(Table 2) Mercury concentration in hair of Northwest Greenland polar bears (Ursus maritimus)

<p>Hair samples from 117 Northwest Greenland polar bears (Ursus maritimus) were taken during 1892-2008 and analyzed for total mercury (hereafter Hg). The sample represented 28 independent years and the aim of the study was to analyze for temporal Hg trends. Mercury concentrations showed yearly significant increases of 1.6-1.7% (p &lt; 0.0001) from 1892 to 2008 and the two most recent median concentrations from 2006 and 2008 were 23- to 27-fold higher respectively than baseline level from 1300 A.D. in the same region (Nuullit). This indicates that the present (2006-2008) Northwest Greenland polar bear Hg exposure is 95.6-96.2% anthropogenic in its origin. Assuming a continued anthropogenic increase, this model estimated concentrations in 2050 and 2100 will be 40- and 92-fold the baseline concentration, respectively, which is equivalent to a 97.5 and 98.9% man-made contribution. None of the 2001-2008 concentrations of Hg in Northwest Greenland polar bear hair exceeded the general guideline values of 20-30 µg/g dry weight for terrestrial wildlife, whereas the neurochemical effect level of 5.4 µg Hg/g dry weight proposed for East Greenland polar bears was exceeded in 93.5% of the cases. These results call for detailed effect studies in main target organs such as brain, liver, kidney, and sexual organs in the Northwest Greenland polar bears.</p>

自1892年至2008年间，对117只西北格陵兰岛北极熊（Ursus maritimus）的毛发样本进行了采集和分析，以测定其总汞含量（以下简称Hg）。这些样本涵盖了28个独立的年份，研究旨在分析汞含量的时间趋势。从1892年至2008年，汞浓度每年以1.6%-1.7%的显著比率（p < 0.0001）逐年上升，而2006年和2008年的最近两年中值浓度分别比1300年该地区（Nuullit）的基线水平高出23-27倍。这表明，当前（2006-2008年）西北格陵兰岛北极熊的汞暴露有95.6%-96.2%源于人为因素。假设人为因素的持续增加，该模型预测到2050年和2100年，浓度将分别达到基线浓度的40倍和92倍，相当于97.5%和98.9%的人为贡献。2001-2008年间，西北格陵兰岛北极熊毛发中的汞浓度均未超过陆地野生动物的一般指导值20-30 µg/g干重，而针对东格陵兰岛北极熊提出的神经化学效应水平5.4 µg Hg/g干重，在93.5%的情况下已被超过。这些研究结果呼吁对西北格陵兰岛北极熊的主要靶器官，如大脑、肝脏、肾脏和性器官等进行详细效应研究。