Assessing toxicity of two industrial zone effluents reaching Kelani River,Sri Lanka

Abstract

Evaluation of the effcaey of waste treatment technologies of industnal waste is a major challenge for sustainable industrial development world-wide. Hence, new strategies are needed to assess interactive toxic effects of all substances present in the treated waste. This study assessed potential toxic hazards of treated effluents discharged from common wastewater treatment plants of two mclustrlal zones located in the Kelani River basin using Allium cepa (common onion) test system. The results showed that the final effluents of both industrial zones under undiluted and diluted (1 IS v/v) conditions mduced cytotoxrcity on all occasions, with evidence of significant (p < 0.05) mlto-depression In the root meristem and retardation of root growth in A. cepa. Genotoxlc hazard of the effuents was evident by frequent mcrease of nuclear and chromosomal abnormalltles, and occasional development of micronuclei in the root merlstem. Dilution of the effluents to 1 reduced the genotoxic effects generated in A. cepa roots by the final effuents_ The results revealed that waste treatment technologies m these two mdustnal zones need to be upgraded m order to ehmmate cytotoxlc and genotoxrc hazards associated with the treated effuents_ The results highlight the importance of incorporatmg practically feasible bioanalytical tools such as A. cepa root based test system on a regular basis for evaluating the efficacy of waste treatment technologies.