[Toxic effects of nonylphenol on the gonad of adult rosy barb].

Acute and sub-acute toxicities of nonylphenol (NP) on fish were investigated with adult rosy barb (Puntius conchonius). The acute toxicity of NP to adult rosy barb was determined in semi-static bioassays. Median lethal concentration (LC50) value of NP was (1.72 +/- 0.06) micromol/L for 96 h exposure. The effects of sub-toxicity of NP (0.17, 0.34 and 0.68 micromol/L) on the adult rosy barb were studied after 21 d exposure. It showed that testis somatic index (TSI) and ovary somatic index (OSI) were reduced significantly by NP in a dose-dependent manner. The histopathological examination showed that the gland structures were impaired by NP as evidenced by hypertrophied Sertoli cells, a loss of germinal cells in testis, retardation of eggs development and increase in atresia in the follicles of ovary. These suggest that NP exerts adverse effects on the testis and the ovary, and disturbs the development of sperm and eggs. In addition, due to rosy barb high sensitivity to NP, it is also possible to apply rosy barb as a potential fish model to the toxicity of NP.