区域地下水污染调查取样点布设量化分配方法

在区域尺度、有限样品的地下水污染调查中,密度控制可以计算区域总样品数量,但取样点布设应综合考虑地质环境、人类活动等方面的差异性。目前,样点布设主要依赖技术人员经验,存在较强的不确定性,如何科学布设取样点是需要解决的一个科学问题。针对这个问题,文章基于实际工作创建了“区域预分配、单元再优选”的解决方法。在区域上,基于层次分析法构建量化分配模型,以背景控制因素和潜在污染因素建立分配因子组合,运用指数标度量化定性因子、标度函数计算定量因子,通过矩阵运算获取每个分配单元的样品预分配数量;在单元内,按照分段控制、条件优选的方法提高取样点针对性和代表性。利用构建的分配方法,以拉萨河流域地下水水质调查为案例进行了取样点布设分配应用,确定了各单元样品分配数量。结果表明:考虑背景控制和潜在污染的层次分析模型及量化计算平衡了拉萨河流域不同分配单元对样品的实际需求,解决了城关区面积小样品需求多、当雄县面积大样品需求少等问题;分段控制、条件优选的方法明确了分配单元内取样点选择依据。本方法的构建为地下水污染调查取样点布设提供了必要的方法支撑。

Quantitative sample distribution in regional groundwater contamination investigation

In the investigation of groundwater pollution of regional scale and limited sample, sampling point distribution should according to the difference of geological environment and human activities et., although the density control can calculate the total number of samples.At present, the issue of uncertainty exist in sample distribution, because it mainly based on the experience of technicians. Scientific choice sampling point is a scientific problem we need to solve.A solution is proposed to solove this problem，based on practical work.The solution mainly contains two aspects:regional pre-distribution and unit re-optimization. A pre-distribution method is based on analytic hierarchy process (AHP) and a unit re-optimization method depend on hydrogeological condition.The distribution factor combination of the background and pollution potential aspects is proposed, and the scaling method of qualitative and quantitative factors are recommended. Taking the Lhasa river basin groundwater quality survey as an example, the solution is used to calculate and allocation samples in region and choose samples in each unit. The results show the hierarchical analysis model and quantification method can satisfy the actual needs of each unit in Lhasa River Basin, such as the contradiction of area and population between Chengguan district and Dangxiong county. Segmental control and condition optimization provide basis for the selection of sampling points. This study provide a method for sample quantitative distribution in regional groundwater pollution investigation.