Comprehensive evaluation of shallow groundwater quality in Central and Southern Jiangsu Province, China

Evaluation of the shallow groundwater quality in Central and Southern Jiangsu Province (CSJ) in China is important not only to public health but also to sustainable development and utilization of groundwater resources. In this work, 968 groundwater samples were collected by field surveys during 2006 to 2010 to investigate spatial distribution and extent of pollution. The single factor pollution standard index method, considering the values of both the natural groundwater background and the standard of safe drinking water, was used to assess the groundwater quality in the study area. Results showed that the shallow groundwater was severely polluted with Grade V and VI (i.e., severe and extremely severe pollution) groundwater covered about 1/3 and 1/4 of the study area, respectively. The main groundwater contaminants that cause the severe and extremely severe pollutions were manganese, iron, arsenic, and nitrogen. Findings from this work showed that natural hydrogeochemical processes were the main causes of the iron and manganese pollution, however, human activities (e.g., industrial, agricultural, and domestic pollutions) mainly contributed to the nitrogen pollution in the study area.