摘要
为阐明乌梁素海沉积物重金属生物活性及理化性质对重金属形态变化的影响,对湖泊重金属污染修复治理方面提供科学依据,2011年1月在乌梁素海9个站点采集表层沉积物样品,采用改进BCR逐级提取法分析Cu、Zn、Pb、Cr、Cd、Hg、As等7种重金属元素的形态,利用活性系数与迁移系数对重金属生物活性进行研究;结合沉积物理化性质,系统探讨影响重金属化学形态与生物活性的因素;应用次生相与原生相比值法,从重金属形态学角度对沉积物重金属状况进行评估。结果表明,(1)沉积物中重金属活性系数的大小顺序为Cd>Hg>Zn>Cu>Pb>As>Cr;重金属的迁移系数为Cd>Hg>Zn>Cu>As>Pb>Cr。(2)沉积物物理化学性质和重金属总量对各种化学形态重金属含量影响程度明显不同。重金属总量对残渣态影响较大;pH对酸可提取态、有机物和硫化物结合态影响较大;有机质与酸可提取态、有机物和硫化物结合态有较大相关性;盐度与酸可提取态、有机物和硫化物结合态有一定的相关性。总氮、总磷与有机物和硫化物结合态有一定的相关性。(3)从重金属形态角度评价,7种重金属除Cd外,污染程度并不大,全湖KRSP的平均值大小顺序为Cd(1.66)>Cu(0.84)>Hg(0.72)>Zn(0.42)>Cr(0.15)>Pb(0.14)>As(0.06)。结合总量、生物可利用性与形态学评价,乌梁素海重金属Cd是生物活性最强、污染最严重的金属,Hg污染次之,应该对Cd与Hg给予特别关注。
Lake surface sediment samples were collected from 9 sites in Wuliangsuhai lake in January 2011 to investigate heavy metal speciation, bioavailability and influence of changing the physicai-chemical properties. The chemical speciation of nine heavy metals （Cu, Zn, Pb, Cr, Cd, Hg and As） was studied based on the BCR fractiouation. Bioavailability of heavy metals was evaluated by mobility factor （MF） and transport factor （M）. The ratio of secondary phase to primary phase （RSF） was calculated to assess severity of metal pollution in sediments. The results showed that the heavy metals in MF were in the order of Cd〉Hg〉Zn〉Cu〉 Pb〉As〉Cr and in M/were in the order of Cd〉Hg〉Zn〉Cu〉As〉pb〉Cr. The different chemical species of heavy metals were affected at different levels of significance and sediments properties. Total content is the most important factor affecting on the residual fraction, pH, organic matter and salinity are the primary factor affecting on acid extractable and organic combination fraction. Total nitrogen and total phosphorus are the primary factor affecting on organic combination fraction. From the chemical speciation of heavy metal evaluation, the pollution levels of seven heavy metals exclude the Cd is not serious. The heavy metals in KRSP were in the order of Cd（ 1,66） 〉 Cu（0.84） 〉 Hg（0.72） 〉 Zn（0.42） 〉 Cr（O. 15） 〉 Pb（O. 14） 〉 As（0,06）. The transport and bioavallability and pollution risk of Cd is biggest based on the results, followed by the Hg pollution. So, more attention should be paid to Cd and Hg pollution.
出处
《生态环境学报》
CSCD
北大核心
2013年第3期481-489,共9页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(440901262
51169017
50669005
51069007
51169011)
国际合作项目(2011DFA90710)
内蒙古自治区高等学校科学研究项目(NJ10061)
校级创新团队
