Effects of TBT on Marine Organisms: Field Assessment of A New Site-Specific Bioassay System

A Portable Environmental Test System (PETS) was evaluated in San Diego Bay over a 7-month period using tributyltin (TBT) antifouling leachates. Three TBT concentrations ( \bar{x} = 0.065, 0.077 and 0.193 ug/l) were tested against seawater controls with three replicates of each usirg 340-1 tanks. Unfiltered seawater was pumped over a TBT-coated panel, creating a TBT-leachate which was diluted with seawater in mixing bins and distributed to test tanks. There were no significant effects attributable to TBT on fouling communities (species abundance and bicmass), mussel and clam condition index, mussel gonad index or oyster growth. TBT reduced juvenile mussel growth rate. Mussels and clams accumulated TBT at all test concentrations. Although mussels accumulated more TBT at higher test concentrations, there was an inverse relationship between dose and bioconcentration factor.