ESTIMATING TOTAL-BODY RESIDUES AND BASE-LINE TOXICITY OF COMPLEX ORGANIC MIXTURES IN EFFLUENTS AND SURFACE WATERS

Recently, a new procedure was developed to estimate total body residue s (TBRs) in biota after exposure to complex mixtures of organic chemic als in water. The procedure is based on a simulation of bioconcentrati on using a hydrophobic phase and on the measurement of total molar con centrations on this hydrophobic phase via vapor pressure osmometry and gas chromatography-mass spectrometry. In this paper, the results of t he application of this procedure to effluents and surface water are pr esented. Estimated TBRs (TBR(est)s) give information on the potential total bioaccumulation of complex mixtures. Moreover, using these estim ated total body burdens, baseline toxicity effects can be predicted, i ncluding the contributions of chemicals with specific modes of action to the overall baseline toxicity. The advantage of the parameter TBRes t is that it determines total molar concentrations of organic chemical s, including those chemicals that are usually not measured because the y cannot be identified or because their concentrations are below the d etection limits of individual compounds.