Assessment of acid neutralizing capacity and potential mobilisation of trace metals from land-disposed dredged sediments.
Assessment of acid neutralizing capacity and potential mobilisation of trace metals from land-disposed dredged sediments.
复制标题
DOI：
10.1016/j.scitotenv.2004.05.007
复制
发表时间：
2004-10
期刊：
影响因子：
--
通讯作者：
Valerie Cappuyns;R. Swennen;J. Verhulst
中科院分区：
文献类型：
--
作者：
Valerie Cappuyns;R. Swennen;J. Verhulst
在过去的几十年里，大量的污染沉积物被疏浚并沿着河流散布。了解疏浚沉积物中污染物的归宿和行为对处理污染沉积物的管理至关重要。采用pH-静态淋溶试验和电位滴定法，对10 ~ 70年不同年龄疏浚沉积物中重金属的淋溶行为进行了研究。根据pH值滴定结果，确定了两个操作定义的重金属池，即，一个不稳定和缓慢不稳定的池的重金属，区分和量化的数学描述的浸出行为。在pH值和电位滴定过程中的浸出行为的数学描述允许扣除四组元素与不同类型的浸出行为。对于重金属，Zn，Cd和Ni表现出类似于酸中和能力（ANC）的淋溶行为，而Cu，Pb和Cr的释放比ANC慢。然而，没有发现关于重金属的淋溶行为之间的差异，不同的时间，因为在陆地上处置的沉积物。在这项研究中分析疏浚沉积物的酸中和能力的提高，大大降低了土壤酸化与相关的重金属浸出的风险。与传统的浸出程序相比，pHstat浸出试验的一个重要优势是可以预测较长时间内的土壤酸化以及微量金属的潜在释放。
In the past decades, large amounts of contaminated sediments have been dredged and spread out along rivers. The understanding of the fate and the behaviour of contaminants in dredged sediments is essential to deal with the management of contaminated sediments. Heavy metal leaching behaviour in dredged sediments of different ages since disposal, varying from 10 to 70 years, was assessed by pHstatleaching test and potentiometric titrations. Based on the pHstattitration results, two operationally defined pools of heavy metals, i.e., a labile and a slowly labile pool of heavy metals, were distinguished and quantified by mathematical description of leaching behaviour. The mathematical description of leaching behaviour during pHstatand potentiometric titrations allowed deduction of four groups of elements with a different type of leaching behaviour. Considering heavy metals, Zn, Cd and Ni displayed a leaching behaviour similar to acid neutralizing capacity (ANC), whereas the release of Cu, Pb and Cr was slower than ANC. However, no significant differences with regard to heavy metal leaching behaviour were found between sediments with different time since disposal on land. The elevated acid neutralizing capacity of the dredged sediments analysed in this study strongly decrease the risk of soil acidification with associated heavy metal leaching. The prediction of soil acidification over an extended period of time, together with the potential release of trace metals, was considered an important advantage of pHstatleaching tests compared to conventional leaching procedures.