Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA.
Environ Toxicol Chem. 2013 Apr;32(5):1178-86. doi: 10.1002/etc.2157. Epub 2013 Apr 1.
Although mercury (Hg) is a well-studied contaminant, knowledge about Hg accumulation in snakes is limited. The authors evaluated Hg bioaccumulation within and among four snake species (northern watersnakes, Nerodia sipedon; queen snakes, Regina septemvittata; common garter snakes, Thamnophis sirtalis; and rat snakes, Elaphe obsoleta [Pantherophis alleghaniensis]) from a contaminated site on the South River (Waynesboro, VA, USA) and two nearby reference sites. Total Hg (THg) concentrations in northern watersnake tail tissue at the contaminated site ranged from 2.25 to 13.84 mg/kg dry weight (mean: 4.85 ± 0.29), or 11 to 19 times higher than reference sites. Blood THg concentrations (0.03-7.04 mg/kg wet wt; mean: 2.24 ± 0.42) were strongly correlated with tail concentrations and were the highest yet reported in a snake species. Within watersnakes, nitrogen stable isotope values indicated ontogenetic trophic shifts that correlated with THg bioaccumulation, suggesting that diet plays a substantial role in Hg exposure. Female watersnakes had higher mean THg concentrations (5.67 ± 0.46 mg/kg) than males (4.93 ± 0.49 mg/kg), but no significant differences between sexes were observed after correcting for body size. Interspecific comparisons identified differences in THg concentrations among snake species, with more aquatic species (watersnakes and queen snakes) accumulating higher mean concentrations (5.60 ± 0.40 and 4.59 ± 0.38 mg/kg in tail tissue, respectively) than the more terrestrial species, garter snakes and rat snakes (1.28 ± 0.32 and 0.26 ± 0.09 mg/kg, respectively). The results of the present study warrant further investigation of potential adverse effects and will aid in prioritizing conservation efforts.
尽管汞 (Hg) 是一种研究充分的污染物，但有关蛇体内汞积累的知识有限。作者评估了来自南河（美国弗吉尼亚州韦恩斯伯勒）受污染地点和两个附近参照点的四种蛇类（北方水蛇、女王蛇、普通锦蛇和黑眉锦蛇）体内和种间的汞生物累积情况。受污染地点北方水蛇尾部组织中的总汞 (THg) 浓度范围为 2.25 至 13.84 毫克/公斤干重（平均值：4.85 ± 0.29），比参照点高 11 至 19 倍。血液 THg 浓度（0.03-7.04 毫克/公斤湿重；平均值：2.24 ± 0.42）与尾部浓度呈强相关性，并且是在蛇类中报告的最高浓度。在水蛇中，氮稳定同位素值表明与 THg 生物累积相关的营养级发育转变，表明饮食在汞暴露中起着重要作用。雌性水蛇的平均 THg 浓度（5.67 ± 0.46 毫克/公斤）高于雄性（4.93 ± 0.49 毫克/公斤），但在校正体型后，两性之间没有观察到显著差异。种间比较确定了蛇类之间 THg 浓度的差异，更多水生物种（水蛇和女王蛇）积累了更高的平均浓度（尾部组织中的 5.60 ± 0.40 和 4.59 ± 0.38 毫克/公斤），而更陆生的物种，锦蛇和黑眉锦蛇（分别为 1.28 ± 0.32 和 0.26 ± 0.09 毫克/公斤）。本研究的结果需要进一步调查潜在的不利影响，并有助于确定保护工作的优先事项。
