Weech Shari A, Scheuhammer Anton M, Elliott John E
Minnow Environmental, 305-1627 Fort Street, Victoria, British Columbia V8R 1H8, Canada.
Environ Toxicol Chem. 2006 May;25(5):1433-40. doi: 10.1897/05-181r.1.
To determine whether Hg from geologic/mining-related sources at Pinchi Lake (BC, Canada) was causing elevated Hg exposure and/or adversely affecting reproduction in fish-eating birds, breeding bald eagles (Haliaeetus leucocephalus) on Pinchi Lake and four nearby reference lakes were sampled for blood and feather Hg concentrations and monitored for reproductive success during the summers of 2000, 2001, and 2002. Eggs of red-necked grebes (Podiceps grisgena) also were collected and analyzed. Mercury levels in species at various trophic levels from Pinchi Lake averaged approximately twice those in the same species from nearby lakes combined, even in the absence of substantial new inputs of Hg to Pinchi Lake over several decades. In Pinchi Lake, Hg concentrations in blood and feathers of eagles and eggs of grebes were significantly higher than those in corresponding samples from reference lakes. However, the mean Hg concentration (0.25 microg/g wet wt) in grebe eggs from Pinchi Lake was substantially lower than accepted threshold levels for reproductive toxicity in most avian species (0.5-1.0 microg/g wet wt). Mercury concentrations in the blood of adult eagles and their chicks were highly correlated (r = 0.91, p = 0.004). Despite elevated Hg exposure in adult eagles nesting on Pinchi Lake (blood Hg concentration, 4.3-9.4 microg/ml), birds appeared to be in good body condition, did not differ significantly in terms of weight from eagles nesting on reference lakes, and exhibited no evidence of obvious abnormal behavior or lack of coordination. Eagle reproductive success and productivity on Pinchi Lake were not significantly different from those on all reference lakes combined (p = 0.483).
为了确定加拿大不列颠哥伦比亚省平奇湖与地质/采矿相关来源的汞是否导致以鱼类为食的鸟类汞暴露增加和/或对其繁殖产生不利影响，在2000年、2001年和2002年夏天，对平奇湖及附近四个参考湖泊上繁殖的白头海雕（Haliaeetus leucocephalus）进行了采样，检测其血液和羽毛中的汞浓度，并监测其繁殖成功率。同时还收集并分析了红颈䴙䴘（Podiceps grisgena）的卵。即使在过去几十年平奇湖没有大量新的汞输入的情况下，平奇湖不同营养级物种的汞含量平均约为附近湖泊相同物种汞含量总和的两倍。在平奇湖，白头海雕血液和羽毛中的汞浓度以及䴙䴘卵中的汞浓度显著高于参考湖泊的相应样本。然而，平奇湖䴙䴘卵的平均汞浓度（0.25微克/克湿重）远低于大多数鸟类物种生殖毒性的公认阈值水平（0.5 - 1.0微克/克湿重）。成年白头海雕及其雏鸟血液中的汞浓度高度相关（r = 0.91，p = 0.004）。尽管在平奇湖筑巢的成年白头海雕汞暴露量增加（血液汞浓度为4.3 - 9.4微克/毫升），但这些鸟类身体状况良好，体重与在参考湖泊筑巢的白头海雕相比无显著差异，也没有明显异常行为或缺乏协调性的迹象。平奇湖白头海雕的繁殖成功率和繁殖率与所有参考湖泊的总和相比没有显著差异（p = 0.483）。
