EVALUATION OF INDUSTRIAL WASTE-WATER QUALITY WITH A CHEMILUMINESCENT PEROXIDASE-ACTIVITY ASSAY

The potential toxicity of industrial wastewater, or effluent, was eval uated with a very rapid and sensitive chemiluminescent peroxidase assa y. The assay, based on the peroxidase-catalyzed oxidation of luminol b y hydrogen peroxide, is responsive to the presence of radical scavenge rs and enzyme-inhibiting substances. The chemical competition of the c hemicals between DNA and the chemiluminescent peroxidase reaction was also investigated in order to evaluate the DNA-binding properties of t hese where DNA binding may lead to harmful adducts. The assay is rapid , requiring only 2-5 min incubation with the test sample at 21 degrees C. For the DNA competition assay, DNA was added to the test sample 15 min before the incubation step in order to evaluate reversal of light inhibition or protection of luminescence. Of the 21 industrial efflue nts studied, 76% had an inhibiting effect on light emission, suggestin g that these effluents are probably toxic. Indeed, it was found that t hese effluents were toxic with at least one of the following: the Micr otox assay, the rainbow trout lethality test, and Ceriopdaphnia dubia survival/reproduction tests. It was found that this assay complied rel atively well (60%) with the Microtox toxicity test, suggesting that th e light inhibiting effects of the effluent correspond to toxic effects in bacteria. The addition of DNA to the reaction mixture prevented in hibition of light emission (i.e., DNA has a protective effect) in 29% of the effluents tested, suggesting that these effluents contained pot entially genotoxic chemicals. Moreover, DNA-reactive effluents proved to be genotoxic to Escherichia coli (SOS Chromotest) most of the time (70%), suggesting that DNA competition is also related to DNA damage. No effluent displayed genotoxicity with the SOS Chromotest and did not show DNA binding with the chemiluminescent peroxidase assay. The chem iluminescent peroxidase assay may be used for prescreening studies whe n the number of test samples is very high or when information about th e potential (geno)toxicity is urgently needed. (C) 1997 by John Wiley & Sons, Inc.