Cardona-Marek Tamara, Schaefer Jeffra, Ellickson Kristie, Barkay Tamar, Reinfelder John R
Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, New Jersey 08901, USA.
Environ Sci Technol. 2007 Dec 15;41(24):8268-74. doi: 10.1021/es070945h.
Speciation and reactivity of mercury were examined in Berry's Creek estuary downstream of a highly mercury-contaminated U.S. EPA Superfund site during the summers of 2002 and 2003. Surface water samples from Berry's Creek estuary, its confluence with the Hackensack River, and upstream of that confluence were analyzed for total (THg), particulate (PHgT), and dissolved (DHg) mercury, total and particulate monomethylmercury (MeHg), dissolved gaseous mercury (DGM), and bacterial merA gene and transcript abundances. Surface water concentrations of THg in Berry's Creek estuary (210-6800 pM) are among the highest in North America. A downstream gradient of Hg contamination is a permanent feature of Berry's Creek estuary, and the upper estuary appears to be a perennial source of Hg to the lower estuary and the Hackensack River. MeHg concentrations in Berry's Creek surface waters ranged from 2 to 14 pM, with the highest concentrations occurring at a midestuary site 2 km downstream of the tide gate. The suspended particle phase dominated Hg and MeHg speciation throughout this system, accounting for > 90% of THg in Berry's Creek estuary and 35-94% of THg in the Hackensack River. Concentrations of DGM in Berry's Creek estuary (0.1-1.0 pM) are similar to levels of DGM in other much less contaminated estuaries (0.04-0.75 pM). In addition, expression levels of the bacterial mercuric reductase gene, merA, a gene of the inorganic Hg(II)-regulated, mercury resistance (mer) operon, were low throughout Berry's Creek estuary. Thus, despite very high concentrations of mercury in Berry's Creek estuary, relatively low concentrations of DGM and merA gene expression levels indicate limited bioavailability of inorganic Hg in the estuary's surface waters. A system-wide limitation on the bioavailability of inorganic Hg, together with bacterial demethylation activity, may account for observed MeHg concentrations that, although elevated, are lower than expected given the concentrations of THg in this estuary.
在2002年和2003年夏季，对位于美国环境保护局一个汞污染严重的超级基金场地下游的贝里溪河口的汞形态和反应活性进行了研究。对来自贝里溪河口、其与哈肯萨克河交汇处以及该交汇处上游的地表水样本进行了总汞（THg）、颗粒汞（PHgT）和溶解汞（DHg）、总甲基汞和颗粒甲基汞（MeHg）、溶解气态汞（DGM）以及细菌merA基因和转录本丰度的分析。贝里溪河口的THg地表水浓度（210 - 6800 pM）位列北美最高水平。汞污染的下游梯度是贝里溪河口的一个永久性特征，河口上游似乎是河口下游和哈肯萨克河汞的常年来源。贝里溪地表水的MeHg浓度范围为2至14 pM，最高浓度出现在潮汐闸下游2公里处的河口中部站点。在整个系统中，悬浮颗粒相主导了汞和甲基汞的形态，占贝里溪河口THg的90%以上，占哈肯萨克河THg的35% - 94%。贝里溪河口的DGM浓度（0.1 - 1.0 pM）与其他污染程度低得多的河口的DGM水平（0.04 - 0.75 pM）相似。此外，细菌汞还原酶基因merA（一种受无机Hg(II)调控的汞抗性（mer）操纵子基因）在整个贝里溪河口的表达水平都很低。因此，尽管贝里溪河口的汞浓度非常高，但相对较低的DGM浓度和merA基因表达水平表明河口地表水无机汞的生物可利用性有限。无机汞生物可利用性的全系统限制，连同细菌去甲基化活性，可能解释了观察到的甲基汞浓度，尽管有所升高，但鉴于该河口的总汞浓度，其低于预期。
