Lin Wen-Jie, Xiao Tang-Fu, Zhou Wan-Chun, Ao Zi-Qiang, Zhang Jun-Fang
Hanshan Normal University, Chaozhou 521041, China.
Huan Jing Ke Xue. 2009 Jul 15;30(7):2065-70.
Indigenous zinc smelting activity, widely spread in western Guizhou, China, had caused serious pollution of heavy metals of lead (Pb), zinc (Zn) and cadmium (Cd) in soil and water and posed risk to the local ecosystem. Geochemical distribution and mobility of Pb, Zn and Cd in soil, waste residue and waters were investigated in a small watershed in order to provide scientific base for the approach to pollution control and remediation. Concentrations of Pb, Zn and Cd in smelting residues averaged at 4 632 mg/kg, 8 968 mg/kg, and 58 mg/kg, respectively; whereas Pb 234 mg/kg, Zn 400 mg/kg and Cd 9.6 mg/kg in average in the soils around the smelting areas were measured. The sequential geochemical extraction test showed that Pb, Zn and Cd in the contaminated soils had high mobility and bioavailability for the metals, whereas smelting waste residues had lower mobility and bioavailability because their concentrations presented small percentages (all less than 0.2%) in the exchangeable fraction. Concentrations of Pb, Zn and Cd were high in the local stream water but low in groundwater. In the surface water, Pb, Zn and Cd were significantly concentrated in the suspended sediment. The results indicated that metal-rich erosion process of smelting residue and contaminated soil contributed to mobility of the metals into stream water.
在中国贵州西部广泛分布的本土锌冶炼活动，已造成土壤和水体中铅（Pb）、锌（Zn）和镉（Cd）等重金属的严重污染，并对当地生态系统构成风险。为了给污染控制和修复方法提供科学依据，对一个小流域内土壤、废渣和水体中铅、锌、镉的地球化学分布及迁移性进行了调查。冶炼废渣中铅、锌、镉的浓度平均分别为4632毫克/千克、8968毫克/千克和58毫克/千克；而冶炼区周边土壤中铅、锌、镉的平均含量分别为234毫克/千克、400毫克/千克和9.6毫克/千克。连续地球化学提取试验表明，污染土壤中的铅、锌、镉具有较高的迁移性和生物有效性，而冶炼废渣的迁移性和生物有效性较低，因为其在可交换态中的浓度占比很小（均小于0.2%）。当地溪流水体中铅、锌、镉浓度较高，而地下水中浓度较低。在地表水中，铅、锌、镉显著富集于悬浮沉积物中。结果表明，富含金属的冶炼废渣和污染土壤的侵蚀过程导致了金属向溪流水体的迁移。
