A Study on the Groundwater Contamination by the Agriculture Fertilizer Inputs and its Spatial Distribution Pattern in the Zhangye Basin, Northwest China

The Heihe River is one of the largest rivers in Gansu province in China, which originates from Qilian Mountains and terminates at Ejina Basin in Gobi desert. The river is the only water source of the region, which is highly dependent on agriculture-based economy. The recent changes of economic and environmental sectors have been affected the sustainable agricultural practices of the region. Those changes may give adverse impacts on water quality. In this context, this study focuses on the water quality of both shallow-groundwater and deep-groundwater in the middle reaches of the Heihe River basin, the main agricultural region of the basin. Total of 35 water samples are used for measure water quality, i.e NO3− , NO2−, NH3 and pH. The water quality measurement results indicate two different spatial distribution patterns of chemical contamination respectively for shallow and deep ground water. This paper discusses the current spatial pattern of nitrogen contamination of the groundwater and its temporal change through the comparison with the past studies.