低分子量有机酸提取土壤中部分重金属的拟合模型研究

为研究不同浓度低分子量有机酸与提取的土壤重金属含量之间的关系,本文以采自安徽省安庆市某铜矿区及其周围的土壤为例,通过浸提法,研究了不同浓度苹果酸、甲酸对采样点土壤中重金属Cu、Mn、Zn、Pb提取能力的影响并进行模型拟合.结果表明:不同浓度苹果酸和甲酸对采样点土壤中重金属的提取量不同,两种有机酸对低pH、高重金属含量采样点及其周围土壤中的重金属提取量较大,两种低分子量有机酸对S6采样点的重金属Mn的提取量最大,分别为322.5 mg·kg~(-1)和193.58 mg·kg~(-1),提取率达70.02%和42.03%,Zn、Pb次之,Cu最低;随着苹果酸、甲酸浓度的升高,土壤中重金属Cu、Mn、Zn、Pb的提取量增加,苹果酸对土壤中重金属的提取能力大于甲酸;拟合模型对于两种低分子量有机酸与其提取的土壤中部分重金属含量之间的关系,具有较好的拟合性,其决定系数R~2在0.8293～0.9990之间,都具有显著性(p0.05),该模型可以定量表征低分子量有机酸对土壤重金属的提取能力,此研究结果为土壤中重金属的固定化和增强植物修复受重金属污染的土壤提供了理论支持.

The fitting model of low molecular weight organic acids extracts heavy metals in soil

The relationship between concentration of exogenous organic acids and the extracted content of heavy metals in soil were investigated in Anqing copper mine area. The influences of different concentrations of malic acid and formic acid on the extracted heavy metals such as Cu, Mn, Zn and Pb in the soil were studied to develop a fitting model describing the relationship between organic acids concentration and heavy metals contents. The results show the organics concentration influenced extraction amounts of heavy metals significantly. The amount of heavy metals were higher in soil samples of the low pH and high background content of heavy metals than that in others soil samples by malic and formic acids extraction. The amount of Mn were higher than that of Zn, Pb and Cu extracted by malic and formic acids in S6 sample, the extracted amounts were 322.5 mg·kg^-1 and 193.58 mg·kg^-1, the values of extracted ability were 70.02% and 42.03%, respectively. The extraction amount of Cu, Mn, Zn and Pb increased as the increasing of malic acid and formic acid concentration, the extraction ability of soil heavy metals of malic acid was higher than that of formic acid. The appropriate fitting model established between the two low molecular weight organic acids and the content of heavy metals in soils were significantly (p<0.05), the determination coefficient of linear equation (R²) ranged from 0.8293~0.9990. The model represented the extracted ability of low molecular weight organic acids on heavy metals quantitatively. This study provided the theoretical support on the immobilization of heavy metals and the enhancement of phytoremediation.