Chapter 35: Risk Assessment Workgroup Report

Risk assessment is a four–stage process used in evaluating the impact of contaminants on the well being of individuals, populations and/or the physical environment. As defined by the National Academy of Sciences (1983), the four components are as follows: hazard identification, dose– response assessment, exposure assessment and risk characterization. The goal of a risk assessment is to utilize existing information coupled with site specific data to quantitatively characterize the potential risk of a stressor to an identified receptor(s). Quantitative risk–based estimates of dose–response relationships integrated with exposure scenarios and information on environmental conditions often become the basis for regulatory measures or management policies to protect the population or physical environment from harm. The precision of the guideline value is impacted by the quantity and quality of scientific data available because uncertainty factors are applied in its derivation to compensate for deficiencies in the database. The more comprehensive the database, the lower the uncertainty in the risk assessment and the more precise the value generated. Risk assessments are one tool used by risk managers when choosing between various options for protecting human health and the environment. They play a significant role in risk management decisions. However, the physical and societal environment is complex. It includes a multitude of