) and Mg(2+) in the supernatant from the sulfurous acid exposed cells. Sulfurous acid treatment enhanced the ability of N. europaea to degrade acetochlor. On this basis, it can be concluded that the increased cell permeability is favor for the absorbability of nutrition. As a result, N. europaea grows faster and the biodegradation efficiency was improved.

  14. Wastewater treatment plant modeling supported toxicity identification and evaluation of a tank truck cleaning effluent.

    PubMed

    De Schepper, W; Dries, J; Geuens, L; Blust, R

    2010-07-01

    The aim of this work is the Toxicity Identification Evaluation (TIE) of highly toxic tank truck cleaning wastewater effluent. Conventional TIE, using EDTA and activated carbon addition, revealed organic compounds as main source of toxicity. Additional toxicant characteristics could be derived from hydraulic wastewater treatment plant simulation being high intake frequency, low biodegradability and high acute toxicity ratio between Pseudokirchneriella subcapitata and Daphnia magna. The risk probability of compounds present in the influent wastewater was simulated using USEPA Estimation Program Interface (EPI) software. Compound toxicity, solubility and removal rate in a wastewater treatment plant were incorporated into one risk number indicative for the probability of a compound to cause toxicity in the effluent. The herbicide acetochlor was deducted from these TIE procedures as major toxicant and this was confirmed by chemical measurements, concentrations in the effluent samples ranged from 3.73+/-0.52 ppm to 7.8+/-2.1 ppm acetochlor equivalents.

  15. 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.

  16. 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.

  17. 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

  18. Water-Quality Assessment of the Trinity River Basin, Texas - Nutrients and Pesticides in the Watersheds of Richland and Chambers Creeks, 1993-95

    USGS Publications Warehouse

    Land, L.F.

    1997-01-01

    from the sampling site. Herbicides were detected in the streams much more often than insecticides were. Nineteen herbicides and 9 insecticides were detected at the 08064100 Chambers Creek near Rice site. Atrazine and metolachlor, the most commonly detected herbicides, occurred in all samples at this site. Other herbicides detected in 25 percent or more of the samples were alachlor, fluometuron, prometon, simazine, trifluralin, and 2,4-D. At the beginning of the study, the number of herbicides detected in the five stream sites was 4 or 5. The greatest number of herbicides detected in the streams occurred in May samples, ranging from 7 to 10. The number of herbicides detected in the Richland-Chambers Reservoir ranged from 6 to 8. Generally, more herbicides were detected in high-streamflow samples than in low-streamflow samples. However, a consistent relation between the number of herbicides in samples and the percentage of cropland in a drainage area was not evident. At the beginning of the study, atrazine concentrations at the stream sites were less than 0.4 microgram per liter, except at one site. In the streams, concentrations peaked in March and April; the greatest peak concentration was 20 micrograms per liter. By the end of the study, atrazine concentrations decreased to less than 0.4 microgram per liter at all the stream sites. In the Richland-Chambers Reservoir, the concentrations were about 1 microgram per liter during February-March and about 3 micrograms per liter in June. Atrazine concentrations tended to increase with increasing streamflow. A consistent relation between atrazine concentrations and the percentage of cropland in a drainage area was not evident. The greatest number of insecticides detected in water samples was two. Diazinon, the most frequently detected insecticide, had slightly greater concentrations in May and June - between 0.01 and 0.02 microgram per liter. The only organochlorine insecticides detected in bed-sedime

  19. Sediment deposition and selected water-quality characteristics in Cedar Lake and Lake Olathe, Northeast Kansas, 2000

    USGS Publications Warehouse

    Mau, D.P.

    2002-01-01

    .91 pound per acre per year for Lake Olathe. Phosphorus yields in the Cedar Lake watershed were largest of the six Kansas impoundment watersheds recently studied. Concentrations of total ammonia plus organic nitrogen as nitrogen in bottom sediment increased from upstream to downstream in both Cedar Lake and Lake Olathe. Mean concentrations of total ammonia plus organic nitrogen as nitrogen (N) ranged from 2,000 to 2,700 milligrams per kilogram in bottom-sediment samples from Cedar Lake and from 1,300 to 2,700 milligrams per kilogram in samples from Lake Olathe. There was no statistical significance between total ammonia plus organic nitrogen as nitrogen and depth of bottom sediment. Concentrations of six trace elements in bottom sediment from Cedar Lake and Lake Olathe (arsenic, chromium, copper, lead, nickel, and zinc) exceeded the U.S. Environmental Protection Agency Threshold Effects Levels (TELs) sediment-quality guidelines for aquatic organisms in sediment except for one lead concentration. Probable Effects Levels (PELs) for trace elements, however, were not exceeded at either lake. Organochlorine and organophosphate insecticides were not detected in bottom-sediment samples from either Cedar Lake or Lake Olathe, but the acetanilide herbicides alachlor and metolachlor were detected in sediment from both lakes. The U.S. Environmental Protection Agency has not proposed TEL or PEL guideline concentrations for bottom sediment for any of the organophosphate, acetanilide, or triazine pesticides. The diatoms (microscopic, single-celled organisms) Cyclotella bodanica, an indicator of low organic-enriched water, and Cyclotella meneghiniana, an indicator of organic-enriched water, were both present in bottom sediment from Lake Olathe. The presence of both of these diatoms suggests varying periods of low and high eutrophication in Lake Olathe from 1956 to 2000. The concentrations of two species in bottom sediment from Cedar Lake, Aulacoseira cf alpigena and Cyclotella meneg

  20. Quality of water on the Prairie Band Potawatomi Reservation, northeastern Kansas, February 1999 through February 2001

    USGS Publications Warehouse

    Trombley, T.J.

