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Evaluating risk, exposure, and detection capabilities for chemical threats in water
Citation:
Pfohl, M., E. Silvestri, J. Lipscomb, E. Snyder, AND S. Willison. Evaluating risk, exposure, and detection capabilities for chemical threats in water. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH - PART A: CURRENT ISSUES. Taylor & Francis, Inc., Philadelphia, PA, 85(15):622-647, (2022). https://doi.org/10.1080/15287394.2022.2064949
Impact/Purpose:
The unexpected release of chemicals into the environment poses issues to the rapid, accurate and transparent estimation of human health risks, followed closely by mitigation actions consistent with risk management decisions. One part of a mitigation response involves the development and application of analytical chemical methods that have a sensitivity sufficient to detect environmental concentrations of priority toxicants. When the environmental concentrations of toxicants are associated with health risk, the limit for analytical measurement should ideally be at or below the risk threshold. A comparison of the risk-relevant environmental concentrations with analytical detection capability must be made on a consistent basis, e.g., relative to concentrations of the toxicant in drinking water. This study focused on priority chemical contaminants with the potential to cause significant and acute human health impacts from oral consumption of contaminated drinking water, including chemicals identified in both the Environmental Protection Agency’s (EPA) Candidate Contaminant List, version 4 (CCL4) and EPA’s Selected Analytical Methods (SAM) document. This analysis indicated that six chemicals (aniline, VX, EA2192, 1,2,3-trichloropropane, N-nitrosopyrrolidine (NPYR), and N-nitrosodiethylamine (NDEA)) do not have analytical detection limits low enough to reliably measure concentrations that are associated with their chronic risk values. Analytical methods for two chemicals (NDEA and NPYR) are estimated to lack sufficient sensitivity to identify their presence at water concentrations relevant to acute risk or risk management decisions. These gaps highlight a need for analytical method research to achieve detection limits that will meet EPA’s water contamination preparedness objectives.
Description:
The U.S. Environmental Protection Agency was developed to protect human health and the environment by ensuring the nation has clean air, land, and water. Towards this effort, the Agency provides scientific solutions through the development of analytical methods and risk-based health levels for hazardous chemical contaminants in the environment, including drinking water. Appropriate analytical methods need to possess adequate sensitivity to be able to measure at or below risk-based health levels for water. Given the sheer number of chemicals in commerce, it is not feasible to derive drinking water risk values and develop adequately sensitive analytical methods for all chemicals that may potentially contaminate drinking water. For the purposes of this paper, EPA priorities dictated the use of specific chemical lists, such as EPA's Fourth Contaminant Candidate List (CCL 4) and EPA’s Selected Analytical Methods (SAM) document, to highlight the current gaps for priority chemicals with the potential to cause significant and acute human health impacts from oral consumption of contaminated drinking water. Twenty-four chemicals were identified from the lists based on adherence to defined selection criteria. The criteria required the chemicals exist as a liquid or a solid, possess acute oral toxicity, defined as LD50 ≤ 500 mg/kg, and moderately high to high solubility, defined as ≥ 500 mg/L. Available data on existing oral toxicity or risk values and detection limits for analytical methods were collected and the most appropriate values were identified. Each of the twenty-four chemicals was assigned to one of four categories that characterize the gap that would impede informed response to a chemical contamination incident. Out of the twenty-four chemicals that present an acutely toxic threat to drinking water, gaps were identified for ten chemicals associated with currently available risk values and/or the analytical sensitivity required to be protective of human health. Category 1, 2, and 3 chemicals highlight current research that is needed to meet EPA’s water contamination preparedness objectives.
URLs/Downloads:
DOI: Evaluating risk, exposure, and detection capabilities for chemical threats in water
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