INTEGRATED APPROACH FOR ENVIRONMENTAL ASSESSMENT OF NEW AND EXISTING SUBSTANCES

To ensure the environmental safety of new and existing substances, the environmental fate and potential effects resulting from their release into the environment must be assessed. This requires the development of reasonable, consistent, and effective methods to conduct environmen tal risk assessments and to prioritize testing for these substances. T his assessment must integrate fate and effects at the point-of-entry; it should also extend to an assessment of the potential to persist, an d the consequences of increases in exposure concentrations, and to bio accumulate. The conventional environmental risk assessment approach is used to assess the fate and effects of a substance at its point-of-en try into the environment. In this paper, an approach is presented for conducting quantitative environmental risk assessments of new and exis ting substances that builds on this conventional, approach by includin g quantitative assessment of the potential for, and consequences of, p ersistence and bioaccumulation. The approach is described for aquatic, sediment, and terrestrial environments. For each environmental compar tment, the approach includes (i) classification of the substance, base d on environmental partitioning processes, to ensure that the appropri ate data are collected and models used; (ii) a fate assessment to unde rstand the ultimate fate of the substance after entry into the environ ment or ''an environmental compartment'' and to predict the exposure c oncentration of the substance at point-of-entry; (iii) a persistence a ssessment which determines the potential for increase in the exposure concentration as a result of repeated additions of the substance; (iv) effects assessment; (v) environmental risk assessment to examine the potential for adverse impact on ecosystems; and (vi) a bioaccumulation assessment to evaluate the potential for direct and indirect effects on the species of interest due to bioaccumulation. The assessment appr oach is illustrated using data for a hypothetical consumer product sub stance that is disposed down-the-drain. (C) 1995 Academic Press, Inc.