The Anoxic Degradation of Deltamethrin in Bohai Coastal Sediment

Abstract

At present, the qualities of the coastal aquatic ecosystems and sediments have seriously deteriorated as a result of excessive using the pyrethroid insecticides in the tidal farms. Deltamethrin is one of the most frequently detected pyrethroid in the coastal sediment. In this paper, the anoxic degradation behavior and mechanism of deltamethrin in bohai coastal sediment was studied. The results showed that deltamethrin could be degraded in natural coastal sedimentary environment at a relatively slow rate. The degradation kinetics followed the first-order kinetic with the rate constant 0.0055 h^-1.The m-phenoxyphenyl-acetonitril was the main metabolic product, and the possible degradation pathway was that deltamethrin was hydrolyzed at ester bond firstly, and then was reduced to be m-phenoxyphenyl-acetonitril. Adequate addition of carbon sources could significantly promote the microbial degradation of deltamethrin, but oversupplying carbon source inhibited it.