Urban land-use effects on groundwater phosphate distribution in a shallow aquifer, Nanfei River basin, China

Groundwater, surface water, soil and river sediment samples, and information on land use in the Nanfei River basin (NRB) of China have been analyzed to study the geochemistry, distribution, and mobilization of phosphorus. The distribution of phosphate (PO ₄ ^3– ) and the relationships between PO ₄ ^3– and several constituents in groundwater were studied. Partial correlation analysis relating PO ₄ ^3– to types of land use was conducted using the data analyzing tool SPSS 15.0. The processes controlling the transport of PO ₄ ^3– are discussed. The conclusions from this study are: (1) urban land use has obvious impact on PO ₄ ^3– in groundwater, the average concentration of PO ₄ ^3– being 4.37 mg/L, greater than that resulting from farmland and mixed land use, which have average PO ₄ ^3– concentrations of 0.10 and 0.18 mg/L, respectively; (2) the partial correlation between PO ₄ ^3– and types of land use is significant with a coefficient of 0.760; (3) the PO ₄ ^3– concentrations in surface water are generally higher than those in groundwater, and the total phosphorus (TP) concentrations in river sediments are generally higher than those in soil samples; (4) groundwater is a carrier of PO ₄ ^3– and is likely responsible for the redistribution of PO ₄ ^3– in different regions of NRB.