湘南丘岗地区3种红壤Cd的化学形态及其影响因素

Chemical fractions of Cd and its influencial factors of 3 types of red soil in hills of Southern Hunan

采用BCR(european community bureau of reference)三步连续提取法,研究了湘南丘岗地区第四纪红土红壤、板岩红壤、石灰岩红壤中Cd的化学形态及其影响因素。结果表明:3种红壤中Cd总量的平均值以板岩红壤最高,第四纪红土红壤最低;3种红壤中不同形态Cd的含量从高到低依次为残渣态、酸提取态、可还原态、可氧化态;3种红壤中酸可提取态占土壤全Cd含量的22%～28%,根据RAC(risk assessment code)风险评价指标体系,均达到中等污染水平,土壤中Cd的分布与土壤的pH值、有机质含量密切相关。

The soil samples of 3 types of red soils,which developed from Quaternary Red Clay,the weathering product of slate,and the weathering product of limestone in the hills of Southern Hunan,were collected to study the total concentrations and chemical fractions of Cd in the soils by BCR sequential extraction and FAAS.The results showed that the concentrations of the different fractions of the 3 types of red soil follow the order of the residual fractionthe acetic extractable fractionthe acid reducible fractionthe organic fraction.The concentrations of the acetic extractable cadmium ranged from 22% to 28%,which would be at medium risk to the environment according to risk assessment code for all the soil samples.Besides the form distribution of cadmium in the soil samples were closely related with soil pH and soil organic matters.