湘江表层沉积物重金属的赋存形态及其环境影响因子分析

采用BCR三步分级提取法分析了湘江衡阳段与岳阳段表层沉积物中4种重金属（Cd、Pb、Cu、Zn）不同赋存形态的含量,阐述了重金属赋存形态及其环境影响因子的关系,评估了这4种重金属的生物有效性.结果表明,4种元素均以弱酸溶解态、可还原态和可氧化态3种可提取态为主,各元素生物有效性即可提取态含量排序为：Cd〉Pb〉Zn〉C...

Speciation of heavy metals in sediments from Xiang River and analysis of their environmental factors

BCR three stages sequential extraction procedure was applied to investigate the speciation and contents of four types of heavy metals (Cd, Pb, Cu, Zn) in the surface sediments in Hengyang-to-Yueyang section of Xiang River. The relationship between the speciation of these heavy metals and their environmental factors were described. Morerover, the bioavailability of these four types of heavy metals was also determined preliminarily. The results showed that all of these four types of metals existed mainly in extractable fractions which included weak soluble fraction, reducible fraction and oxidisable fraction, and the bioavailability for four types of metals were in the descending order of Cd>Pb>Zn>Cu. Heavy metals had positive correlation with their contents of extractable fractions. Correlation Analysis showed that organic matter was the most important environmental factor that influenced the contents and speciation of heavy metals deposited on surface sediments of Xiang River. Accumulation and ecological risk of these four types of metals in the middle and lower reaches were higher than that in the upper reaches, peaking at Shuikoushan aera in Hengyang. This phenomenon showed that emissions from industries along the river was the main impact factor of spatial distribution of heavy metals in sediments in Xiang River area.