两种不同的地下水污染风险评价体系对比分析:以北京市平原区为例

地下水污染风险评价对地下水的污染防治区划及合理开采利用地下水资源具有重要意义.目前国际上最具代表性的评价体系包括UN体系和WP体系.两种体系基础要素均包括地下水固有防污性能、含水层富水性、地下水水质、地下水源保护区和污染负荷,但是5个基础要素的组合方式不同.为探讨两种体系评价结果的差异性及造成差异性的原因,对北京市平原区地下水分别采用UN体系和WP体系进行污染风险评价,将评价结果进行对比分析.结果表明,UN体系和WP体系存在明显差异,2种体系的评价等级空间分布趋势相似,均符合实际情况,但是同等级覆盖范围差异较大;并且评价体系构成的层次问题、评价要素的叠加规则及评价过程中运用的分级方法都可能对UN体系和WP体系的地下水污染风险评价结果造成影响.UN体系和WP体系评价方法都适用于平原区的地下水污染风险评价,但是2种评价体系考虑的侧重点不同.

Comparative Analysis of Two Different Methods for Risk Assessment of Groundwater Pollution: A Case Study in Beijing Plain

Groundwater contamination risk assessment has important meaning to groundwater contamination prevention planning and groundwater exploitation potentiality. Recently, UN assessment system and WP assessment system have become the focuses of international research. In both systems, the assessment framework and indices were drawn from five aspects: intrinsic vulnerability, aquifer storage, groundwater quality, groundwater resource protection zone and contamination load. But, the five factors were built up in different ways. In order to expound the difference between the UN and WP assessment systems, and explain the main reasons, the UN and WP assessment systems were applied to Beijing Plain, China. The maps constructed from the UN and WP risk assessment systems were compared. The results showed that both kinds of groundwater contamination risk assessment maps were in accordance with the actual conditions and were similar in spatial distribution trends. However, there was quite significant different in the coverage area at the same level. It also revealed that during the system construction process, the structural hierarchy, relevant overlaying principles and classification method might have effects on the groundwater contamination risk assessment map. UN assessment system and WP assessment system were both suitable for groundwater contamination risk assessment of the plain, however, their emphasis was different.