Peterson Sarah H, Ackerman Joshua T, Hartman C Alex, Casazza Michael L, Feldheim Cliff L, Herzog Mark P
U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA.
U.S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive Suite D, Dixon, CA, 95620, USA.
Environ Pollut. 2021 Mar 15;273:115808. doi: 10.1016/j.envpol.2020.115808. Epub 2020 Oct 12.
Bioaccumulation of environmental contaminants in mammalian predators can serve as an indicator of ecosystem health. We examined mercury concentrations of raccoons (Procyon lotor; n = 37 individuals) and striped skunks (Mephitis mephitis; n = 87 individuals) in Suisun Marsh, California, a large brackish marsh that is characterized by contiguous tracts of tidal marsh and seasonally impounded wetlands. Mean (standard error; range) total mercury concentrations in adult hair grown from 2015 to 2018 were 28.50 μg/g dw (3.05 μg/g dw; range: 4.46-81.01 μg/g dw) in raccoons and 4.85 μg/g dw (0.54 μg/g dw; range: 1.53-27.02 μg/g dw) in striped skunks. We reviewed mammalian hair mercury concentrations in the literature and raccoon mercury concentrations in Suisun Marsh were among the highest observed for wild mammals. Although striped skunk hair mercury concentrations were 83% lower than raccoons, they were higher than proposed background levels for mercury in mesopredator hair (1-5 μg/g). Hair mercury concentrations in skunks and raccoons were not related to animal size, but mercury concentrations were higher in skunks in poorer body condition. Large inter-annual differences in hair mercury concentrations suggest that methylmercury exposure to mammalian predators varied among years. Mercury concentrations of raccoon hair grown in 2017 were 2.7 times greater than hair grown in 2015, 1.7 times greater than hair grown in 2016, and 1.6 times greater than hair grown in 2018. Annual mean raccoon and skunk hair mercury concentrations increased with wetland habitat area. Furthermore, during 2017, raccoon hair mercury concentrations increased with the proportion of raccoon home ranges that was wetted habitat, as quantified using global positioning system (GPS) collars. The elevated mercury concentrations we observed in raccoons and skunks suggest that other wildlife at similar or higher trophic positions may also be exposed to elevated methylmercury bioaccumulation in brackish marshes.
环境污染物在哺乳动物捕食者体内的生物累积可作为生态系统健康状况的一个指标。我们检测了加利福尼亚州苏森沼泽地浣熊（北美浣熊；37只个体）和条纹臭鼬（北美臭鼬；87只个体）的汞浓度，苏森沼泽是一个大型咸淡水沼泽，其特征是有连片的潮汐沼泽和季节性蓄水湿地。2015年至2018年生长的成年浣熊毛发中的平均（标准误差；范围）总汞浓度为28.50μg/g干重（3.05μg/g干重；范围：4.46 - 81.01μg/g干重），条纹臭鼬为4.85μg/g干重（0.54μg/g干重；范围：1.53 - 27.02μg/g干重）。我们查阅了文献中哺乳动物毛发汞浓度，苏森沼泽地浣熊的汞浓度是野生哺乳动物中观测到的最高值之一。尽管条纹臭鼬毛发汞浓度比浣熊低83%，但仍高于中捕食者毛发汞的建议背景水平（1 - 5μg/g）。臭鼬和浣熊的毛发汞浓度与动物体型无关，但身体状况较差的臭鼬汞浓度更高。毛发汞浓度存在较大的年际差异，这表明哺乳动物捕食者接触甲基汞的情况在不同年份有所不同。2017年生长的浣熊毛发汞浓度是2015年生长毛发的2.7倍，是2016年生长毛发的1.7倍，是2018年生长毛发的1.6倍。浣熊和臭鼬毛发汞浓度的年平均值随湿地栖息地面积增加而升高。此外，在2017年，浣熊毛发汞浓度随着使用全球定位系统（GPS）项圈量化的浣熊家域中被水淹没栖息地的比例增加而升高。我们在浣熊和臭鼬中观察到的汞浓度升高表明，处于相似或更高营养级的其他野生动物也可能在咸淡水沼泽中接触到更高水平的甲基汞生物累积。
