Fluoride Levels In Groundwater Research Articles

Employing machine learning to predict the occurrence and spatial variability of high fluoride groundwater in intensively irrigated areas

Groundwater serves as a vital source of drinking water in the Hetao Basin of northwestern China. However, the occurrence and intense spatial variability of high fluoride (F−>1.5 mg/L) groundwater poses a significant health threat to local residents. In this study, the Random Forest (RF) machine learning algorithm was employed to develop two prediction models for high fluoride groundwater in Qiantao and Houtao plain, northwestern China, based on 650 groundwater samples. The models incorporated hydrochemical and geospatial datasets (climatic factors, topographic factors, and soil properties) to predict the probability of fluoride in groundwater exceeding 1.5 mg/L at a 250 m spatial resolution. The results show that the high-risk areas of the Qiantao Plain and Houtao Plain cover 33.0 % and 6.7 % of the total area of the plains, respectively. The ratio of high risk (F > 1.5 mg/L) samples correctly detected in Qiantao plain and Houtao plain were 86.7% and 94.5%, indicated an increased sensitivity to high fluoride category. Hydrochemical parameters were proven to be the most effective predictors. The spatial variability of high fluoride groundwater in two plains was dominated by the lithology, tectonic evolution, and hydrogeologic settings. Hyper-parameter optimized RF models demonstrate an outstanding performance in predicting the risk of high fluoride groundwater. This research presents a cooperative and successful effort to integrate hydrochemical and geospatial variables for prediction model, which can enhance the understanding of the geological origin and anthropogenic causes, and facilitate decision-making to identify potential risks in the areas affected by high levels of fluoride in groundwater.

Stratified control of chemical crystallization in a pellet fluidized bed for pH-Adjusted fluoride and phosphate reduction: An experimental study

Chemical crystallization granulation in a fluidized bed offers an environmentally friendly technology with significant promise for fluoride removal. This study investigates the impact of stratified pH control in a crystallization granulation fluidized bed for the removal of fluoride and phosphate on a pilot scale. The results indicate that using dolomite as a seed crystal, employing sodium dihydrogen phosphate (SDP) and calcium chloride as crystallizing agents, and controlling the molar ratio n(F):n(P):n(Ca) = 1:5:10 with an upflow velocity of 7.52 m/h, effectively removes fluoride and phosphate. Stratified pH control—maintaining weakly acidic conditions (pH = 6–7) at the bottom and weakly alkaline conditions (pH = 7–8) at the top—facilitates the induction of fluoroapatite (FAP) and calcium phosphate crystallization. This approach reduces groundwater fluoride levels from 9.5 mg/L to 0.2–0.6 mg/L and phosphate levels to 0.1–0.2 mg/L. Particle size analysis, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray diffraction physical characterizations reveal significant differences in crystal morphology between the top and bottom layers, with the lower layer primarily generating high-purity FAP crystals. Further analysis shows that dolomite-induced FAP crystallization offers distinct advantages. SDP not only dissolves on the dolomite surface to provide active sites for crystallization but also, under weakly acidic conditions, renders both dolomite and FAP surfaces negatively charged. This allows for the effective adsorption of PO43−, HPO42−, and F− anions onto the crystal surfaces. This study provides supporting data for the removal of fluoride from groundwater through induced FAP crystallization in a chemical crystallization pellet fluidized bed.

Elevated fluoride levels in groundwater in the Himalayan aquifers of upper Indus basin, India: Sources, processes and health risk

