福建省表层土壤环境质量地球化学评价及空间分布特征

    Geochemical assessment and spatial distribution characteristics of the environmental quality of topsoils in Fujian Province

    • 摘要: 基于福建省1∶25万多目标区域地球化学调查所获得的8种重金属元素高精度、高质量数据,以表层土壤(0~20 cm)为研究对象,参照土壤环境质量标准 (GB 15618—2018),建立了与评价标准结构特点相匹配的单指标和综合指标土壤环境质量地球化学评价方法,首次对福建省全域表层土壤环境质量进行评价。结果表明:①福建省表层土壤以强酸性和酸性为主,两者土壤面积分别占全省总面积的36.5%和57.89%。②优先保护类土壤面积占全省总面积的91.06%,土壤环境质量总体上较好,土壤重金属超标率为8.94%,远低于全国土壤总超标率(16.1%);超标率最大的元素为Pb,占4.95%,其次为Cd,占2.84%,Zn、Hg、Cu、As、Ni、Cr超标率极小。③表层土壤元素空间分布特征主要表现为Pb、Cd、Zn、Cu、As、Cr超标区主要分布于武夷山成矿带金属或非金属硫化物矿床、矿(化)点及其周边,Hg超标区主要分布于尤溪县与德化县接壤处以及福建沿海地区的城市,Ni超标区主要分布于漳浦县东北的佛昙组玄武岩、橄榄玄武岩地质背景区,总体上表现为沿海地区土壤环境质量好于内陆地区。本次评价结果填补了福建省土壤环境质量地球化学评价研究的空白,首次获得了福建省整装性的土壤环境质量地球化学评价成果,为相关领域的科学研究及福建省地质化信息工程大数据平台建设提供了基础地球化学资料,掌握了福建省土壤资源环境质量状况,为福建省土壤环境治理、国土空间规划、国家生态文明试验区(福建)建设等提供了决策参考,具有重要的科学价值。

       

      Abstract: Based on the high-precision and high-quality data of eight heavy metals obtained from the 1∶250,000 multi-purpose regional geochemical survey in Fujian Province, this study investigated the topsoils (depths: 0~20 cm) throughout the province, with reference to the Environmental Quality Standard for Soils (GB 15618—2018). A geochemical assessment method for soil environmental quality based on individual/composite indices, matching the structural characteristics of the assessment standard, was developed to first assess the environmental quality of topsoils across Fujian Province. The results indicate that the topsoils in Fujian Province are dominated by strongly acidic and acidic soils, representing 36.5% and 57.89% of the total area in the province, respectively. The soils for prioritized conservation cover 91.06% of the total area, suggesting overall high soil environmental quality in the province. The over-limit ratio of 8.94% for soil heavy metals in the province is significantly below the total over-limit ratio of 16.1% in China. The element with the highest over-limit ratio is Pb, accounting for 4.95%, followed by Cd, accounting for 2.84%. In contrast, elements like Zn, Hg, Cu, As, Ni, and Cr show minimal over-limit ratios. Regarding the spatial distribution characteristics of topsoil elements, zones with over-limit Pb, Cd, Zn, Cu, As, and Cr are primarily distributed in the metal or non-metal sulfide deposits/ore occurrences/mineralized spots within the Wuyishan metallogenic belt and their surrounding areas. Zones with over-limit Hg are primarily distributed in the junction zone between Youxi and Dehua counties, as well as in cities along the coastal area of Fujian Province. The zone with over-limit Ni is predominantly located in the geological background area of the Fotan Formation basalts and olivine basalts in the northeast of Zhangpu County. Overall, the soil environmental quality is higher in the coastal area compared to the inland area. The assessment results of this study fill the gap in the geochemical assessment of soil environmental quality in Fujian Province, first providing the comprehensive geochemical assessment data of soil environmental quality for the province. These data, revealing the environmental quality of soil resources in Fujian Province, serve as fundamental geochemical data for scientific research in related fields and for constructing the geological information engineering big data platform for Fujian Province. Overall, this study provides a decision-making reference for soil environment management, territorial space planning, and the construction of the national ecological civilization pilot zone (Fujian) in Fujian Province, holding significant scientific value.

       

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