Notice of Retraction: Impacts of seawater intrusion on the fluorine content in groundwater: A case study in Shandong province, China

Endemic fluorosis can be caused by the drinking water with high-fluorine content. The groundwater with high-fluorine was observed in coastal regions of Shandong province, China. In this study, two sets of ten-year monitoring data from the coastal wells were analyzed. The groundwater properties are characterized by a mixture of seawater and freshwater, resulting in increasing of Na⁺, HCO₃^-, pH, hardness, salinity and decreasing of Ca²⁺. It is found that fluorine contents in groundwater are closely associated with high Na⁺, HCO₃^-, pH, hardness, salinity and low Ca²⁺. Seawater intrusion, especially the paleo-seawater intrusion, can greatly change the groundwater fluorine-releasing conditions under the rock-water interaction and cause the high fluorine in the groundwater. Thus, the geological process, seawater intrusion should be noticed when we study the fluorosis in coastal areas.