Fluoride Action Network

Hydrogeochemical evidence for fluoride behavior in groundwater and the associated risk to human health for a large irrigation plain in the Yellow River Basin.

Source: Science of The Total Environment | August 3rd, 2021 | Authors: Chen J, Gao Y, Qian H, Ren W, Qu W.
Location: China

Highlights

  • Infiltration of irrigation water diluted groundwater fluoride.
  • Factors controlling fluoride were distinct along the groundwater flow paths.
  • Health risks of fluoride through drinking water were increased with decreasing age.

Abstract

A hydrochemical analysis of groundwater (GW) was conducted to investigate the factors controlling GW fluoride (F) in a large irrigation plain in the Yellow River Basin, Guanzhong Plain, China. Area-dependent variations in F were observed in the study region. The F concentrations of 93% of samples on the south bank of the Weihe River and the western part of the Qishui River were <1 mg L-1, whereas those of 73% of GW samples for the eastern part of the Qishui River exceeded the national limit. A forward model based on mass budget equations identified carbonate weathering as the dominant factor regulating hydrochemistry in low-F GW, whereas the factors in the high-F zone were evaporate dissolution and evaporation. The high-F GW displayed a distinctive major ion chemistry, which could be attributed to a high pH, low Ca2+, and high HCO3 and Na+ concentrations. An analysis of the correlation between F/Cl and F concentrations and fluid-mineral equilibria indicated distinct forces driving the behavior of F in the subparts of the high-F GW zone, including irrigation-induced F dilution, F enrichment through Na-Ca exchange, and adsorption of F on clay minerals. The order of vulnerable segments of the population in terms of risk posed by F in GW was: infants > children > adults. These results can enhance the understanding of F behaviors in GW and provide insights into the effect of irrigation practices on GW F concentration.

Keywords

Groundwater
Fluoride
Human health risk
Yellow River Basin
Hydrogeochemistry