Fifth Institute of Geological and Exploration of Qinghai Province, Xining, 810000, China.
Qinghai Engineering Research Center for Selenium-Rich Resource Utilization, Xining, 810099, Qinghai, China.
Environ Geochem Health. 2024 Jul 30;46(9):351. doi: 10.1007/s10653-024-02138-5.
To understand the soil toxic and hazardous elements content, pollution level, and ecological risk status in the northern margin of the Tibetan Plateau, we collected and analyzed 8273 sets of surface soil samples. Evaluations were conducted using the single-factor pollution index, geo-accumulation, pollution load, and potential ecological risk indices, and source identification correlation and principal component analysis. The results revealed that, compared with the background levels in China, the accumulation of soil arsenic, cadmium, nickel, and chromium was greater in the surface soil of the study area. Additionally, in comparison with Qinghai Province, more mercury accumulated in the surface soil of the study area and owing to the influence of anthropogenic activities. Benchmarking against soil environmental quality standards, the study area exhibited pollution control zones primarily dominated by arsenic and cadmium (3.9%). The spatial distribution revealed distinct zones: a ridge mountain type characterized by arsenic-cadmium-chromium-nickel, a Daban mountain type with solely cadmium presence, and a Longyangxia-Jianzha South type dominated by arsenic. Compared with the Qinghai Province soil background values, evaluations using the Pollution loading index, Geological Cumulative Index, and Potential Ecological Risk Index methods revealed varying degrees of potentially toxic element content exceedance. From an ecological risk perspective, the individual element with the highest potential ecological risk coefficients were mercury, followed by cadmium and arsenic; however, the region's overall ecological risk index was classified as low. Three distinct sources were identified: natural sources leading to high background levels of chromium, nickel, copper, zinc, and mercury; mixed natural and industrial/agricultural sources contributing to elevated cadmium levels; and human activity-related mercury enrichment. Based on the evaluation results, synergistic monitoring of soil and biota in naturally occurring risk zones is recommended to ensure the safety of agricultural and pastoral products. Additionally, ecological impact assessments and pollution source mitigation studies should be conducted in regions influenced by human activities to curb the further degradation of soil ecological quality.
为了了解青藏高原北缘土壤有毒有害元素的含量、污染水平和生态风险状况，我们采集和分析了 8273 个表层土壤样品。采用单项污染指数、地积累指数、污染负荷和潜在生态风险指数进行评价，并进行了来源识别相关性和主成分分析。结果表明，与中国背景值相比，研究区表层土壤砷、镉、镍和铬的积累量较大。此外，与青海省相比，研究区表层土壤中汞的积累量更大，这是由于人为活动的影响。与土壤环境质量标准相比，研究区主要存在以砷和镉为主的污染控制区（3.9%）。空间分布呈现出明显的区域特征：砷-镉-铬-镍脊状山型、单纯镉存在的大巴山型和以砷为主的龙羊峡-尖扎南型。与青海省土壤背景值相比，采用污染负荷指数、地质累积指数和潜在生态风险指数评价方法，均存在不同程度的潜在有毒元素含量超标。从生态风险角度看，汞的潜在生态风险系数最高，其次是镉和砷；但该地区的整体生态风险指数被归类为低风险。研究确定了三个明显的来源：自然来源导致铬、镍、铜、锌和汞的高背景水平；混合自然和工业/农业来源导致镉含量升高；以及人类活动引起的汞富集。基于评价结果，建议对自然发生风险区的土壤和生物群进行协同监测，以确保农牧产品的安全。此外，应在受人类活动影响的地区进行生态影响评估和污染源头缓解研究，以遏制土壤生态质量的进一步恶化。
