Potential Toxicity of Complex Mixtures in Surface Waters from a Nationwide Survey of United States Streams: Identifying in Vitro Bioactivities and Causative Chemicals

Abstract

While chemical analysis of contaminant mixtures remains an essential component of environmental monitoring, bioactivity-based assessments using in vitro systems increasingly are used in the detection of biological effects. Historically, in vitro assessments focused on a few biological pathways, for example, aryl hydrocarbon receptor (AhR) or estrogen receptor (ER) activities. High-throughput screening (HTS) technologies have greatly increased the number of biological targets and processes that can be rapidly assessed. Here we screened extracts of surface waters from a nationwide survey of United States streams for bioactivities associated with 69 different end points using two multiplexed HTS assays. Bioactivity of extracts from 38 streams was evaluated and compared with concentrations of over 700 analytes to identify chemicals contributing to observed effects. Eleven primary biological end points were detected. Pregnane X receptor (PXR) and AhR-mediated activities were the most commonly detected. Measured chemicals did not completely account for AhR and PXR responses. Surface waters with AhR and PXR effects were associated with low intensity, developed land cover. Likewise, elevated bioactivities frequently associated with wastewater discharges included endocrine-related end points ER and glucocorticoid receptor. These results underscore the value of bioassay-based monitoring of environmental mixtures for detecting biological effects that could not be ascertained solely through chemical analyses.

Assessing the Ecological Risks of Per‐ and Polyfluoroalkyl Substances: Current State‐of‐the Science and a Proposed Path Forward

“…In that study, the in vitro HTP Attagene system described in Section 5 of this paper was used to evaluate pathwaybased bioactivities of 38 surface water samples from around the US, which also had been subjected to extensive instrumental analytical characterization. Blackwell et al (2018)…”

Mutagenicity assessment downstream of oil and gas produced water discharges intended for agricultural beneficial reuse

“…Many PW treatment studies have focused on a "treat for use" approach. As such, assay trigger values should be defined for different downstream users (Blackwell et al, 2019).…”

“…endocrine disruption, mutagenicity, etc.) are elevated in surface water downstream of partially treated industrial discharges and wastewater treatment plant (WWTP) effluents (Ohe et al, 2004;Blackwell et al, 2019). Additionally, studies have demonstrated both acute and chronic toxicity in organisms exposed to PW and its constituents (Blewett et al, 2017;Cozzarelli et al, 2017;Folkerts et al, 2017aFolkerts et al, , 2017bHe et al, 2017aHe et al, , 2017bKassotis et al, 2014Kassotis et al, , 2015Kassotis et al, , 2016a.…”

Assessment of pesticides in surface water samples from Swedish agricultural areas by integrated bioanalysis and chemical analysis

“…The use of in vitro bioassays for environmental monitoring is a rapidly expanding field of research [15][16][17][18][19][20][21][22][23][24][25]. While the bioassays cannot discriminate between the toxic effects of two or more compounds that are present in the same sample, the great strength with bioassays is that they show the total toxicity exerted by a sampleregardless whether the toxicity is caused by a known anthropogenic compound, an unknown anthropogenic compound, a naturally occurring compound, or a combination of these [6,26,27].…”

“…While the bioassays cannot discriminate between the toxic effects of two or more compounds that are present in the same sample, the great strength with bioassays is that they show the total toxicity exerted by a sampleregardless whether the toxicity is caused by a known anthropogenic compound, an unknown anthropogenic compound, a naturally occurring compound, or a combination of these [6,26,27]. The contribution of micropollutants to the bioactivity in surface water affected by wastewater has been evaluated in recent studies, showing that the major part of the bioactivities cannot be explained by target compounds [16,22,[28][29][30][31][32]. Bioanalytical studies focusing on pesticides in water from agricultural areas are scarce.…”