Ecology, Environment and Conservation Paper

IMPACT OF MALATHION ON OXIDATION POND PERFORMANCE

N.C. Tharavathy and M. Krishnamurthy

Abstract

Studies were carried out on the toxic effects of rnaiathion on sewage quality, algae, and protozoan density.The pond performance was evaluateci in terms of reduction of BUD level and phosphate. On day 20, BOD level was reduced to 82%, 67%, 40%, 34% and 1 0% of the original value respectively in control, 0.05%, 0.1%, 0.2% and 0.3% malthion treated ponds. Similarly catalase amylase; protease and phosphatase activities were reduced drastically with the increase in pesticide levels.The densities of algae and protozoa were maximum in the untreated control than malathion treated ponds. Among the 15 algae recorded, Oscillatoria brevis was found to be most resistant and Pinnularia viridis was found to be most sensitive to malathion toxicity. In case of 8 protozoa species studied, Oikomonas termo was relatively resistant but Lionotus sp. was most sensitive to malathion toxicity.