Toxicity of Chlorpyrifos and and its Bioremediation using Pseudomonas putida

The toxicity of chlorpyrifos (CP) against the fish Ctenopharyngodon idella, (Grass carp), evaluated according to the OECD guidelines for testing of chemicals 203, showed its 96 h LC50 to be 12.387 μgL−1 at 95 per cent confidence limits. The toxicity was also evident from the degeneration of gill lamellae. A microcosm study in normal, CP amended and CP amended soil with Pseudomonas putida provided the microbial strength and dehydrogenase activity. Statistical significance of the calculated Karl Pearson correlation coefficient (r) using the t-test procedure revealed that all the treatments correlated at 0.05 level of significance. Effect of CP on germination of rice seed revealed that as the exposure concentration of CP increased, the germination percentage as well as the germination rate, decreased. Decrease in the plant growth parameters also confirmed the high toxic effect of CP on rice seed germination. Enzyme activity was found to be higher in CP treated rice plants whereas a significant decrease was seen in the induction of defense enzymes; poly phenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and peroxidase (PO) in plants being augmented with Pseudomonas putida.