Chemical toxicity indicators for human health: case study for classification of chronic noncancer chemical hazards in life-cycle assessment.
The classification scheme for human health indicators in life-cycle assessment (LCA) and other toxicity scores is proposed based on identifiable target organ or system toxicity. This scheme represents a compromise between a subjective single overall score and highly detailed toxic mechanisms of action. A case study was used to evaluate the proposed classification scheme. The data on 117 high production volume organic chemicals were extracted from the U.S. Environmental Protection Agency (U.S. EPA) integrated risk information system (IRIS) database. Based on the critical effect listed in the database, almost all chemicals were easily and clearly classified into the proposed categories. However, there were significant variations in test species, protocol, duration, toxicological parameter measured, etc., among different toxicity studies. Importantly, the toxicological critical effects observed, even for the same target organ or system, differed from chemical to chemical and were not equivalent. Using hepatotoxicity as an example, critical effects included changes in organ weight, a variety of different histopathological changes, and changes in circulating hepatic enzyme levels. Therefore, no universal, common basis was identified for biological equivalency in order to compare or to aggregate chemicals into an overall toxicity score. A recent proposal to develop a characterization system based on disability-adjusted life years (DALYs) was also evaluated. No means were found to extrapolate animal critical effects data to predict any diminution in human lifetimes or the appearance and intensity of human disability. Still, LCA presents an ideal starting point for toxicological analysis by conducting a system-wide analysis that inventories and maps the sources of potentially important human pollutants. The LCA results could then facilitate initial toxicological and risk evaluations for those sources and chemicals and set the stage for a more detailed and informed analysis by professional toxicologists.
Owens
J William
JW
Central Product Safety, Procter & Gamble, Cincinnati, Ohio 45253, USA. owens.jw@pg.com
D016208:Databases, Factual; D015386:Hazardous Substances / Q000009:adverse effects* / Q000145:classification; D006801:Humans; D019057:Quality-Adjusted Life Years; D018570:Risk Assessment
D015386:Hazardous Substances