School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Canada.
Department of Biology, University of Saskatchewan, Saskatoon, Canada.
Sci Total Environ. 2018 Mar 15;618:916-926. doi: 10.1016/j.scitotenv.2017.08.278. Epub 2017 Oct 14.
Previous gold mining activities and arsenopyrite ore roasting activities at the Giant mine site (1948 to 2004) resulted in the release of high amounts of arsenic and trace metals into the terrestrial and aquatic ecosystems of Yellowknife, Northwest Territories, Canada. While elevated levels of arsenic has been consistently reported in surface soils and vegetation near the vicinity of the Giant mine area and in surrounding locations, systematic studies evaluating the overall health status of terrestrial small mammals endemic to the area are lacking. The purpose of this present study was to evaluate and comparatively assess the biochemical responses and histopathological effects induced by chronic arsenic and cadmium exposure in wild snowshoe hares breeding near the city of Yellowknife, specifically around the vicinity of the abandoned Giant mine site and in reference locations. Analysis included measurement of total arsenic and cadmium concentration in nails, livers, kidneys, bones, stomach content of hares, in addition to histopathological evaluation of hepatic and ocular lesions. Biochemical responses were determined through measurement of lipid peroxidation levels and antioxidant enzymes activities (catalase, superoxide dismutase, glutathione peroxidase, and glutathione disulfide). The results revealed that arsenic concentration was 17.8 to 48.9 times higher in the stomach content, and in the range of 4 to 23 times elevated in the nails of hares from the mine area compared to the reference location. Arsenic and cadmium levels were also noted to be increased in the bones, renal and hepatic tissues of hares captured near the mine area compared to the reference site. Specifically, hares from the mine area showed nail cadmium levels that was 2.3 to 17.6 times higher than those from the reference site. Histopathological examination of the eyes revealed no specific ocular lesions, such as lens opacity (cataracts) or conjunctivitis; however, hares from both locations exhibited hepatic steatosis (fatty liver change). Lipid peroxidation levels were relatively increased and accompanied with reduced antioxidant enzyme activities in hares from the mine area compared to the hares from the reference site. The results of this preliminary study suggest that the snowshoe hares breeding near the vicinity of Yellowknife, including near the Giant mine area have been chronically exposed to elevated levels of arsenic and cadmium, which consequently led to the increased levels of oxidative stress and perturbation of antioxidant defense system in exposed animals. The results of this present study constitute the first observation of chronic arsenicosis in wild small mammal species in Canada.
过去在加拿大西北地区耶洛奈夫市的 Giant 矿区（1948 年至 2004 年）的金矿开采活动和毒砂矿石的烘烤活动，导致大量的砷和痕量金属释放到陆地和水生生态系统中。虽然在 Giant 矿区附近和周围地区的地表土壤和植被中一直报告存在高浓度的砷，但缺乏对该地区特有陆地小型哺乳动物整体健康状况进行系统研究。本研究的目的是评估和比较评估慢性砷和镉暴露对耶洛奈夫市附近（特别是在废弃的 Giant 矿区及其附近地区）和参考地区繁殖的野生雪兔的生化反应和组织病理学影响。分析包括测量指甲、肝脏、肾脏、骨骼、雪兔胃内容物中的总砷和镉浓度，以及肝和眼部病变的组织病理学评估。生化反应通过测量脂质过氧化水平和抗氧化酶活性（过氧化氢酶、超氧化物歧化酶、谷胱甘肽过氧化物酶和谷胱甘肽二硫化物）来确定。结果表明，矿区雪兔胃内容物中的砷浓度比参照区高 17.8 至 48.9 倍，指甲中的砷浓度比参照区高 4 至 23 倍。矿区附近捕获的雪兔的骨骼、肾脏和肝脏组织中的砷和镉水平也高于参照点。具体来说，矿区雪兔的指甲中镉含量比参照区高 2.3 至 17.6 倍。对眼睛的组织病理学检查未发现特定的眼部病变，如晶状体混浊（白内障）或结膜炎；然而，来自两个地点的兔子都表现出肝脂肪变性（脂肪肝变化）。与参照区相比，矿区的雪兔的脂质过氧化水平相对升高，同时抗氧化酶活性降低。这项初步研究的结果表明，在耶洛奈夫市附近繁殖的雪兔，包括 Giant 矿区附近，已经长期暴露于高水平的砷和镉，这导致暴露动物的氧化应激水平增加和抗氧化防御系统受到干扰。本研究的结果首次观察到加拿大野生小型哺乳动物慢性砷中毒。
