Endemic Fluorosis In China Research Articles

Fluoride promotes the secretion of inflammatory factors in microglia through NLRP3/Caspase-1/GSDMD pathway.

It is widespread of endemic fluorosis in China, and the exposure of excessive fluoride will cause nervous system disease and activate microglia. However, the mechanism of the damage is not clear. It is well-known that NLRP3/Caspase-1/GSDMD pathway, a classic pyroptosis pathway, is widely involved in the occurrence and development of nervous system-related diseases, infectious diseases, and atherosclerotic diseases. This research aimed to explore the molecular mechanism of sodium fluoride on inflammation and pyroptosis in BV2 microglia based on the NLRP3/Caspase-1/GSDMD signaling pathway. BV2 microglia was treated with sodium fluoride at the dose of 0.25, 1, and 2mmol/L for 24, 48, and 72h, respectively. Cell viability, cell morphology, lactate dehydrogenase content, and related proteins and genes were examined to investigate if sodium fluoride caused damage to BV2 microglia through the pyroptosis pathway. Dithiolam (5μmol/L), a pyroptosis inhibitor, was added for further verification. NaF could induced BV2 cells injury in a dose-dependent fashion through disrupting the integrity of cell membranes and increasing IL-1β via upregulating NLRP3, Caspase-1, and its downstream protein GSDMD. Disulfiram couldimprove these changes caused by NaF. In conclusion, our results suggested that NLRP3/Caspase-1/GSDMD-mediated classical pyroptosis pathway was involved in fluoride-induced BV2 microglia damage.

Spatial-Temporal Analysis of Drinking Water Type of Endemic Fluorosis - China, 2009-2022.

Endemic fluorosis, caused by high fluoride levels in drinking water, has been a significant health issue in rural areas of China for many decades. There has been a notable decline in the detection rate of dental fluorosis in children aged 8-12 years in drinking water fluorosis areas across the country from 2009 to 2022. While 14 provincial-level administrative divisions are classified as low-probability clusters, Tianjin remains classified as a high-probability cluster. The current policy for preventing and controlling endemic fluorosis in China needs adjustment. Rather than focusing solely on regions with high incidence, there should be a shift towards monitoring and early warning of fluoride exposure. Additionally, local containment measures should be intensified.

Fluorine speciation and origin of Early-Middle Triassic bentonite deposits in Sichuan Basin, South China

Fluorine (F) is one of the most important environmentally harmful elements released by volcanic activity, and the bentonite deposits that formed from volcanic ashes are potentially harmful to the environment. However, the mechanisms governing F-rich bentonite formation and its F speciation composition remain enigmatic. The F-rich bentonite deposits are widely distributed in the Early-Middle Strata of the Sichuan Basin, South China. Detailed mineralogical and geochemical studies were conducted on the bentonite deposits from five sections of the Sichuan Basin. X-ray diffraction (XRD) analyses indicate that the F-rich bentonites mainly contain quartz, carbonates (calcite and dolomite) or gypsum, and clay minerals, while the clay minerals are dominated by illite and illite/smectite (I/S). Clay mineralogical studies suggest that bentonites were transformed from volcanic ashes during diagenesis by smectite illitization. The major and trace element distribution in F-rich bentonite deposits altered from volcanic ashes is most likely derived from felsic magmas, and alteration of the parent rocks (e.g., rhyolites) to bentonite is associated with leaching and subsequent removal of F. The total fluorine content (FTOT) of the bentonite samples ranged from 1,162 mg/kg to 2,604 mg/kg (average = 1773 mg/kg), well above the average FTOT contents of soils in the world. The results of the sequential extraction experiments show that the highest content is residual-fluorine (Fres), followed by carbonate-fluorine (Fcar) with a mean value of 1,556 mg/kg and 186 mg/kg, indicating carbonate is an important F sink in bentonite deposits. The average fluorine value of organic fluorine (For), Fe/Mn oxide-fluorine (Ffm) and exchangeable fluorine (Fex) are relatively low with an average value of 17.5 mg/kg, 6.8 mg/kg and 4.1 mg/kg, respectively. However, water-soluble fluorine (Fws) has a mean value of 4.0 mg/kg, which is higher than the corresponding average value in soils in an area susceptible to endemic fluorosis in China. Based on the characteristic of fluorine speciation, the fluorine in bentonite deposits may pose a risk to the environment. This study makes an important contribution to a better understanding of the characteristic of fluorine speciation in bentonites and the formation mechanism that governs fluorine enrichment in bentonites.

