铅锌矿区浮萍中铅的XANES形态分析

南京栖霞山铅锌矿是华东地区最大的铅锌矿床之一，已开采50多年，由此引发的环境问题日益突出。当地环境中铅含量较高，但铅的迁移和毒性机理不明。为此在该地区开展了铅锌矿生物地球化学研究，借助ICP-MS铅含量分析和Pb-LⅢ边XANES形态分析技术，在该污染区发现了耐受并富集重金属的浮萍样品，浮萍中铅的含量为39.4 mg·kg-1。XANES分析和形态拟合结果显示其含硬脂酸铅65%和硫化铅36.9%，从而揭示浮萍样品中铅以含硫的有机酸铅形式存在。

XANES Study of Lead Speciation in Duckweed

Qixiashan lead-zinc mine of Nanjing was one of the largest lead zinc deposits in East China. Its exploitation has been over 50 years, and the environmental pollution has also been increasing. The lead concentration in the local environment was high, but lead migration and toxic mechanism has not been clear. Therefore, biogeochemistry research of the lead zinc mine was carried out. Using ICP-MS and Pb-LⅢ edge XANES, lead concentration and speciation were analyzed respectively, and duckweed which can tolerate and enriched heavy metals was found in the pollution area. The results showed that the lead concentration of duckweed was 39.4 mg·kg-1. XANES analysis and linear combination fit indicated that lead stearate and lead sulfide accounted for 65% and 36.9% respectively in the lead speciation of duckweed, suggesting that the main lead speciation of duckweed was sulfur-containing lead-organic acid.