Whole-lake nitrate addition for control of methylmercury in mercury-contaminated Onondaga Lake, NY
Whole-lake nitrate addition for control of methylmercury in mercury-contaminated Onondaga Lake, NY
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DOI：
10.1016/j.envres.2013.03.011
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发表时间：
2013-08-01
影响因子：
8.3
通讯作者：
Kuhr, Kenneth M.
中科院分区：
文献类型：
--
作者：
Matthews, David A.;Babcock, David B.;Kuhr, Kenneth M.
甲基汞 (MeHg) 在水生食物网中具有强烈的生物累积性，导致人类和野生动物通过食用鱼类而接触到甲基汞。厌氧条件和无机汞 (Hg2+)、硫酸盐 (SO42-) 和不稳定有机碳的供应促进了甲基汞的产生。分层湖泊的厌氧沉积物是 Hg2+ 甲基化特别活跃的区域，并且可能是夏季缺氧和秋季更替期间水体中甲基汞的重要来源。最近提出添加硝酸盐（NO3-）作为一种新方法来控制汞污染湖泊低浓度中甲基汞的积累。 2011 年，在纽约州受汞污染的奥农达加湖进行了全湖 NO3 添加试点试验，目的是通过维持 NO3--N 浓度 >1 mg NIL 来限制 MeHg 从远洋沉积物释放到下层水层中。在夏季分层期间，每周大约 3 次将液态硝酸钙溶液作为中性浮力羽流添加到下层水层中。 MeHg 和可溶性活性磷 (SRP) 的最大低湖浓度较 2009 年水平下降了 94% 和 95%，表明表面沉积物中 Fe 和 Mn 羟基氧化物的吸附增加是调节机制。秋季更替期间上层水域甲基汞浓度升高这一普遍现象在 2011 年并未出现，导致水生生物接触甲基汞的情况减少。在 1992-2011 年间，低浅湖区 NO3 供应分别解释了 85% 和 95% 低浅湖区 SRP 和 MeHg 积累的年际变化。 (C) 2013 Elsevier Inc. 保留所有权利。
Methylmercury (MeHg) strongly bioaccumulates in aquatic food webs resulting in exposure to humans and wildlife through consumption of fish. Production of MeHg is promoted by anaerobic conditions and the supply of inorganic Hg (Hg2+), sulfate (SO42-), and labile organic carbon. The anaerobic sediments of stratified lakes are particularly active zones for methylation of Hg2+ and can be an important source of MeHg to the water column during summer anoxia and fall turnover. Nitrate (NO3-) addition has recently been proposed as a novel approach for the control of MeHg accumulation in the hypolimnia of Hg-contaminated lakes. In 2011, a whole-lake NO3- addition pilot test was conducted in Hg-contaminated Onondaga Lake, NY with the objective of limiting release of MeHg from the pelagic sediments to the hypolimnion through maintenance of NO3--N concentrations >1 mg NIL A liquid calcium-nitrate solution was added to the hypolimnion as a neutrally buoyant plume approximately three times per week during the summer stratification interval. Maximum hypolimnetic concentrations of MeHg and soluble reactive phosphorus (SRP) decreased 94% and 95% from 2009 levels, suggesting increased sorption to Fe and Mn oxyhydroxides in surficial sediments as the regulating mechanism. Increased MeHg concentrations in the upper waters during fall turnover, which had been a generally recurring pattern, did not occur in 2011, resulting in decreased exposure of aquatic organisms to MeHg. Over the 1992-2011 interval, the hypolimnetic NO3- supply explained 85% and 95% of the interannual variations in hypolimnetic accumulations of SRP and MeHg, respectively. (C) 2013 Elsevier Inc. All rights reserved.