A FRAMEWORK FOR ASSESSING PUBLIC-HEALTH RISKS OF PESTICIDE-CONTAMINATED GROUNDWATER

The long-term health risk assessments for three commonly used pesticid es are presented in this paper. These pesticides, alachlor, lindane, a nd parathion, have been detected in groundwater monitoring wells and a re suspected carcinogens. A multimedia transport model is employed to predict the long-term fate of these chemicals in the environment. Conc entrations in each environmental compartment are calculated and used t o determine the dominant exposure pathways and, hence, the dose rate. The public health risk is then quantified using a modified time averag ed cancer potency factor. The effect of using the average dose rate ov er a lifetime (steady-state) as a representative measure of exposure t o carcinogens is investigated by comparing the multistage time-depende nt low dose excess risk to the constant dose lifetime risk. A correcti on factor is introduced so that a simple calculation based on steady-s tate exposure can be used for estimating the long-term health risk. Th e methods presented in this paper can be used as screening tools for d esigning remediation, mitigation or interdiction measures and can serv e as a basis for evaluating risk management strategies.