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E.M. Thurman

Publications and source records attributed to E.M. Thurman.

At least 19 recordsLinked to original sources
USGS2010

Groundwater as a nonpoint source of atrazine and deethylatrazine in a river during base flow conditions

Alluvial groundwater adjacent to the main stem river is the principal nonpoint source of atrazine and deethylatrazine in the Cedar River of Iowa after the river has been in base flow conditions for 5 days. Between two sites along a 116-km reach of the Cedar River, tributaries contributed about 25% of the increase in the atrazine and deethylatrazine load, whereas groundwater from the alluvial aquifer contributed at least 75% of the increase in load. Within the study area, tributaries aggregate almost all of the discharge from tile drains, and yet the tributaries still only contribute 25% of the increase in loads in the main stem river. At an unfamned study site adjacent to the Cedar River, the sources of atrazine and deethylatrazine in the alluvial groundwater are bank storage of river water and groundwater recharge from areas distant from the river. Atrazine and deethylatrazine associated with bank storage water will provide larger concentrations to the river during early base flow conditions. After the depletion of bank storage, stable and smaller concentrations of atrazine and deethylatrazine, originating from groundwater recharge, continue to be discharged from the alluvial aquifer to the river; thus these results indicate that alluvial aquifers are an important nonpoint source of atrazine and deethylatrazine in rivers during base flow.

Iowa↗
USGS2010

A first application of enzyme-linked immunosorbent assay for screening cyclodiene insecticides in ground water

A commercially available enzyme-linked immunosorbent assay (ELISA) plate kit for screening of cyclodiene insecticides (aldrin, chlordane, dieldrin, endosulfan, endrin, and heptachlor) was evaluated for sensitivity, cross reactivity, and overall performance using ground-water samples from a contaminated site. Ground-water contaminants included several pesticide compounds and their manufacturing by-products, as well as many other organic and inorganic compounds. Cross-reactivity studies were carried out for the cyclodiene compounds, and results were compared to those listed by the manufacturer. Data obtained were used to evaluate the sensitivity of the ELISA kit to the cyclodiene compounds in ground water samples with a contaminated matrix. The method quantitation limit for the ELISA kit was 15 μg/L (as chlordane). Of the 56 ground-water samples analyzed using the ELISA plate kits, more than 85% showed cyclodiene insecticide contamination. The ELISA kit showed excellent potential as a screening tool for sites with suspected ground-water contamination by insecticides.

ACS Symposium Series↗
USGS2009

Herbicide metabolites in surface water and groundwater: Introduction and overview

Several future research topics for herbicide metabolites in surface and ground water are outlined in this chapter. They are herbicide usage, chemical analysis of metabolites, and fate and transport of metabolites in surface and ground water. These three ideas follow the themes in this book, which are the summary of a symposium of the American Chemical Society on herbicide metabolites in surface and ground water. First, geographic information systems allow the spatial distribution of herbicide-use data to be combined with geochemical information on fate and transport of herbicides. Next these two types of information are useful in predicting the kinds of metabolites present and their probable distribution in surface and ground water. Finally, methods development efforts may be focused on these specific target analytes. This chapter discusses these three concepts and provides an introduction to this book on the analysis, chemistry, and fate and transport of herbicide metabolites in surface and ground water.

ACS Symposium Series↗
USGS2009

Relation of landscape position and irrigation to concentrations of alachlor, atrazine, and selected degradates in regolith in northeastern Nebraska

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 µg/kg) and ethanesulfonic acid (maximum 10 µg/kg) were associated with landscape position, but not with irrigation. Alachlor (maximum 24 µg/kg), deethylatrazine (maximum 1.5 µg/kg), and deisopropylatrazine (maximum 3.5 µg/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.

