ABSTRACT
Potential toxicants are present in air, water, and food. "Toxicant" refers to any synthetic or natural chemical which can produce adverse health effects (see Appendix 1 for a Glossary of Terms, Abbreviations, and Acronyms). Several federal agencies evaluate potential health effects and establish standards of exposure. Each agency uses a variation of a methodology generally referred to as risk assessment. This process includes:
• characterization of the types of health effects expected • characterization of exposure • evaluation of experimental studies (animal and/or epidemiologic) • characterization of the relationship between dose and response • estimation of the risk (synonyms: probability, frequency) of occurrence
of health effects • estimation of the number of cases expected • characterization of the uncertainty of the analysis • recommendation of an acceptable concentration in air, food, or water
Risk assessments are necessary for informed regulatory decisions regarding:
• worker exposures • industrial emissions and effluents • ambient air and water contaminants • chemical residues in foods • cleanup of hazardous waste sites • naturally occurring contaminants
It is important to encourage diversity of risk assessment methodology. This helps to ensure that all possible risk models and outcomes have been considered and minimizes the potential for error. By the late 1980s, federal
agencies had created their own standardized risk assessment methodologies. The ''standardization'' of the risk assessment process is almost a contradiction in terms. Each scenario of exposure has unique characteristics which makes the application of a uniform methodology problematic. In 1990, the Environmental Protection Agency (EPA) announced that only the EPA's risk assessments were to have regulatory standing regarding the management of Superfund sites. Risk assessments are used to determine appropriate cleanup techniques and acceptable levels of residual contamination. Critics labeled EPA as having become arrogant in the area of risk assessment. This type of regulatory approach leads to isolation, mistakes, and stagnation. The process of risk assessment can only benefit from the contributions of many disciplines and viewpoints. It is highly likely that EPA will change its position and allow all impacted parties to contribute to the decision-making process.
