Department of Earth Sciences, University of Kashmir, Srinagar, 190006, India.
Geosciences Division, Physical Research Laboratory (PRL), Ahmadabad, 380009, India.
Environ Monit Assess. 2019 Mar 9;191(4):213. doi: 10.1007/s10661-019-7338-y.
Snowpack and glacial melt samples were collected to understand the hydrochemical, isotopic characteristics and the source of Hg contamination in high altitude glacierized Himalayan catchment. Both the snow and glacial melt were acidic in nature with calcium and magnesium as the dominant cations and bicarbonate and chloride as the dominant anions. The major ion concentrations for cations were found to be Ca > Mg > Na > K and HCO > Cl > SO > NO for anions. The atmospheric processes like the precipitation source and aerosol scavenging control the snow chemistry and the weathering of the rocks modify the hydrochemistry of glacial melt. The samples of both the snow and glacial melt were classified as Ca-Mg-HCO type. The concentration of Hg in snow (154.95 ng L) and glacial melt (112.04 ng L) was highest (still lower compared to the maximum permissible limit (1000 ng L) by WHO in drinking water) during summer season (August-September) and lowest (snow 2.2 and 40.01 ng L for glacial melt) during winter (November). The results reveal that mercury concentration in snowpacks is attributed to the combined mixing of long-range transport of pollutants via westerlies throughout the year and the industrial effluents coming from highly industrial belts of Panjab, Haryana, Rajasthan, Indo-Gangetic plains, and neighboring areas via southwest monsoons during August-September. However, in glacial melt, the Hg concentration was typically controlled by rate of melting, leaching, and percolation. Higher degree and rate of glacial melting decreases the Hg concentration in glacial melt. Stable isotopic analysis and backward air mass trajectory modeling also corroborate the source of precipitation from southwest monsoons during August-September, with its air mass trajectories passing through the highly industrialized belts of Indo-Gangetic plain and adjoining areas.
采集了雪和冰川融水样本，以了解喜马拉雅高海拔冰川流域中汞污染的水文地球化学、同位素特征和来源。雪和冰川融水均呈酸性，主要阳离子为钙和镁，主要阴离子为碳酸氢根和氯离子。发现阳离子的主要离子浓度为 Ca > Mg > Na > K，阴离子的主要离子浓度为 HCO > Cl > SO > NO。降水源和大气气溶胶清除等大气过程控制着雪的化学性质，而岩石风化则改变了冰川融水的水化学性质。雪和冰川融水的样本均被归类为 Ca-Mg-HCO 型。雪（154.95 ng L）和冰川融水（112.04 ng L）中的 Hg 浓度在夏季（8-9 月）最高（与世界卫生组织规定的饮用水中最大允许浓度（1000 ng L）相比仍然较低），在冬季（雪为 2.2 和 40.01 ng L，冰川融水）最低。结果表明，雪堆积中汞浓度的升高是由于污染物通过西风全年的长距离传输以及来自旁遮普邦、哈里亚纳邦、拉贾斯坦邦、印度恒河平原和邻近地区的工业废水通过西南季风在 8-9 月期间的混合造成的。然而，在冰川融水中，Hg 浓度通常受融冰速率、淋溶和渗透的控制。冰川融解程度和速率越高，冰川融水中的 Hg 浓度越低。稳定同位素分析和后向轨迹模型也证实了 8-9 月期间降水的来源是西南季风，其气团轨迹穿过印度恒河平原和邻近地区的高度工业化地带。
