Heavy metal levels and sources in suspended particulate matters of the glacier watersheds in Northeast Tibetan Plateau
Heavy metal levels and sources in suspended particulate matters of the glacier watersheds in Northeast Tibetan Plateau
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DOI：
10.3389/fenvs.2022.918514
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Rui Wu;Z. Dong;Xiping Cheng;J. Brahney;Xiaoyu Jiao;Lihua Wu
中科院分区：
文献类型：
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作者：
Rui Wu;Z. Dong;Xiping Cheng;J. Brahney;Xiaoyu Jiao;Lihua Wu
本研究收集了2017年6月至7月期间青藏高原东北部几个冰川流域夏季融水径流样品，并测量了17种微量元素的浓度（Li，Be，Sc，V，Cr，Co，Ni，Cu，Zn，Ga，Rb，Mo，Cd，In，Sb，Cs，Ba），以揭示融水悬浮颗粒物（SPM）中元素的浓度、空间分布、区域人类活动对偏远冰川流域水质的影响。结果表明，玉珠峰冰川流域重金属元素含量较高，在0.57 μg/L（In）~ 1551.6 μg/L（Ba）之间，七一冰川流域最低，在0.02 ~ 85.05 μg/L之间;其他冰川流域的元素总量相对中等，为1503.9 ~ 1726.2 μg/L。此外，SPM重金属的富集因子（EFs）显示，在下游比上游冰川流域的值显着较高。大多数具有低EFs的重金属主要来源于地壳灰尘，而其他具有较高EFs的重金属（例如，Cd、Sb）可能来源于人为污染。在空间上，玉珠峰和老虎沟冰川流域的重金属富集系数较高，而其他区域的富集系数相对较低，这可能是由于各冰川流域周围的区域地表和大气环境差异造成的。与全球范围内其他偏远地区相比，重金属水平（例如，Cu、Ni、Zn）含量相对较高。同时发现，青藏高原东北部冰川流域的水质虽然相对清洁无污染，但仍明显受到区域人类活动的影响。研究区的采矿活动、交通运输和自然风化侵蚀过程对冰川流域河水SPM中重金属污染物的含量有重要影响。此外，向后的气团轨迹表明，潜在的大气污染物从周围的城市和郊区，存款在积雪和冰川，然后融化，释放到融水径流。该研究为更全面地了解冰川流域重金属分布提供了新的视角，也为青藏高原地区冰冻圈水环境评价提供了新的认识。
This study collected summer meltwater runoff samples from several glacier watersheds of the northeast Tibetan Plateau during June-July 2017, and measured the concentrations of 17 trace elements (Li, Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Mo, Cd, In, Sb, Cs, Ba) in meltwater suspended particulate matter (SPM), in order to reveal the elemental concentration, spatial distribution, and water quality in remote glacier watershed under regional anthropogenic activities. Results showed that, the concentration of heavy metal elements was relatively high in Yuzhufeng Glacier basin, ranging from 0.57 μg/L (In) to 1,551.6 μg/L (Ba), whereas in Qiyi Glacier basin it was the lowest, ranging from 0.02 to 85.05 μg/L; and relatively medium in other glacier watersheds, with total elemental concentration varying from 1,503.9 to 1726.2 μg/L. Moreover, enrichment factors (EFs) of SPM heavy metals showed significantly higher value in the downstream than that of upper glacier region of the watershed. Most heavy metals with low EFs mainly originated from crust dust, while others with higher EFs (e.g., Cd, Sb) probably originated from anthropogenic sources. Spatially, the EFs of heavy metals were higher in Yuzhufeng and Laohugou Glacier basins; while in other regions the EFs were relatively low, which may be caused by regional land-surface and atmospheric environmental differences surrounding the various glacier watersheds. Compared with other remote locations in global range, heavy metals level (e.g., Cu, Ni, and Zn) in this region is relatively higher. Meanwhile, we find that, though the water quality of the glacier basin in northeast Tibetan Plateau was relatively clean and pollution-free, it is still obviously affected by regional anthropogenic activities. Mining activities, transportation and natural weathering and erosion processes in the study areas have important effects on the content of heavy metal pollutants of river-water SPM in the glacier watershed. Moreover, backward air-mass trajectories demonstrated the potential atmospheric pollutants transport from the surrounding cities and suburbs, to deposit in the snowpack and glaciers, and then melted out and released into meltwater runoff. This study provides a new perspective on more complete view of heavy metals distribution in glacier watershed, and new understanding for the cryosphere water environment evaluation in the Tibetan Plateau region.