Bi Xiangyang, Feng Xinbin, Yang Yuangen, Li Xiangdong, Sin Grace P Y, Qiu Guangle, Qian Xiaoli, Li Feili, He Tianrong, Li Ping, Liu Taoze, Fu Zhiyou
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, PR China.
Sci Total Environ. 2007 Nov 15;387(1-3):257-68. doi: 10.1016/j.scitotenv.2007.07.059. Epub 2007 Sep 5.
Historical zinc smelting in Hezhang, southwestern China, has resulted in significant heavy metal contamination of the surrounding ecosystems. The Caohai wetland system, which is an important national nature reserve close to the Hezhang zinc smelting area, was investigated in the present study. Results showed that sediments from the Caohai wetland system have been seriously contaminated by Cd, Pb and Zn with the highest concentrations in the surface sediments being up to 71, 160 and 1,200 microg g(-1), respectively. The heavy metals in the sediments were strongly associated with the organic/sulphide and residual fractions. A more oxidized condition induced by aquatic plants tended to cause the Cd, Pb and Zn bound to the Fe-Mn oxide fraction to become more dominant. Pb isotopic compositions in the sediments indicated that the inventories of Pb in the Caohai wetland sediments were mainly derived from the historical zinc smelting in the Hezhang area, although other anthropogenic sources, such as the gasoline Pb, also made a substantial contribution to the Pb in the sediments. Heavy metal contamination in aquatic plants was also studied and the results indicated that heavy metals accumulated by plants may pose a potential threat to the higher trophic-level organisms, including humans.
中国西南部赫章县过去的锌冶炼活动导致周边生态系统受到严重重金属污染。本研究对靠近赫章锌冶炼区的重要国家级自然保护区——草海湿地系统进行了调查。结果表明，草海湿地系统的沉积物已受到镉、铅和锌的严重污染，表层沉积物中这些元素的最高浓度分别高达71、160和1200微克/克。沉积物中的重金属与有机/硫化物及残渣态部分密切相关。水生植物引起的更氧化环境往往会使与铁锰氧化物结合的镉、铅和锌占比更大。沉积物中的铅同位素组成表明，草海湿地沉积物中的铅存量主要来自赫章地区过去的锌冶炼活动，不过其他人为来源，如汽油中的铅，也对沉积物中的铅有很大贡献。本研究还对水生植物中的重金属污染进行了调查，结果表明植物积累的重金属可能对包括人类在内的更高营养级生物构成潜在威胁。
