摘要
针对福建三明地区实际受重金属污染的土壤样品,采用模拟酸雨淋溶土柱的试验方法,研究了不同酸度模拟酸雨(pH=2.5、3.6和5.6)对污染土壤中重金属元素的淋滤液性质的影响。结果表明,随着模拟酸雨pH值的降低,淋滤液的电导呈递增变化,而淋滤液pH值呈递减变化;随着淋溶量的增加,淋滤液电导逐渐下降,而淋滤液pH值呈现先迅速下降后逐渐升高的总趋势。研究发现,模拟酸雨作用于该受重金属污染土壤时,污染土壤中不同重金属呈现不同的溶出规律。淋滤液中锌、镍、铜、铬和铅的含量均随模拟酸雨pH值的降低而增加,但锌、镍和铜的释放过程可分为快速释放和准稳定两个阶段,铬和铅的释放过程则分为快速释放和慢速释放两个阶段。相同pH值模拟酸雨条件下,该污染土壤中重金属累积释放量由大到小的顺序为Zn>Cu>Cr>Ni>Pb。pH=3.6时,每千克污染土壤中Zn、Cu、Cr、Ni和Pb的最大累积释放量分别为750、60、0.9、0.9和0.48mg。
The soil column leaching model was used to study the leaching process of heavy metals with the simulated acid rain. The soil samples polluted by heavy metals were obtained from Sanming, Fujian Province. The pH of the simulated acid rain was controlled in three levels of 2.5, 3.6 and 5.6. The tested metals included zinc, nickel, copper, lead and chromium. The investigation revealed that, with the pH decrement of the acid rain, the conductivity of the soil leachate increased gradually while the pH of the leachate decreased under the same conditions. With the pH increment of the acid rain, the total content of all the five heavy metals in the leachate tended to increase. However, the resuits also showed that different kinds of heavy metals had their own leaching characteristics. The release of zinc, nickel and copper from the polluted soil increased rapidly in the first stage and then maintained a relatively stable state. For the release process of chromium or lead, it can be divided into two stages of fast leaching and slow leaching. The order of the total released amount of five heavy metals was Zn〉Cu〉Cr〉 Ni〉Pb under the same condition. When the pH of the simulated acid rain was 3.6, the total released amount of Zn, Cu, Cr, Ni and Pb was 750, 60, 0.9, 0.9 and 0.48 mg for per kg polluted soils respectively.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2008年第1期151-155,共5页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(50478103)
福建省教育厅A类科技项目([2006]JA06046)
关键词
污染土壤
模拟酸雨
重金属
释放
polluted soil
simulated acid rain
heavy metals
leaching
