POTENTIAL ECOTOXIC EFFECTS PROBE (PEEP) - A NOVEL INDEX TO ASSESS AND COMPARE THE TOXIC POTENTIAL OF INDUSTRIAL EFFLUENTS

An index allowing the assessment and comparison of the toxic potential of industrial effluents is described. Integrating the results of practical small-scale screening bioassays (Photobacterium phosphoreum Microtox(R) test, Selenastrum capricornutum growth inhibition microtest, Ceriodaphnia dubia lethality and reproduction inhibition tests, Escherichia coli genotoxicity SOS Chromotest), this index takes into account persistence of toxicity, (multi)specificity of toxic impact, as well as effluent flow. The resulting Potential Ecotoxic Effects Probe (PEEP) index number is reflected by a log10 value that varies from 0 to infinity but normally will not surpass a value of 10. The structure of the mathematical formula generating PEEP values is simple and ''user friendly'' in that it can accommodate numbers and types of bioassays to fit particular needs. Thirty-seven effluents from 8 industrial sectors (pulp and paper, petroleum refining, inorganic/organic chemical production, mining, metallurgy, metal plating, textile production) were appraised and compared with the proposed PEEP scale. The pulp and paper sector effluents (n = 15) markedly stood out from the others owing to their greater toxicity and higher discharge volume, with reported PEEP values lying between 4.4 and 7.5. For most of these effluents, toxicity was found to be persistent, multitrophic (i.e., affecting our bacterial, algal, and crustacean bioindicators), and it expressed itself at all levels of assessment (i.e., lethal, acute sublethal, chronic sublethal, and genotoxic levels). The usefulness of the PEEP index in the environmental management of industrial effluent toxicity is discussed herein.