江西贵溪冶炼厂重金属环境污染特征及生态风险评价

金属矿物开采、冶炼等活动引起土壤金属污染是世界普遍存在的问题,由此引起的人类健康问题和环境生态的恶化,越来越受到世界各国环境学家关注。本文调查了冶炼厂周围农田重金属元素的纵向分布,并利用连续浸提法分析主要污染元素的化学形态,结果表明,土壤Cu,Zn,Cd和Pb的非残渣态含量远远高于未污染土壤,污染元素的生物可利用性高;同时采用多指标生态评价体系,对铜矿冶炼厂周围农田土壤重金属污染进行综合的潜在生态风险评价。根据风险指标体系和空间分异规律,将冶炼厂周围农田分成3种生态风险功能区。

THE VIRTICAL DISTRIBUTION AND POTENTIAL ECLOGICAL RISK ASSESSMENT OF HEAVY MENTALS IN AGRICALTURAL SOILS NEAR SMELTER

The contamination arising from mining or smelting activities is a global or worldwide problem. There is a growing public concern over the potential accumulation of heavy metals in agricultural soils in China. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but elevated heavy metal uptake by crops may also affect food quality and safety. This paper investigated the vertical distribution and chemical fractions of heavy metals in the paddy soils surrounding copper smelter. The results suggested that Pb was largely associated with the residual and NH_2OH HC1 extracted fractions, on the other hand, Cd was predominantly associated with the MgCl_2 extracted fraction. A significant percent fraction of Cu was bound in the acidic H_2 O_2 extracted fractions, while Zn was predominantly found in the residual phase. The fraction of mobile species, which potentially is the most harmful for the environment, was found to be higher than the one normally present in unpolluted soils, where heavy metals are, to a higher extent, strongly bound to the matrix. The index of potential ecological risk allows us to assess the potential risk of heavy metal pollutants in the paddy soils and evaluate the contamination area can be divided into 3 types.