| 基于总量及形态的土壤重金属生态风险评价对比:以龙岩市适中镇为例 |
| 摘要点击 2148 全文点击 724 投稿时间：2017-02-22 修订日期：2017-05-01 |
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| 中文关键词 重金属 土壤 生态风险评价 总量 形态 |
| 英文关键词 heavy metals soil ecological risk assessment total amount speciation |
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| 中文摘要 |
| 以龙岩市适中镇为例，在蓝田-洋东一带采集110个表层土壤样品和61件农作物样品，测试了其中重金属元素Pb、Cd、As的总量，分析了土壤中3种重金属的形态分布规律，结合研究区特定农作物吸收重金属的特征，以重金属赋存形态及其生物可利用性为评价指标，根据地球化学统计学分析原理，建立了基于形态的土壤重金属生态风险评价的新方法，利用新方法评价了土壤重金属的生态风险，并与传统的潜在生态风险指数法（RI）的评价结果进行了对比.结果表明，蓝田-洋东一带的土壤重金属是以自然地质成因为主，人为干扰作用较弱的典型区域.全区基本无重金属Pb、As污染，Cd是最主要的污染因子，污染强度较低.Pb、Cd、As主要以残渣态形式赋存，除残渣态以外的4种生物可利用形态的占比排序为Cd（53.28%） > Pb（43.28%） > As（30.71%）.工作区土壤重金属总量-形态-作物吸收量三者之间的相关分析和回归分析表明，土壤重金属的总量与活动性高的离子交换态、碳酸盐结合态等形态的相关度低，甚至表现为非线性相关关系.离子交换态是对薏米和水稻吸收重金属Pb、Cd、As影响最大的形态.从生物可利用的角度来说，基于形态的生态风险评价新方法相比于传统的基于总量的潜在生态风险方法，评价结果更加准确. |
| 英文摘要 |
| A total of 110 topsoil samples and 61 crop samples along the Lantian-Yangdong Villages were collected in Shizhong, Longyan City. The total amount and speciation of heavy metals(Pb, Cd, As) in soil and crops were determined. The characteristics of the absorption of heavy metals by specific crops in the study area were analyzed, and a new method of risk assessment based on the heavy metal speciation and its bioavailability was established by statistical analysis. This new method was used to evaluate the soil ecological risk and to compare it with the traditional method of potential ecological risk index (RI). The results indicated that the Lantian-Yangdong Villages were located in an area where Pb, Cd, and As mainly originate from the natural soil parent material with weak human disturbance. There was no significant Pb or As pollution in the whole region. Cd was the main pollutant with low pollution intensity. Four types of biological components except for the residual form followed the order of Cd(53.28%) > Pb(43.28%) > As(30.71%). Correlation and regression analyses of total metal concentrations, heavy metal speciation, and crop uptake in the study area showed that the correlations between the total amount of heavy metals and the ion exchange state, carbonate state, and other active forms were low; the results even showed nonlinear relationships between those variables.The ion exchange state had the greatest effect on the absorption of Pb, Cd, and As by coix seed and rice. From the perspective of bioavailability, the new method based on the heavy metal speciation was more accurate than the traditional method based on the total amount of heavy metals. |
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