ACS Symposium Series↗
USGS2009

Cyanazine, atrazine, and their metabolites as geochemical indicators of contaminant transport in the Mississippi River

The geochemical transport of cyanazine and its metabolite cyanazine amide (CAM) was compared to atrazine and its metabolite deethylatrazine (DEA) at three sites in the Mississippi River basin during 1992 and six sites during 1993. The floods of 1993 caused an uninterrupted exponential decline in herbicide concentrations; whereas, in 1992 herbicide concentrations varied mostly in response to two discrete discharge pulses in the spring and midsummer and were stable during an extended period of summer low-flow. Concentration half-lives calculated from the 1993 data for atrazine were approximately twice those of cyanazine at all sites. The half-life for atrazine and cyanazine was shortest, 22 and 14 days, respectively at the Mississippi River at Clinton, Ill. -- the farthest upstream site -- and longest, 42 and 22 days, respectively, at the Baton Rouge, La. site -- the farthest downstream site. The concentration of CAM exceeded the concentration of DEA through September at all sites where the mean ratio of atrazine-to-cyanazine (ACR) was less than 4.0. The ratio of CAM-to-cyanazine (CAMCR) increased from 0.2 to more than 1.0 and the ratio of DEA-to-atrazine (DAR) increased from less than 0.1 to 0.3 from application in May through early to mid- July. Temporal changes in the CAMCR were used to identify pre- and post-application "slugs" of water transported along the reaches of the Mississippi River.

Arkansas, Illinois, Kentucky, Louisiana, Mississip↗
USGS2009

Organic geochemistry and sources of natural aquatic foams

Aquatic foams and stream-water samples were collected from two pristine sites for humic substances isolation and characterization. Biomarker compounds identified in foam and stream humic substances included phospholipid fatty acids, steroids, and lignin. Results showed that foams had a 10 to 20 fold greater DOC concentration and were enriched in humic substances (90% by weight of DOC) that showed increased hydrophobicity, aliphatic character, and compositional complexity compared to host stream humic substances (55 to 81% by weight of DOC). Foam humic substances also were enriched in humic acid (36 to 83% by weight) compared to host stream humic substances (10 to 14% by weight). Biomarkers, which contributed less than 5% by weight to the DOC pool, indicated higher plants, bacteria, algae, fungi, and diatoms as DOC sources. It is proposed that aquatic foams may be important media for the concentration and transport of organic substances in the aquatic environment.

ACS Symposium Series↗
USGS2009

Environmental immunoassays: Alternative techniques for soil and water analysis

Analysis of soil and water samples for environmental studies and compliance testing can be formidable, time consuming, and costly. As a consequence, immunochemical techniques have become popular for environmental analysis because they are reliable, rapid, and cost effective. During the past 5 years, the use of immunoassays for environmental monitoring has increased substantially, and their use as an integral analytical tool in many environmental laboratories is now commonplace. This chapter will present the basic concept of immunoassays, recent advances in the development of immunochemical methods, and examples of successful applications of immunoassays in environmental analysis.

ACS Symposium Series↗
USGS2009

Evaluation of immunoassay for the determination of pesticides at a large-scale groundwater contamination site

Pesticide concentrations in ground water at Rocky Mountain Arsenal (RMA) near Denver, Colorado, were determined using solid-phase extraction (SPE) gas chromatography/mass spectrometry (GC/MS) procedures and enzyme-linked immunosorbent assay (ELISA) for cyclodiene insecticides and triazine herbicides. Matrix interferences resulted in inconclusive results for some GC/MS analyses due to baseline disturbances and co-elution, but ELISA analyses consistently gave definitive results in a minimum amount of time. ELISA was used initially as a screening method, and pesticide concentrations and plume extents identified by ELISA were confirmed by SPE-GC/MS. A high degree of correlation was seen between results from GC/MS and ELISA methods for the triazine herbicides (correlation coefficient (R 2 ) = 0.99). All areas with high pesticide concentrations were found to be within the boundaries of RMA.

Colorado↗
USGS2009

Source and transport of desethylatrazine and desisopropylatrazine to groundwater of the midwestern United States

Based on usage of the parent compounds and studies of their dissipation in corn fields, atrazine (6-chloro-N-ethyl-N'-(1-methylethyl-1,3,5-triazine-2,4-diamine)), cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile), and simazine (6-chloro-N,N'diethyl-1,3,5-triazine-2,4-diamine) are thought to be the important contributors of desethylatrazine (6-chloro-N-(1-methylethyl)-1,3,5-triazine-2,4-diamine) or DEA and desisopropylatrazine(6-chloro-N-ethyl)-1,3,5-triazine-2,4-diamine) or DIA to ground water. Atrazine degrades to both DEA and DIA by dealkylation. DEA is transported through the unsaturated zone more readily than DIA because of the more rapid degradation of DIA in the shallow unsaturated zone. Both cyanazine and simazine degrade to DIA by dealkylation, and DIA may be an indicator of leaching and subsequent degradation from both parent compounds. Because cyanazine has an acid intermediate that is mobile in the unsaturated zone, it may be an important source for DIA transport to ground water. Based on a regional survey of ground water of the Midwest during the Spring and Summer of 1991, DEA occurs most frequently with detections of DEA (15.4%) > atrazine (14.7%) > DIA (4%) > simazine (0.7%) > cyanazine (0.3%) > propazine (no detections). The DEA to atrazine ratio (DAR) is an indicator of atrazine source and transport, with the lowest ratios indicating most rapid transport.

