Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, USA.
Environ Toxicol Chem. 2012 Jul;31(7):1657-61. doi: 10.1002/etc.1839. Epub 2012 May 9.
Emissions from coal-fired power plants are the major anthropogenic source of mercury (Hg) in the environment. Because emitted Hg can be deposited near the source, concerns arise about the effects of coal-burning facilities on levels of toxic methylmercury (MeHg) in biota near such sources. We investigated the potential impact of a large Hg-emitting (450 kg in 2005) coal-fired power station in Conesville, Ohio, on MeHg levels in adult mosquitoes near the plant. In July 2010, mosquitoes were sampled at 23 locations within a 60-km radius of the plant and at three reference sites distant from major combustion sources of Hg. Nearly all of the Hg in mosquitoes appeared in the form of MeHg (mean=91%). Concentrations of MeHg in mosquitoes were unrelated to either distance or direction from the Conesville plant and did not differ from those at the three reference sites. Moreover, measured levels of MeHg in mosquitoes near Conesville are in good agreement with those predicted from an empirical relationship to wet atmospheric Hg fluxes alone. This suggests that either little of the Hg emitted from the Conesville plant is deposited locally or near-source deposition of Hg does not have a significant impact on MeHg in mosquitoes and, by extension, other insects with similar life histories in the local food web.
燃煤电厂排放的废气是环境中汞（Hg）的主要人为来源。由于排放的汞可以在源附近沉积，因此人们担心燃煤设施会对靠近这些源的生物体内有毒的甲基汞（MeHg）水平产生影响。我们研究了俄亥俄州科内斯维尔的一个大型汞排放（2005 年排放 450 公斤）燃煤电厂对该电厂附近成年蚊子体内 MeHg 水平的潜在影响。2010 年 7 月，在距离该工厂 60 公里半径范围内的 23 个地点以及远离主要汞燃烧源的三个参考地点对蚊子进行了采样。蚊子体内几乎所有的汞都以 MeHg 的形式存在（平均值=91%）。蚊子体内的 MeHg 浓度与距离科内斯维尔工厂的距离或方向无关，也与三个参考地点的浓度没有差异。此外，在科内斯维尔附近蚊子体内测量的 MeHg 水平与仅根据湿大气 Hg 通量的经验关系预测的水平非常吻合。这表明，科内斯维尔工厂排放的汞中只有很少一部分被当地或近源沉积，或者近源沉积的汞对蚊子体内的 MeHg 没有显著影响，进而对当地食物网中具有类似生活史的其他昆虫也没有显著影响。
