Faculty of Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
Environ Pollut. 2010 Mar;158(3):649-57. doi: 10.1016/j.envpol.2009.10.030. Epub 2009 Nov 13.
A derelict canal contains an estimated 9800 tonnes of anoxic sediment with highly elevated concentrations of trace elements. Lack of maintenance, reduced water levels and vegetation colonization threaten the stability of pollutants by removing existing waterlogged reduced conditions. A column leaching study of the sediment under increasingly oxidized conditions showed reductions in As mobility but increased heavy metal concentrations. In a reduced state, As mobility was higher (as a consequence of enhanced Fe and organic carbon solubility) whilst heavy metal concentrations in leachates were lower (due to markedly higher pH). Over 10 contiguous wetting and drying cycles, the consequences were profound; all trace elements were continuously leached with enhanced flushing of Fe, As, Zn and Cu. This raises concern over possible mobilization of pollutants to the wider environment, including groundwater. Options for management to stabilize contaminants are discussed that point to the importance of limiting water flow through the sediment.
一条废弃的运河中估计含有 9800 吨缺氧沉积物，其中痕量元素的浓度非常高。缺乏维护、水位降低和植被定植，通过去除现有的积水还原条件，威胁着污染物的稳定性。在不断氧化条件下对沉积物进行的柱浸出研究表明，砷的迁移率降低，但重金属浓度增加。在还原状态下，砷的迁移率更高（由于增强的铁和有机碳溶解度），而浸出液中的重金属浓度更低（由于 pH 值明显更高）。经过 10 多个连续的干湿循环，其后果是深远的；所有痕量元素都被连续浸出，铁、砷、锌和铜的冲洗作用增强。这引起了对污染物可能向更广泛的环境（包括地下水）迁移的关注。讨论了稳定污染物的管理选项，这些选项表明限制水流通过沉积物的重要性。
