Perspectives on cumulative risks and impacts

Cumulative risks and impacts have taken on different meanings in different regulatory and programmatic contexts at federal and state government levels. Traditional risk assessment methodologies, with considerable limitations, can provide a framework for the evaluation of cumulative risks from chemicals. Under an environmental justice program in California, cumulative impacts are defined to include exposures, public health effects, or environmental effects in a geographic area from the emission or discharge of environmental pollution from all sources, through all media. Furthermore, the evaluation of these effects should take into account sensitive populations and socioeconomic factors where possible and to the extent data are available. Key aspects to this potential approach include the consideration of exposures (versus risk), socioeconomic factors, the geographic or community-level assess-ment scale, and the inclusion of not only health effects but also environmental effects as contributors to impact. Assessments of this type extend the boundaries of the types of information that toxicologists generally provide for risk management decisions. Keywords cumulative risk, cumulative impact, environmental justice, environmental policy, environmental regulation, socioeconomic factors The assessment of potential human health and environmental impacts created by exposures to multiple chemical pollutants presents a challenge both to those charged with assessing th