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S. Alex. Covert

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In 2015–16, the U.S. Geological Survey, in cooperation with the Muskingum Watershed Conservancy District, led a study to assess baseline (2015–16) surface-water quality in six lake drainage basins within the Muskingum River watershed that are in the early years of shale-gas development. In 2015, 9 of the 10 most active counties in Ohio for oil and gas development were wholly or partially within the Muskingum River watershed. In addition to shale gas development, the area has a history of conventional oil and gas development and coal mining.In all, 30 surface-water sites were sampled: 20 in tributaries flowing to the lakes, 4 in lakes themselves, and 6 downstream of the lakes. At each of the 30 sites, 6 samples were...
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In 2015-16, the U.S. Geological Survey (USGS), in cooperation with the Muskingum Watershed Conservancy District, conducted a study to assess baseline (2015-16) surface-water quality in six lake basins within the Muskingum River watershed that are in the early years of shale-gas development. Six samples were collected at each of 30 sites to characterize surface-water chemistry over a range of hydrologic conditions. Quality-control (QC) samples collected before and during sampling included blanks and replicates. Blank samples were used to check for contamination during sample collection, processing, equipment cleaning, and/or analysis. Replicate samples were used to determine the reproducibility/variability in the...
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During 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, collected water samples year-round from the National Water Quality Network – Rivers and Streams (NWQN) and reported on 221 pesticides at 72 sites across the US in agricultural, developed, and mixed land use watersheds. Pesticide Toxicity Index (PTI) scores, a screening-level tool that uses an additive, toxic-unit model, were calculated to estimate the potential chronic and acute toxicity to 3 taxonomic groups – fish, cladocerans, and benthic invertebrates. The pesticide that makes the single largest (maximum) contribution to the PTI is called TUmax. This dataset consists of the PTI and TUmax scores, as well as, the TUmax...
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