ACS Symposium Series↗
USGS2007

Herbicides and transformation products in surface waters of the Midwestern United States

Most herbicides applied to crops are adsorbed by plants or transformed (degraded) in the soil, but small fractions are lost from fields and either move to streams in overland runoff, near surface flow, or subsurface drains, or they infiltrate slowly to ground water. Herbicide transformation products (TPs) can be more or less mobile and more or less toxic in the environment than their source herbicides. To obtain information on the concentrations of selected herbicides and TPs in surface waters of the Midwestern United States, 151 water samples were collected from 71 streams and five reservoir outflows in 1998. These samples were analyzed for 13 herbicides and 10 herbicide TPs. Herbicide TPs were found to occur as frequently or more frequently than source herbicides and at concentrations that were often larger than their source herbicides. Most samples contained a mixture of more than 10 different herbicides or TPs. The ratios of TPs to herbicide concentrations can be used to determine the source of herbicides in streams. Results of a two-component mixing model suggest that on average 90 percent or more of the herbicide mass in Midwestern streams during early summer runoff events originates from the runoff and 10 percent or less comes from increased ground water discharge.

Journal of the American Water Resources Associatio↗
USGS2006

Terbuthylazine and deethylterbuthylazine in rain and surface water: Determination by enzyme immunoassay and gas chromatography/mass spectrometry

Rain and surface water samples from Southern Germany were investigated from 1991 to 1995 for terbuthylazine and one of its major metabolites, deethylterbuthylazine. The concentrations observed were compared to the concentrations found for atrazine and deethylatrazine in the same water samples. Concentrations ranged from < 0.02 μg/L to 0.7 μg/L for terbuthylazine and from < 0.02 μg/L to 0.6 μg/L for deethylterbuthylazine, compared to concentrations of < 0.02 μg/L to 3 μg/L and < 0.02 μg/L to 0.5 μg/L for atrazine and deethylatrazine, respectively. The ratios of metabolite concentrations to parent compound concentrations were calculated for deethylterbuthylazine to terbuthylazine ( DTR ) and deethylatrazine to atrazine ( DAR ). In rain water, DTR of 0.8…3.0 and DAR of 0.3… 1.9 were determined with mean values of 0.9… 1.7 for DTR and 0.6…0.9 for DAR in the different years. The ratios increased during summer periods. The highest ratios were observed in samples from forest stands, showing that degradation of the herbicide has occurred during transport between the source and the sampling site. The DTR in rain water were about 50… 100% higher than the DAR . This indicates a higher degradation rate of terbuthylazine during atmospheric transport. In surface water, DTR of 0.3… 1.2 with mean values of 0.5…0.8 and DAR of 0.2…2.2 with mean values of 0.2… 1.3 were observed. The ratios increased from June to September.

Acta Hydrochimica et Hydrobiologica↗
USGS2006

Urban contributions of glyphosate and its degradate AMPA to streams in the United States

Glyphosate is the most widely used herbicide in the world, being routinely applied to control weeds in both agricultural and urban settings. Microbial degradation of glyphosate produces aminomethyl phosphonic acid (AMPA). The high polarity and water-solubility of glyphosate and AMPA has, until recently, made their analysis in water samples problematic. Thus, compared to other herbicides (e.g. atrazine) there are relatively few studies on the environmental occurrence of glyphosate and AMPA. In 2002, treated effluent samples were collected from 10 wastewater treatment plants (WWTPs) to study the occurrence of glyphosate and AMPA. Stream samples were collected upstream and downstream of the 10 WWTPs. Two reference streams were also sampled. The results document the apparent contribution of WWTP effluent to stream concentrations of glyphosate and AMPA, with roughly a two-fold increase in their frequencies of detection between stream samples collected upstream and those collected downstream of the WWTPs. Thus, urban use of glyphosate contributes to glyphosate and AMPA concentrations in streams in the United States. Overall, AMPA was detected much more frequently (67.5%) compared to glyphosate (17.5%).

