Environment and Climate Change Canada, National Wildlife Research Centre, Ottawa, Ontario K1A 0H3, Canada.
River Institute, Cornwall, Ontario K6H 4Z1, Canada.
Sci Total Environ. 2018 Jun 1;626:668-677. doi: 10.1016/j.scitotenv.2018.01.044. Epub 2018 Feb 19.
Wildlife are exposed to neurotoxic mercury at locations distant from anthropogenic emission sources because of long-range atmospheric transport of this metal. In this study, mercury bioaccumulation in insectivorous bat species (Mammalia: Chiroptera) was investigated on a broad geographic scale in Canada. Fur was analyzed (n=1178) for total mercury from 43 locations spanning 20° latitude and 77° longitude. Total mercury and methylmercury concentrations in fur were positively correlated with concentrations in internal tissues (brain, liver, kidney) for a small subset (n=21) of little brown bats (Myotis lucifugus) and big brown bats (Eptesicus fuscus), validating the use of fur to indicate internal mercury exposure. Brain methylmercury concentrations were approximately 10% of total mercury concentrations in fur. Three bat species were mainly collected (little brown bats, big brown bats, and northern long-eared bats [M. septentrionalis]), with little brown bats having lower total mercury concentrations in their fur than the other two species at sites where both species were sampled. On average, juvenile bats had lower total mercury concentrations than adults but no differences were found between males and females of a species. Combining our dataset with previously published data for eastern Canada, median total mercury concentrations in fur of little brown bats ranged from 0.88-12.78μg/g among 11 provinces and territories. Highest concentrations were found in eastern Canada where bats are most endangered from introduced disease. Model estimates of atmospheric mercury deposition indicated that eastern Canada was exposed to greater mercury deposition than central and western sites. Further, mean total mercury concentrations in fur of adult little brown bats were positively correlated with site-specific estimates of atmospheric mercury deposition. This study provides the largest geographic coverage of mercury measurements in bats to date and indicates that atmospheric mercury deposition is important in determining spatial patterns of mercury accumulation in a mammalian species.
野生动物在远离人为排放源的地方接触到神经毒性汞，这是因为这种金属的长距离大气传输。在这项研究中，在加拿大广泛的地理范围内调查了食虫蝙蝠物种（哺乳动物：翼手目）中的汞生物积累。对来自跨越 20°纬度和 77°经度的 43 个地点的 1178 只蝙蝠的皮毛进行了总汞分析。皮毛中的总汞和甲基汞浓度与小棕蝠（Myotis lucifugus）和大棕蝠（Eptesicus fuscus）的一小部分（n=21）内部组织（脑、肝、肾）中的浓度呈正相关，验证了使用皮毛来表示内部汞暴露。大脑中的甲基汞浓度约占皮毛中总汞浓度的 10%。主要收集了三种蝙蝠物种（小棕蝠、大棕蝠和北方长耳蝠[M. septentrionalis]），在采样的两个物种存在的地点，小棕蝠的皮毛总汞浓度低于其他两个物种。平均而言，幼蝠的总汞浓度低于成年蝠，但同一物种的雌雄个体之间没有差异。将我们的数据集与之前发表的加拿大东部的数据结合起来，11 个省和地区小棕蝠皮毛中的总汞浓度中位数范围为 0.88-12.78μg/g。在东部，由于引入疾病，蝙蝠最濒危，那里的浓度最高。大气汞沉积的模型估计表明，加拿大东部比中部和西部地区受到更多的汞沉积。此外，成年小棕蝠皮毛中的总汞浓度平均值与特定地点的大气汞沉积估计值呈正相关。本研究提供了迄今为止蝙蝠中汞测量的最大地理覆盖范围，并表明大气汞沉积对确定哺乳动物物种中汞积累的空间模式具有重要意义。
