The AltEn bioenergy plant (Mead, Nebraska, USA) previously (2015 to 2021) generated ethanol from almost 100% unused/expired treated corn seeds. This use of treated corn seeds as a feedstock for ethanol production resulted in accumulation of large amounts of contaminated wastewater and solid residue at the plant, a portion of which was applied to surrounding farmland. To better understand the potential long-term environmental effects from the processing of treated seeds, five nearby stream sites were sampled from March to July 2022 after the closure of the AltEn plant. Water and bed sediment were collected in March (prior to crop planting) through July and algae, fish, and insect samples were collected in July. Overall, 60 pesticide compounds (parents and transformation products) were detected across all matrices. In surface water samples, 52 pesticides were detected with thiamethoxam degradate (NOA-407475) having the highest concentration of 4556.2 nanograms per liter (ng/L). Algae samples had 19 pesticides detected with atrazine having the highest concentration of 191.37 nanograms per gram dry weight (ng/g d.w.). Bed sediment (bottom material) had a total of 15 pesticides detected with the highest concentration of 2.30 ng/g d.w. of acetochlor. Insect samples had 14 pesticides detected with the highest concentration of 116.10 ng/g d.w. of clothianidin. The last matrix, fish, had a total of 5 pesticides detected with the highest concentration being for atrazine of 2.21 ng/g d.w.

Dissolved pesticides were measured in weekly water samples from 100 wadeable freshwater streams across eleven states in the Midwestern U.S. during May-August, 2013, as part of the Midwest Stream Quality Assessment study conducted by the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Project. Of the 100 stream sites, 12 were urban indicator sites and the remaining 88 sites were located along an agricultural gradient of watershed land use. Twelve depth- and width-integrated water samples were collected at each site within the 14-week study period. Water samples were filtered (0.7 micrometers) and analyzed for 227 pesticide compounds by direct-injection liquid chromatography with tandem mass-spectrometry, and for glyphosate by Enzyme-Linked Immunoassay in a separate analysis. Potential aquatic toxicity was evaluated using the Pesticide Toxicity Index and by comparison to U.S. Environmental Protection Agency aquatic-life benchmarks. This data release provides sampling site locations, method information, summaries of quality-control data, and concentration data for pesticide compounds in environmental weekly water samples, in support of the journal article, "Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams," by Nowell, L.H., Moran, P.W., Schmidt, T., Norman, J.E., Nakagaki, N., Shoda, M.E., Mahler, B.J., Van Metre, P.C., Stone, W.W., Sandstrom, M.W., and Hladik, M.L.

Dissolved pesticides were measured in weekly water samples from 100 wadeable freshwater streams across eleven states in the Midwestern U.S. during May-August, 2013, as part of the Midwest Stream Quality Assessment study conducted by the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Project. Of the 100 stream sites, 12 were urban indicator sites and the remaining 88 sites were located along an agricultural gradient of watershed land use. Twelve depth- and width-integrated water samples were collected at each site within the 14-week study period. Water samples were filtered (0.7 micrometers) and analyzed for 227 pesticide compounds by direct-injection liquid chromatography with tandem mass-spectrometry, and for glyphosate by Enzyme-Linked Immunoassay in a separate analysis. Potential aquatic toxicity was evaluated using the Pesticide Toxicity Index and by comparison to U.S. Environmental Protection Agency aquatic-life benchmarks. This data release provides sampling site locations, method information, summaries of quality-control data, and concentration data for pesticide compounds in environmental weekly water samples, in support of the journal article, “Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams,” by Nowell, L.H., Moran, P.W., Schmidt, T., Norman, J.E., Nakagaki, N., Shoda, M.E., Mahler, B.J., Van Metre, P.C., Stone, W.W., Sandstrom, M.W., and Hladik, M.L.

Dissolved pesticides were measured in weekly water samples from 100 wadeable streams across eleven states in the Midwestern U.S. during May-August, 2013, as part of the Midwest Stream Quality Assessment study conducted by the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Project. Of the 100 stream sites, 12 were urban indicator sites and the remaining 88 sites were located along an agricultural gradient of watershed land use. Twelve depth- and width-integrated samples were collected at each site within the 14-week study period. Water samples were filtered (0.7 micrometers) and analyzed for 227 pesticide compounds by direct-injection liquid chromatography with tandem mass-spectrometry, and for glyphosate by Enzyme-Linked Immunoassay (ELISA) in a separate analysis. Potential aquatic toxicity was evaluated using the Pesticide Toxicity Index and by comparison to U.S. Environmental Protection Agency aquatic-life benchmarks. A mesocosm experiment was conducted to investigate the effects of the insecticide imidacloprid on natural stream communities transported to experimental streams in the laboratory, where they were exposed to imidacloprid under controlled conditions. This Data Release provides sampling site locations and watershed characteristics, pesticide analyte information, agricultural pesticide use data, summaries of quality control data, concentration data for pesticide compounds in environmental weekly water samples, and a summary of invertebrate metrics and imidacloprid concentration data from the mesocosm study, in support of the journal article, "Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams," by Nowell, L.H., Moran, P.W., Schmidt, T., Norman, J.E., Nakagaki, N., Shoda, M.E., Mahler, B.J., Van Metre, P.C., Stone, W.W., Sandstrom, M.W., and Hladik, M.L.

