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

发布时间：2018-09-04 12:22

【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.
[Abstract]:Taking Pingzhong Town of Longyan City as an example, 110 surface soil samples and 61 crop samples were collected in Lantian-Yangdong area. The total amount of heavy metal elements Pb,Cd,As was tested, and the speciation and distribution of three heavy metals in soil were analyzed. Combined with the characteristics of heavy metal uptake by special crops in the study area, the occurrence forms of heavy metals and their bioavailability were taken as evaluation indexes, and the principles of geochemical statistical analysis were used. A new method of soil heavy metal ecological risk assessment based on morphology was established. The ecological risk of soil heavy metals was evaluated by using the new method, and the results were compared with the traditional potential ecological risk index method (RI). The results show that the soil heavy metals in the Lantian-Yangdong area are typical areas where the natural geological origin is dominant and the anthropogenic interference is weak. The pollution intensity of CD and CD was mainly in the form of residuals, and the proportion of the four bioavailable forms except residue was Cd (53.28%) Pb (43.28%) As (30.71%). The correlation analysis and regression analysis between the total heavy metal content, speciation and crop uptake in the soil in the working area showed that the correlation between the total heavy metal content and the ion exchange state with high activity and the carbonate bound state was low. It even shows nonlinear correlation. Ion exchange state is the most important form of heavy metal Pb,Cd,As uptake in rice and barley. From the point of view of biological availability, the new method of ecological risk assessment based on morphology is more accurate than the traditional method of potential ecological risk based on total amount.
【作者单位】：中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室;环境保护部环境发展中心;成都理工大学管理科学学院;国家地质实验测试中心;
【基金】：中央级公益性科研院所基本科研业务费专项(K1507) 地质矿产调查评价专项(12120115049201)
【分类号】：X825

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