Department of Wildlife and Fisheries Sciences, Texas A&M University , College Station, Texas 77843-2258, United States.
Environ Sci Technol. 2014 Jun 3;48(11):6359-65. doi: 10.1021/es4048076. Epub 2014 May 9.
Lake Chapala is the largest tropical lake in Mexico. The objectives of this study were to determine bioaccumulation of Hg in fish and to evaluate the potential impacts of Hg in the diet of aquatic birds, particularly the American white pelican (AWPE), in Lake Chapala. Hg concentrations in three fish species ranged from 0.021 to 0.568 μg/g wet weight. Mercury in fish was positively and significantly correlated with total fish length (R2=0.44, P<0.05). The δ15N values in fish were significantly correlated with Hg concentrations in Chapala and the San Antonio Reservoir (R2=0.69, P<0.001 and R2=0.40, P<0.001, respectively). However, Hg concentrations in bird feathers were not significantly different between years, among locations, or among species. Hg concentrations in fish from Lake Chapala were within values reported in many parts of the world. The Hg (mean range of 2.75 to 4.54 μg/g dw) and δD (mean range of -62‰ to -11‰) values in bird feathers suggested a wide pattern of exposure for highly migratory AWPE and egrets, although birds with lower δD values in feathers appeared to have greater concentrations of Hg than those with higher δD values. Contaminant exposure in aquatic birds in Chapala during the breeding season should be monitored next to better determine the potential effects of Hg on resident aquatic birds.
查帕拉湖是墨西哥最大的热带湖泊。本研究的目的是确定鱼类体内汞的生物累积情况，并评估汞在查帕拉湖水鸟饮食中的潜在影响，特别是美洲白鹈鹕（AWPE）。三种鱼类的汞浓度范围为 0.021 至 0.568μg/g 湿重。鱼体内的汞与总鱼体长呈正相关且显著（R2=0.44，P<0.05）。鱼类的 δ15N 值与查帕拉湖和圣安东尼奥水库的汞浓度呈显著相关（R2=0.69，P<0.001 和 R2=0.40，P<0.001）。然而，鸟类羽毛中的汞浓度在年份之间、地点之间或物种之间均无显著差异。查帕拉湖鱼类的汞浓度在世界许多地区报告的值范围内。鸟类羽毛中的汞（均值范围为 2.75 至 4.54μg/g dw）和 δD（均值范围为-62‰至-11‰）值表明，高度迁徙的 AWPE 和白鹭存在广泛的暴露模式，尽管羽毛中 δD 值较低的鸟类体内的汞浓度似乎高于 δD 值较高的鸟类。在繁殖季节，应在查帕拉湖的水鸟旁监测污染物暴露情况，以更好地确定汞对当地水鸟的潜在影响。
