城市扩张与集约农业背景下浅层地下水重金属污染特征空间分析

地下水是城乡结合部和农村地区的重要饮用水源之一,城市的扩张和农业集约经营对地下水的影响日益明显。本文以典型区—沈阳沈北新区为例,以地下水重金属为评价指标,采用经典统计和地统计的方法,分析城乡交错地区地下水污染程度和空间分异性特征,旨在为类似地区土地利用规划和地下水环境管理提供科学依据。结果显示:Fe、Mn超标率较高,分布范围较广;Cd、Hg分布集中,受城镇化的影响较为明显;Pb与集中养殖产业分布关系密切;As的分布与当地化工企业有关;Fe、Mn空间变异性强,空间异质性主要受自然条件等结构性因素控制;Cd、Pb、Hg空间变异性中等,As空间变异性弱,Cd、Pb、Hg、As这四种元素空间异质性的形成主要受人为活动等随机因素的影响;初步发现Fe和Mn,Mn和As有相似的来源。

Spatial analysis of heavy metals contamination of shallow groundwater in relation to urban sprawl and intensive

Groundwater is an important source of drinking water in suburban districts and rural areas. Impacts of urban expansion and intensive agricultural development in Rural-Urban Fringe on the groundwater quantity and quality have become increasingly evident. We took a typical area of Shenbei district of Shenyang city as a case, seven kinds of heavy metals in shallow groundwater were evaluated using the traditional statistical and geostatistical methods to analyze the level of groundwater contamination and their spatial variability. The main objectives are to identify preliminarily contaminants sources and to provide a scientific basis for land use planning and groundwater management in this area and other similar areas. The results showed 1) contamination level of Fe and Mn were higher, spatial distribution of them were wide; Cd and Hg distributed mainly in urbanized four towns; Pb distributed mainly in centralized farming areas; and As was related into larger local chemical companies; 2) Fe and Mn showed strong spatial heterogeneity which mainly from structural factors, Cd, Pb and Hg showed moderate spatial heterogeneity, As showed weaker spatial heterogeneity, the latter fours mainly from random factors of human activities; and 3) there are similar sources of Fe and Mn, As and Mn as well.