了解土壤有毒有害元素含量,污染水平,和青藏高原北缘的生态风险状况,我们收集并分析了8273组表层土壤样品。使用单因素污染指数进行评价,地质积累,污染负荷,和潜在的生态风险指数,源识别相关性和主成分分析。结果显示,与中国的背景水平相比,土壤砷的积累,镉,镍,研究区表层土壤中铬含量较高。此外,与青海省相比,由于人为活动的影响,研究区表层土壤中积累了更多的汞。对照土壤环境质量标准,研究区的污染控制区主要以砷和镉为主(3.9%)。空间分布揭示了不同的区域:以砷-镉-铬-镍为特征的山脊型,只有镉存在的达班山类型,和以砷为主的龙羊峡-尖扎南型。与青海省土壤背景值相比,使用污染负荷指数进行评估,地质累积指数,和潜在生态风险指数方法揭示了不同程度的潜在有毒元素含量超标。从生态风险的角度来看,潜在生态风险系数最高的单个元素是汞,其次是镉和砷;然而,该地区的总体生态风险指数被归类为低。确定了三种不同的来源:天然来源导致高背景含量的铬,镍,铜,锌,和汞;导致镉水平升高的自然和工业/农业混合来源;和与人类活动相关的汞富集。根据评估结果,建议对自然发生的危险区的土壤和生物群进行协同监测,以确保农业和牧草产品的安全。此外,应在受人类活动影响的区域进行生态影响评估和污染源缓解研究,以遏制土壤生态质量的进一步退化。
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.