    2001-01-01

    concern on the reservation with fecal coliform concentrations ranging from 4 to greater than 31,000 colonies per 100 milliliters of water with a median concentration of 570 colonies per 100 milliliters. More than one-half of the surface-water-quality samples exceeded the Kansas Department of Health and Environment contact recreation criteria of 200 and 2,000 colonies per 100 milliliters of water and were collected mostly during the spring and summer. Two wells had sodium concentrations of about 10 times the U.S. Environmental Protection Agengy health advisory level (HAL) of 20 mg/L; concentrations ranged from 241 to 336 mg/L. In water from two wells, sulfate concentrations exceeded 800 mg/L, more than three times the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level (SMCL) for drinking water of 250 mg/L. All but two of the eight ground-water-quality samples had dissolved-solids concentrations exceeding the SMCL of 500 mg/L. The highest concentration of 2,010 mg/L was more than four times the SMCL. Dissolved boron concentrations exceeded the U.S. Environmental Protection Agency 600-?g/L HAL in water from two of the seven wells sampled. Because the HAL is for a lifetime of exposure, the anticipated health risk due to dissolved boron is low. Dissolved iron concentrations in ground-water samples exceeded the 300-?g/L SMCL for treated drinking water in three of the seven wells sampled. Dissolved manganese concentrations in water from the same three wells also exceeded the established SMCL of 50 ?g/L. Dissolved pesticides were not detected in any of the well samples; however, there were degradation products of the herbicides alachlor and metolachlor in several samples. Insecticides were not detected in any ground-water-quality samples. Low concentrations of E. coli and fecal coliform bacteria were detected in water from two wells, and E. coli was detected in water from one well. Much higher concentrations of E. coli, fecal coliform, and fecal strepto

  1. Mode of carcinogenic action of pesticides inducing thyroid follicular cell tumors in rodents.

    PubMed Central

    Hurley, P M

    1998-01-01

    Of 240 pesticides screened for carcinogenicity by the U.S. Environmental Protection Agency Office of Pesticide Programs, at least 24 (10%) produce thyroid follicular cell tumors in rodents. Thirteen of the thyroid carcinogens also induce liver tumors, mainly in mice, and 9 chemicals produce tumors at other sites. Some mutagenic data are available on all 24 pesticides producing thyroid tumors. Mutagenicity does not seem to be a major determinant in thyroid carcinogenicity, except for possibly acetochlor; evidence is less convincing for ethylene thiourea and etridiazole. Studies on thyroid-pituitary functioning, including indications of thyroid cell growth and/or changes in thyroxine, triiodothyronine, or thyroid-stimulating hormone levels, are available on 19 pesticides. No such antithyroid information is available for etridiazole, N-octyl bicycloheptene dicarboximide, terbutryn, triadimefon, and trifluralin. Of the studied chemicals, only bromacil lacks antithyroid activity under study conditions. Intrathyroidal and extrathyroidal sites of action are found: amitrole, ethylene thiourea, and mancozeb are thyroid peroxidase inhibitors; and acetochlor, clofentezine, fenbuconazole, fipronil, pendimethalin, pentachloronitrobenzene, prodiamine, pyrimethanil, and thiazopyr seem to enhance the hepatic metabolism and excretion of thyroid hormone. Thus, with 12 pesticides that mode of action judgments can be made, 11 disrupt thyroid-pituitary homeostasis only; no chemical is mutagenic only; and acetochlor may have both antithyroid and some mutagenic activity. More information is needed to identify other potential antithyroid modes of thyroid carcinogenic action. PMID:9681970

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  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. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. Herbicide incorporation by irrigation and tillage impact on runoff loss.

    PubMed

    Potter, Thomas L; Truman, Clint C; Strickland, Timothy C; Bosch, David D; Webster, Theodore M

    2008-01-01

    Runoff from farm fields is a common source of herbicide residues in surface waters. Incorporation by irrigation has the potential to reduce herbicide runoff risks. To assess impacts, rainfall was simulated on plots located in a peanut (Arachis hypogaea L.) field in Georgia's Atlantic Coastal Plain region after pre-emergence application of metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1S)-2-methoxy-1-methylethyl]-acetamide) and pendimethalin (N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitro-benzenamine). Runoff, sediment, and herbicide loss as function of strip tillage (ST) versus conventional tillage (CT) were compared with and without irrigation (12.5 mm) after application of an herbicide tank mixture. For the CT system, metolachlor runoff was reduced 2x and pendimethalin 1.2x when compared with the non-irrigated treatment. The difference in irrigated and non-irrigated metolachlor means was significant (P = 0.05). Irrigation reduced metolachlor runoff by 1.3x in the ST system, but there was a 1.4x increase for pendimethalin. Overall results indicated that irrigation incorporation reduces herbicide runoff with the greatest impact when CT is practiced and products like metolachlor, which have relatively low K(oc) and high water solubility, are used. The lower ST system response was likely due to a combination of spray interception and retention by the ST system cover crop mulch and higher ST soil organic carbon content and less total runoff. During the study, the measured K(oc) of both herbicides on runoff sediment was found to vary with tillage and irrigation after herbicide application. Generally, K(oc) was higher for ST sediment and when irrigation incorporation was used with the CT system. These results have significant implications for simulation model parametization.

  13. 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.

  14. 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

  15. 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.

  16. Detection of pesticides and pesticide metabolites using the cross reactivity of enzyme immunoassays.

    PubMed

    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.

