Acute and chronic toxicities of tributyltin to various life stages of the marine polychaete Hydroides elegans

Experiments were performed to determine the acute and chronic toxicities of tributyltin (TBT) (nominal concentrations) to polychaete Hydroides elegans. Firstly, static tests were performed to examine the lethal effect of TBT on five life stages of H. elegans. The 48-h LC₅₀ (95% CI) for the eggs, 2-cells, trochophores, juveniles and adults was 0.18 (0.15-0.20), 0.97 (0.77-1.23), 2.36 (2.11-2.65), 2.86 (2.63-3.12) and 4.36 (4.04-4.71) μg TBT l^-1, respectively. Secondly, a 17-d static renewal chronic test was conducted to study sensitivity of the early development (egg to juvenile) to TBT. The survivorship, percent settlement and time to reach settlement were significantly reduced at ≥0.01 μg TBT l^-1. Effects of TBT on the juvenile growth and maturation were also studied through a 44-d chronic test. Lower survivorship and reduced tube growth were observed only at ≥1 μg TBT l^-1, however, only H. elegans exposed to ≤ 0.1 μg TBT l^-1 reached maturity. The final experiment examined effects of TBT on the fecundity of female worms through a 60-d chronic test. Although survivorship remained high even at 1 μg TBT l^-1, egg production, success in fertilization and egg development were all reduced at ≥0.1 μg TBT l^-1. Our results indicate that the early development of H. elegans is highly sensitive to TBT and this polychaete can be routinely employed as a test organism for both acute and chronic ecotoxicity bioassays in tropical and subtropical regions such as southern China.