Science of the Total Environment↗
USGS2005

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

Since 1995, a network of municipal wells in Iowa, representing all major aquifer types (alluvial, bedrock/karst region, glacial drift, bedrock/nonkarst region), has been repeatedly sampled for a broad suite of herbicide compounds yielding one of the most comprehensive statewide databases of such compounds currently available in the United States. This dataset is ideal for documenting the insight that herbicide degradates provide to the spatial and temporal distribution of herbicides in ground water. During 2001, 86 municipal wells in Iowa were sampled and analyzed for 21 herbicide parent compounds and 24 herbicide degradates. The frequency of detection increased from 17% when only herbicide parent compounds were considered to 53% when both herbicide parents and degradates were considered. Thus, the transport of herbicide compounds to ground water is substantially underestimated when herbicide degradates are not considered. A significant difference in the results among the major aquifer types was apparent only when both herbicide parent compounds and their degradates were considered. In addition, including herbicide degradates greatly improved the statistical relation to the age of the water being sampled. When herbicide parent compounds are considered, only 40% of the wells lacking a herbicide detection could be explained by the age of the water predating herbicide use. However, when herbicide degradates were also considered, 80% of the ground water samples lacking a detection could be explained by the age of the water predating herbicide use. Finally, a temporal pattern in alachlor concentrations in ground water could only be identified when alachlor degradates were considered.

Iowa↗
USGS2005

Occurrence of selected herbicides and herbicide degradation products in Iowa's Ground Water, 1995

Herbicide compounds were prevalent in ground water across Iowa, being detected in 70% of the 106 municipal wells sampled during the summer of 1995. Herbicide degradation products were three of the four most frequently detected compounds for this study. The degradation product alachlor ethanesulfonic acid was the most frequently detected compound (65.1%), followed by atrazine (40.6%), and the degradation products deethylatrazine (34.9%), and cyanazine amide (19.8%). The corn herbicide acetochlor, first registered for widespread use in the United States in March 1994, was detected in a single water sample. No reported herbicide compound concentrations for this study exceeded currem U.S. Environmental Protection Agency's maximum contaminant levels or health advisory levels for drinking water, although the herbicide degradation products examined have yet to have such levels established. The occurrence of herbicide compounds had a significant, inverse relation to well depth and a significant, positive relation to dissolved-oxygen concentration. It is felt that both well depth and dissolved oxygen are acting as rough surrogates to ground-water age, with younger ground water being more likely to contain herbicide compounds. The occurrence of herbicide compounds was substantially different among the major aquifer types across Iowa, being detected in 82.5% of the alluvial, 81.8% of the bedrock/ karst region, 40.0% of the glacial-drift, and 25.0% of the bedrock/nonkarst region aquifers. The observed distribution was partially attributed to variations in general ground-water age among these aquifer types. A significant, inverse relation was determined between total herbicide compound concentrations in ground water and the average soil slope within a 2-km radius of sampled wells. Steeper soil slopes may increase the likelihood of surface runoff occurring rather than ground-water infiltration&ndash;decreasing the transport of herbicide compounds to ground water. As expected, a significant positive relation was determined between intensity of herbicide use and herbicide concentrations in ground water.

Iowa↗
USGS2005

Widespread detection of N, N-diethyl-m-toluamide in U.S. streams: Comparison with concentrations of pesticides, personal care products, and other organic wastewater compounds

One of the most frequently detected organic chemicals in a nationwide study concerning the effects of wastewater on stream water quality conducted in the year 2000 was the widely used insect repellant N , N -diethyl- m -toluamide (DEET). It was detected at levels of 0.02 &mu;g/L or greater in 73% of the stream sites sampled, with the selection of sampling sites being biased toward streams thought to be subject to wastewater contamination (i.e., downstream from intense urbanization and livestock production). Although DEET frequently was detected at all sites, the median concentration was low (0.05 &mu;g/L). The highest concentrations of DEET were found in streams from the urban areas (maximum concentration, 1.1 &mu;g/L). The results of the present study suggest that the movement of DEET to streams through wastewater-treatment systems is an important mechanism that might lead to the exposure of aquatic organisms to this chemical.

Environmental Toxicology and Chemistry↗