  17. Characterization of covalent protein conjugates using solid-state sup 13 C NMR spectroscopy

    SciTech Connect

    Garbow, J.R.; Fujiwara, Hideji; Sharp, C.R.; Logusch, E.W. )

    1991-07-23

    Cross-polarization magic-angle spinning (CPMAS) {sup 13}C NMR spectroscopy has been used to characterize covalent conjugates of alachlor, an {alpha}-chloroacetamide hapten, with glutathione (GSH) and bovine serum albumin (BSA). The solid-state NMR method demonstrates definitively the covalent nature of these conjugates and can also be used to characterize the sites of hapten attachment to proteins. Three different sites of alachlor binding are observed in the BSA system. Accurate quantitation of the amount of hapten covalently bound to GSH and BSA is reported. The solid-state {sup 13}C NMR technique can easily be generalized to study other small molecule/protein conjugates and can be used to assist the development and refinement of synthetic methods needed for the successful formation of such protein alkylation products.

  18. 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.

  19. Population Dynamics of Heterodera glycines and Soybean Response in Soils Treated with Selected Nematicides and Herbicides.

    PubMed

    Schmitt, D P; Corbin, F T; Nelson, L A

    1983-07-01

    Two field experiments were conducted in two locations to determine the effects of the nematicides aldicarb, phenamiphos, and ethoprop and/or the herbicides alachlor, linuron, or metribuzin on the population dynamics of Heterodera glycines and soybean growth and yield. Population densities of H. glycines were greater, at some time during the growing season, in several treatments with alachlor alone and in combination with nematicides. Numbers of H. glycines at harvest were greater in plots treated with aldicarb than in those treated with ethoprop or phenamiphos. The numbers in aldicarb treated plots were generally reduced when plots also received a herbicide. Soybean yields were negatively correlated with numbers of H. glycines eggs and juveniles in early to mid season but positively correlated with late season population densities.

  20. Evaluating Microtox as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes.

    PubMed

    Lapertot, Milena; Ebrahimi, Sirous; Oller, Isabel; Maldonado, Manuel I; Gernjak, Wolfgang; Malato, Sixto; Pulgarín, César

    2008-03-01

    To shorten phototreatment time is of major concern for the cost and energy benefits of the xenobiotics degradation performed by photocatalytic processes. Using photo-Fenton and TiO(2) phototreatments, partially photodegraded solutions of 6 separate pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) were tested for biocompatibility, which was evaluated according to the Zahn-Wellens procedure. This study investigated if Microtox could be considered as a suitable global indicator capable of giving information on the evolution of biocompatibility of the water solution contaminated with organic pollutants during the phototreatment in order to promote biotreatment. The obtained results demonstrated that biodegradability increased significantly after short photo-Fenton treatment times for alachlor, diuron and pentachlorophenol. Uncertain results were obtained with atrazine and isoproturon. Microtox acute toxicity testing was shown to correctly represent dynamics and efficiency of phototreatment.

  1. 40 CFR Appendix Vi to Part 265 - Compounds With Henry's Law Constant Less Than 0.1 Y/X

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Acetylaminofluorene 53-96-3 3-Acetyl-5-hydroxypiperidine 3-Acetylpiperidine 618-42-8 1-Acetyl-2-thiourea 591-08-2 Acrylamide 79-06-1 Acrylic acid 79-10-7 Adenine 73-24-5 Adipic acid 124-04-9 Adiponitrile 111-69-3 Alachlor 15972-60-8 Aldicarb 116-06-3 Ametryn 834-12-8 4-Aminobiphenyl 92-67-1 4-Aminopyridine 504-24-5...

  2. 40 CFR Appendix Vi to Part 265 - Compounds With Henry's Law Constant Less Than 0.1 Y/X

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Acetylaminofluorene 53-96-3 3-Acetyl-5-hydroxypiperidine 3-Acetylpiperidine 618-42-8 1-Acetyl-2-thiourea 591-08-2 Acrylamide 79-06-1 Acrylic acid 79-10-7 Adenine 73-24-5 Adipic acid 124-04-9 Adiponitrile 111-69-3 Alachlor 15972-60-8 Aldicarb 116-06-3 Ametryn 834-12-8 4-Aminobiphenyl 92-67-1 4-Aminopyridine 504-24-5...

  3. 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.

  4. Human skin binding and absorption of contaminants from ground and surface water during swimming and bathing

    SciTech Connect

    Wester, R.C.; Maibach, H.I. )

    1989-10-01

    Contaminants exist in ground and surface water. Human skin has the capacity to bind and then absorb these contaminants into the body during swimming and bathing. Powdered human stratum corneum will bind both lipid-soluble (alachlor, polychlorinated biphenyls (PCBs), benzene) and water-soluble (nitroaniline) chemicals. In vitro (Human skin) and in vivo (Rhesus monkey) studies show that these chemicals readily distribute into skin, and then some of the chemical is absorbed into the body. Linearity in binding and absorption exists for nitroaniline over a 10-fold concentration range. Multiple exposure to benzene is at least cumulative. Binding and adsorption can be significant for exposures as short as 30 minutes, and will increase with time. Adsorption with water dilution increased for alachlor, but not for dinoseb. Soap reversed the partitioning of alachlor between human stratum corneum and water. The PCBs could be removed from skin by soap and water for up to 3 hours and the decontamination potential decreased, due to continuing skin absorption. The model that in vitro and in vivo systems used should permit easy estimation of this area of extensive human exposure effect on risk assessment. 5 refs., 9 tabs.

