摘要
试验表明,造林等引起土壤有机质积累和pH降低可改变污染土壤重金属的化学形态和它们的释放潜力。重金属释放潜力随pH下降而增加,但不同重金属对土壤pH下降的敏感性不同,Zn和Cd对pH的变化很敏感,当pH下降至6时,其释放潜力明显增加;而Pb、Cu和Cr在pH下降至5时,释放潜力也明显增加。有机质积累对重金属释放潜力的影响与pH和有机质积累程度有关,当pH在6以上时,低量和中量有机质的积累可促进重金属的活化;而当pH在5以下或有机质积累达到很高水平时,有机质的积累降低了重金属的有效性。因此,在重金属污染土壤上植树造林应注意因土壤性质改变引起的重金属释放强度的增加和对周围水体的污染。
Afforestation of degraded soils could cause soil acidification and accumulation of organic matter, which increases the risk of heavy metal leaching. In this study, the chemical forms and release potential of heavy metals in a heavy metals-contaminated soil were investigated in the laboratory following the simulated acidification and organic matter accumulation of the soil. The release potential of the metals in the soil increased with decreasing pH. The effect of pH on metal release from soil varied with types of heavy metals. The releases of Zn and Cd were very sensitive to pH, and the release increased significantly when pH decreased to 6.0. The release of Pb, Cu and Cr from the soil increased significantly when pH decreased to 5.0. The effect of organic matter accumulation on release of the metals was related to soil pH and degree of organic matter accumulation. When soil pH was over 6, low and middle accumulation of organic matter could active heavy metals in the soils, and increase release potential of the metals from the soil. When pH was below 5 or the accumulation of organic matter reached high level, the accumulation of organic matter could decrease release of the metals from the soil.
出处
《土壤通报》
CAS
CSCD
北大核心
2009年第3期538-541,共4页
Chinese Journal of Soil Science
基金
浙江省自然科学基金(No.R306011)
国家自然科学基金(40771090)资助
关键词
有机质积累
污染土壤
重金属
释放
Accumulation of organic matter
Contaminated soil
Heavy metals
Release
