【摘要】 采用化学连续浸提试验研究了贵溪市污灌水田污染元素(Cd、Cu、Zn、Pb)的化学形态分布。结果表明,土壤中不同重金属元素化学形态分布具有不同的特点:Cd以离子交换态最高(80%),而残渣态比例较低;Cu以有机物结合态最高,残渣态最低;Zn以残渣态为主,有机物结合态最低;Pb以残渣态为主,水溶态最低。由冶炼厂废渣污水引起的土壤重金属污染的重要特征是元素生物可利用性较高;Cd、Cu、Zn、Pb各形态间存在明显的转化能力。此外,通过研究确定了研究区内主要污染元素是Cd和Cu,其次是Zn,而Pb的影响较小。更多还原

【Abstract】 Contamination of soils by potentially toxic elements (PTEs) (e.g. Cu , Zn, Cd, Pb) from sewerage is now widespread. Anthropogenic of PTEs now exceed and dominate the mobilization of heavy metals from global weathering process wit h significant implications for the biosphere. This paper highlights the need for bioavailability data for the assessment of PTEs (from melt plant) impacts. The chemical fractions of PTEs play an essential role in determining mobility levels of heavy metals in paddy soil, being intimately associated with the biogeochemi cal cycling of essential plant nutrients and bioavailability of PTEs. The measur ement of chemical fractions of PTEs can provide insight into the bioavailability and impact of PTEs., where PTEs total concentration analysis alone can often be inadequate to assess contaminant effects on essential components of the soil ec osystem. According the sequential extraction, the author analyzed the chemical f orms of Cd, Cu, Zn and Pb in swage-irrigated paddy soil in Guixi city in this s tudy. The results indicated that the mean Cd, Cu, Zn and Pb concentrations in sw age-irrigated paddy soils were 1.97 mg·kg-1, 235.26 mg·kg-1, 122.94 mg·kg-1 and 17.66 mg·kg-1 respectively, and 80 percent of Cd was dominated by the exchangeable fraction, and followed by the order of exchangeable water solutio n > Fe-Mn oxides > carbonate >residual > organic. Cu was dominated by organic f raction, and was least present in residual fraction, and followed by the order o f organic > exchangeable > carbonate > Fe-Mn oxides > water solution> residual. Zn was dominated by residual fraction, and followed by the order of residual > water solution > Fe-Mn oxides > exchangeable > carbonate > organic. Pb was domi nated by residual fraction, and was least present in water solution fraction, an d followed by the order of residual > Fe-Mn oxides >carbonate > exchangeable > organic > water solution. Five chemical factions of Cd, water solution, exchange able, carbonate, Fe-Mn oxides and organic, translate each other and the chemica l fractions of Cu has the same character, which provided some theory for soil re mediation. According the class of bioavailability, potentially bio availability and non-bioavailability, the author calculated and the obtained results showed that the order of bioavailability was Cd>>Cu>Zn>pb and their potentially bioavai labilities were high. The most important pollution characters for the area pollu ted by swage of melt plant was that the bioavailabilities of Cu, Zn, Cd and Pb w ere high and the main pollution elements were Cd and Cu, and followed by Zn.更多还原