  5. Adsorption of pesticides on resins.

    PubMed

    Kyriakopoulos, Grigorios; Hourdakis, Adamadia; Doulia, Danae

    2003-03-01

    The objective of this work was to assess the capability of organic hydrophobic polymeric resins Amberlite XAD-4 and XAD-7 to remove the pesticides alachlor and amitrole from water. The pesticides adsorption on the two different adsorbents was measured by batch equilibrium technique and isotherm types and parameters were estimated. Two theoretical models were applied based on a Freundlich and a Langmuir isotherms. The effect of pesticides chemical composition and structure as well as the nature of solid surface on the efficiency of adsorption was evaluated. The influence of pH also was studied. In low pH solutions adsorption of amitrole was higher upon the nonionic aliphatic acrylic ester copolymer XAD-7 in comparison to the nonionic, crosslinked macroreticular copolymer of styrene divinylbenzene XAD-4. In neutral and intermediate pH solutions the polar acrylic ester copolymer XAD-7 was more effective to the retention of alachlor. The acrylic ester copolymer showed at pH 3 the lower effectiveness in alachlor removal from water. The data of the adsorption isotherms of pesticides upon the examined polymeric resins seemed to conform to both the Freundlich and the Langmuir isotherm models.

  6. 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

  7. Adsorption and desorption behavior of selected pesticides as influenced by decomposition of maize mulch.

    PubMed

    Aslam, Sohaib; Garnier, Patricia; Rumpel, Cornelia; Parent, Serge E; Benoit, Pierre

    2013-06-01

    Assessing pesticide fate in conservation agricultural systems requires a detailed understanding of their interaction with decomposing surface crop residues (mulch). Adsorption and desorption behavior of glyphosate, s-metolachlor and epoxiconazole was investigated on maize mulch residues decomposed under laboratory and field conditions. Our conceptual approach included characterization of chemical composition and hydrophobicity of mulch residues in order to generate parameters to predict sorption behavior. Adsorption of s-metolachlor and epoxiconazole greatly increased with mulch decomposition, whereas glyphosate adsorption was less affected but its desorption was increased. Mulch characteristics including aromaticity, hydrophobicity and polarity indices were strongly correlated to Koc of the non-ionic pesticides. A predictive model based on compositional data (CoDa) analysis revealed that the sorption capacity of decomposing mulch can be predicted from descriptors such as aromatic and alkyl C corresponding respectively to lignin and NDF biochemical fractions. The decomposition degree of mulch residues should be taken into account while predicting the fate of pesticides.

  8. 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.

  9. Occurrence of selected trace elements and organic compounds and their relation to land use in the Willamette River basin, Oregon, 1992-94

    USGS Publications Warehouse

    Anderson, C.W.; Rinella, F.A.; Rounds, S.A.

    1996-01-01

    Results from repeated samplings at two sites during sequential storms in the fall of 1994 indicated that concentrations and loads of several constituents, including suspended sediment, suspended organic carbon, DDT, metolachlor, and atrazine were highest during peak flows of the first or second significant storms of the fall. Samplings during subsequent storms indicated that instantaneous concentrations and loads were generally reduced; however, data were not sufficient to compare overall transport during sequential storms.

  10. Comparative assessment of herbicide and fungicide runoff risk: a case study for peanut production in the Southern Atlantic Coastal Plain (USA).

    PubMed

    Potter, Thomas L; Bosch, David D; Strickland, Timothy C

    2014-08-15

    Peanut (Arachis hypogaea) is produced intensively in the southern Atlantic Coastal Plain of the eastern USA. To effectively protect the region's water quality data are needed which quantify runoff of pesticides used to protect these crops. Fungicides are used intensively yet there is little published data which describe their potential for loss in surface runoff. This study compared runoff of a fungicide, tebuconazole (α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), and an herbicide, metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide) from 0.2 ha fields in strip (ST), a commonly used conservation-tillage practice, and conventional tillage (CT) near Tifton, GA (USA). Following their first application, metolachlor and tebuconazole were detected at high frequency in runoff. Concentrations and their annual losses increased with application frequency and runoff event timing and frequency with respect to applications, and when fields were positioned at the top of the slope and CT was practiced. Runoff one day after treatment (DAT) contributed to high tebuconazole runoff loss, up to 9.8% of the amount applied on an annual basis. In all cases, metolachlor loss was more than 10 times less even though total application was 45% higher. This was linked to the fact that the one metolachlor application to each crop was in May, one of the region's driest months. In sum, studies showed that fungicide runoff rates may be relatively high and emphasize the need to focus on these products in future studies on peanut and other crops. The study also showed that peanut farmers should be encouraged to use conservation tillage practices like ST which can substantially reduce pesticide runoff.

  11. 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.

  12. Pesticides in streams in New Jersey and Long Island, New York, and relation to land use

    USGS Publications Warehouse

    Reiser, Robert G.; O'Brien, Anne K.

    1999-01-01

    Only three of the seven most frequently detected compounds?atrazine, metolachlor, and carbaryl?are among the seven most heavily applied pesticides in New Jersey. This is because detection frequencies are the result of physical and chemical properties of the pesticide compounds as well as application rates. Water solubility and soil-adsorption coefficients appear to be the two physical properties of pesticides that most influence their presence in streams.

