Details

Autor(en) / Beteiligte

• Wei, Chao
• Guo, Huaming
• Zhang, Di
• Wu, Yang
• Han, Shuangbao
• An, Yonghui
• Zhang, Fucun

Titel

Occurrence and hydrogeochemical characteristics of high-fluoride groundwater in Xiji County, southern part of Ningxia Province, China

Ist Teil von

• Environmental geochemistry and health, 2016-02, Vol.38 (1), p.275-290

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2016

Quelle

MEDLINE

Beschreibungen/Notizen

• High-F − groundwater is widely distributed in Xiji County, which endangers the safety of drinking water. In order to evaluate the key factors controlling the origin and geochemical mechanisms of F − enrichment in groundwater at Xiji County, one hundred and five groundwater samples and sixty-two sediment samples were collected. Fluoride concentration in the groundwater samples ranged from 0.2 to 3.01 mg/L (mean 1.13 mg/L), with 17 % exceeding the WHO drinking water guideline value of 1.5 mg/L and 48 % exceeding the Chinese drinking water guideline value of 1.0 mg/L. High-F − groundwaters were characterized by hydrochemical types of Na–HCO 3 and Na–SO 4 ·Cl, which were found in Quaternary sediment aquifer and in Tertiary clastic aquifer, respectively. Conditions favorable for F − enrichment in groundwater included weakly alkaline pH (7.2–8.9), low concentration of Ca 2+ , and high concentrations of HCO 3 − and Na + . Calcite and fluorite were the main minerals controlling F − concentration in groundwaters. The hydrolysis of F-bearing minerals in aquifer sediments was the more important process for F − release in Tertiary clastic aquifer, which was facilitated by long residence time of groundwater, in comparison with Quaternary sediment aquifer. Cation exchange would also play important roles, which removed Ca 2+ and Mg 2+ and led to more free mobility of F − in groundwater and permitted dissolution of fluorite, especially in Tertiary clastic aquifer. However, evapotranspiration and competing adsorption of B and HCO 3 − were the more important processes for F − enrichment in Quaternary groundwater. Groundwater in Lower Cretaceous aquifer had relatively low F − concentration, which was considered to be the potential drinking water resource.