Risk assessments in the pesticide regulatory process

The risk assessment process offers regulators, registrants, public interest groups and users a means of weighing apparent health effects of pesticides and other chemicals, and measuring their safety for use. This report contains the method for developing relative measures of safety for acute toxicity and expressions of risk for chronic toxicity and assesses-human exposure under a variety of extreme scenarios. Since workplace exposures usually exceed environmental exposures by two or more orders of magnitude, occupational experience with pesticides is critical to the regulatory process. Default assumptions, the adoption of conventional numbers in the absence of empirical data, for factors such as dermal absorption, metabolism, clearance and worker protective measures that seem conservative may weaken the reliability of the risk characterization process and may reduce the likelihood of recognizing significant risk. An exposure-based regulatory policy should feature measurements of absorbed dose validated using biomonitoring and margins of safety and estimates of risk that reflect human experience. This paper lists basic characteristics of unit processes of risk assessment and presents some strategies and pitfalls of the process as practiced in California in recent years.