巢湖沉积物中重金属的BCR形态分析

以巢湖沉积物为研究对象,利用BCR(European Communities Bureau of Reference)连续提取法分析了沉积物样品中Zn、Cu、Pb、Cd、Mn赋存特征,分为可交换态及碳酸盐结合态、铁锰氧化物结合态、有机物及硫化物结合态和残渣态。结果表明:南淝河入湖区S1采样点五种金属总量都达到最高,兆河入湖区S2采样点金属总量浓度最低。五种金属中锌和锰的质量较高,重金属回收率分别为:锌(93%),铜(92%),铅(90%),镉(92%),锰(93%)。Cu以残渣态为主(54.7%),Zn以铁锰氧化物结合态为主(40.5%),Pb以有机物、硫化物结合态为主(35.3%),Cd和Mn以可交换态及碳酸盐结合态为主,所占比例分布为41.9%、58.6%。研究表明,应用BCR连续提取法有助于确定沉积物中重金属的污染状况和潜在释放能力。

Chemical Speciation of Heavy Metals from Chaohu Lake Sediments Using BCR Procedure

Heavy metals induding Zn, Cu, Pb, Cd and Mn content of Chaohu Lake sediments were studied using BCR(European Communities Bureau of Reference ) sequential extraction procedure. The metals were partitioned into four operationally defined chemical forms: acid extractable, reducible, oxidizable and residual. Results showed that the sediments from Nanfei River contain the highest amount of total metal concentration whereas the lower amounts were found in the Zhaohu River inlet sediments. Compared to three other metals concentration, Zn and Mn concentrations are high. The percentage recovery for all metals when comparing total metal concentration with the fractional sum of the BCR procedure were as follows: Zn(93%),Cu(92%),Pb(90%),Cd (92%), Mn (93%). Cu was associated with residual fraction of 54.7%, Zn prevailed in Fe/Mn oxide fractions with 40.5%, Pb is distributed mainly in organic/sulphide fractions with 35.3%. The percentage fractionation of Cd and Mn showed the highest amount in the acid extractable fractions with 41.9% and 58.6% respectively. Application of sequential extraction of BCR was useful in assessing the pollution and release capacity of heavy metals in sediment.