Formation and In Situ Treatment of High Fluoride Concentrations in Shallow Groundwater of a Semi-Arid Region: Jiaolai Basin, China.

Zongjun Gao,Jianguo Feng,Yechen Cui,Hongying Zhang,Mengjie Shi,Shaoyan Fang

doi:10.3390/ijerph17218075

Abstract

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the formation of shallow high-fluoride groundwater (SHFGW); (2) identify appropriate methods for in situ treatment of SHFGW. A field investigation into the formation of SHFGW was conducted, and the results of experiments using soils from high-fluoride areas were examined to investigate the leaching and migration of fluoride. The results showed that the formation of SHFGW in the Jiaolai Basin is due to long-term geological and evaporation processes in the region. Stratums around and inside the basin act as the source of fluoride whereas the terrain promotes groundwater convergence. The hydrodynamic and hydrochemical conditions resulting from slow groundwater flow along with high evaporation and low rainfall all contribute to the enrichment of fluoride in groundwater. In situ treatment of SHFGW may be an effective approach to manage high SHFGW in the Jiaolai Basin. Since soil fluoride in high-fluoride areas can leach into groundwater and migrate with runoff, the construction of ditches can shorten the runoff of shallow groundwater and accelerate groundwater loss, resulting in the loss of SHFGW from high-fluoride areas through river outflow. The groundwater level will be reduced, thereby lowering the influence of evaporation on fluoride enrichment in shallow groundwater. The results of this study can act a reference for further research on in situ treatment for high-fluoride groundwater.

Highlights

Humans depend on the natural environment for survival, and the quality of the natural environment directly affect the health of people [1]
Water-soluble fluoride has a considerable impact on human health, with excessive groundwater fluoride content often resulting in regions of endemic fluorosis [2]
Endemic fluorosis is a geochemical disease occurring in a specific geographical environment [3,4], and since its spatiotemporal distribution is positively correlated with the distribution of groundwater fluoride content, excessive fluoride content in groundwater is considered to be the main cause of regional fluorosis [5]

Summary

Introduction

Humans depend on the natural environment for survival, and the quality of the natural environment directly affect the health of people [1]. Water-soluble fluoride has a considerable impact on human health, with excessive groundwater fluoride content often resulting in regions of endemic fluorosis [2]. High groundwater fluoride contents can result in excessive uptake of fluoride into the human body through the direct consumption of drinking water, thereby posing a risk to human. Gao et al [49] proposed the concept of in Situ Fluoride Dispelling through field investigation as a method of reducing the hazard to human health resulting from the high fluorine environment in the Jiaolai Basin and referred to the saline-alkali land treatment method. Measures to control saline-alkali land mainly include applying specific fertilizer, planting specific crops, adding amendments and physical drainage. Physical drainage measures are mainly applied in areas in which there is high salinization and shallow groundwater and in which a drainage system can be established (Figure 9). In the physical drainage measures, reasonable spacing of ditches can effectively control the water level of shallow groundwater (Formula (3)) [68] and accelerate the loss of shallow groundwater

Objectives

Methods

Conclusion