Gagné F, Blaise C, Salazar M, Salazar S, Hansen P D
St. Lawrence Centre, 105 McGill Street, 7th Floor, Montreal, Quebec H2Y-2E7, Canada.
Comp Biochem Physiol C Toxicol Pharmacol. 2001 Feb;128(2):213-25. doi: 10.1016/s1532-0456(00)00189-7.
Municipal effluents are an important source of estrogens to the aquatic environment. The purpose of this study was to examine the estrogenicity of municipal effluents to the indigenous freshwater mussel, Elliptio complanata. First, estradiol-binding sites in gonad homogenates were characterized to determine the binding affinity and specificity of estrogens. Mussels were exposed to increasing concentrations of a municipal effluent for 96 h at 15 degrees C. In another experiment, mussels were placed in cages and submerged for 62 days at 1.5 km upstream and 5 km downstream of a municipal effluent plume in the St. Lawrence River. Mussels were harvested for assessment of vitellogenin-like proteins in the hemolymph and determination of total lipid, carbohydrate and protein in the gonad. The presence of specific estrogen-binding sites was found in both male and female gonads. Binding of estradiol to cytosol proteins reached saturation, yielding a dissociation constant of 0.4 nM. Vitellogenin (Vg) levels increased significantly in both the hemolymph and the gonad after exposure to the effluent. Moreover, females appeared to be more sensitive than males to producing Vg. Mussels exposed in situ to contaminated surface waters had higher levels of Vg at the downstream site, again, females had higher levels of Vg than did males. On the other hand, lipid and sugar levels in male gonads were significantly increased at the downstream site. Moreover, mussels at the downstream site had decreased shell growth length and increased total and soft tissue weights. We conclude that municipal effluents contain bio-available xenoestrogens at levels sufficient to elicit effects in freshwater mussels.
城市污水是雌激素进入水生环境的一个重要来源。本研究的目的是检测城市污水对本地淡水贻贝椭圆萝卜螺（Elliptio complanata）的雌激素活性。首先，对性腺匀浆中的雌二醇结合位点进行表征，以确定雌激素的结合亲和力和特异性。将贻贝在15摄氏度下暴露于浓度不断增加的城市污水中96小时。在另一个实验中，将贻贝置于笼中，在圣劳伦斯河城市污水羽流上游1.5公里和下游5公里处浸没62天。采集贻贝以评估血淋巴中类卵黄蛋白原的含量，并测定性腺中的总脂质、碳水化合物和蛋白质含量。在雄性和雌性性腺中均发现了特定的雌激素结合位点。雌二醇与胞质溶胶蛋白的结合达到饱和，解离常数为0.4 nM。暴露于污水后，血淋巴和性腺中的卵黄蛋白原（Vg）水平均显著升高。此外，雌性在产生Vg方面似乎比雄性更敏感。原位暴露于受污染地表水的贻贝在下游位点的Vg水平较高，同样，雌性的Vg水平高于雄性。另一方面，雄性性腺中的脂质和糖含量在下游位点显著增加。此外，下游位点的贻贝壳生长长度减少，总重量和软组织重量增加。我们得出结论，城市污水中含有生物可利用的外源雌激素，其含量足以对淡水贻贝产生影响。
