Department of Fish and Wildlife Conservation, 100 Cheatham Hall, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States.
Environ Sci Technol. 2013 Mar 5;47(5):2416-22. doi: 10.1021/es304261s. Epub 2013 Feb 12.
Mercury (Hg), a ubiquitous and highly toxic bioaccumulative contaminant, can maternally transfer and elicit deleterious effects on adult reproduction and offspring phenotype in fish, amphibians, and birds. However, the effects of Hg on reproduction remain largely unstudied in reptiles. We evaluated the consequences of maternally transferred Hg on a long-lived aquatic omnivore, the common snapping turtle (Chelydra serpentina). We collected eggs and tissues from gravid female turtles along a broad Hg contamination gradient in a river in central Virginia. We incubated eggs in the laboratory, quantified embryonic mortality, infertility, and hatching success of each clutch, and assessed all hatchlings and dead embryos for gross morphological malformations. As predicted, Hg concentrations in eggs were strongly and positively correlated with Hg levels in female tissues. We found that Hg in eggs was negatively correlated with hatching success, and this effect was driven by both increased egg infertility and embryonic mortality. In comparison to previous effect-based studies on other amniotes, our findings suggest that C. serpentina may be more resilient to Hg exposure and perhaps better suited for long-term monitoring of bioavailability of Hg than as indicators of adverse effects.
汞（Hg）是一种普遍存在且具有高度毒性的生物蓄积性污染物，可通过母体传递，并对鱼类、两栖类和鸟类的成年生殖和后代表型产生有害影响。然而，Hg 对爬行动物生殖的影响在很大程度上仍未得到研究。我们评估了母体传递的 Hg 对一种长寿水生杂食动物——普通 snapping 龟（Chelydra serpentina）的影响。我们沿着弗吉尼亚州中部一条河流中的广泛 Hg 污染梯度收集了怀孕雌龟的卵和组织。我们在实验室孵化了这些卵，量化了每个卵群的胚胎死亡率、不孕率和孵化成功率，并对所有孵化幼龟和死胚胎进行了大体形态畸形评估。正如预测的那样，卵中的 Hg 浓度与雌龟组织中的 Hg 水平呈强烈正相关。我们发现，卵中的 Hg 与孵化成功率呈负相关，而这种影响是由卵的不孕率和胚胎死亡率增加共同驱动的。与之前对其他羊膜动物的基于效应的研究相比，我们的发现表明，C. serpentina 可能对 Hg 暴露更具弹性，也许比作为 Hg 生物利用度不良影响的指标更适合长期监测。
