Keywords: 
• organotin /
• tributyltin /
• sediment /
• fishing port /
• Yangtze estuary

Abstract: Surface sediments were collected from five fishing ports in Chongming Island and the Yangtze (Changjiang) Estuary. Organotin compounds in the sediment samples were investigated by using gas chromatography coupled with mass spectrometry (GC-MS) after ultrasonic extraction and ethyl derivatization. The re-suits showed that organotin was not detected in the sediments of reference sites in the Yangtze Estuary while butyltin compounds were widely distributed in all the sediments from fishing ports, varying from 1.6 to 58.8 ng Sn·g^-1(dry weight, the same as below). Concentrations of tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT) ranged from not detectable level (ND) to 28.7 ng Sn·g^-1, ND to 22.1 ng Sn·g^-1, 1.6-8 ng Sn·g^-1, respectively. Among them, contamination level of TBT in the sediment was highest in Baozheng port; TBT concentrations in the sediment from the entrance of Laoyao port and Xijia port were almost the same as that of Xinhe port (average value was 17.2 ng Sn·g^-1). In the inner ports, TBT was not detected and only small amounts of MBT were residual. All of the TBT-contaminated sites were found in the neighborhood of large fishing boats dock, marinas or shipyards. TBT concentrations of these sites exceeded 5 ng Sn·g^-1-the Interim Sediment Quality Guideline (ISQG) trigger value of Australian and New Zealand. Besides, the ratio between predicted exposure value (PEC_sed) and predicted no effect value (PNEC_sed) of all the sites were all above 1. Consequently, both ISQG and PEC_sed/PNEC_sed indicated an ecological risk of TBT existed in sediments from Chongming Island fishery ports. Overall, organotin concentrations and species showed large variation in the sediment from the Yangtze Estuary area, and organotin contamination in the sediments around docks or shipyard should be concerned in priority.