Efficacy of Four Microbial Cultures in Dissipation of Chlorpyriphos in Mollisols

The efficacy of four microbial cultures strains i.e. P (Fluorescent pseudomonas sp.), S8 (Sphingomonas sp.), Cf (Gordonia sp.), S9P (Consortia of Bacillus and Pseudomonas sp.) was evaluated in dissipation of chlorpyriphos (O,O-diethyl-O-3,5,6-trichloro-2-pyridinyl phosphorothioate), an organophosphate insecticide in mollisols under laboratory conditions. The data obtained in dissipation of chlorpyriphos treated with four cultures in (0-15cm) depth soil was evaluated after eight consecutive samplings (0, 1, 3, 5, 7, 10, 15 and 30 days). The results indicate that the degradation of chlorpyriphos was at slower rate during the first 5 days but thereafter became faster from 7 to 30 days. Dissipation studies could be better accounted by biphasic pattern involving an initial slower and a later faster phase. The kinetics of dissipation of chlorpyriphos from soil was accounted by first order kinetics. As per the data obtained indicates that S9P consortia have shortest half life of 5.37 d with chlorpyriphos in intial phase while P, S8, Cf and control showed half life of 6.53, 9, 8.45 and 9.62 d. While in later phase culture P and S8 showed more effectiveness followed by S9P and Cf in comparison to control in dissipation of chlorpyriphos. Thus S9P consortia was found to be most potent in degradating chlorpyriphos in comparison with rest of cultures.