Laboratório Genética de Aves, Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rodovia Washington Luís km 235, 13565-905 São Carlos, São Paulo, Brazil.
Environ Res. 2011 Nov;111(8):1091-5. doi: 10.1016/j.envres.2011.07.007. Epub 2011 Aug 17.
Sedentary organisms that are at top trophic levels allow inference about the level of local mercury contamination. We evaluated mercury contamination in feather tissue of nestling Wood Storks (Mycteria americana), sampled in different parts of the Brazilian Pantanal that were variably polluted by mercury releases from gold mining activities. Levels of mercury in feathers sampled in seven breeding colonies were determined by atomic absorption spectroscopy, and the mean value of mercury concentration was 0.557 μg/g, dry weight (n=124), range 0.024-4.423 μg/g. From this total sample, 21 feathers that represent 30% of nestlings collected in Porto da Fazenda and Tucum colonies, in the northern region, ranged from 1.0 to 4.43 μg/g, dry weight (median value=1.87 μg/g). We found significant differences among regions (H=57.342; p=0<0.05). Results suggest that permanently flooded areas, or along mainstream rivers are more contaminated by mercury than dry areas, regardless of the distance from the gold mining center, which is located in the northern Pantanal. Highest values found in nestlings feathers were similar to those found in feathers of adult birds and in tissues of adult mammals that are less sedentary and were captured in the same region of Pantanal. These findings indicate that mercury released has been biomagnified and it is present in high concentrations in tissues of top consumers. We suggest a program to monitor mercury availability in this ecosystem using sedentary life forms of top predators like Wood Storks or other piscivorous birds.
处于顶级营养级的久坐生物可以推断当地汞污染的程度。我们评估了在巴西潘塔纳尔的不同地区采集的雏鸟伍德鹳（Mycteria americana）羽毛组织中的汞污染情况，这些地区受到金矿开采活动释放的汞的污染程度不同。通过原子吸收光谱法测定了七个繁殖群体中采集的羽毛中的汞含量，汞浓度的平均值为 0.557μg/g，干重（n=124），范围为 0.024-4.423μg/g。在这个总样本中，有 21 根羽毛代表了在北部地区 Porto da Fazenda 和 Tucum 繁殖群体中收集的 30%的雏鸟，其范围为 1.0 至 4.43μg/g，干重（中位数=1.87μg/g）。我们发现不同地区之间存在显著差异（H=57.342;p=0<0.05）。结果表明，永久性洪水区或主流河流比干燥地区受到更多的汞污染，而不论与金矿中心的距离如何，金矿中心位于潘塔纳尔的北部。在雏鸟羽毛中发现的最高值与在成年鸟类羽毛和成年哺乳动物组织中发现的值相似，这些成年哺乳动物的活动范围较小，是在潘塔纳尔的同一地区捕获的。这些发现表明，释放的汞已经被生物放大，并且在顶级消费者的组织中存在高浓度的汞。我们建议使用伍德鹳或其他食鱼鸟类等顶级捕食者的久坐生命形式来监测该生态系统中汞的可用性。
