北京平原区两年内土壤中五种重金属元素化学形态变化及生物有效性  

Chemical speciation and bioavailability of five heavy metals in soil of Beijing plain area in two years

作　　者：安永龙[1] 黄勇[1] 孙朝[1] 邓凯文[1] 李迪[1] 黄丹[1] AN Yonglong;HUANG Yong;SUN Zhao;DENG Kaiwen;LI Di;HUANG Dan(Beijing Institute of Geo-exploration Technology,Beijing 102218,China)

机构地区：[1]北京市地质勘察技术院,北京102218

出　　处：《地质通报》2018年第6期1142-1149,共8页Geological Bulletin of China

基　　金：北京市政府公益性项目<北京市土壤地质环境监测网运行项目>(编号:PXM2018_158307_000004)

摘　　要：为了监测北京市平原区2015年和2016年土壤中5种重金属As、Cd、Hg、Pb、Zn化学形态的变化趋势,运用Tessier连续提取法对土壤重金属进行了形态分析,并对影响重金属元素生物有效性的因素进行研究。结果表明,2年内研究区表层土壤重金属元素的形态变化微弱,有效态含量以Cd元素最高,达到45.67%,故潜在生态危害性最大;其次为Zn元素,达12.16%,其中碳酸盐结合态占比虽大,但由于研究区土壤呈偏碱性,Zn元素的迁移能力较弱,潜在危害性较小;As、Hg、Pb均以难迁移态存在,故潜在危害性也较小。土壤重金属元素的生物活性系数及迁移系数分别为:Cd>Zn>Pb>As>Hg和Cd>As>Zn>Pb=Hg,其中Cd元素2年的生物活性系数和迁移系数最高,展现出较强的生物活性和迁移能力,其余重金属元素的活性系数和迁移系数较低,潜在危害性较弱。影响重金属元素生物有效性的因素较复杂,以重金属元素全量为主,p H、有机质、CEC等理化性质次之。To effectively monitor the overall variation trend of the chemical forms for 5 heavy metals （As, Cd, Hg, Pb and Zn） in the soil in Beijing plain area during the year 2015 and 2016, the authors employed the Tessier sequential extraction method to ana-lyze the morphological characteristics of these soil heavy minerals. The authors studied the factors controlling the bio-avai labi l ity of these heavy minerals. The results show that there is only minor change in the morphology of soil heavy metals in these 2 years. The element with highest effective concentration is Cd （45.67%）, which thus poses greatest potential ecological risk. The fol lowing ele-ment is Zn with concentration of 12.16%. Though Zn is largely incorporated in carbonates, the mobi lity of Zn is reduced by the al-kaline soil, thus having less ecologically hazardous effect. The elements As, Hg and Pb are immobile with little potential hazards on ecology. The orders of activity coefficients and migration coefficients of the heavy metal elements in topsoil in the study area are Cd 〉 Zn 〉Pb〉 As 〉 Hg and Cd 〉As 〉 Zn 〉Pb=Hg respectively. This suggests that Cd has the highest values in both the 2-year biological activity coefficient and transfer coefficient, implying a strong biological activity and migration capability, while other soil heavy metals have smaller activity coefficients and migration coefficients, indicating relatively low potential ecological risks. In the study area, the factors that affect the bio-availability of heavy metals are complex, and the dominant one is the total amount of heavy metal elements, followed by pH, organic matter, CEC, and other physical and chemical properties, and the connections of these factors are complicated.

关 键 词：北京市 土壤 重金属元素 形态 生物有效性 

分 类 号：P611[天文地球—矿床学]