  13. Transgenic rice containing human CYP2B6 detoxifies various classes of herbicides.

    PubMed

    Hirose, Sakiko; Kawahigashi, Hiroyuki; Ozawa, Kenjirou; Shiota, Noriaki; Inui, Hideyuki; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-05-04

    The human gene for CYP2B6, a cytochrome P450 monooxygenase that inactivates xenobiotic chemicals, was introduced into Oryza sativa cv. Nipponbare by Agrobacterium-mediated transformation. At germination, R(1) seeds of transgenic rice plants expressing CYP2B6 (CYP2B6 rice) showed a high tolerance to 5 microM metolachlor, a preemergence herbicide that is degraded by CYP2B6. Thin-layer chromatography after culture with (14)C-labeled metolachlor revealed that the amounts of residual metolachlor decreased in plant tissues and the medium of CYP2B6 rice faster than those of untransformed Nipponbare. CYP2B6 rice plants were able to grow in the presence of 13 out of 17 herbicides: five chloroacetamides and mefenacet, pyributicarb, amiprofos-methyl, trifluralin, pendimethalin, norflurazon, and chlorotoluron. These herbicides differ in their modes of action and chemical structures. Transgenic rice expressing a xenobiotic-degrading human CYP2B6, which has broad substrate specificity, should be good not only for developing herbicide tolerant rice but also for reducing the environmental impact of agrochemicals.

  14. 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 western 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, which 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 (μg/L) for deethylatrazine to 3.58 μg/L for metolachlor ESA.

  15. Ground-water quality in alluvial aquifers in the eastern Iowa basins, Iowa and Minnesota

    USGS Publications Warehouse

    Sadorf, Eric M.; Linhart, S. Michael

    2000-01-01

    The effects of land use on ground-water quality also were examined. There was a positive correlation between percentage of land used for soybean production and concentrations of metolachlor, metolachlor ethanesulfonic acid, and metolachlor oxanilic acid in ground-water samples.Data from this study and from previous studies in the Eastern Iowa Basins were compared statistically by well type (domestic, municipal, and monitoring wells). Well depths were significantly greater in domestic and municipal wells than in monitoring wells. pH, calcium, sulfate, chloride, and atrazine concentrations were significantly higher in municipal-well samples than in domestic-well samples. pH and sulfate concentrations were significantly higher in municipal-well samples than in monitoring-well samples. Ammonia was significantly higher in domestic-well samples than in monitoring-well samples, chloride was significantly higher in monitoring-well samples than in domestic-well samples, and fluoride was significantly higher in domestic-well samples than in municipal-well samples.

  16. Herbicide and insecticide loadings from the Susquehanna River to the northern Chesapeake Bay.

    PubMed

    Liu, Bo; McConnell, Laura L; Torrents, Alba

    2002-07-17

    The Susquehanna River watershed has a large drainage area (71200 km(2)) containing heavy agricultural land usage. The river provides approximately half the total freshwater input to the Chesapeake Bay. Water samples were collected at Conowingo Dam near the mouth of the river every 9 days from February 1997 through March 1998. Atrazine, its transformation product 6-amino-2-chloro-4-(isopropylamino)-s-triazine (CIAT), and metolachlor were found in the highest concentrations with maximums of 500, 150, and 330 ng/L, respectively. The annual mass loads for atrazine, CIAT, metolachlor, simazine, and 6-amino-2-chloro-4-(ethylamino)-s-triazine (CEAT) from the Susquehanna River to the Chesapeake Bay were 1600, 1600, 1100, 820, and 720 kg/year, respectively. Annual loadings of insecticides and organochlorine compounds ranged from 2.8 kg/year for alpha-HCH to 34 kg/year for diazinon. Strong correlations between loading data from this and previous studies and total annual water discharge through the dam were used to estimate total metolachlor and atrazine loads (12400 and 9950 kg, respectively) to the northern Chesapeake Bay from 1992 to 1997.

  17. Preferential bromide and pesticide movement to tile drains under different cropping practices.

    PubMed

    Fortin, J; Gagnon-Bertrand, E; Vézina, L; Rompré, M

    2002-01-01

    Subsurface drainage systems are useful tools to study chemical leaching in soils. Our objective was to compare the breakthrough behavior of bromide, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamid] to tile drains under two fall tillage practices (conventional tillage [CT] with a moldboard plow, and reduced tillage [RT] with a chisel plow) in field plots cultivated with corn (Zea mays L.). Leachate volume were greater in RT than in CT, with no statistical differences. Soil analysis showed that bromide migrated deeper in the soil profile than both herbicides, with little tillage effect. All chemicals were detected in drainage water at the same time and followed an event-driven behavior. Tillage had no effect on atrazine and metolachlor found in drainage water, while bromide concentration peaks were higher in RT than in CT in 1999. Concentration peaks were recorded earlier for atrazine and metolachlor than for bromide. Plots of cumulative relative chemical mass (cumulative mass divided by total mass measured in drainage) as a function of cumulative drainage were mostly linear for bromide, while they were S-shaped for both herbicides. Drainage that corresponded to 50% of relative cumulative mass ranged from 40 to 55% for bromide and from 5 to 28% for both herbicides. Rapid chemical movement to tile drains suggested that preferential flow was important in both CT and RT, and that these tillage practices had little influence on this phenomena.

  18. Estimates of pesticide concentrations and fluxes in two rivers of an extensive French multi-agricultural watershed: application of the passive sampling strategy.

