Methods used to characterize the chemical composition and biological activity of environmental waters throughout the United States, 2012-14

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Safe drinking water at the point-of-use (tapwater, TW) is a United States public health priority. Multiple lines of evidence were used to evaluate potential human health concerns of 482 organics and 19 inorganics in TW from 13 (7 public supply, 6 private well self-supply) home and 12 (public supply) workplace locations in 11 states. Only uranium (61.9 μg L−1, private well) exceeded a National Primary Drinking Water Regulation maximum contaminant level (MCL: 30 μg L−1). Lead was detected in 23 samples (MCL goal: zero). Seventy-five organics were detected at least once, with median detections of 5 and 17 compounds in self-supply and public supply samples, respectively (corresponding maxima: 12 and 29). Disinfection byproducts predominated in public supply samples, comprising 21% of all detected and 6 of the 10 most frequently detected. Chemicals designed to be bioactive (26 pesticides, 10 pharmaceuticals) comprised 48% of detected organics. Site-specific cumulative exposure−activity ratios (ΣEAR) were calculated for the 36 detected organics with ToxCast data. Because these detections are fractional indicators of a largely uncharacterized contaminant space,ΣEAR in excess of 0.001 and 0.01 in 74 and 26% of public supply samples, respectively, provide an argument for prioritized assessment of cumulative effects to vulnerable populations from trace-level TW exposures.

Section: Introductionmentioning

confidence: 99%

Reconnaissance of Mixed Organic and Inorganic Chemicals in Private and Public Supply Tapwaters at Selected Residential and Workplace Sites in the United States

Bradley

Kolpin

Romanok

et al. 2018

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“…Surface water samples were collected between 2012 and 2015 as a part of a nation-wide survey of U.S. streams or as a part of regional river assessments. Grab samples from the states of Colorado, Illinois, Massachusetts, or Minnesota were collected into 1 L glass bottles following established protocols . Collected samples were shipped overnight on ice and processed within 96 h of sample collection.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…Grab samples from the states of Colorado, Illinois, Massachusetts, or Minnesota were collected into 1 L glass bottles following established protocols. 18 Collected samples were shipped overnight on ice and processed within 96 h of sample collection. The water samples were filtered through 0.7 μm glass-fiber filters followed by extraction by Oasis HLB glass cartridges.…”

Section: T H Imentioning

confidence: 99%

Harmonized Cross-Species Assessment of Endocrine and Metabolic Disruptors by Ecotox FACTORIAL Assay

Medvedev

Medvedeva

Martsen

et al. 2020

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Environmental pollution is a threat to humans and wildlife species. Of particular concern are endocrine disrupting chemicals (EDCs). An important target of EDCs is nuclear receptors (NRs) that control endocrine and metabolic responses through transcriptional regulation. Owing in part to structural differences of NRs, adverse effects of EDCs vary significantly among species. Here, we describe a multiplexed reporter assay (the Ecotox FACTORIAL) enabling parallel assessment of compounds’ effects on estrogen, androgen, thyroid, and PPARγ receptors of representative mammals, birds, reptiles, amphibians, and fish. The Ecotox FACTORIAL is a single-well assay comprising a set of species-specific, one-hybrid GAL4-NR reporter constructs transiently transfected into test cells. To harmonize cross-species assessments, we used a combination of two approaches. First, we used the same type of test cells for all reporters; second, we implemented a parallel detection of reporter RNAs. The assay demonstrated excellent quality, reproducibility, and insignificant intra-assay variability. Importantly, the EC50 values for NR ligands were consistent with those reported for conventional assays. Using the assay allowed ranking the hazard potential of environmental pollutants (e.g., bisphenols, polycyclic aromatic hydrocarbons, and synthetic progestins) across species. Furthermore, the assay permitted detecting taxa-specific effects of surface water samples. Therefore, the Ecotox FACTORIAL enables harmonized assessment of the endocrine and metabolic disrupting activity of chemicals and surface water in humans as well as in wildlife species.

“…A single grab sample was collected from the center of flow from each stream from November 2012 to June 2014. Most samples were homogenized in Teflon churns, and individual aliquots were shipped to various USGS and EPA laboratories . Samples that were shipped to the EPA-Athens laboratory for the vertebrate cell-based metabolomic analyses reported here were received frozen in 500 mL high-density polyethylene bottles and stored at −20 °C prior to cell culture exposures.…”

Section: Methodsmentioning

confidence: 99%

“…Details of site selection and site descriptions, along with those of water sampling and chemical analysis methods, have been published elsewhere. 11 Briefly, the USGS selected 34 stream sites that were impacted by human activity along with four underdeveloped (or "reference") sites that were expected to have low anthropogenic organic loads, across 24 U.S. States and Puerto Rico based on previous chemical monitoring studies. The goal was to select sites that spanned a wide range of agricultural uses and/or urban development.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Cell-Based Metabolomics for Untargeted Screening and Prioritization of Vertebrate-Active Stressors in Streams Across the United States

Collette

Ekman

Zhen

et al. 2019

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The U.S. Geological Survey and the U.S. Environmental Protection Agency have assessed contaminants in 38 streams across the U.S., using an extensive suite of target-chemical analysis methods along with a variety of biological effects tools. Here, we report zebrafish liver (ZFL) cell-culture based NMR metabolomic analysis of these split stream samples. We used this untargeted approach to evaluate the sites according to overall impact on the ZFL metabolome and found that neither the total number of organics detected at the sites, nor their cumulative concentrations, were good predictors of these impacts. Further, we used partial least squares regression to compare ZFL endogenous metabolite profiles to values for 455 potential stressors (organics, inorganics, and physical properties) measured in these waters and found that the profiles covaried with at most 280 of the stressors, which were subsequently ranked into quartiles based on the strength of their covariance. While contaminants of emerging concern (CECs) were well represented in the top, most strongly covarying quartilesuggesting considerable potential for eliciting biological responses at these sitesthere was even higher representation of various well-characterized legacy contaminants (e.g., PCBs). These results emphasize the importance of complementing chemical analysis with untargeted bioassays to help focus regulatory efforts on the most significant ecosystem threats.