TBT contamination of an artisanal subsistence fishery in Suva harbour, Fiji

The intertidal zone around the Suva Peninsula, Fiji, supports separate finfish and invertebrate subsistence fisheries. This important source of fresh marine food for many low-income families around metropolitan Suva is under threat from foreshore reclamation projects and from anthropogenic biochemical pollution. Damage to or loss of this invertebrate intertidal fishery would remove a significant area where urban dwellers can pursue this traditional (non-cash) means of seafood acquisition. In 1996, Suva Peninsula was considered for the development of a marina, hotel, aquarium, roads, walls, and other structures. There is also increasing evidence of a serious anthropogenic TBT (tributyltin) pollution threat to the local invertebrate fishery. Although this substance is well known to have ecologically deleterious effects, its use is unregulated in Fiji. The inputs are likely to be large commercial vessels, and in particular the shipyards around the west side of Suva Harbour, where TBT antifouling coatings are both applied and removed, the old paint debris being allowed to wash into the harbour. Inputs from small boats are probably less important as there are relatively few (<150 boats) but uses of TBT, as a wood treatment chemical, for example, may lead to other inputs (but these have not been investigated). Samples of Anadara antiquata and Gafarium tumidum contained high levels of TBT ranging from <50 ng TBT gm−1 to 240 ng TBT gm−1. Samples of the edible bivalve G. tumidum taken from the Lami Dump intertidal zone had accumulated 10,500 ng TBT gm−1. The values of TBT in Suva Harbour and Laucala Bay sediments have reached levels that are among the highest in the world and indicate that these sediments are functioning as geochemical sinks for this toxic organotin substance.