安菜生长土壤中重金属的环境质量及来源

安徽省舒城县庐镇乡安菜村出露有秦岭—大别造山带超高压变质岩榴辉岩, 并产出特色农产品安菜, 为查明安菜生长区土壤中重金属的环境质量及来源, 揭示安菜生长土壤的独特性, 文章在安菜村系统采集了岩石、土壤和安菜样品, 测定 Ni、Cu、Zn、As、Hg 和 Pb 等 6 种重金属的质量比。结果表明, 研究区安菜生长土壤中 6 种重金属的质量比较低, 均未超过相关环境质量标准值, 区内天然土壤无重金属污染的风险。安菜中 Cu 和 Zn 的质量比较高, 而 Ni、As、Hg 和 Pb 的质量比较低, 但土壤和母岩中这 4 种元素的质量比却较高, 表明安菜对 Ni、As、Hg 和 Pb 等重金属的生物富集作用较小。百丈崖土壤和岩石均富集 Zn, 棋盘石山岩石富集 Pb, 土壤富集 Ni、Zn、Hg 和 Pb, 土壤和岩石样品中重金属的质量比具有一致的变化趋势, 表明成土母岩是该区土壤中重金属质量比的决定因素。此外, 土壤中 Cu、As 和 Hg 的质量比均高于成土母岩中的 Cu、As 和 Hg 在成土过程中有一定的富集趋势。

The Ancai village, located in Luzhen Town of Shucheng County in Anhui Province, is famous for the outcrop of eclogite, an ultra-high pressure metamorphic rock in the Qinling-Dabie orogenic belt, and the production of Ancai, a special agricultural plant. To investigate the environmental quality and possible provenances of heavy metals in the uncultivated soils for the wild Ancai growing, and to unveil the unique geochemical features of the soils, a series of rocks, residual soils, and Ancai plants were collected and analyzed. The concentrations of Ni, Cu, Zn, As, Hg, and Pb were determined by ICP-MS and AFS. Results showed that the concentrations of six heavy metals in the uncultivated soils were low and not higher than the thresholds of relevant environmental quality standards. The uncultivated soils did not have any risks of heavy metal pollution. The Ancai plants were of high Cu and Zn contents and low Ni, As, Hg, and Pb contents. The soils and parent rocks showed an opposite feature, with high contents of Ni, As, Hg, and Pb, indicating that the Ancai plants did not biologically enrich these heavy metals. Zinc was enriched in the soil and rock samples from the Baizhangya Hill. Lead was enriched in rock samples from the Qipanshi Hill; in addition, Ni, Zn, Hg, and Pb were enriched in their residual soil. The heavy metals in soil and rock samples presented a similar distribution.