Anaerobic biotransformations of organochlorine pesticides in Manzala Lake, Egypt

Abstract

The anaerobic transformations of four organochlorine pesticides, HCB, HCH, o,p’‐DDT and p,p'‐DDT were examined in a sediment collected from Manzala lake in Egypt. Sediment samples collected from different locations in the lake were mixed with lake water to make a sediment slurry. The slurry from each site was spiked with a mixture of organo chlorine pesticides at known concentrations. Degradation of all pesticide chemicals followed a first‐order reaction kinetics. The rate constants ranged from 0.0037 to 0.0091 day‐1 or half‐lives between 76 and 364 days. The results indicated that HCH and HCB were transformed at higher rates compared to DDT isomers. The rates of transformation of each pesticide at various sites in the lake was of the same order of magnitude as shown by the rate constants.