Search

Competing Interests: Conflict of interest The authors declare that they have no conflict of interest.

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. [ABSTRACT FROM AUTHOR]

Abstract: Suzhou is located at the lower reaches of the Yangtze River in southeastern Jiangsu, China. It is part of the Su-Xi-Chang area including Suzhou, Wuxi and Changzhou. As one of the most developed areas in China, this region has suffered from severe land subsidence caused by extensive groundwater exploitation since 1980s. The land subsidence was controlled by prohibition of groundwater exploration in the past several years. However, the surface water pollution prompted a new task of how to sustainably utilize the groundwater resource, especially to satisfy the emergency demands of water supply. In this paper, we took Suzhou as a representative case to discuss how to develop groundwater resources while controlling the land subsidence. The relationship between the deformation and the groundwater level was analyzed, with focus on the deformation features after the period of groundwater exploitation ban. The results confirmed the conclusion by Shi et al. (2007, 2008a): even in the period of rising groundwater level, same units may manifest different deformation characteristics, such as elasticity, elasto-plasticity, and visco-elasto-plasticity, at different locations of the cone of depression. A land subsidence model that couples a 3-D groundwater model and a 1-D deformation model was developed to simulate the groundwater level and deformation. A high-resolution local grid (child model) for Suzhou was built based on the regional land subsidence model of Su-Xi-Chang area by Wu et al. (2009). The model was used for a number of predictive scenarios up to the year of 2012 to examine how to develop sustainable use of groundwater resources under the conditions of land subsidence control. Our results indicated that about 3.08×107 m3/a groundwater could be provided as emergency and standby water source while meeting the land subsidence control target of 10mm/a. [Copyright &y& Elsevier]