基于土壤—农作物迁移途径重金属镉化学形态研究  

The chemical forms of Cadmium through soil-crop transport

作　　者：蔡楠[1] 肖青青[2] 许振成[1] 叶志鸿[2] 黄建洪[1] 陈晓燕[1] 陈婵[1] 

机构地区：[1]环境保护部华南环境科学研究所,广东广州510655 [2]中山大学生命科学学院,广东广州510006

出　　处：《中国环境科学》2013年第S1期13-18,共6页China Environmental Science

基　　金：中央及公益性科研院所基本科研业务专项基金资助项目(zx021-201304-014)

摘　　要：通过对某典型金属矿冶炼区重金属镉污染农用地的调查,共采集36个土壤样和9种(36个)农作物样,分析测定土壤中Cd全量及DTPA提取态、作物不同部位Cd含量及6种不同化学形态.结果表明:土壤中和农作物中Cd含量相对于现有标准均出现超标;土壤中Cd的DTPA提取态平均占总量的63%,可见土壤Cd的生物可利用性较大;农作物对土壤Cd吸收能力的种间差异性显著,不同作物可食部分对镉的富集能力为:叶菜类>块根类>葱蒜类;作物中Cd主要以果胶酸盐及蛋白质结合或吸着态(NaCl提取态)为主,土壤Cd的DTPA提取态与作物根系中Cd的有效态呈明显的正相关.从健康风险角度考虑,可利用土壤DTPA提取态Cd含量来衡量土壤中Cd污染情况,农作物Cd污染可通过其生物有效态来衡量.A field survey including 36soil samples and 36crop samples of 9crop species was conducted to determine Diethylene triamine pentacetate acid(DTPA) extractable cadmium(Cd) and total content of Cd in soil and Cd contents in different parts of crops and its six different chemical forms in a farmland contaminated by Cd in a typical metal smelting area. The results showed that the concentrations of Cd in soil at the studied site all exceeded GB 15618-1995(Grade Ⅱ); the average DTPA extractable Cd accounted for 63% of the total content of Cd in soil, which demonstrated higher Cd bioavailability of the soil; there were obvious crop species differences regarding Cd absorption and Cd accumulation in different edible parts of the crops is as leaf vegetable > root vegetable > bulb vegetable; Cd in crops mainly existed as pectates and protein binding or sorption Cd(NaCl extraction), and a significantly positive correlation was observed between DTPA extractable Cd in soil and available Cd in the roots of crops. In consideration of health risk, it was advised that DTPA extraction and bioavaliable form be used for measuring Cd polluted extents in soil and in crop respectively.

关 键 词：土壤-农作物 镉污染 化学形态 累积 

分 类 号：X53[环境科学与工程—环境工程]