TOXIC EFFECTS OF CHLORPYRIFOS AND Cr6+ ON RED CALIFORNIAN EARTHWORM (EISENIA FETIDA)

Abstract

Eisenia fetida are commonly used for water and soil ecotoxicology tests. Here, we use Eisenia fetida as a model organism to investigate the effect of cartap and Cr 6+ on the physiological and biochemical indicators, such as mortality, protein content, superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA). The results showed that with an increasing content of cartap, protein contents in Eisenia fetida increased in the beginning, then decreased, and finally stabilized after prolonged exposure. In the case of increasing Cr 6+ , protein contents in Eisenia fetida decreased in the beginning, then increased, and finally decreased after prolonged exposure. The SOD activity in Eisenia fetida was simulated under low concentration and short durations of contaminations, while the SOD activity decreased after prolonged exposure. Meanwhile, under low contaminations, CAT contents were stimulated. The MDA contents in Eisenia fetida were significantly negatively correlated with SOD activity. This indicated that when the organisms are subjected to pollutant stress, the activity of SOD will be rapidly induced for removing excess oxygen free radicals and producing H2O2, accompanied by enhanced activity of CAT converting H2O2 to H2O. With the prolonged exposure time, the SOD activity decreased, and the organisms were harmed by oxidative damage with enhanced MDA contents.