Abstract: To evaluate the degradation of sulfonamides in aquaculture sediments， sulfadiazine （SD）， sulfamethazine （SM2） and sulfamethoxazole （SMZ） which exhibited relatively high detection rates in aquaculture sediments were chosen as the research objects. Through laboratory simulation degradation experiment， a series of environment factors including temperature， microorganism， illumination and initial concentrations in sediments were tested to determine their impacts on degradation of SD， SM2 and SMZ. It was shown that raising temperature could effectively promote the degradation of SD， SM2 and SMZ in sediments， and these sulfonamides exhibited e a higher degradation rate under 25 ℃ and 35 ℃ than that under 5 ℃. SD and SM2 degradation in sediments were mainly attributed to abiotic degradation， and microbial degradation was complementary. SMZ in sediments was significantly influenced by microbial degradation， and the contribution rate of microbial degradation reached 55%. Illumination had no significant effect on the degradation of the three kinds of sulfa drugs in sediments. With the increase of the initial concentrations， the degradation efficiency of SD， SM2 and SMZ declined gradually， and the halflife period of degradation was extended. Under the condition of the lower concentration as 0.01 and 0.1 mg·kg-1， the halflife period of SD， SM2 and SMZ was short. Within the initial concentration of 1～50 mg·kg-1， the halflife period of SD， SM2 and SMZ was 11.13～128.36 d.

Key words: aquaculture sediments, sulfonamides, degradation