Tavshunsky Ilana, Eggert Susan L, Mitchell Carl P J
Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada.
United States Forest Service, Northern Research Station, 1831 Hwy 169 E, Grand Rapids, MN, 55744, USA.
Bull Environ Contam Toxicol. 2017 Dec;99(6):673-678. doi: 10.1007/s00128-017-2198-z. Epub 2017 Oct 23.
Mercury (Hg) methylation is often elevated at the terrestrial-peatland interface, but methylmercury (MeHg) production at this "hot spot" has not been linked with in situ biotic accumulation. We examined total Hg and MeHg levels in peat, invertebrates and tissues of the insectivore Sorex cinereus (masked shrew), inhabiting a terrestrial-peatland ecotone in northern Minnesota, USA. Mean MeHg concentrations in S. cinereus (71 ng g) fell between concentrations measured in spiders (mean 70-140 ng g), and ground beetles and millipedes (mean 29-42 ng g). Methylmercury concentrations in S. cinereus increased with age and differed among tissues, with highest concentrations in kidneys and muscle, followed by liver and brain. Nearly all Hg in S. cinereus was in the methylated form. Overall, the high proportional accumulation of MeHg in peat at the site (3.5% total Hg as MeHg) did not lead to particularly elevated concentrations in invertebrates or shrews, which are below values considered a toxicological risk.
汞（Hg）甲基化在陆地 - 泥炭地界面处通常会升高，但在这个“热点”区域甲基汞（MeHg）的产生与原位生物累积并无关联。我们研究了美国明尼苏达州北部一个陆地 - 泥炭地交错带中泥炭、无脊椎动物以及食虫动物灰鼩鼱（Sorex cinereus，蒙面鼩）组织中的总汞和甲基汞水平。灰鼩鼱体内的甲基汞平均浓度（71纳克/克）介于蜘蛛（平均70 - 140纳克/克）以及步甲和千足虫（平均29 - 42纳克/克）所测浓度之间。灰鼩鼱体内的甲基汞浓度随年龄增长而增加，且在不同组织间存在差异，肾脏和肌肉中的浓度最高，其次是肝脏和大脑。灰鼩鼱体内几乎所有的汞都以甲基化形式存在。总体而言，该地点泥炭中甲基汞的高比例累积（占总汞的3.5%为甲基汞）并未导致无脊椎动物或鼩鼱体内的浓度特别升高，这些浓度低于被认为存在毒理学风险的值。
