Custer Christine M, Custer Thomas W, Hill Elwood F
US Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI 54603, USA.
Arch Environ Contam Toxicol. 2007 Jan;52(1):129-36. doi: 10.1007/s00244-006-0103-6. Epub 2006 Nov 2.
Mercury (Hg) concentrations were 15-40 times higher in the eggs and livers of tree swallows (Tachycineta bicolor) and house wrens (Troglodytes aedon) that nested along the Carson River at and below Dayton, Nevada than in the same species above the mining-impacted areas. Hg contamination was mainly the result of processing mills in the 1800s that used Hg to separate gold and silver from ore. The exposure pattern of tree swallows and house wrens along the Carson River was consistent with their trophic status (i.e., lower levels in liver tissue of aquatic insectivores than in piscivorous birds nesting nearby). Even though they are aquatic insectivores, tree swallows and house wrens were exposed to the same amount of Hg as piscivores in the Florida Everglades; this indicated the extreme level of Hg contamination in the Carson River. Only 70-74% of the eggs hatched. This was less than the nationwide average for these two species that generally hatch > or =85% of eggs. Although the sample size was small, Hg might be impacting reproductive end points in cavity-nesting birds from the Carson River. Other trace elements were present at background concentrations.
在内华达州代顿及以下的卡森河沿岸筑巢的树燕（双色树燕）和家鹪鹩（冬鹪鹩）的卵和肝脏中的汞（Hg）浓度，比在受采矿影响区域上游的同物种中的浓度高出15至40倍。汞污染主要是19世纪使用汞从矿石中分离金和银的加工厂造成的。卡森河沿岸树燕和家鹪鹩的暴露模式与其营养级状态一致（即水生食虫动物肝脏组织中的汞含量低于附近筑巢的食鱼鸟类）。尽管树燕和家鹪鹩是水生食虫动物，但它们接触的汞量与佛罗里达大沼泽地的食鱼动物相同；这表明卡森河的汞污染程度极高。只有70 - 74%的卵孵化。这低于这两个物种通常孵化率≥85%的全国平均水平。尽管样本量较小，但汞可能正在影响卡森河中空洞筑巢鸟类的繁殖终点。其他微量元素的浓度处于背景水平。