Groundwater plays an important role in socio-economics and ecosystem development in mountainous catchments of Himalaya. However, enriched geogenic pollutants in groundwater e.g. Fluoride (F−) and Arsenic (As) in many aquifer systems has deteriorated its suitability for drinking purpose. Although, F− enrichment in other Himalayan basins is well documented but its sources, fate and transport in groundwater of upper reaches of Indus Basin, western Himalaya is still unknown. In the present study, we collected groundwater samples (n = 334) across Upper Indus Basin, (UIB) India to assess the distribution, hydrogeological and geochemical processes controlling the origin, fate and transport of F− in the complex aquifer system. The groundwater is circum-neutral to alkaline with HCO3− -Na+, HCO3−- Ca2+- Na+ and HCO3−- Ca2+- Mg2+ type suggesting the dominance of silicate and carbonate weathering. The results showed that F− enriched groundwater is widespread in the basin with 70% samples having F− above the maximum permissible limit of 1.5 mg/L. High F− groundwater showed distinct hydrochemical evolution attributed to higher pH, HCO3−, Na+, low Ca2+ with Na+/Ca2+ ratio >1 exhibiting F− in groundwater is geogenic, facilitated by the release of Na+ and HCO ions via silicate and carbonate dissolution. F− release in groundwater is also assisted by the incessant dissolution of fluorinated minerals (fluoride) with active exchange between Na+ and Ca+. High HCO3− also facilitates exchange of hydroxides (OH−) and F− on sediment surfaces that contributes to F− enrichment in groundwater through desorption. Geochemical modelling indicated that the precipitation of calcite, dolomite and aragonite is conducive for F− release. F− risk assessment exhibited that people living in UIB are highly vulnerable to the potential risk of dental and skeletal fluorosis. Therefore, it is highly substantial to provide an alternative drinking water source or treat the contaminated water before consumption to mitigate human health hazards.

Assessment of fluoride exposure and associated health risks from different sources of drinking water to various age groups in Bathinda City, Punjab, India

The presence of elevated fluoride levels in Bathinda City, Punjab, India, has been a major health concern for residents. Previous studies have primarily focused on groundwater but have neglected other drinking water sources. The primary aims of this investigation are to analyze fluoride levels in various drinking water sources in Bathinda City, establish their relationship with physicochemical parameters, and appraise the non-carcinogenic health hazards associated with fluoride exposure for various age categories. A total of 296 water samples were collected, including groundwater (GW), surface water (SW), public water supply (PWS), bottled water (BW), private reverse osmosis water (PROW), municipal reverse osmosis water (MROW) (pre-and post-monsoon), and rainwater (RW). Fluoride levels were determined using a photometer (model: HI97739; make: Hanna Instruments) employing the SPADNS colorimetric procedure. The mean fluoride levels in different water sources were as follows: GW (3.77 mg L−1), SW (0.76 mg L−1), PWS (1 mg L−1), BW (1.4 mg L−1), PROW (0.94 mg L−1), MROW (pre-monsoon) (1.62 mg L−1), MROW (post-monsoon) (1.29 mg L−1), and RW (0.63 mg L−1). A significant proportion of GW (78.4%), PWS (14.3%), BW (37.5%), PROW (25%), and MROW (72.1% in pre-monsoon and 27.9% in post-monsoon) samples surpassed the World Health Organization guideline value. The study findings highlight the high fluoride levels in GW, BW, PROW, and MROW, making them hazardous for consumption. Hazard quotient analysis suggests that children face the highest risk of non-carcinogenic health effects from fluoride exposure, followed by teenagers, adults, senior citizens, and infants.

Release of geogenic fluoride from contaminated soils of Rajasthan, India: Experiments and geochemical modeling

Management of groundwater contaminants, that are primarily of geogenic origin, such as fluoride, is a major public health concern. Worldwide, around 200 million people are dependent on drinking water resources that contain elevated levels of fluoride that exceeds WHO’s drinking water threshold limit of 1.5 mg/L. According to the Ministry of Drinking Water and Sanitation of India, about 11.7 million people, mostly in the Rajasthan state, are exposed to high fluoride risk. It is important to understand the soil–water interaction mechanisms to properly assess the fluoride contamination that are primrily due to geogenic origins prevalent in the region. In this study, batch desorption experiments were performed with soils obtained from varied depths at two sites in Rajasthan that has high fluoride levels in groundwater. The fluoride release kinetics followed a pseudo first-order kinetic model. The results of the batch experiments indicate higher release of fluoride from lower soil layers when compared to the upper layers. Further, the release of fluoride was dependent on pH wherein higher release was noticed under basic pH. Since the natural pH of the soils from this region is ca. pH 8 it is expected to play a vital role in the continued release of fluoride to the groundwater system. Furthermore, a simplified geochemical model, incorporating a general composite approach, has been used to simulate the experimental results that include dissolved Al and Al-F surface complexes. The model was able to capture the observed experimental results for various soils within a reasonable RMSE of 11.74%. The results of this study not only further the current understanding of the fate and transport mechanisms of fluoride in the contaminated subsurface but also would aid in designing remedial strategies to ensure future water security in this region.

