【作者】 邱海源；

【导师】 戴民汉； 王宪；

【作者基本信息】 厦门大学 ， 环境科学， 2008， 博士

【摘要】 土壤重金属化学行为与环境质量的研究是土壤圈物质循环研究的重要组成部分。随着区域社会经济的快速发展,土壤重金属的污染问题日益凸显,直接关系到土壤质量和人类生存质量。翔安区是厦门市重点农田保护区域,是厦门基础农业生产基地。本论文通过对厦门翔安区土壤重金属的分布、形态的研究,旨在全面评估翔安区土壤重金属的现状及其潜在生态效应。基于对翔安区土壤重金属全量的测定,分析了翔安区土壤重金属含量及分布特征,并与1990年全国土壤普查数据进行了比较,结果表明该区域土壤重金属含量相对于1990年,均有所增加,但其环境质量基本仍处于国家环境质量标准2级状态。根据翔安区土壤柱状样的分析,发现翔安区土壤重金属具有较强的表聚性,耕层内的重金属含量高于亚耕层,且随土壤深度的增加而逐步减少。结合对厦门市社会经济发展统计数据的多元因子、聚类和灰色关联的统计,分析了影响翔安区土壤重金属分布的三个主要多元因子及其相关程度,初步揭示了影响翔安区土壤重金属分布的主要社会经济来源因子分别是人类生活、第二产业、汽车流通量和农业生产活动。进一步对翔安区土壤重金属5种不同形态的空间变异及控制因子进行分析得出如下空间分布特征:交换态主要呈现片状和斑块状分布;碳酸盐结合态主要呈片状和斑块状分布,仅有Cu呈条状和少量斑状分布;铁锰氧化物结合态Cd、Cu、Zn和Ni呈大面积片状分布、Pb和Cr呈片状、块状和少量斑状分布;有机物结合态主要呈明显片状分布和少量块状分布,仅有Cu呈大面积片状分布;活性态主要呈片状和少量斑状分布,仅Cd呈不规律斑块状分布。通过对翔安区土壤重金属的潜在生态风险的评估,得出翔安区土壤基本处于中等生态危害状态。翔安区表层土壤重金属的健康风险基准值均处于国家一级土壤要求,但翔安区表层土壤实测值远远大于该基准值,具有一定的潜在健康风险。同时,通过对胡萝卜、花菜和地瓜等3种典型作物的可食部分所含重金属含量与翔安区土壤不同重金属形态含量的回归方程拟合表明土壤中5种不同重金属形态与3种典型作物可食部分所含重金属存在相关关系。最后,还给出了翔安区土壤重金属5种不同重金属形态的质量标准值。本研究结果可为翔安区土壤重金属的污染与治理提供科学依据,其中的定量化的土壤环境质量评估,也可作为农业安全生产的重要参考依据。更多还原

【Abstract】 Heavy metals in soils have been received increasing attention due primarily to their potential environmental and ecological consequences. This is particularly true in China and issues related to soil metals have been emerging along with the rapid social and economic development during the past 30 years. Xiang’an, a district of Xiamen is a primary base of agricultural production with protected farmlands. This study is sought to assess the current status of heavy metals in this important region by investigations of their contents, speciation and potential risk assessment.Based on the bulk concentrations of heavy metals in soils at Xiang’an measured in 2005 and their comparison with the national census data of soils monitored in 1990, we observed an increase in soil metal concentrations during the past 15 years. Overall, the quality of soils in terms of heavy metals is relatively good, at second-level by the national standard of environmental quality.Data from soil columns reveal that heavy metals assemble in the top layers of the soil. The concentration gradually declines with depth. Taking into account the key indexes of socio-economic development in Xiamen, we reason that three major multi-dimensional factors such as human lives, secondary industry, automobile circulation and agricultural production have affected the distribution of heavy metals in soils at Xiang’an. At the same time, we examined the spatial variation and the controls of five species of heavy metals in the soils at Xiang’an.We also evaluated the latent ecological hazard and health risk of heavy metals in soils at Xiang’an, which appears that Xiang’an is at the medium level ecological hazard. The reference value of health risk of heavy metals in surface soils at Xiang’an is in the fist-level of national request, but the measured value is higher than the reference value, which has certain latent health risk. Moreover, through regression equation fitting of the concentrations of heavy metals in 3 typical crops (carrot, cauliflower and pachyrhizus) and the concentrations of different species of heavy metals in soils at Xiang’an, we obtained the correlation of 5 different species of heavy metals in the soils and the concentrations of heavy metals in 3 typical crops.更多还原