INVESTIGATIONS INTO USING THE NEMATODE CAENORHABDITIS-ELEGANS FOR MUNICIPAL AND INDUSTRIAL WASTE-WATER TOXICITY TESTING

This investigative study assesses the ease and usefulness of the nemat ode Caenorhabditis elegans for identifying contributors to effluent to xicity within an industrial and municipal wastewater treatment plant ( WWTP) system. Several different types of industries, including fibergl ass manufacturing, paper packaging, and yarn dyeing, discharge effluen t into the municipal wastewater treatment plant, which in turn dischar ges into a local creek. A major objective of this study was to identif y primary sources of toxicity throughout the system with a nematode to xicity test. Twenty-four-hour composite water samples were taken perio dically over a ten-month period at five strategic points within the sy stem: (1) at the point of discharge at each of the three industries, ( 2) at the combined industrial influent of the wastewater treatment pla nt, (3) at the effluent of the WWTP (4) upstream of the WWTP discharge , and (5) downstream of the WWTP discharge. Samples were analyzed for basic water chemistry. and each sample was tested for whole effluent t oxicity using a 72-h nematode test with mortality as the end point. Re sults suggest that interactions between the wastewaters of certain ind ustries may increase the overall nematode toxicity in the wastewater t reatment facility's composite influent and effluent. Nematode mortalit y trends indicate relatively high toxicity levels in wastewater enteri ng the WWTP from contributing industries. High WWTP influent toxicity may potentially be due to varying flow rate ratios of industrial disch arges, release of varying toxic constituents in wastewaters, and toxic interactions between chemical constituents of industrial wastewaters. The evaluation of toxicity within the treatment system may pinpoint l ocations where pollution prevention strategies may be implemented to r educe overall toxicity at the point of discharge.