Determination and eco-friendly suppression of fluoride contamination in ground water samples using activated carbon constituents of carica papaya – A natural adsorbent

A significant contribution to increasing water supply comes from ground water and thereby meets the ever increasing demands for almost 90% of the Indian population. Problems are being faced due to the presence of excess fluoride, arsenic and nitrate in groundwater. It is also observed that low levels of fluoride in ground water can help prevent dental cavities, at the same time, higher levels of fluoride can induce dental fluorosis & skeletal fluorosis. Therefore, the fluoride level in ground water needs to be monitored and strictly controlled. Fluoride levels in drinking water should not be more than 1.5 mg/l, as recommended by the WHO and the Bureau of Indian Standards. The ideal fluoride limit for drinking and cooking is 1 mg/l, while 1.5 mg/l is acceptable if there is no other source available. Therefore, the present study analysis the water samples taken from various bore holes (provided with the locations of water sample using a Global Positioning System (GPS)) for all possible parameters like hardness, alkalinity, pH, TDS, EC, chloride, sulphate and fluoride followed by the removal of fluoride contamination in ground water samples using adsorptive filtration technique with the help of a novel, low cost natural adsorbent (activated charcoal obtained from carica papaya leaves). This work aims to determine and suggest a low cost material (Activated carbon obtained from carica papaya leaves) as an effective natural adsorbent for the defluoridation of ground water using the natural adsorbents in experimental testing. In addition to this, a mobile app for providing the related information and a separate Geographical Information System (GIS) mapping are also done. From the adsorption study, a reduction of about 84% fluoride was achieved. The obtained results were compared with the previously reported results. It is found that the prepared activated charcoal from papaya leaves is highly efficient than previously reported methods. Therefore, for the suppression of fluoride content in ground water samples, an eco-friendly reduction method using papaya leaf charcoal is suggested.

Effect of Fluoride on Oral Health Status Among General Population Residing in High- and Low-Level Fluoride Blocks in Erode District, Tamil Nadu, India: A Cross-Sectional Study.

The aim of this study was to evaluate the fluoride levels in groundwater and their effect on oral health status among the general population of Erode district, Tamil Nadu, India. A descriptive cross-sectional study was conducted among the general population of index age groups 5, 12, 15, 35-44, and 65-74 years. A total of 540 subjects participated in the study. High fluoride blocks of Erode district were selected based on the Central Ground Water Board (CGWB), Ministry of Jal Shakti, Department of Water Resources, River Development and Ganga Rejuvenation, Government of India, 2010, and the low fluoride were taken from the Groundwater Year Book (GWYB) of Tamil Nadu and UT of Puducherry, 2018. The Oral Health Assessment Form 2013 (adult and children) of the World Health Organization (WHO) was used to assess dental caries and enamel fluorosis. Clinical examination was performed using a mouth mirror and explorer under natural illumination by a single examiner. Data obtained were processed and analyzed using IBM SPSS Statistics version 26. A Chi-squared test was employed to analyze the difference between the high and low fluoride blocks. A P value of 0.05 was set to be statistically significant. The current study had a contrary finding with the CGWB on water quality analysis of fluoride levels in drinking water for high fluoride block, Ammapet (1.12 ppm) and Anthiyur (1.08 ppm). The prevalence of enamel fluorosis in high fluoride block Ammapet was 44.4% and Anthiyur was 54.8%. The prevalence of dental caries in high fluoride block Ammapet was 45.9% and in Anthiyur was 43%. The prevalence of enamel fluorosis in low fluoride block Bhavanisagar was 27.4% and in Gobichettipalayam was 28.2%. The prevalence of dental caries in low fluoride block Bhavanisagar was 61.5%, and in Gobichettipalayam was 54.8%. This study's contradictory finding emphasizes the importance of drinking water; sanitation staff should monitor and report water fluoridation data on a monthly basis in accordance with the Water Fluoridation Reporting System, and CGWB should plan and organize a team for the upgradation of water quality in India. The National Program for Prevention and Control of Dental Diseases should look on to the endemic areas for the prevention of dental fluorosis, which should be assessed, implemented, and monitored by the public health dentist who should be recruited as oral health program officers in both central and state governments.

