Factors Affecting Sampling Strategies for Design of an Effects-Directed Analysis for Endocrine-Active Chemicals

Toxicity Evaluation and Effect-Based Identification of Chlorine Disinfection Products of the Anti-COVID-19 Drug Chloroquine Phosphate

Antiviral transformation products (TPs) generated during wastewater treatment are an environmental concern, as their discharge, in considerable amounts, into natural waters during a pandemic can pose possible risks to the aquatic environment. Identification of the hazardous TPs generated from antivirals during wastewater treatment is important. Herein, chloroquine phosphate (CQP), which was widely used during the coronavirus disease-19 (COVID-19) pandemic, was selected for research. We investigated the TPs generated from CQP during water chlorination. Zebrafish (Danio rerio) embryos were used to assess the developmental toxicity of CQP after water chlorination, and hazardous TPs were estimated using effect-directed analysis (EDA). Principal component analysis revealed that the developmental toxicity induced by chlorinated samples could be relevant to the formation of some halogenated TPs. Fractionation of the hazardous chlorinated sample, along with the bioassay and chemical analysis, identified halogenated TP387 as the main hazardous TP contributing to the developmental toxicity induced by chlorinated samples. TP387 could also be formed in real wastewater during chlorination in environmentally relevant conditions. This study provides a scientific basis for the further assessment of environmental risks of CQP after water chlorination and describes a method for identifying unknown hazardous TPs generated from pharmaceuticals during wastewater treatment.

Comparison of Two Estrogen Chemically Activated Luciferase Expression Cell Bioassays to Liquid Chromatography-Mass Spectrometry for Quantifying Estrone in Water Samples

Chemically activated luciferase expression (CALUX) cell bioassays are popular tools for assessing endocrine activity of chemicals such as certain environmental contaminants. Although activity equivalents can be obtained from CALUX analysis, directly comparing these equivalents to those obtained from analytical chemistry methods can be problematic because of the complexity of endocrine active pathways. We explored the suitability of two estrogen CALUX bioassays (the Organisation for Economic Co-operation and Development-approved VM7Luc4E2 cell bioassay and the VM7LucERβc9 cell bioassay) for quantitation of estrogen. Quadrupole-time of flight ultraperformance liquid chromatography-mass spectrometry (LC/MS) was selected as a comparative method. Regression analysis of measured estrone (E1) calibration samples showed all three methods to be highly predictive of nominal concentrations (p ≤ 7.5 × 10-51 ). Extracts of water sampled from laboratory dilutor tanks containing E1 at 0, 20, and 200 ng/L alone and in combination with atrazine were selected to test the quantitative capabilities of the CALUX assays. Process controls (0 and 100 ng E1/L) and a separate E1 standard (10 ng/ml, used to prepare the E1 process control) were also tested. Levels of E1 determined by LC/MS analysis and bioanalytical equivalents (ng E1/L) determined by CALUX analyses were comparable except in certain instances where the samples required dilution prior to CALUX analyses (e.g., the E1 process control and E1 standard). In those instances, measurements by CALUX were slightly but significantly decreased relative to LC/MS. Atrazine had no effect on the ability of either LC/MS or the CALUX bioassays to quantify E1. The present study illustrates the CALUX bioassays as successful in quantifying an estrogen in simple water samples and further characterizes their utility for screening. Environ Toxicol Chem 2023;42:333-339. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.

Substances of emerging concern in Baltic Sea water: Review on methodological advances for the environmental assessment and proposal for future monitoring

The Baltic Sea is among the most polluted seas worldwide. Anthropogenic contaminants are mainly introduced via riverine discharge and atmospheric deposition. Regional and international measures have successfully been employed to reduce concentrations of several legacy contaminants. However, current Baltic Sea monitoring programs do not address compounds of emerging concern. Hence, potentially harmful pharmaceuticals, UV filters, polar pesticides, estrogenic compounds, per- and polyfluoroalkyl substances, or naturally produced algal toxins are not taken into account during the assessment of the state of the Baltic Sea. Herein, we conducted literature searches based on systematic approaches and compiled reported data on these substances in Baltic Sea surface water and on methodological advances for sample processing and chemical as well as effect-based analysis of these analytically challenging marine pollutants. Finally, we provide recommendations for improvement of future contaminant and risk assessment in the Baltic Sea, which revolve around a combination of both chemical and effect-based analyses.

Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Identifying Chemicals and Mixtures of Potential Biological Concern Detected in Passive Samplers from Great Lakes Tributaries Using High-Throughput Data and Biological Pathways

Waterborne contaminants were monitored in 69 tributaries of the Laurentian Great Lakes in 2010 and 2014 using semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS). A risk-based screening approach was used to prioritize chemicals and chemical mixtures, identify sites at greatest risk for biological impacts, and identify potential hazards to monitor at those sites. Analyses included 185 chemicals (143 detected) including polycyclic aromatic hydrocarbons (PAHs), legacy and current-use pesticides, fire retardants, pharmaceuticals, and fragrances. Hazard quotients were calculated by dividing detected concentrations by biological effect concentrations reported in the ECOTOX Knowledgebase (toxicity quotients) or ToxCast database (exposure-activity ratios [EARs]). Mixture effects were estimated by summation of EAR values for chemicals that influence ToxCast assays with common gene targets. Nineteen chemicals-atrazine, N,N-diethyltoluamide, di(2-ethylhexyl)phthalate, dl-menthol, galaxolide, p-tert-octylphenol, 3 organochlorine pesticides, 3 PAHs, 4 pharmaceuticals, and 3 phosphate flame retardants-had toxicity quotients >0.1 or EARs for individual chemicals >10^-3 at 10% or more of the sites monitored. An additional 4 chemicals (tributyl phosphate, triethyl citrate, benz[a]anthracene, and benzo[b]fluoranthene) were present in mixtures with EARs >10^-3 . To evaluate potential apical effects and biological endpoints to monitor in exposed wildlife, in vitro bioactivity data were compared to adverse outcome pathway gene ontology information. Endpoints and effects associated with endocrine disruption, alterations in xenobiotic metabolism, and potentially neuronal development would be relevant to monitor at the priority sites. The EAR threshold exceedance for many chemical classes was correlated with urban land cover and wastewater effluent influence, whereas herbicides and fire retardants were also correlated to agricultural land cover. Environ Toxicol Chem 2021;40:2165-2182. Published 2021. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.