Hydrochemical characteristics and geochemistry evolution of groundwater in the plain area of the Lake Baiyangdian watershed, North China Plain

Water cycle and water quality in the Lake Baiyangdian watershed of the North China Plain have undergone great changes due to over-pumping of groundwater and wastewater discharge. In this paper, hydrogeochemical data was collected to analyze the hydrochemical characteristics and geochemistry evolution of groundwater. The study area was divided into two typical parts. One was in the upstream plain area, where over-pumping had resulted in significant decline of groundwater level; the other one was located in the downstream area near the Fu River and Lake Baiyangdian (Lake BYD region). In addition to the natural weathering of minerals, excessive fertilizer was also a main factor of higher ion concentration in groundwater. According to studies, due to good permeability, these regions were easy to be polluted even with deep groundwater depth. However, upstream shallow groundwater and surface water, including lake water, domestic along with industrial wastewater were all sources of present shallow groundwater in the Lake BYD region. Results indicated that anthropogenic activities rather than minerals much matter to the groundwater in these regions. Particularly, wastewater largely decided the groundwater quality, which suggested that the management and restoration of surface water quality was crucial to groundwater protection.