A Cross-Sectional Study to Find the Correlation between the Level of Fluoride in Drinking Water, Dental Fluorosis and Associated Risk Factors- A Original Research.

The present study was conducted to assess the relationship between drinking water fluoride (F) levels, dental fluorosis dental caries, and associated risk factors in the elderly population. A cross-sectional analytical study was conducted on 50 patients aged 25-60 years, selected by stratified random sampling from different areas with different levels of naturally occurring F in drinking water. The patients were assessed for dental fluorosis according to WHO basic survey guidelines. The overall oral health status of the patients was assessed by decayed missing filled teeth DMFT index and the bacterial count of saliva was calculated using the Caries Risk Test (CRT). Statistical analysis was done using mean, standard deviation, standard error, Z-test, Mann-Whitney U Test, and Chi-square test. The results of the present study revealed that the prevalence of fluorosis was 24%. The number of patients with dental fluorosis was highest in those who consumed water with high groundwater fluoride levels irrespective of the source of drinking water. Caries prevalence in the study population was about 5.56 ± 1.95. There was a moderate prevalence of fluorosis in patients, and caries prevalence is high in areas below optimal F areas. Caries prevalence and mean DMFT scores were least common in patients with optimal fluoride levels in drinking water and highest in those with below optimal fluoride in drinking water.

IMPACT OF FLUORIDE TOXICITY- A WORLDWIDE THREAT

Fluoridation of water is a significant issue globally since millions of people utilise groundwater for drinking, causing health problems such dental and skeletal fluorosis as well as numerous other health hazards. Earlier studies were restricted to local or regional scales. The World Health Organization (WHO) states that 1.5 mg/l of fluoride is the safe limit for groundwater. Globally, Pakistan, China, and India are the most severely impacted nations. Fluoride pollution can induce osteosarcoma, dental fluorosis, and skeletal fluorosis, among other conditions. Since the issue has significant socioeconomic implications as well, there is a need for a serious concern in managing the fluoride level in ground water from a worldwide perspective. The investigation will assess more than a century's worth of studies conducted globally on the effects of fluoride pollution on human health. The researchers looked at the sources, mobilisation, association, and spread of fluoride contamination in water; these topics are covered here. Although research has been done all over the world, especially in developing nations like India, one area that is still urgently in need of attention is the cleanup of this contamination in ground water supplies.

Prevalence of Arrested Caries in Three Areas of South India with Different Groundwater Fluoride Levels: An Epidemiological Study.

BackgroundDental caries, though a progressive disease, if intervened early may become arrested, provided there is a change in the oral environment. One such factor which may lead to caries arrest is prolonged exposure to naturally available groundwater fluoride.AimThe aim of the study is to know the prevalence of arrested caries in three geographical areas with different levels of fluoride in groundwater and to attribute if there is any correlation between the natural high fluoride levels in groundwater and the prevalence of arrested caries.DesignA cross-sectional study is conducted on schoolchildren residing in three geographical areas of south India with high, moderate, and low groundwater fluoride levels. A total of 5,982 children, from all the three regions between the age-groups 5-9 years, are examined and 1,514 children with caries are included in the study. The teeth and surfaces with active and arrested caries are identified and recorded in a structured pro forma. All the data obtained was tabulated and subjected to statistical analysis.ResultsThe prevalence of arrested carious lesions is found to be significantly higher in areas with high groundwater fluoride level when compared to the other two areas.ConclusionIt can be concluded that the progression of caries in children residing in areas with high groundwater fluoride level is slow and gets arrested early in the presence of a high amount of fluoride.How to cite this articleMudusu SP, Jampanapally SR, Konda S, et al. Prevalence of Arrested Caries in Three Areas of South India with Different Groundwater Fluoride Levels: An Epidemiological Study. Int J Clin Pediatr Dent 2022;15(S-2):S186-S190.