Dissolved pesticides were measured in weekly water samples from 100 wadeable streams across eleven states in the Midwestern U.S. during May-August, 2013, as part of the Midwest Stream Quality Assessment study conducted by the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Project. Of the 100 stream sites, 12 were urban indicator sites and the remaining 88 sites were located along an agricultural gradient of watershed land use. Twelve depth- and width-integrated samples were collected at each site within the 14-week study period. Water samples were filtered (0.7 micrometers) and analyzed for 227 pesticide compounds by direct-injection liquid chromatography with tandem mass-spectrometry, and for glyphosate by Enzyme-Linked Immunoassay (ELISA) in a separate analysis. Potential aquatic toxicity was evaluated using the Pesticide Toxicity Index and by comparison to U.S. Environmental Protection Agency aquatic-life benchmarks. A mesocosm experiment was conducted to investigate the effects of the insecticide imidacloprid on natural stream communities transported to experimental streams in the laboratory, where they were exposed to imidacloprid under controlled conditions. This Data Release provides sampling site locations and watershed characteristics, pesticide analyte information, agricultural pesticide use data, summaries of quality control data, concentration data for pesticide compounds in environmental weekly water samples, and a summary of invertebrate metrics and imidacloprid concentration data from the mesocosm study, in support of the journal article, “Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams,” by Nowell, L.H., Moran, P.W., Schmidt, T., Norman, J.E., Nakagaki, N., Shoda, M.E., Mahler, B.J., Van Metre, P.C., Stone, W.W., Sandstrom, M.W., and Hladik, M.L.

This dataset presents the results of 475 unique organic compounds collected from 54 wadeable streams within the Southeastern, USA, collected within 10 weeks during 2014. Maximum and median exposure conditions were evaluated in relation to watershed characteristics and for potential biological effects. This dataset contains the summary statistics (maximum and median concentrations)of detected compounds, as well as a summary of quality-assurance (blanks and replicates) samples. Also included are the statistical summaries as related to analyte specific contaminant detection/concentration data and site-specific land-use matrices, spearman-rank correlations, and ToxCast evaluations.

This dataset presents the results of 475 unique organic compounds collected from 54 wadeable streams within the Southeastern, USA, collected within 10 weeks during 2014. Maximum and median exposure conditions were evaluated in relation to watershed characteristics and for potential biological effects. This dataset contains the summary statistics (maximum and median concentrations)of detected compounds, as well as a summary of quality-assurance (blanks and replicates) samples. Also included are the statistical summaries as related to analyte specific contaminant detection/concentration data and site-specific land-use matrices, spearman-rank correlations, and ToxCast evaluations.

These datasets are one component of the multistressor studies conducted in Midwest streams in 2013 (MSQA) and in Southeast streams in 2014 (SESQA) by the U.S. Geological Survey National Water Quality Assessment Project. High-frequency small-volume autosamplers were deployed at 7 sites each in MSQA and SESQA that collected daily and weekly composite water samples, which were analyzed for 225 pesticides and pesticide degradates. Five of the MSQA autosampler sites were in agricultural watersheds and two in urban watersheds, whereas all seven SESQA autosampler sites were in urban watersheds. The daily and weekly composite samples were compared with results from traditional discrete water samples collected weekly at the sites. Mixtures of pesticides were present in most samples and the Pesticide Toxicity Index (PTI) and acute invertebrate benchmarks were used to evaluate the potential for acute invertebrate toxicity of mixtures. This Data Release provides concentration data for pesticide compounds in environmental weekly and daily composite water samples, pesticide analyte information, summaries of quality control data, and PTI scores, in support of the journal article “Daily-composite stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life,” by Norman, J.E., Mahler, B.J., Nowell, L.H., Van Metre, P.C., Sandstrom, M.W., Corbin, M.A., Qian, Y., Pankow, J.F., Luo, W., Fitzgerald, N.B., Asher, W.E., and McWhirter, K.J.

These datasets are one component of the multistressor studies conducted in Midwest streams in 2013 (MSQA) and in Southeast streams in 2014 (SESQA) by the U.S. Geological Survey National Water Quality Assessment Project. High-frequency small-volume autosamplers were deployed at 7 sites each in MSQA and SESQA that collected daily and weekly composite water samples, which were analyzed for 225 pesticides and pesticide degradates. Five of the MSQA autosampler sites were in agricultural watersheds and two in urban watersheds, whereas all seven SESQA autosampler sites were in urban watersheds. The daily and weekly composite samples were compared with results from traditional discrete water samples collected weekly at the sites. Mixtures of pesticides were present in most samples and the Pesticide Toxicity Index (PTI) and acute invertebrate benchmarks were used to evaluate the potential for acute invertebrate toxicity of mixtures. This Data Release provides concentration data for pesticide compounds in environmental weekly and daily composite water samples, pesticide analyte information, summaries of quality control data, and PTI scores, in support of the journal article “Daily-composite stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life,” by Norman, J.E., Mahler, B.J., Nowell, L.H., Van Metre, P.C., Sandstrom, M.W., Corbin, M.A., Qian, Y., Pankow, J.F., Luo, W., Fitzgerald, N.B., Asher, W.E., and McWhirter, K.J.

Human-use pharmaceutical, pesticide, and wastewater indicator compounds were analyzed at the U.S. Geological Survey, National Water Quality Laboratory, Denver, Colorado, in wadeable streams in 4 Regional Stream Quality Assessments: Northeast (NESQA), Southeast (SESQA), Pacific Northwest (PNSQA) and California (CSQA). Multiple (with few exceptions) samplings occurred at each site, during base flow, between 2014 and 2017. Sites were located in the headwaters of perennial, wadeable streams in urban and agricultural watersheds. Site selection and methodology for each assessment can be found in Van Meter and others (2015), Sheibley and others (2015), Van Meter and others (2017), Coles and others (2016), Van Meter and others (2016), Journey and others (2015), and Van Meter and others (2014). Additional results for this study can be found in Bradley and others, 2020 and Mahler and others, 2020. See cross-reference section for full citation information.