    PubMed

    Poulier, Gaëlle; Lissalde, Sophie; Charriau, Adeline; Buzier, Rémy; Cleries, Karine; Delmas, François; Mazzella, Nicolas; Guibaud, Gilles

    2015-06-01

    In this study, the passive sampling strategy was evaluated for its ability to improve water quality monitoring in terms of concentrations and frequencies of quantification of pesticides, with a focus on flux calculation. Polar Organic Chemical Integrative Samplers (POCIS) were successively exposed and renewed at three sampling sites of an extensive French multi-agricultural watershed from January to September 2012. Grab water samples were recovered every 14 days during the same period and an automated sampler collected composite water samples from April to July 2012. Thirty-nine compounds (pesticides and metabolites) were analysed. DEA, diuron and atrazine (banned in France for many years) likely arrived via groundwater whereas dimethanamid, imidacloprid and acetochlor (all still in use) were probably transported via leaching. The comparison of the three sampling strategies showed that the POCIS offers lower detection limits, resulting in the quantification of trace levels of compounds (acetochlor, diuron and desethylatrazine (DEA)) that could not be measured in grab and composite water samples. As a consequence, the frequencies of occurrence were dramatically enhanced with the POCIS compared to spot sample data. Moreover, the integration of flood events led to a better temporal representation of the fluxes when calculated with the POCIS compared to the bimonthly grab sampling strategy. We conclude that the POCIS could be an advantageous alternative to spot sampling, offering better performance in terms of quantification limits and more representative data.

  19. Contaminant-mediated photobleaching of wetland chromophoric dissolved organic matter.

    PubMed

    Langlois, Maureen C; Weavers, Linda K; Chin, Yu-Ping

    2014-09-20

    Photolytic transformation of organic contaminants in wetlands can be mediated by chromophoric dissolved organic matter (CDOM), which in turn can lose its reactivity from photobleaching. We collected water from a small agricultural wetland (Ohio), Kawai Nui Marsh (Hawaii), the Everglades (Florida), and Okefenokee Swamp (Georgia) to assess the effect of photobleaching on the photofate of two herbicides, acetochlor and isoproturon. Analyte-spiked water samples were irradiated using a solar simulator and monitored for changes in CDOM light absorbance and dissolved oxygen. Photobleaching did not significantly impact the indirect photolysis rates of either herbicide over 24 hours of irradiation. Surprisingly, the opposite effect was observed with isoproturon, which accelerated DOM photobleaching. This phenomenon was more pronounced in higher-CDOM waters, and we believe that the redox pathway between triplet-state CDOM and isoproturon may be responsible for our observations. By contrast, acetochlor indirect photolysis was dependent on reaction with the hydroxyl radical and did not accelerate photobleaching of wetland water as much as isoproturon. Finally, herbicide indirect photolysis rate constants did not correlate strongly to any one chemical or optical property of the sampled waters.

  20. 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.

  1. Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants.

    PubMed

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

    2017-03-30

    In this study, we construct a surface Fenton system with hydroxylamine (NH2OH), goethite (α-FeOOH), and H2O2 (α-FeOOH-HA/H2O2) to degrade various organic pollutants including dyes (methyl orange, methylene blue, and rhodamine B), pesticides (pentachlorophenol, alachlor, and atrazine), and antibiotics (tetracycline, chloramphenicol, and lincomycin) at pH 5.0. In this surface Fenton system, the presence of NH2OH could greatly promote the H2O2 decomposition on the α-FeOOH surface to produce •OH without releasing any detectable iron ions during the alachlor degradation, which was different from some previously reported heterogeneous Fenton counterparts. Moreover, the •OH generation rate constant of this surface Fenton system was 102 - 104 times those of previous heterogeneous Fenton processes. The interaction between α-FeOOH and NH2OH was investigated with using attenuated total reflectance Fourier transform infrared spectroscopy and density functional theory calculations. The effective degradation of organic pollutants in this surface Fenton system was ascribed to the efficient Fe(III)/Fe(II) cycle on the α-FeOOH surface promoted by NH2OH, which was confirmed by X-ray photoelectron spectroscopy analysis. The degradation intermediates and mineralization of alachlor in this surface Fenton system were then systematically investigated using total organic carbon and ion chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. This study offers a new strategy to degrade organic pollutants, and also sheds light on the environmental effects of goethite.

  2. Quality of ground water used for selected municipal water supplies in Iowa, 1982-96 water years

    USGS Publications Warehouse

    Schaap, B.D.; Linhart, S.M.

    1998-01-01

    Maps show the general location of wells that have been sampled in the various aquifers. Other maps show the location of wells where sulfate and nitrite plus nitrate concentrations exceed the respective Maximum Contaminant Levels and wells where concentrations of the pesticides alachlor, atrazine, or cyanazine exceeded the respective minimum reporting levels. The compact disc included with this report has information about water-quality properties and concentrations of dissolved solids, major ions, nutrients, trace elements, radionuclides, total organic carbon, pesticides, and synthetic organic compounds for water years 1982 through 1996.

  3. 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.

  4. Determination of low-level pesticide residues in soft drinks and sports drinks by liquid chromatography with tandem mass spectrometry: collaborative study.

    PubMed

    Miller, Kathleen D; Milne, Paul

    2008-01-01

    A collaborative study was conducted on a method for the measurement of 11 low-level pesticide residues in soft drinks and sports drinks by liquid chromatography with tandem mass spectrometry. The pesticide residues determined in this study were alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-dichlorophenoxyacetic acid (2,4-D). Blind fortification solutions containing 3 different levels of pesticide residues were provided to 9 collaborating laboratories to create test samples at concentrations of 0, 0.1, and 0.5 microg/L with a 10-fold concentration for phorate in a total of 6 matrixes (2 colas, 1 diet cola, 1 clear lemon-lime soft drink, 1 orange soft drink, and 1 sports drink). Good qualitative performance of the method was demonstrated for all pesticide residues. Reproducibility relative standard deviation (RSDR) ranged from 7 to 151% for alachlor, atrazine, butachlor, isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D at the 0.1 microg/L level (1.0 microg/L for phorate). At 0.5 microg/L (5.0 microg/L for phorate), RSDR ranged from 9 to 57% for alachlor, atrazine, butachlor isoproturon, malaoxon, monocrotophos, methyl paraoxon, phorate, phorate sulfone, phorate sulfoxide, and 2,4-D in all matrixes. Repeatability relative standard deviation (RSDr), applicable to the diet cola and sports drink, ranged from 0 to 124% for the 11 pesticide residues at the 0.1 microg/L level (1.0 microg/L for phorate). At 0.5 microg/L (5.0 microg/L for phorate), RSDr ranged from 4 to 26%. Recoveries for the 11 pesticide residues in all matrixes ranged from 84 to 300% at the 0.1 microg/L level (1.0 microg/L for phorate) and from 66 to 127% at the 0.5 microg/L (5.0 microg/L for phorate) level. Coefficients of determination (r2) of the matrix-matched calibration curves were > or = 0.95. It is recommended that the method be accepted by AOAC

