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Person

Mark W Sandstrom


Office of the Chief Operating Officer

Email: sandstro@usgs.gov
Office Phone: 303-236-3943
ORCID: 0000-0003-0006-5675
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This data release includes tables and plots of results for pesticide compounds (pesticides and degradates) analyzed in groundwater samples collected by the USGS National Water-Quality Assessment Project during water years 2013-18 and in associated quality-control samples that are used to assess the quality of the reported pesticide results. All samples were analyzed by the USGS National Water Quality Laboratory (NWQL) using laboratory schedule 2437. The table of groundwater data includes pesticide results as reported by the laboratory, along with results that represent the application of censoring levels at the 90-percent upper confidence limit of the 95th percentile of laboratory blank concentrations determined...
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Dissolved pesticides were measured in weekly water samples from 482 wadeable streams in five regions of the United States during 2013-2017, as part of the U.S. Geological Survey's (USGS) Regional Stream Quality Assessment (RSQA). One study was conducted each year, starting with the Midwest (2013), followed by the Southeast Piedmont (2014), Pacific Northwest (2015), Northeast (2016), and Central California Coast (2017). Within each region, 77-100 streams were sampled over 6-14 weeks, followed by ecological surveys of fish, invertebrate and fish communities. The first study (Midwest) is an agricultural-gradient study, where the majority of sites were located along a gradient from undeveloped to 100% agricultural land...
Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Alabama, California, Central California Foothills ecoregion, Coastal Mountains ecoregion, Connecticut, All tags...
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In 2013, the U.S. Geological Survey and the U.S. Environmental Protection Agency characterized water-quality stressors and ecological conditions in 100 wadeable streams across the Midwestern United States. The goal of the study was to determine the relative effects of multiple ecological stressors – contaminants, nutrients, sediment, and habitat – on ecological communities in the streams. The Midwest is an intensely agricultural region where pesticides in streams pose risks to aquatic biota, but temporal variability in pesticide concentrations makes characterization of their exposure to organisms challenging. To compensate for the effects of temporal variability, we deployed polar organic chemical integrative samplers...
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This data release includes tables and time-series plots of results for volatile organic compounds (VOCs) analyzed in samples of groundwater used for public supply that were collected by the USGS National Water-Quality Assessment (NAWQA) Project and the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) during 2013-19; results for associated quality-control samples also are included. All samples were analyzed by the USGS National Water Quality Laboratory (NWQL) using laboratory schedules 4436 and 4437. The table of groundwater data includes VOC results as reported by the laboratory, along with results that represent the application...
Analytical recovery is the concentration of an analyte measured in a water-quality sample expressed as a percentage of the known concentration added to the sample (Mueller and others, 2015). Analytical recovery (hereafter referred to as “recovery”) can be used to understand method bias and variability and to assess the temporal changes in a method over time (Martin and others, 2009). This data set includes two tables: one table of field spike recovery data and one table of lab reagent spike recovery data. The table of field spike recovery data includes results from paired environmental and spike samples collected by the National Water Quality Program, National Water-Quality Assessment (NAWQA) Project in surface...
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