Occurrence of butyltin compounds in marine sediments and bivalves from three harbour areas (Saigon,Da Nang and Hai Phong) in Vietnam

A survey of organotin compounds comprising tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) in sediment and clam (Meretrix meretrix) was undertaken in Vietnam in 2003. Samples were collected from dry docks and cargo harbours in Ho Chi Minh (south), Da Nang (centre) and Hai Phong (north) cities. Measurable amounts of TBT, DBT and MBT were found in all samples. The total concentration of the butyltin compounds (ΣBTs) in sediment from shipyards and vessel repair yards (Nam Trieu, Song Cam, Lach Tray and Ba Son) were always higher than those measured in cargo ports (Hai Phong, Da Nang, and Sai Gon). The highest ΣBTs concentration (as tin: 122 ng g^?1 dry wt) was found in the sediment from Song Cam station, where seven shipyards are located. The lowest concentrations of ΣBTs occurred in sediments from the Da Nang and Hai Phong cargo ports (as tin: 21–22 ng g^?1 dry wt). This implies that the major source of BTs in the marine environment in Vietnam is from the shipbuilding activities. The ratio of TBT to Σ(MBT + DBT) in sediment was 0.67 ± 0.03 for all the sampling sites, indicating the recent use of TBT in Vietnam. For the clam (M. meretrix), the concentration of ΣBTs (as tin) varied in the range 11.2–60.1 ng g^?1 wet wt. There was a good correlation (R² = 0.85) between total organic matter‐normalized ΣBTs in sediment and hexane‐extractable organic matter‐normalized ΣBTs in clam soft tissue. The mean biota–sediment accumulation factors (organic carbon/lipid) for MBT, DBT and TBT in clam's soft tissue were found to be 1.83 ± 0.66, 1.44 ± 0.23 and 1.16 ± 0.47 respectively, indicating that sediment‐bound BTs might be an important source of contamination for the clam. Copyright © 2005 John Wiley & Sons, Ltd.