High levels of fluoride in groundwater from Northern parts of Indo-Gangetic plains reveals detrimental fluorosis health risks

Fluoride contamination in groundwater is a worldwide phenomenon. Excess fluoride in drinking water causes serious health risks, and as a result, fluoride contamination of water resources is a global concern. In this study, an attempt has been made to provide the distribution of fluoride and related non-carcinogenic health hazards to local individual groups (males, females, and children separately) in the fluoride endemic region of Patiala, Punjab located in the Northern Indo-Gangetic Plain (IGP). The study shows that the dissolved groundwater fluoride concentration ranged between 1.5 and 9.2 mg/L with ∼98% of the sampling locations having fluoride levels higher than the permissible limit. Samples collected from deeper aquifers (>284 m bgl) showed ∼27% more fluoride contamination compared to those collected from <284 m bgl. Maximum incidence of elevated fluoride concentrations was observed in the eastern part of the study area in-sync with groundwater movement. The hazard quotient of fluoride (HQFluoride) calculated to assess the non-carcinogenic health risk was higher than the unitary value in all individual groups suggesting a prevalence of distressful fluorosis and chronic health risk. Results show that the children are the most vulnerable to fluoride toxicity followed by males and females. Our results are consistent with the recent trends in an increase in dental, skeletal fluorosis, and liver functional damage problems reported in children and adults of the studied region. The study area, therefore, needs the urgent attention of policymakers and government agencies to implement proper water management and cost-effective fluoride remedial measures to reduce the current and future chronic health risks associated with high fluoride intake.

Fluoride-leaching simulation of aquifer sediment and its influence on groundwater fluoride levels along coastal plains

Abstract Seawater intrusion and drinking-water fluorosis are frequently documented along coastal plains. Groundwater is characterized by high OH−, Na+, total dissolved solids, and low Ca2+ because of seawater intrusion, and such conditions favor sediment fluoride-leaching and fluorosis. But the geological process of seawater intrusion has not been noticed when high-fluoride groundwater along coastal areas is discussed. The groundwater and sediments in a typical seawater intrusion and fluorosis area are gained, and fluoride-leaching simulation experiments are performed. Sediment fluoride levels are equal to or lower than average sediment fluoride levels in China and Shandong province, but strong fluoride-leaching in aquifers is observed. Compared with the supplied water from the non-intruded neighboring area, the local groundwater has higher fluoride levels, together with higher pH, total dissolved solids, HCO3−, Cl−, Br−, SO42−, Na+, K+, and low Ca2+ because of seawater intrusion. Aquifer sediment fluoride-leaching ability increases with an increase in seawater (brine water) mixing ratios, and NaCl or NaHCO3 levels, but with a decrease in CaCl2 levels. This directly confirms that seawater (brine water) intrusion promotes sediment fluoride-leaching, and the high pH, Na+, HCO3−, and low Ca2+ levels caused by seawater intrusion are responsible for the high-fluoride groundwater along coastal plains.

Synthesis of Bio-Adsorbent for Removal of Fluoride from Groundwater – A column study

High fluoride levels in groundwater used for drinking have caused health concerns for millions of people across the world. Pakistan is one of the countries that have been contaminated by these toxins. However, a little amount of fluoride is required for tooth and bone strength. In any event, the presence of too much of it in drinking water can cause diseases in both people and animals. This study is focused on the synthesis of bio-adsorbent bone char to adsorbent for the removal of fluoride from groundwater obtained from Islamkot district Tharparkar. The bone char was synthesized by pyrolysis of used cow bones at a temperature of 550 degrees C. The fluoride removal efficiency of bone char was optimized. The impacts of different operating parameters such as flow rates (5mL/min, 10mL/min, and 15mL/min), bed height of adsorbent (2cm, 4cm, and 6cm), initial fluoride concentration 7.85 mg/L, and contact time (30min, 60min, and 90min) were studied. The removal efficiency was enhanced by increasing the adsorbent bed height and decreasing contact time and flow rate. With an initial concentration of fluoride 7.85mg/L, the maximum removal efficiency of 90.2% was obtained when the adsorbent bed height, flow rate, and contact time were optimized to 6 cm, 5 mL/min, and 30min, respectively. The finding showed that bone char can be used as an eco-friendly, inexpensive, and efficient adsorbent for removing fluoride from groundwater.

