Holm Peter E, Rootzén Helle, Borggaard Ole K, Møberg Jens Peter, Christensen Thomas H
Chemistry Dep., The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
J Environ Qual. 2003 Jan-Feb;32(1):138-45. doi: 10.2134/jeq2003.1380.
Cadmium (Cd) distribution between the soil solid phase and the soil solution is a key issue in assessing the environmental effect of Cd in the terrestrial environmental. Previous studies have shown that many individual minerals and other components found in soils can bind Cd, but most studies on whole soil samples have shown that pH is the main parameter controlling the distribution. To identify further the components that are important for Cd binding in soil we measured Cd distribution coefficients (Kd) at two fixed pH values and at low Cd loadings for 49 soils sampled in Denmark. The Kd values for Cd ranged from 5 to 3000 L kg(-1). The soils were described pedologically and characterized in detail (22 parameters) including determination of contents of the various minerals in the clay fraction. Correlating parameters were grouped and step-wise regression analysis revealed that the organic carbon content was a significant variable at both pH values. Cation exchange capacity (CEC) and gibbsite were important at the low pH (5.3) while iron oxides also were important at the high pH (6.7). None of the other clay minerals present in the soils (illite, smectite, kaolinite, hydroxy interlayered clay minerals [HIM], chlorite, quartz, microcline, plagioclase) were significant in explaining the Cd distribution coefficient.
镉（Cd）在土壤固相和土壤溶液之间的分布是评估陆地环境中镉的环境效应的关键问题。先前的研究表明，土壤中发现的许多单一矿物质和其他成分都能结合镉，但大多数对全土样的研究表明，pH值是控制这种分布的主要参数。为了进一步确定土壤中对镉结合起重要作用的成分，我们在丹麦采集的49种土壤的两个固定pH值和低镉负荷条件下测量了镉的分配系数（Kd）。镉的Kd值范围为5至3000 L·kg⁻¹。对这些土壤进行了土壤学描述并详细表征（22个参数），包括测定粘粒部分各种矿物质的含量。将相关参数分组，逐步回归分析表明，在两个pH值下，有机碳含量都是一个显著变量。在低pH值（5.3）时，阳离子交换容量（CEC）和三水铝石很重要，而在高pH值（6.7）时，铁氧化物也很重要。土壤中存在的其他粘土矿物（伊利石、蒙脱石、高岭石、羟基间层粘土矿物[HIM]、绿泥石、石英、微斜长石、斜长石）在解释镉分配系数方面均不显著。