  5. Office of Naval Research High School Intern Program (ONR HSIP), (1987-1991)

    DTIC Science & Technology

    1991-09-01

    Advisors ft. K. Renset (Narine ecology) Reseorch TopiecP~per Title: Effects of fiddler crab foraging and tidal inundation an amcromielg biommes on Bird...mud crab , Rhithraboe hu ri (Gould). Estuaries 11(2):79- 82. 1989 Diamond, D.L., Scott, L.K., Forward, R.B., Jr., and Kirby- Smith, W.V. Respiration and...osmoregulatLon of the estuarLne crab Rhithrooanooaeus. hbrL= (Gould): Effects of the herbicide alachlor. Coop. Biochen. Physiol. 93A(2):313-318

  6. 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

  7. 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.

  8. Comparison of experimental methods for determination of toxicity and biodegradability of xenobiotic compounds.

    PubMed

    Polo, A M; Tobajas, M; Sanchis, S; Mohedano, A F; Rodríguez, J J

    2011-07-01

    Different methods for determining the toxicity and biodegradability of hazardous compounds evaluating their susceptibility to biological treatment were studied. Several compounds including chlorophenols and herbicides have been evaluated. Toxicity was analyzed in terms of EC50 and by a simple respirometric procedure based on the OECD Method 209 and by the Microtox® bioassay. The values of EC50 obtained from respirometry were in all the cases higher than those from the Microtox® test. The respirometric inhibition values of chlorophenols were related well with the number of chlorine atoms and their position in the aromatic ring. In general, herbicides showed lower inhibition, being alachlor the less toxic from this criterion. For determination of biodegradability an easier and faster alternative to the OECD Method 301, with a higher biomass to substrate ratio is proposed. When this test was negative, the Zahn-Wellens one was performed in order to evaluate the inherent biodegradability. In the fast test of biodegradability, 4-chlorocatechol and 4-chlorophenol showed a complete biodegradation by an unacclimated sludge upon 48 h. These results together with their low respirometric inhibition, allow concluding that these compounds could be conveniently removed in a WWTP. Alachlor, 2,4-dichlorophenol, 2,4,6-trichlorophenol and MCPA showed a partial biodegradation upon 28 days by the Zahn-Wellens inherent biodegradability test.

  9. Cloning and expression of a cDNA encoding a maize glutathione-S-transferase in E. coli.

    PubMed

    Moore, R E; Davies, M S; O'Connell, K M; Harding, E I; Wiegand, R C; Tiemeier, D C

    1986-09-25

    The isolation and characterization of a family of maize glutathione-S-transferases (GST's) has been described previously. These enzymes are designated GSTs I, II and III based on size, substrate specificity and responsiveness to safeners. GST III has been shown to act on the herbicide alachlor as well as the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Clones were isolated from a maize cDNA library in lambda gt10. Three clones contained the entire coding region for GST III. The sequences of these clones were consistent with the known amino terminal GST III protein sequence. Moreover, expression of one of these clones in E. coli resulted in a GST activity as measured with both CDNB and alachlor, proving that at least one of the clones encodes an active GST III species. With the enzyme expressed in E. coli it will become possible to study enzyme structure-function relationships ex planta. While a number of different GST proteins are present in maize tissue the GST III gene is present in single or low copy in the genome.

  10. Cloning and expression of a cDNA encoding a maize glutathione-S-transferase in E. coli.

    PubMed Central

    Moore, R E; Davies, M S; O'Connell, K M; Harding, E I; Wiegand, R C; Tiemeier, D C

    1986-01-01

    The isolation and characterization of a family of maize glutathione-S-transferases (GST's) has been described previously. These enzymes are designated GSTs I, II and III based on size, substrate specificity and responsiveness to safeners. GST III has been shown to act on the herbicide alachlor as well as the commonly used substrate 1-chloro-2,4-dinitrobenzene (CDNB). Clones were isolated from a maize cDNA library in lambda gt10. Three clones contained the entire coding region for GST III. The sequences of these clones were consistent with the known amino terminal GST III protein sequence. Moreover, expression of one of these clones in E. coli resulted in a GST activity as measured with both CDNB and alachlor, proving that at least one of the clones encodes an active GST III species. With the enzyme expressed in E. coli it will become possible to study enzyme structure-function relationships ex planta. While a number of different GST proteins are present in maize tissue the GST III gene is present in single or low copy in the genome. Images PMID:3532034

  11. Degradation of some biorecalcitrant pesticides by homogeneous and heterogeneous photocatalytic ozonation.

    PubMed

    Farré, Maria José; Franch, Maria Isabel; Malato, Sixto; Ayllón, José Antonio; Peral, José; Doménech, Xavier