Effects of Tamarindus indica Fruit Pulp Powder on Blood and Serum Profile of Fluorosed Rats

Aims: Water containing a fluoride concentration of up to 1.0 mg/L is safe. It was found that the level of fluoride in groundwater is higher than surface water, which may lead to various health problems related to fluorosis. T. indica fruit pulp powder may help to reduce fluorosis condition in rats.&#x0D; Methods: In the present study, healthy adult rats of Wister strain (Rattus norvegicus) weighing between 180-200gm were used for experiments. The animal was divided into five groups. Group I, control rats received only tap water (0.9ppm F). Group II rats were treated with Tamarindus indica fruit pulp powder (4mg/day/rat) for 60 days. Group III rats were exposed to Fluoride water (100ppm F) for 60 days. Group IV treated with fluoride water (100ppm F) along with T. indica fruit pulp powder (4mg/day/rat) for 60 days. whereas, group V rats were ingested fluoride water (100ppm F) for 60 days and Withdrawal from treatment for 30 days. After respective treatment animals were autopsied and biochemical parameters of blood (erythrocyte and leukocyte count, hemoglobin, hematocrits); serum (protein, glucose, cholesterol); serum enzyme activity of SGOT SGPT, Acid phosphatase, and serum fluoride and calcium level was estimated using standard techniques.&#x0D; Results: Results revealed that total erythrocyte, hemoglobin, and hematocrit values were (P=.01) reduced significantly after rats were exposed to fluoride (100 ppm) water for 60 days. whereas total leucocyte count increased with fluoride (100ppm) water exposure for 60 days as compared to control values. The serum enzyme activity of SGOT, SGPT, and alkaline phosphate elevated significantly (P=.01), whereas enzyme activity of acid phosphatase diminished following fluoride water treatment to rats, as composed to control value. The level of serum fluoride enhanced significantly (P=.01) in fluorotic rats as compared to the control value. However, when fluorosed rats were treated with T. indica for 60 days restored all altered parameters almost to control value. Withdrawal of fluoride water for 30 days revealed that there is partial recovery in all parameters studied.&#x0D; Conclusion: Fluoride water consumption increases free radical generation, limits enzyme activity, and results in altered hematological and blood biochemistry. Tamarindus indica pulp powder was found to be beneficial in mitigating fluoride toxicity in rats.

Geomedical Assessment of Areas Having Varying Groundwater Fluoride Levels in Rudraprayag District, Uttarakhand

Background: Fluorosis is a public health problem caused by excess intake of fluoride through drinking water. Groundwater around the rocks composed of fluoride-rich compounds may have a high concentration of fluoride. Thus, analyzing the geology of the area may serve as a guide for easy surveillance of fluorosis disease. Methods: The geological maps of the district were analyzed to develop a fluoride risk map for the occurrence of fluorosis i.e., the district was divided into three geological categories; high risk, intermediate, and low-risk areas. This map was correlated to the groundwater fluoride levels and prevalence and severity of dental fluorosis in the population of the corresponding area. A cross-sectional study was conducted using a purposive cluster sampling method, a total of 12 villages were selected from the district. Dental fluorosis was recorded in 558 children and 36 groundwater samples of these villages. Results: Fluoride contamination was almost nil (&lt; 0.6ppm) in the areas composed of quartz and limestone which also showed an absence of fluorosis in the dependent population. It was moderate (0.6-1.5ppm) in areas ofaugen gneiss, porphyritic gneiss with mica schist which showed around 59.9% prevalence of fluorosis. Whereas, heavy contamination of fluoride (&gt; 1.5ppm) was seen where granite was the main soil-forming parent rock and around 93% of the related population was affected by fluorosis. Conclusions: This study confirms the positive association between the presence of fluoride-rich rocks around the water source and the prevalence of fluorosis in the population of the area. Based on the finding of this study, geological maps of each district of the state may help in indicating the higher chances of occurrence of fluorosis in the respective districts.

