U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis Research Group, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
U. S. Geological Survey, Western Ecological Research Center, Dixon Field Station, 800 Business Park Drive, Suite D, Dixon, CA, USA.
Environ Pollut. 2014 Oct;193:147-155. doi: 10.1016/j.envpol.2014.06.015. Epub 2014 Jul 12.
Estuaries are globally important areas for methylmercury bioaccumulation because of high methylmercury production rates and use by fish and wildlife. We measured total mercury (THg) concentrations in ten fish species from 32 wetland and open bay sites in San Francisco Bay Estuary (2005-2008). Fish THg concentrations (μg/g dry weight ± standard error) differed by up to 7.4× among estuary habitats. Concentrations were lowest in open bay (0.17 ± 0.02) and tidal wetlands (0.42 ± 0.02), and highest in managed seasonal saline wetlands (1.27 ± 0.05) and decommissioned high salinity salt ponds (1.14 ± 0.07). Mercury also differed among fishes, with Mississippi silversides (0.87 ± 0.03) having the highest and longjaw mudsuckers (0.37 ± 0.01) the lowest concentrations. Overall, 26% and 12% of fish exceeded toxicity benchmarks for fish (0.20 μg/g wet weight) and piscivorous bird (0.30 μg/g wet weight) health, respectively. Our results suggest that despite managed wetlands' limited abundance within estuaries, they may be disproportionately important habitats of Hg risk to coastal wildlife.
河口是全球范围内甲基汞生物累积的重要区域，因为这里的甲基汞生成率高，鱼类和野生动物也会利用这些甲基汞。我们测量了旧金山湾河口（2005-2008 年）32 个湿地和开阔海湾地点的 10 种鱼类中的总汞（THg）浓度。鱼类的 THg 浓度（μg/g 干重±标准误差）在河口栖息地之间相差可达 7.4 倍。开放海湾（0.17±0.02）和潮汐湿地（0.42±0.02）中的浓度最低，管理季节性咸水湿地（1.27±0.05）和退役高盐盐田（1.14±0.07）中的浓度最高。汞在鱼类之间也存在差异，其中密西西比银汉鱼（0.87±0.03）的浓度最高，长颌粘盲鳗（0.37±0.01）的浓度最低。总体而言，26%和 12%的鱼类分别超过了鱼类（0.20μg/g 湿重）和食鱼鸟类（0.30μg/g 湿重）健康的毒性基准。我们的研究结果表明，尽管管理湿地在河口内的数量有限，但它们可能是对沿海野生动物的汞风险具有不成比例重要性的生境。