    2005-02-01

    Photo-Fenton/ozone (PhFO) and TiO2-photocatalysis/ozone (PhCO) coupled systems are used as advanced oxidation processes for the degradation of the following biorecalcitrant pesticides: alachlor, atrazine, chlorfenvinfos, diuron, isoproturon and pentachlorophenol. These organic compounds are considered Priority Hazardous Substances by the Water Framework Directive of the European Commission. The degradation process of the different pesticides, that occurs through oxidation of the organic molecules by means of their reaction with generated OH radical, follows a first and zero-order kinetics, when PhFO and PhCO are applied, respectively. These two Advanced Oxidation Processes, together with the traditional ozone+UV, have been used to investigate TOC reduction of the different pesticide aqueous solutions. The best results of pesticide mineralization are obtained when PhFO is applied; with the use of this advanced oxidation process the aqueous pesticide solutions become detoxyfied except in the case of atrazine and alachlor aqueous solutions for which no detoxification is achieved at the experimental conditions used in the work, at least after 2 and 3 h of treatment, respectively.

  12. 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.

  13. Simultaneous removal of nitrate and pesticides from groundwater using a methane-fed membrane biofilm reactor.

    PubMed

    Modin, O; Fukushi, K; Yamamoto, K

    2008-01-01

    Nitrate and pesticide contaminated ground- and surface-waters have been found around the world as a result of the use of these compounds in agricultural activities. In this study we investigated a biological treatment method to simultaneously remove nitrate and pesticides from contaminated water. Methane was supplied as the sole source of carbon to the microbial culture. A methane-fed membrane biofilm reactor (M-MBfR) was developed in which the methane was supplied through hollow-fiber membranes to a biofilm growing on the membrane surface. A methane-oxidizing culture enriched from activated sludge was used as inoculum for the experiments. Removal of nitrate and the four pesticides atrazine, aldicarb, alachlor, and malathion was examined both in suspended culture and in the M-MBfR. The maximum denitrification rate with suspended culture was 36.8 mg N gVSS(-1) d(-1). With the M-MBfR setup, a hydraulic retention time of approximately one hour was required to completely remove an incoming nitrate concentration of about 20 mg NO3-N l(-1). The microbial culture could remove three of the pesticides (aldicarb, alachlor, and malathion). However, no atrazine removal was observed. The removal rates of both nitrate and pesticides were similar in suspended culture and in membrane-attached biofilm.

  14. 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.

  15. Characterization of cholinesterases in Chironomus riparius and the effects of three herbicides on chlorpyrifos toxicity.

    PubMed

    Pérez, Joanne; Monteiro, Marta S; Quintaneiro, Carla; Soares, Amadeu M V M; Loureiro, Susana

    2013-11-15

    In this study, the toxicities of four pesticides (the herbicides atrazine, terbuthylazine, metolachlor and the insecticide chlorpyrifos) previously detected in the Alqueva reservoir/dam (south of Portugal) were evaluated individually and in binary combinations of the herbicides and the insecticide using fourth-instar larvae of the aquatic midge Chironomus riparius. Chlorpyrifos induced toxicity to midges in all the 48 h toxicity bioassays performed. The swimming behaviour of the larvae was impaired, with EC50 values ranging from 0.15 to 0.17 μg/L. However, neither s-triazine (atrazine and terbuthylazine) herbicides nor metolachlor alone at concentrations up to 200 μg/L caused significant toxicity to C. riparius. When combined with both s-triazine herbicides, chlorpyrifos toxicity was enhanced by approximately 2-fold when tested in a binary mixture experimental setup, at the 50% effective concentration levels. To evaluate how chlorpyrifos toxicity was being increased, the cholinesterases (ChE) were characterized biochemically using different substrates and selective inhibitors. The results obtained suggested that the main enzyme present in this species is acetylcholinesterase (AChE) and therefore it was assayed upon C. riparius exposures to all pesticides individually and as binary mixtures. Although atrazine and terbuthylazine are not effective inhibitors of AChE, the potentiation of chlorpyrifos toxicity by the two s-triazine herbicides was associated with a potentiation in the inhibition of AChE in midges; both s-triazine herbicides at 200 μg/L increased the inhibition of the AChE activity by 7 and 8-fold, respectively. A strong correlation was observed between swimming behaviour disturbances of larvae and the inhibition of the AChE activity. In contrast, metolachlor did not affect chlorpyrifos toxicity at any of the concentrations tested. Therefore, the herbicides atrazine and terbuthylazine can act as synergists in the presence of chlorpyrifos, increasing

  16. 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.

  17. 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.

  18. Chemoproteomic Profiling of Acetanilide Herbicides Reveals Their Role in Inhibiting Fatty Acid Oxidation.

    PubMed

    Counihan, Jessica L; Duckering, Megan; Dalvie, Esha; Ku, Wan-Min; Bateman, Leslie A; Fisher, Karl J; Nomura, Daniel K

    2017-03-17

    Acetanilide herbicides are among the most widely used pesticides in the United States, but their toxicological potential and mechanisms remain poorly understood. Here, we have used chemoproteomic platforms to map proteome-wide cysteine reactivity of acetochlor (AC), the most widely used acetanilide herbicide, in vivo in mice. We show that AC directly reacts with >20 protein targets in vivo in mouse liver, including the catalytic cysteines of several thiolase enzymes involved in mitochondrial and peroxisomal fatty acid oxidation. We show that the fatty acids that are not oxidized, due to impaired fatty acid oxidation, are instead diverted into other lipid pathways, resulting in heightened free fatty acids, triglycerides, cholesteryl esters, and other lipid species in the liver. Our findings show the utility of chemoproteomic approaches for identifying novel mechanisms of toxicity associated with environmental chemicals like acetanilide herbicides.