FLUORIDE CONTENT IN GROUNDWATER OF BAPOLI BLOCK OF PANIPAT (NCR) HARYANA, INDIA

In India more than 70% population relay on ground water for their daily needs. Ground water may be contaminated from natural contaminants e.g. fluoride, iron, arsenic and salinity etc. It has been proved that more than 21 states of Indian Republic are suffering from fluoride problem in their ground water. It is pertinent to mention here that fluoride in water and diet has both i.e. positive as well as negative effects on animals including humans. Haryana is one of the states facing the problem of fluorosis hence; the study under reference was carried out to monitor the level of fluoride in groundwater of Bapoli block of Panipat district of Haryana. In Bapoli block fluoride content varied between 0.24 - 1.76 mg/l and mean fluoride content was 0.99 mg/l. Out of 40 samples analyzed from Bapoli block, 34 samples had fluoride content within permissible limit and 06 samples had fluoride content above the permissible limit. The different studies carried out globally have shown that underground water includes larger amount of fluoride. It may be due to dissolution of fluoride minerals from rocks laden with fluoride minerals.

Study on Fluoride Contamination in Ground Water (Drinking water) of Deoghar, Jharkhand, India

Fluoride contamination in groundwater is one of the foremost natural mishaps for the different districts of Jharkhand. The present study was carried out to know the concentration of fluoride in the groundwater of Deoghar city. For this experiment, twelve samples were selected from each zone namely East, West, North and South. In each zone three places were selected to check the fluoride level in groundwater. Overall 36 water samples (36 samples used and the experiment was done in triplicate) from 12 different tube wells of Deoghar city were collected and investigated by using fluoride test kit. The lowest average value observed 0.343 ppm in civil lines (west zone). The highest average value 1.670 ppm observed in the Jaruadih (north part) of the Deoghar city respectively. In this study, it was observed that few locations showed fluoride contamination near the permissible limit or just above the limit (1.5 mg/L) but the remaining all areas are safe as they possess fluoride concentration within desirable limits (0.5-1 mg/L). Thus this study indicated that most of Deoghar city is free from Fluoride contamination and statistically insignificant difference of fluoride concentration was observed in Jhousagari and Jaruadih area when compared with WHO standards. The present study clearly showed that different areas of four zones are free from fluoride contamination but much more study is also needed for further more information.

Optimum Operating Conditions of Drinking Water Treatment System for Fluoride Removal using High Adsorption Bone Char

Objectives : Bone char is used in many eastern countries in Africa to remove high levels of fluoride from groundwater. However, due to the low adsorption efficiency of bone char, it is necessary to replace bone char frequently, which cause significant burden to the people in those areas. In this study, we developed a water treatment system to remove high level of fluoride in groundwater using a high efficiency bone char.Methods : In order to make a high efficiency bone char, cow bones were washed, dried and cut into small pieces. Then the bones were burned for 1, 3 and 5 hours at 350, 450 and 550℃ in electric furnaces. After that, the burned bones were sieved with 600~2,000 µm to match the size of bone char being used in Ethiopia. Surface analysis of bone char was performed using SEM and BET. The removal efficiency of bone char was conducted with various level of turbidity, TOC, and fluoride concentration for 90 minutes under the flow rate conditions of 100, 200, 300, and 400 L/day with an initial fluoride concentration of 4.8 mg/L.Result and Discussion : There was a significant difference between the bone char from Ethiopia and our study in terms of their surface roughness and specific surface area according to SEM and BET analysis. The adsorption capacity of the bone char produced in this study was 3.7 mg F/g, compared to 1 mg/L from the one from Ethiopia. In terms of turbidity and organic matter removal with column test, 200 L/d showed the shortest operating time to reach turbidity of less than 0.5 NTU, and was an effective operation for TOC removal. However, It took the longest to 1.5 mg/L of fluoride after breakthrough under 100 L/d operating conditions. In terms of operating time, bed volume, and energy efficiency, 100 L/d was found to be an effective operating condition.Conclusions : We developed a high efficiency bone char in this study with modification of its production process and tested it at various operating conditions. Our study showed that the bone char developed in this study is about 4 times more effective than traditional bone char and it is most effective at operation with low flow rates. Column operation is most effective at 100 L/d for fluoride removal under operating time and bed volume and energy efficiency. Therefore operating condition of drinking water treatment system for the fluorine removal using bone char in developing countries is effective in low flow rate operation.

Appraisal of subsurface hydrogeochemical processes in a geologically heterogeneous semi-arid region of south India based on mass transfer and fuzzy comprehensive modeling.

