大多数研究评价土壤环境容量时忽略了重金属来源的影响,而基于物质来源解析探讨土壤重金属环境容量,能更好地评估区域环境容量特征及其动态变化原因,对有效防控、预警和治理重金属污染具有重要意义。汕头市是广东省的经济特区之一,拥有较高的工业化和城市化水平,土壤重金属污染不容忽视,而目前区域环境容量状况尚不明确。因此本研究以汕头市表层土壤为研究对象,采集了511件土壤样品,以进行土壤环境容量研究。基于GIS技术和地统计学方法,我们采用富集因子法评估研究区土壤重金属富集程度,运用主成分分析和相关性分析方法判断土壤重金属来源,根据综合指数法分析土壤重金属的环境容量特征以及各环境容量指数空间分布规律。结果表明:汕头市表层土壤As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量分别为4.84(0.23~119.4)、0.14(0.013~4.94)、36.05(2.2~109.1)、19.08(2.9~453.1)、0.18(0.008~1.394)、13.29(3.7~229.6)、51.73(9.9~1 000)和79.83(9.2~309.5)mg/kg。除土壤Pb整体为中度富集,研究区其他土壤重金属整体为轻度富集。主成分分析结果表明:5个主成分来源分别为自然和农业混合源、农业和工业混合源、工业来源、采矿来源和石材开采来源。土壤重金属静态环境容量大小排序为Zn>Cr>Ni>Pb>Cu>As>Hg>Cd。土壤重金属综合环境容量为中等容量水平,受地质背景的影响,但盐鸿镇、贵屿镇和陈店镇等区域由于综合人类活动导致重金属环境容量普遍较低,存在一定风险。本研究结果可为汕头市预警和管控土壤重金属污染,修复和治理污染土壤,提高环境容量和土壤质量提供科学参考依据。

Soil environmental capacity assessments often overlook the influence of heavy metal sources, yet analyzing these sources is essential for understanding regional environmental dynamics and mitigating heavy metal pollution effectively. In Guangdong Province, Shantou stands as a prominent economic hub with significant industrial and urban development, raising concerns about soil heavy metal pollution and the region’s environmental capacity. This study focused on surface soil in Shantou, utilizing 511 soil samples to investigate environmental capacity. Employing GIS technology and geostatistics, we applied the enrichment factor method to evaluate heavy metal enrichment. Principal component analysis and correlation analysis were used to discern heavy metal sources, while the comprehensive index technique was employed to analyze soil heavy metal environmental capacity features and spatial distribution. The surface soil in Shantou exhibited concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were 4.84 (0.23-119.4), 0.14 (0.013-4.94), 36.05 (2.2-109.1), 19.08 (2.9-453.1), 0.18 (0.008-1.394), 13.29 (3.7-229.6), 51.73 (9.9-1000), and 79.83 (9.2-309.5) mg/kg. Except for moderate enrichment of soil Pb, other heavy metals showed mild enrichment. Principal component analysis revealed five principal component sources: mixed natural background and agricultural activities, mixed agricultural activities and industrial production, industrial production, mining activities, and stone mining sources. Soil heavy metals’ static environmental capacity ranking was As > Zn > Cr > Ni > Pb > Cu > As > Hg > Cd, with a moderate comprehensive environmental capacity level. However, extensive human activities have led to generally low environmental capacities for heavy metals in the towns of Yanhong, Guiyu, and Chendian, posing certain risks. The findings of this study can serve as a scientific reference for early warning and management of soil heavy metal pollution, as well as the remediation and governance of contaminated soil in Shantou City. Additionally, it provides valuable insights for enhancing environmental capacity and soil quality.