Laboratorio de Análisis por Activación Neutrónica, Comisión Nacional de Energía Atómica, Centro Atómico Bariloche, 8400 Bariloche, Argentina.
Chemosphere. 2009 Oct;77(4):471-7. doi: 10.1016/j.chemosphere.2009.07.055. Epub 2009 Aug 20.
Seasonal trends of benthic methylmercury (methyl-Hg) production were examined in both littoral and open water sites of three lakes (Escondido, Moreno, and Morenito) in the North Andean Patagonia region of Argentina. Potentials of methyl-Hg production were measured by amending sediment samples with inorganic (197)Hg(II), incubating for either 24 and 32 h at room temperature, and subsequently assaying the radiolabelled organomercury produced. Seasonal variations of benthic methyl-Hg production were studied but no significant correlation was observed. Lake littoral sites exhibited up to two fold higher methyl-Hg production potentials in most cases. Sediment from lakes Moreno and Morenito generally exhibited much lower (up to 10 fold) methyl-Hg production potentials than those from Lake Escondido, possibly due to differences in particulate and dissolved organic matter quantity and quality, which is higher in Lake Escondido and primarily allochthonous, whereas in lakes Moreno and Morenito is primarily autochthonous. This study represents the first to directly examine benthic microbial Hg(II)-methylation in aquatic ecosystems of Patagonia.
本研究考察了阿根廷北安第斯巴塔哥尼亚地区三个湖泊（埃斯孔迪多、莫雷诺和莫雷尼托）的浅湖和开阔水域底层沉积物中甲基汞（甲基-Hg）的季节性生产趋势。通过向沉积物样品中添加无机（197）Hg（II），在室温下分别孵育 24 和 32 小时，并随后测定放射性标记的有机汞的产生，来测量甲基-Hg 的潜在生产能力。研究了底层甲基-Hg 生产的季节性变化，但未观察到显著相关性。在大多数情况下，湖泊浅湖地点的甲基-Hg 生产潜力最高可达两倍。莫雷诺湖和莫雷尼托湖的沉积物通常表现出比埃斯孔迪多湖低得多（高达 10 倍）的甲基-Hg 生产潜力，这可能是由于颗粒态和溶解态有机物数量和质量的差异所致，埃斯孔迪多湖的有机物数量和质量更高，主要是异源的，而在莫雷诺湖和莫雷尼托湖中则主要是同源的。本研究首次直接考察了巴塔哥尼亚水生态系统中底层微生物 Hg（II）-甲基化作用。