The main aim of the present study was to examine the quality of the groundwater and decipher the sources of groundwater fluoride through mass balance modeling based on fluoride exposure in a geologically heterogeneous semi-arid region of southern India. This was achieved by hydrogeochemical analysis, graphical methods, and mass transfer modeling approaches. Fuzzy comprehensive technique was applied to evaluate the quality of groundwater for groundwater management. In this regard, 61 groundwater samples were obtained from open wells and bore wells and analyzed for different physicochemical parameters. The major cation and anion abundances follow the order Na+ > Ca2+ > Mg2+ > K+ and Cl- > HCO3- > SO42- > NO3- > PO43-. About 88.4% and 34.4% of the total water samples were dominated with Na+ and Cl- ions in this region, respectively. The fluoride level in groundwater ranged from 0.10 to 3.30mg/l with a mean value of 1.04mg/l. Nearly 25% of the groundwater samples collected from 15 villages showed fluoride concentrations exceeding the maximum permissible limit of 1.5mg/l as per the World Health Organization recommendations for human intake. More than 85% of the samples fell under strong acid (Cl- and SO42-) type. The amount of groundwater salinization in this region was 70.5% since the Revelle index (RI) was excess in the groundwater samples (RI > 0.5meq/l). Silicate weathering, cation exchange, and gypsum dissolution were the dominant geogenic processes in the aquifer system influencing groundwater chemistry and nullified the possibility of carbonate dissolution. Saturation indices revealed the contribution of sequestration of CaCO3 in F- enrichment. Total dissolved solids showed strong positive correlations with Na+, Ca2+, Mg2+, Cl-, SO42- and NO3- indicating the contribution of anthropogenic inputs to groundwater chemistry in addition to geogenic sources. The results of the fuzzy comprehensive method indicated that 33% of the groundwater samples fell under fair water type, 2% and 11% of the samples fell under poor and very poor quality water types, respectively. Therefore, this work will be helpful for the decision-makers to plan for the sustainable management of groundwater resources.

Geochemical process of groundwater fluoride evolution along global coastal plains: Evidence from the comparison in seawater intrusion area and soil salinization area

High-fluoride groundwater along coastal plains is frequently documented. The typical geological processes of seawater intrusion and soil salinization both result in conditions of high Na+, HCO3−, Cl−, TDS (Total Dissolved Solid), and the previous related researches argue high-fluoride groundwater is favored in such conditions, together with low Ca2+. But the fluorosis in soil salinization area contrarily does not occur although more seawater mixes, and the region is characterized by higher Na+, Cl−, TDS. Thus, groundwater in Kenli District of soil salinization area and Buzhuang Town of seawater intrusion area was analyzed and compared, to reveal the potential groundwater fluoride evolution. Generally, the groundwater fluoride levels in Kenli District (0.19–1.27 mg/L) are within but those in Buzhuang Town (0.65–9.87 mg/L) are beyond the safe limit. Geochemical properties indicate a direct cation exchange in Kenli District but a reverse cation exchange in Buzhuang Town. The reverse cation exchange results in the decreasing of groundwater Ca2+(Mg2+) and under-saturation of CaF2, MgF2, CaCO3, MgCO3, CaSO4‧2H2O, MgSO4 minerals, which permits more fluoride dissolving and causes high-fluoride groundwater in seawater intrusion areas. However, the direct cation exchange increases groundwater Ca2+(Mg2+) levels to the saturation of CaF2, CaCO3 and MgCO3 minerals, and the high Ca2+ restricts the fluoride dissolution and causes low fluoride groundwater in soil salinization areas. Moreover, the calculated Ca2+, Mg2+ originating from cation exchange (△(Ca2++Mg2+)C) occupies a large proportion because of the high Na+ levels in Kenli District, and is positively correlated with the degree of mixed seawater. The difference of cation exchange processes and orientations in the two areas is confirmed to be the key to groundwater fluoride levels. Moreover, extraordinarily high levels of groundwater Na+ is found to contrarily decrease groundwater fluoride levels because of cation exchange, which is different from the previous observation that Na+ always enhances groundwater fluoride. A new insight into the function of Na+ on groundwater fluoride evolution was proposed. These findings provide some information about groundwater fluoride evolution along coastal plains.