School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; School of Science, Tibet University, Lhasa 850012, Tibet Autonomous Region, China.
Sci Total Environ. 2020 May 1;715:136639. doi: 10.1016/j.scitotenv.2020.136639. Epub 2020 Jan 10.
Due to the utilization of landfill technology and geothermal energy production in Tibet, the contamination of the soils and underground water by trace element has currently become a serious problem, both ecologically and to the human health point of view. However, relevant studies concerning this critical problem, particularly in the Tibet area has not been found. Therefore, this study investigated the soil contamination and the spatial distribution of the trace elements in the areas surrounding the Tibetan landfill sites (LS) and geothermal sites (GS) through several pollution evaluation models. In addition, the possible sources of trace elements and their potential impact on public health were also investigated. Results showed that the trace elements in soils nearby LS and GS had moderate to high contamination risk. In soils surrounding LS, mercury had the highest concentration of 0.015 mg/kg and was 6 times higher than the background value of 0.008 mg/kg while in GS, arsenic had the highest concentration of 66.55 mg/kg, and exceeded the soil contamination risk value of 25 mg/kg. Maizhokunggar LS was the most polluted site with an average pollution load index value of 2.95 compared to Naqu, Nyingchi, Shigatse, and Lhasa. 42% of LS were with considerable ecological risk, and all GS had low ecological risk. Both carcinogenic and non-carcinogenic risk for children and adults (male, female) were within the acceptable range. According to the source analysis, unscientific anthropogenic activities including accumulated MSW, industrial discharges, and vehicle emissions significantly contributed 51.83% to soil trace element contamination. Considering that Tibet is an environment-ecologically vulnerable region with very weak self-adjustment ability, accumulated municipal solid waste in the landfill sites should be well disposed of, and even soil remediation should be well implemented.
由于西藏采用了垃圾填埋技术和地热能生产，土壤和地下水中的微量元素污染已成为一个严重的问题，从生态和人类健康的角度来看都是如此。然而，目前尚未发现关于这一关键问题的相关研究，特别是在西藏地区。因此，本研究通过几种污染评估模型，调查了西藏垃圾填埋场（LS）和地热场（GS）周围地区的土壤污染和微量元素的空间分布。此外，还研究了微量元素的可能来源及其对公众健康的潜在影响。结果表明，LS 和 GS 附近土壤中的微量元素具有中到高的污染风险。在 LS 周围的土壤中，汞的浓度最高，为 0.015mg/kg，是背景值 0.008mg/kg 的 6 倍，而在 GS 中，砷的浓度最高，为 66.55mg/kg，超过了 25mg/kg 的土壤污染风险值。与那曲、林芝、日喀则和拉萨相比，马孜雄朗 LS 是污染最严重的地区，平均污染负荷指数值为 2.95。42%的 LS 具有相当大的生态风险，而所有的 GS 都具有低生态风险。儿童和成人（男性、女性）的致癌和非致癌风险均在可接受范围内。根据源分析，包括积累的 MSW、工业排放和车辆排放在内的非科学人为活动对土壤微量元素污染的贡献率为 51.83%。考虑到西藏是一个环境生态脆弱、自我调节能力较弱的地区，应妥善处理垃圾填埋场中的城市固体废物，并甚至应实施土壤修复。
