Calgary Zoo, Centre for Conservation Research, 1300 Zoo Rd NE, Calgary, AB, Canada T2E 7V6.
Sci Total Environ. 2011 Sep 1;409(19):3757-70. doi: 10.1016/j.scitotenv.2011.06.043. Epub 2011 Jul 16.
Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential concern for breeding bird populations.
污染物暴露是导致全球滨鸟数量减少的一种假设，也是北极地区日益关注的问题。我们评估了加拿大努纳武特省一个滨鸟繁殖地的潜在污染物（砷、铍、镉、钴、铬、铜、铁、汞、锰、钼、镍、铅、锑、硒、铊、钒和锌）。我们比较了土壤、无脊椎动物和滨鸟血液中的元素水平，以评估在北极食物链中生物浓缩和生物放大的证据。我们测试了六种滨鸟（斑胸滨鹬、黑腹滨鹬、红腹滨鹬、斑尾塍鹬、环颈鸻和黑腹滨鹬）的血液、羽毛和卵中的元素是否与适应度终点有关：成鸟体况、血液寄生虫负荷、卵大小、蛋壳厚度、筑巢持续时间和孵化成功率。为了便于与其他地点进行比较，我们总结了有关滨鸟血液和卵中有毒金属的已发表数据。元素浓度和无脊椎动物组成在栖息地之间差异很大，而栖息地利用和元素浓度在滨鸟物种之间也存在差异。汞、硒、镉、铜和锌从土壤到无脊椎动物中生物浓缩，而汞、硒和铁从无脊椎动物到滨鸟血液中生物放大。砷、镍、铅、钴和锰从土壤到无脊椎动物到滨鸟中显示出明显的生物稀释。土壤元素水平符合加拿大指南，无脊椎动物的汞水平低于保护野生动物的建议膳食水平。然而，血液和卵中的最大汞含量接近与毒理学效应相关的水平，并且与其他鸟类物种中的汞污染水平相当。亲鸟血液中的汞与卵体积呈负相关，尽管这种关系在物种之间有所不同。没有其他元素接近既定的毒理学阈值。总之，尽管我们发现该地点的元素暴露几乎没有导致所研究物种的减少，但在加拿大北极地区其他地方发现的汞对繁殖鸟类种群构成潜在威胁。
