Monitoring Endocrine Disrupters Through Seawater Fish

Trinbutylin (TBT) has been widely used as biocide, especially as a component in anti-fouling paints for ships and net cages in aquaculture. It was also used as a chemical stuff in the production of agriculture and industry. 4-tert-octylphenol (OP) is a nonionic surfactant, and is widely used in the pesticide, cleanser and industry production. The contamination of TBT and OP is very serious and they can poison the organisms significantly. Fish play an important role in the aquatic ecosystem, and are also endangered by TBT and OP. In order to explore the possibility of using the seawater fish to monitor the oceanic contamination such as TBT and OP, the euryhaline rabbitfish (Siganidac oramin) was utilized as the experimental animals in the present. By the static exposure to tributyltin chloride (TBTCl) or fed with the diets containing OP, the toxic effect of TBTCl or OP on the rabbitfish were evaluated from the toxic symptom, hepatosomatic index (HSI), histopathology, hepatic metabolic enzymatic activity and plasma steroid hormone level. The main results are as follows.1. The toxic symptom and effect of TBTCl and OP on HSIThe rabbitfish were sensitive to TBTCl. After 4 d exposure, the fish began to die in the 4000 ng/L group. At the end of the exposure (20d), the total death rate reached 48 %. The livers of the dead individuals became swollen, brittle and opalescent; the cornea and sclera appeared opalescent cloudy, and the mouth haematose.After the rabbitfish were exposed to 40, 400, 4000 ng/L TBTCl for 10 - 20 days, the HSI was increased. Ater 10 d exposure, the HSI of 4000 ng/L group was significantly higher than the control group and the 40, 400 ng/L group (p<0.05); after 20 d, the HSI of 4000 ng/L group was very significantly higher than the above mentioned groups (P<0.01), and that of 400 ng/L group was also obviously higher than the control group (P<0.05). After the rabbitfish were fed with the diets containing OP of 5, 25 or 125 mg/kg BW for 14 days, the HSI of 25 mg/kg BW group in female individuals was very significantly higher than that of any other group (P<0.01), and that in male individuals was very significantly higher than that of control or 125 mg/kg BW group (P<0.01), and significantly higher than that of 5 mg/kg BW group (P<0.05). After the feeding of OP for 28 d, no obvious HSI difference was obtained between groups.