四湖总干渠环境雌激素不同浓度江段鱼繁殖生物学比较研究

选取湖北四湖总干渠污染水平不同的3个江段(A、B、C), A离源头较近, B位于一农药厂排污口下方, C位于一城镇居民排污口下方, 比较鱼繁殖群体的生物学特征。A江段水体中未检测出环境雌激素, 而B、C两江段主要含有壬基酚和双酚A, 两种污染物总浓度在20 μg/L左右。与A江段相比, B、C江段鱼繁殖群体中雌性个体的比例明显较高, 卵粒较小; 雄性个体精巢组织间隙增大, 精原细胞和精子细胞密度低; 肝体指数增大、肝组织出现大量空泡, 肝细胞密度降低等特点。壬基酚和双酚A已被证明具有显著的雌激素活性和生殖毒性。因此, B、C江段壬基酚和双酚A环境雌激素浓度较高可能是导致鱼繁殖群体生物学特征改变的重要原因。

A COMPARATIVE STUDY ON REPRODUCTIVE BIOLOGY OF HEMICULTER LEUCISCULUS FROM DIFFERENT SECTIONS OF THE MAIN IRRIGATION CHANNEL WITH VARIED LEVELS OF ENVIRONMENTAL ESTROGENS

Reproductive characteristics were compared for Hemiculter leucisculus which collected from 3 sections of the Main Irrigation Channel of the Four-lake area in Hubei province with different levels of environmental estrogens. Section A was in the upstream of the channel; section B was below an outlet of a pesticide factory, and section C was below the sewage outlet of a town. No environmental estrogens were detected in section A. Both nonylphenol and bisphenol-A were detected in sections B and C with the total concentrations about 20 mg/L in each sections. H. leucisculus in B and C showed higher percentage of female, and smaller egg size when compared with the fish from section A. Histological observation on the testis showed enlarged tissue interval and lower densities of spermatogonium and spermatid for males from sections B and C. Meanwhile, the fish from sections B and C had higher hepatosomatic index and lower density of liver cell with the occurrence of some histological vacuoles in liver compared to the fish from section A. Both nonylphenol and bisphenol-A were demonstrated of estrogen activity and reproductive toxicity. High concentrations of them in the B and C sections should likely contribute to the variations in reproductive characteristics of H. leucisculus there compared to the A section.