The Toxic Effect Of Tributyltin On The Guppy (Poecilia Reticulates)

It is well known that tributyltin (TBT) has been widely used as a biocide, especially as a component in antifouling paints for ships and net cages in aquaculture. After ablation and flaking off of these paints from ship hulls, tributyltin and its derivatives will result to serious environmental contamination and produce toxicity to various aquatic species. Fish, which locate at the top position in the aquatic ecosystem, are the ideal experimental animals for toxicity study. Thus the establishment of effective and sensitive fish model could greatly help to disclose the potential danger of tributyltin at environmental levels. The guppy (Poecilia reticulates) is sensitive to toxic compounds and suitable for toxicity study. In this study, by the static exposure of fry, adults, and those from birth to sexually matured to tributyltin chloride (TBTCl), the toxic effects of TBTCl on the guppies were systematically investigated based on the toxic symptom, hepatosomatic index (HSI), histopathology, growth, gonadal development, the reproductive capability, and the morphological index of adults. The main results are as follows:When the fry were exposed to TBTCl at the dose of 1.25-7.90 μg/L, obvious toxicosis appeared and death happened in the 2.0 μgfL or the higher dose groups. The toxic symptom became more serious and the death rate rose with the increase in dose or time of exposure. Toxicosis appeared after 6 h exposure to 5.0 μg/L and 7.9 μg/L TBTCl; After 72 h, the livability of fish at 7.9 μg/L TBTCl was only 20%. The 50 % lethal concentration (LC₅₀) was declined as the exposure time prolonged, and the 96h-LC₅₀ was 5.82 μg/L. The results demonstrated that TBT was virulent and has strong toxicity to the guppies.After the adult female guppies were exposed to 0.14, 0.71, 3.56 μg/L TBTCl for 10 - 30 days, the main toxic effects observed as follow: (1) The hepatosomatic index (HSI) was increased. After 10 days exposure, the HSI of 3.56 μg/L TBTCl group was significantly higher than those in control; After 20 d, the HSI in both 0.71 and 3.56 μg/L TBTCl group was obviously higher than that in control or 0.14 μg/L TBTCl group; After 30 d, the HSI of 3.56 μg/L TBTCl group was very significantly higher than any other group, and 0.71 μg/L group higher than that in control or 0.14μg/L group. In the 0.71 or 3.56 μg/L TBTCl/L group, the HSI after 20 d exposure was significantly higher than that after 10 d exposure, and that after 30 d was very significantly higher than that after 10 d. These showed that the increase of HSI after TBTCl...