| The synthetic pyrethroid insecticides are the large kind of insecticides which have better biological activity and environmental compatibility than the organ-chlorine insecticides and organo-phosphates insecticides. In the farm of the coastal zone, pyrethroids are often used as the disinfectant, and causes the polluting the sea water, sediments and aquatic organisms.In this research, the three typical pyrethroids , fenpropathrin, cypermethrin and deltamethrin were selected as research objects. The anoxic biodegradation of the pyrethroid insecticides in coastal sediments of the Bohai Sea was studied using the organic pollutants'attenuation.In this research, firstly, the adsorption behavior of the three synthetic pyrethroid insecticides in coastal sediment was determined. Then , the characteristics of anoxic biodegradations of the three synthetic pyrethroid insecticides with different degrading bacteria sources in sediment of Bohai Sea were studied. At last, the influence of carbon source(glucose, sodium acetate) and heavy metals (Cu2+, Cd2+) on the anoxic biodegradations of the three synthetic pyrethroid insecticides in sediment of Bohai Sea were determined.The results showed that the adsorption behavior of pyrethroid insecticides in the coastal sediment could be illuminated by Langmuir isothermal adsorption equation preferably. When the indigenous bacteria were used as degrading bacteria source, the anoxic biodegradation rate constants of fenpropathrin, cypermethrin and deltamethrin were 0.0129 h-1, 0.0067 h-1 and 0.0052 h-1, respectively, while the corresponding biodegradation rates decreased to 0.0057 h-1, 0.0027 h-1and 0.0025 h-1 in the case of anaerobic activated sludge used as degrading bacteria source. With the external carbon sources, the anoxic biodegradation of cypermethrin and deltamethrin in the coastal sediments were promoted. But with the external heavy metals, the anoxic biodegradation of three pyrethroids were inhibited.
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