Source apportionment of fluorine pollution in regional shallow groundwater at You’xi County southeast China

• Systematic study on source apportionment and migration of regional fluorine pollution at You’xi County Southeast China.
• Water-rock interaction, mixing of groundwater, and human activity demonstrated to be responsible for fluorine pollution.
• Ratio of soluble ions (K+ + Na+)/Ca2+ (R) applied as a viable factor for prediction of fluorine water availability.

Source apportionment of fluorine pollution in the regional shallow groundwater at You’xi County, southeast China, has been analyzed by means of monitoring F− ion change characteristics in this area. Meanwhile, pollution sources and influencing factors of the shallow groundwater have been uncovered by studying the correlation between F− and other related ions such as Na+, Ca2+, Cl−, NO3−, HCO3−, as well as (K+ + Na+)/Ca2+ ratio (R) and pH effect. The results show that F− ions in shallow groundwater at the study area come mainly from the dissolution of fluorinated minerals in a form of fluorite (CaF2), the so-called water-rock interaction, and there is a higher possibility for the occurrence of fluorine water where the ratio of (K+ + Na+)/Ca2+ exceeds a value of 2.1. Moreover, the release and migration of F− ions have been favored by the alkaline environment in this study area.