(华盛顿 - 2009年11月10日）美国环保局最近一项调研结果显示，美国几乎所有50州的湖泊和水库的鱼体中都检出有毒化学物质。环保局有史以来第一次能估计全国范围湖泊和水库的鱼体内含有汞和多氯联苯等可能有害化学物质浓度的百分比。
“这一调查结果加强了杰克逊局长对重振全国水道保护和期盼已久的保护民众行动的强烈呼吁” 环保局水管理副局长彼得席尔瓦说。 “环保局正积极解决报告中所揭示的突出问题。甚至在结果未完成前，环保局已致力于有效削减有毒汞污染，并加强清洁水法的执法力度。 这些行动都是又一次为保护国民健康和环境所作的努力。“
调查数据显示，全国百分之四十九的湖泊和水库的鱼体内汞含量超过环保局的推荐限值，百分之十七的湖泊和水库的鱼体内多氯联苯含量已达到可能受到关注的程度。这些发现来自于一项全国范围的调研，收集了比以往更多的鱼类污染数据。
在美国燃烧煤炭等化石燃料所产生的汞排放量几乎占全国人为造成的大气汞排放总量的一半，而排放到大气中的汞却是水体汞污染的主要来源。从1990年至2005年，大气汞排放量已降低了58%。环保局也正致力于建立一套新法规，以大幅减少发电厂排放的汞。奥巴马政府也正在积极促进新国际协议的签署，将为减少全球汞排放而努力。National Lake Fish Tissue Study
Environmental monitoring provides crucial data for describing the condition of the environment and for assessing the effectiveness of pollution control activities. In the 1990s, EPA identified a lack of information necessary to accurately characterize the condition of the Nation’s surface waters and responded by designing a series of statistically-based surveys to produce information on the condition of lakes, streams, rivers, and coastal waters in the United States. The National Study of Chemical Residues in Lake Fish Tissue (or National Lake Fish Tissue Study) is one of the statistically-based surveys conducted by EPA since the late 1990s.
This study is a national screening-level survey of chemical residues in fish tissue from lakes and reservoirs in the conterminous United States (lower 48 states), excluding the Laurentian Great Lakes and Great Salt Lake. It is unique among national assessments of fish contamination in lakes because the sampling sites were selected according to a statistical (random) design. Study results allow EPA to estimate the percentage of lakes and reservoirs in the United States with chemical concentrations in fish tissue that are above levels of potential concern for humans or for wildlife that eat fish. This study also includes the largest set of chemicals ever studied in fish. Whole fish and fillets were analyzed for 268 persistent, bioaccumulative, and toxic (PBT) chemicals, including mercury, arsenic, dioxins and furans, the full complement of polychlorinated biphenyl (PCB) congeners, and a large number of pesticides and semivolatile organic compounds.
Partnerships made this study possible. Prior to beginning field sampling for the study, EPA built a national network of partners that included 47 states, three tribes, and two other federal agencies. Fisheries staff from more than 50 agencies worked for nearly five years to evaluate the suitability of lakes for sampling and to collect fish for the study. This study provides an excellent example of state, federal, and tribal collaboration. Participating agencies made a critical contribution to the success of this study through their voluntary commitments and dedicated efforts.