Laboratório de Biogeoquímica Ambiental Wolfgang C. Pfeiffer, Fundação Universidade Federal de Rondônia, Porto Velho, Brazil.
Santo Antônio Energia, Rondônia, Brazil.
Environ Res. 2021 Oct;201:111574. doi: 10.1016/j.envres.2021.111574. Epub 2021 Jun 25.
In the Amazon rainforest, methylmercury (MeHg) is easily biomagnified and bio-accumulated in the aquatic food chain. This unique biome has been studied for occupational and environmental issues related to human health and contamination through fish consumption; however, wildlife studies have not yet addressed fish-eating birds. Different species of birds categorized by foraging strategies and life-stages were studied in the Madeira River Basin (Western Amazon rainforest). Feather and tissue (muscle, liver, kidneys, lungs, heart, brain, and blood) samples were collected opportunistically from six bird species feeding on fish and aquatic fauna and a scavenger (a saprophagous species) during the low-water season (July 2017). All collected samples were analyzed for total Hg (THg); methyl-Hg (MeHg) was determined only in feathers. The mean THg concentrations in feathers (dw) were as follows: Ardea cocoi (4.05 μg g, n = 51) > Egretta thulla (3.94 μg g, n = 5) > Ardea alba (3.80 μg g, n = 61) > Anhinga anhinga (3.69 μg g, n = 8) > Nannopterum brasilianus (3.07 μg g, n = 10). The scavenger Coragyps atratus showed mean THg in feathers (9.93 μg g, n = 30) to be significantly higher than in fish-eating birds. Across species, THg levels in feathers correlated significantly with THg (p = 0.022) and THg (p = 0.002). THg concentrations varied in tissues (feather > liver > kidneys > lungs > heart > muscle > blood > brain). The Hg:Hg, Hg:Hg, and Hg:Hg ratios were 0.031, 0.503 and 0.516, respectively. The mean [MeHg:THg] ratio in feathers from aquatic birds varied between species from 14 to 74% with a mean of 38%. Scavenger birds that forage in the terrestrial Amazonian environments concentrate more THg than species that forage in the aquatic environment. None of the aquatic species showed THg concentration in internal organs that were above threshold for risk of Hg toxicity; additionally, they are not listed in the categories of threat by the International Union for Conservation of Nature (IUCN).
在亚马逊雨林中，甲基汞（MeHg）很容易在水生食物链中被生物放大和生物积累。该独特的生物群落一直是研究人类健康和鱼类消费相关的职业和环境问题的对象；然而，野生动物研究尚未涉及吃鱼的鸟类。在马德拉河流域（亚马逊西部雨林），我们研究了按觅食策略和生活阶段分类的不同鸟类物种。在枯水季节（2017 年 7 月），从六种以鱼类和水生动物为食的鸟类和一种食腐动物（腐生动物）中随机采集羽毛和组织（肌肉、肝脏、肾脏、肺、心脏、大脑和血液）样本。所有采集的样本均分析总汞（THg）；仅在羽毛中测定甲基汞（MeHg）。羽毛（dw）中的平均 THg 浓度如下：Ardea cocoi（4.05μg/g，n=51）>Egretta thulla（3.94μg/g，n=5）>Ardea alba（3.80μg/g，n=61）>Anhinga anhinga（3.69μg/g，n=8）>Nannopterum brasilianus（3.07μg/g，n=10）。食腐动物 Coragyps atratus 的羽毛中总汞（9.93μg/g，n=30）平均值明显高于吃鱼的鸟类。在物种间，羽毛中 THg 水平与 THg（p=0.022）和 THg（p=0.002）显著相关。THg 浓度在组织中变化（羽毛>肝脏>肾脏>肺>心脏>肌肉>血液>大脑）。Hg:Hg、Hg:Hg 和 Hg:Hg 比值分别为 0.031、0.503 和 0.516。水生鸟类羽毛中的平均[MeHg:THg]比值在物种间变化范围为 14%至 74%，平均值为 38%。在陆地亚马逊环境中觅食的食腐鸟类比在水生环境中觅食的鸟类积累了更多的 THg。没有一种水生物种的内部器官中的 THg 浓度超过汞毒性风险的阈值；此外，它们没有被列入国际自然保护联盟（IUCN）的威胁类别。
