Impacts of urban land use on the spatial distribution of groundwater pollution, Harbin City, Northeast China

Groundwater is the major available water resources in Harbin City, China, but rapid urbanization has adversely affected it in recent years and groundwater quality is deteriorating. In this study, the groundwater pollution indexes of groundwater monitoring wells were analyzed by using the projection pursuit dynamic clustering model and its spatial distribution was interpolated by using the modified local polynomial interpolation method. The "searchlight" shape model was used to extract the types of land use within the scope of each monitoring well in order to evaluate the relationship between the spatial distribution of groundwater pollution and land use. The correlation between the groundwater pollution indexes and land use was evaluated using Kendall's tau-b analysis. The groundwater pollution index is generally high. It has obvious spatial distribution characteristics and it mainly occurs in DaoW-NanG district and the eastern part of DongL-XiangF district. The results of Kendall's tau-b analysis show that the groundwater pollution indexes have a good correlation with land use. Residential and commercial areas, industrial area and agricultural area greatly influence the distribution of groundwater pollution. Moreover, the main impact indicators of groundwater pollution in the study area are NH4+, NO3- and CaCO3.