USE OF BIOASSAYS IN ASSESSING HEALTH-HAZARDS FROM COMPLEX-MIXTURES - A RASH ANALYSIS

The Finney harmonic mean model for joint toxicity of ingredients in mi xtures can be used to estimate the toxicity of the neat compound if ea ch component can be substituted in potency-adjusted-doses for any of t he other components. Chemical analysis of constituent substances and t heir associated concentrations and relative toxicological potency valu es (computed according to the RApid Screening of Hazard (RASH) method) . were used to compare the toxicities as predicted from ingredients of cigarette smoke, PAHs in diesel exhaust, asphalt, coal tar, pitch, an d creosote with the measured toxicities of the corresponding neat mixt ures. Accuracy for cigarette smoke condensate, coal tar, pitch, and cr eosote were within a factor of three based on the PAH fraction; asphal t was within a factor of 18; but the PAH fraction of diesel particulat e was again found to be inadequate to describe the composite toxicity of diesel emissions.