Fluoride enrichment in drinking groundwater at Huaibei leads to potential health risk to the residents. A total of 49 groundwater samples from groundwater sources were collected to evaluate the potential health risk of fluoride ingestion through drinking water for children and adults in Huaibei. Results shown that the average concentration of fluoride in centralized sources is less than that of decentralized sources, which may be attributed to different geological conditions including fluoride-rich minerals, environmental conditions and high fluoride waste discharge. The corresponding health risk value of fluoride in centralized source is lower than that in decentralized one, and the HI values of fluoride in the three exposed groups varied in the same order: infants?>?children?>?adults. Infants and children were more sensitive receptors to the non-carcinogenic health hazards of fluoride than adults. Special care should be taken to infants and children for the highly prone to health risk compared to adults.
Groundwater is one of the major sources of drinking water specifically in the arid and semi-arid regions on the earth1,2. Occurrence of fluoride in groundwater has attracted wide attention in the world due to it closely related to human health3. Fluoride is an essential micronutrient to maintain human bone development and growth4. Moderate fluoride intake can reduce the incidence rate of dental caries and promote bone development. Insufficient intake will cause incidence rate of dental caries5, while the excessive intake will cause endemic fluorosis6,7. Many studies show that fluoride content in drinking water is positively correlated with the incidence rate of fluorosis8,9. Long-term drinking of high fluoride water can cause maladjustment of calcium and phosphorus metabolism in human body, resulting in calcium deficiency and fluorosis10. Fluorosis can also make pregnant women postpartum paralysis11. Acute fluorosis can cause serious corrosion of stomach and degeneration of liver and kidney cells, fertility reduction including miscarriage, birth abnormalities and cancer in lungs, bone, bladder and uterus10,12,13. Studies have shown that developing children are more sensitive receptors than adults and face higher health risk of fluoride. High concentration of fluoride in drinking water have a negative effect on the children’s intelligence quotient (IQ), and dental fluorosis may be the early indicator of children’s IQ impairment14,15. In view of the above facts, it is of great practical significance to limit the intake of high fluoride for people’s health. High fluoride groundwater health implication is a worldwide public health problem, especially in developing countries. It was reported that more than 60 million people are at high risk of fluorosis (dental and skeletal) in northwest China16. In order to ensure the safety of drinking water, the guideline fluoride value of 1.5 mg/L for drinking water was suggested by the World Health Organization17,18,19.
High concentration of fluoride in groundwater is mainly existed in the arid and semi-arid area with high evapotranspiration and low rainfall1,20. Elevated fluoride in groundwater is primary originated from lasting water–rock interactions and mineral weathering from fluoride bearing minerals such as fluorit, fluor apatite, biotite and phlogopite9,21,22. The concentration and transformation of fluorine in groundwater are determined by various factors, such as hydrogeochemical settings, temperature, pH, solubility of fluoride rich minerals and complexing ions12,23,24. In addition, high fluoride groundwater could be related to anthropogenic activities, such as phos-phate fertilizer application, burning of coal, glass and ceramic industry25,26. Meanwhile, fluoride could be released from fluoride-containing waste and waste residue by leaching and infiltration of rainfall and snowfall, finally resulted in potential soil and groundwater pollution. With the development of economy, the improvement of people’s living standards and the strengthening of health awareness, more and more attention has been paid to the health problems related to drinking water. Because the fluoride in drinking groundwater has a direct impact on human health, it is necessary to study the distribution characteristics and influencing factors of fluoride in groundwater, and carry out health risk assessment on the residents, which is of great significance to ensure the safety of drinking water.
Huaibei is located in the arid and semi-arid area. Groundwater is the main water source to ensure its social and economic development27. For the high concentration of fluoride in the groundwater of Huaibei City (China), and the prevalence of dental fluorosis is more than 50–90%28. In recent years, the demand for water resources is increasing greatly with the accelerate development of socioeconomic and urbanization. The urban water supply of Huaibei is supplied by tap water. Due to the lack of water purification and other infrastructure in rural areas, some areas still use groundwater with high fluoride content as the main drinking and irrigation water source. Long-term excessive fluoride intake will affect the health of residents. Many studies had focused on the distribution characteristics and quality evaluation of groundwater fluoride in Wanbei Plain27,29,30,31. However, there is no comprehensive and systematic analysis on the distribution and causes of high fluoride water in Huaibei City, and there is no literature on the health risk assessment of fluoride in groundwater. Therefore, the spatial distribution characteristics, influencing factors analysis and health risk assessment of fluoride in Huaibei city provide the basis for the accurate evaluation of groundwater situation in Huaibei City, and have important practical significance for the prevention and control of fluoride disease and urban drinking water safety.
The groundwater system with typical representativeness and can be partitioned into the Quaternary aquifer and the Carboniferous limestone aquifer in Huaibei27. And groundwater plays an important role in economic and social development. The analysis of groundwater fluoride distribution characteristics and health risk assessment are of great significance to the protection of groundwater safety and residents’ health. The main objectives of this study are to (1) determine the spatial distribution characteristics of fluorine; (2) analysis on influencing factors of fluoride in groundwater; (3) comparison of health risk assessment of fluoride in groundwater between infants, children and adults. The results from this study will provide scientific basis for managers to formulate health promotion strategies and measures, carry out fluorosis prevention and ensure groundwater drinking safety, so as to protect the health of residents…
*Read the full-study online at https://www.nature.com/articles/s41598-021-87699-6