Surveillance on drinking-water-born endemic fluorosis in China, 2013

To investigate the prevalence of fluorosis and related control measures on drinking water type of endemic fluorosis in China. According to the national program- "Surveillance Scheme of Drinking-Water-Borne Endemic Fluorosis" , 136 counties were selected in 29 provinces, autonomous regions and municipalities. Three epidemic villages were randomly selected as fixed monitoring sites in each county. Dental fluorosis of all the children aged 8-12 living in the villages under the monitoring program, was identified under the ariteria from "Diagnosis of dental fluorosis" (WS/T 208-2011). Operating conditions and contents of fluoride in all the'water-improved projects' were investigated. Contents of fluoride in drinking water were tested in villages without the 'water-improved projects'. "Standard Test Method for Drinking Water" (GB/T 5750.5-2006) was used to detect the water fluoride. The overall prevalence of dental fluorosis among children aged 8-12 in all the villages under monitor program, was 28.58% (7 950/27 817), with the dental fluorosis index (DFI) as 0.58. Among them, the prevalence was 22.28% (3 917/17 583) and DFI was 0.44 in the'water-improved projects' villages that under normal operation and with qualified fluoride contents. The prevalence appeared as 38.74% (1 926/4 971) with DFI as 0.84 in those villages with 'water-improved projects' but mal-operated or with excessive fluoride. The prevalence was 40.03% (2 107/5 263), and DFI was 0.81 in those villages without 'water-improved projects'. The prevalence rates of dental fluorosis in children from the three types of endemic areas were significantly different. For 'water-improved projects', the normal opration rate was 93.77% (286/305) and the qualification rate of fluoride content was 76.77% (228/297). Dental fluorosis in children living in the drinking-water-born endemic fluorosis areas was on the edge of epidemics in China. Effective improvement on the quality of drinking water can significantly reduce the severity of dental fluorosis in children. The rate of proper operation on 'water-improved projects' was near to 95% in the endemic area. However, rate that met the criteria on qualified fluoride contents of these projects was still below 80%.

Epidemiological analysis of endemic Fluorosis in China

(1997). Epidemiological analysis of endemic Fluorosis in China. Journal of Environmental Science and Health, Part C: Vol. 15, No. 2, pp. 123-138.

Outline of control practice of endemic fluorosis in China

Endemic fluorosis is prevalent in China covering 29 provinces, municipalities and autonomous regions. The endemically affected areas can be divided, according to the sources of fluoride, into three types: high fluoride water, pollution from coal burning, and drinking brick tea in excess. Since the 1960's, several pilot surveys of the disease have been made and control programmes carried out in some of the areas. An Expert Consultation Committee on Endemic Fluorosis Control of the Ministry of Public Health was formally established in 1979. A national survey programme and series of working criteria for the disease were drawn up at the First National Congress of Endemic Fluorosis Control in 1981. Under the Central Government of China, administrative organizations and institutions concerned at all levels have been set up, forming a nation-wide network of control. Cooperation and coordination among such departments as health, water conservancy, geology and finance have been achieved in the planning and implementation of control programmes. Since 1980, many projects for improving drinking water quality through de-fluoridation have been completed. At the same time, new methods and technologies for improving stove and grain baking have become widely used in some of the areas where environmental fluoride pollution exists from burning coal. After all the control programmes had been introduced, the incidence of the illness was reduced with some patients making a complete recovery.

Endemic fluorosis in China from ingestion of food immersed in hot spring water

Fengliang was identified as a town with endemic dental fluorosis during an overall screening to identify areas with endemic fluorosis in Guangdong Province. Fengliang is situated in a hot spring area in the eastem part of Guangdong. Among a population of 8000, the prevalence of dental fluorosis inchildren aged 8 to 15 years (total 837) reached 50%, but the fuoride content of drinking water was less than 0.4ppm. In comparison, the United States federal standard for fluoride in drinking water is 4 ppm (Federal Register, 1985). The California drinking water standard is 1.4 to 2.4 ppm, depending on ambient temperature (California Administrative Code Title 22). In order to determine the cause of the dental fluorosis in Fengliang, a systemic study was conducted to investigate dietary intake of fluoride as a possible source of exposure. Researchers examined hot spring water and foods for fluoride content on the basis that the local population routinely immersed their vegetables in hot spring water.

Geographical environmental characteristics of endemic fluorosis in China

Endemic fluorosis is given rise to by human intake of excess fluorine from environment by way of food chain. In China it is one of the extensively prevalent endemic diseases and its distribution shows clearly regional characteristics. In macroscopic sight, three large fluorosis zones may be divided: (1) The arid and semi-arid plains in the north of China. These regions have a dry climate, making fluorine accumulation in the Quaternary deposits. Thus, the drinking water with high content of fluorine is the main cause of the disease formation. (2) The Yunnan-Guizhou Plateau. In the region, rocks and soils rich in fluorine bring about fluorine excess in crop food. This plays an important role in the disease formation. (3) Southeast hills. The hot spring with high content of fluorine leads to fluorosis.