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题名	再生水灌溉对土壤重金属累积的影响及风险预测
作者	赵忠明
学位类别	硕士
答辩日期	2012
授予单位	中国科学院研究生院
授予地点	北京
导师	陈卫平
关键词	再生水 reclaimed water 灌溉 irrigation 重金属 heavy metal 镉 Cd 风险预测 risk predictiont
其他题名	Influnence of Reclaimed Water Irrigation on Soil Heavy Metal Accumulation and Risk Prediction
中文摘要	随着我国城市化进程的加快，一方面造成用水量不断增长，城市水资源短缺，而另一方面城市污水排放量迅速增长，不仅造成水环境的污染，同时制约了城市经济的发展。而城市污水作为一种再生的水资源，具有量大、集中、水质和水量都较稳定的特点，能够用于农业、工业和市政用水。然而在再生水回用过程中对环境和健康的负面影响也是人们比较关注的问题。近年来，土壤重金属污染越来越受到人们的关注。在我国北方地区，由于干旱缺水，城市污水的农田灌溉已经相当普遍，致使污灌区土壤重金属污染问题也越来越重。 早在20世纪60年代，北京郊区就开展了污水再利用的项。由于早期污水处理技术的缺乏，导致污水灌溉给农田土壤带来一定程度的污染。早期有关研究表明北京郊区污水灌溉导致土壤重金属的污染累积。近年来，随着政府环境投入的加大、环保技术的提高，北京市污水处理厂的出水状况已经得到很好地改善，但是仍不排除不达标而造成污染的情况。 本研究以北京市通州区凉水河再生水灌区和大兴区北野场再生水灌区为研究对象，采用野外定位采集样品，实验室分析样品土壤理化性质和重金属含量，评价再生水灌区重金属污染状况以及他们之间的关系；利用Stem-profile模型对凉水河灌溉区土壤中金属镉进行模拟，预测分析其在土壤中的环境风险。 通过对土壤理化性质和重金属含量的分析我们可以得出如下结论：北京市再生水灌溉导致土壤pH值降低、土壤有机质含量和总氮总碳含量升高，并呈现表层累积。再生水灌溉造成土壤重金属累积，其含量由上至下逐渐降低。通过污染评价得出Cd污染最严重，但均没有超出国家标准。通过相关分析可以看出，土壤重金属之间以及与土壤理化性质指标之间的相关性随深度而增加。重金属分布受有机质含量影响。 借助于运用Stem-profile模型对再生水灌溉农田中镉的含量进行模拟预测。在目前外界输入条件不变的情况下100年后土壤表层中的镉含量将超出国家土壤环境质量二级标准，达到0.866 mg.kg-1。通过对输入因素进行分析，单独的有机肥施用和再生水灌溉均会导致金属镉的累积，前者100年后的累积浓度将超出土壤环境质量二级标准，地下水灌溉同时施用化肥不会造成镉累积。输入镉的有机形态的比例对于土壤中镉的分部有一定影响，当金属镉的输入全部为有机结合态时，土壤耕作层中的金属镉含量增加为0.943 mg.kg-1。作为污染物向下运移的主要力量，随着降水灌溉量的加大，土壤表层中镉的含量逐渐降低，主要原因为灌溉量的增加加大了淋溶量，减低了土壤溶液浓度进而降低了植物吸收量。
英文摘要	Abstract Following with the acceleration of urbanization in China, water resource shortage in cities is getting more and more serious and also with municipal sewage This situation not only make water pollution and shortage but also be a limitation of city development and harm people’s health. As a regeneration resource, however, municipal sewage has the character of fixed in amount and quality, and could be used in agriculture, industry and municipal projects. This could make the need of water resource lower, and protect the water environment. But the negative effects of reclaimed water usage is an public concern. Recent years, heavy metal pollution in soil is an increasing concern. At the north part of China irrigation with reclaim water is popular because of the shortage of water, and make soil pollution of heavy metal getting more serious. During the 60s of 20C Beijing began reclaim water irrigation in the suburban districts mainly including Tongzhou and Daxing. This action lead to the pollution of farmland because the technology of sewage treatment is poor. Early research has shown that reclaim water irrigation will cause the accumulation of heavy metal in soil. And nowadays the quality of reclaimed water is better based on the increasing investment in environment protection and the improvement of technology. But there may be exceptions. In this research work we study about the pollution of classic reclaimed water irrigation land in Beijing suburban areas-liangshuihe and beiyechang. Research work include field work, laboratory works pollution assessment and model simulation. After the analysis of soil characters and soil heavy metal contents, the conclusion is as follow: reclaimed water make the pH value decreased and raise the content of soil organic matter and total N total C, especially in soil surface. The heavy metal is accumulated in the surface of soil, and decreasing with the depth. The worst pollution is Cd but do not get out of national standard. The correlation analysis outputs show that the correlation between heavy metals and soil characters increase with the increa- seing of depth. The heavy metal distribution is influenced by soil organic matter. Simulation of Cd in soil with reclaimed water irrigation is taken by stem-profile model. With the same input situation, the Cd content will exceed the national standard 100 years later, about 0.866 mg.kg-1. When change the input factors we found that single organic fertilizer or reclaimed water irrigation will lead to Cd accumulation, and groundwater irrigation with chemistry fertilizer will not cause Cd accumulation. The input proportion of organic style Cd also could influence its distribution in soil, when the whole input is organic style the Cd content in plow layer is 0.943 mg.kg-1. With the increasing of irrigation amount the Cd content in soil surface is getting lower, mainly because that it strong the effect of leaching and reduce the plant uptake.
内容类型	学位论文
源URL	[http://ir.rcees.ac.cn/handle/311016/35171]
专题	生态环境研究中心_城市与区域生态国家重点实验室
推荐引用方式 GB/T 7714	赵忠明. 再生水灌溉对土壤重金属累积的影响及风险预测[D]. 北京. 中国科学院研究生院. 2012.

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