基于GIS的农业面源硝酸盐地下水污染动态风险评价

摘要

地下水中的硝酸盐污染具有全球性,这不仅是一个环境问题,也是一个经济和人类健康问题.DRASTIC方法可以进行地下水污染的脆弱性评价,但是却没有涵盖风险的概念,也忽视了污染物随地表水流运动的动态特性.因此,所得结果可能有碍于"欧洲水管理框架指南"在地下水水质管理中的执行.笔者基于DRASTIC方法开发了一个动态风险评价方法,并将其运用于英国北爱尔兰Upper Bann流域中的一个小流域.研究区地下水硝酸盐污染风险评价结果表明,此方法将有效地帮助决策者在流域范围内开展农业面源地下水污染预防措施."非常高风险"和"高风险"区分别占研究区面积的5.1%和10.5%.此结果可帮助当地政府针对流域内这些"非常高风险"和"高风险"区的特点制订地下水质保护政策.此方法同样适用于任何面源可溶性污染物的地下水污染动态风险评价.%Groundwater nitrate pollution,as a global problem,is not only an environmental issue but also an economic and human health problem.The DRASTIC method can provide groundwater vulnerability to pollution but does not contain risk concept and ignore hazard's dynamic nature of water movement.The obtained results may baffle the implementation of the EU Water Framework Directive in groundwater quality management field.We developed a dynamic risk assessment method based on DRASTIC and applied it in a watershed of the Upper Bann Catchments,Northern Ireland,for the purpose of groundwater nitrate pollution risk assessment.The framework will support decision makers efficiently and effectively carry out groundwater diffuse pollution prevention practices at watershed scale."Very high" and "high" ranked areas for groundwater nitrate pollution occupy 5.1%and 10.5%of the study area respectively.The results are helpful for local government's policies making by focusing on "very high" and "high" groundwater pollution risk zones in a watershed.The dynamic risk assessment method is applicable for any soluble groundwater pollutants from diffuse sources.