浙江省中部萤石产区氟环境与地方性氟病

通过对浙江省中部萤石产区氟地球化学环境的初步研究，探讨了该区地方性氟病的成因和分布规律，指出了地方性氟病与高氟环境的关系。     

Groundwater fluoride and dental fluorosis in southwestern Nigeria

This study was carried out to assess the fluoride levels of groundwater from open wells, consumed by the residents of three communities located in two distinct geological terrains of southwestern Nigeria. Fluoride concentration was determined using spectrophotometric technique, while analysis of other parameters like temperature, pH and total dissolve solids followed standard methods. Results of the analysis indicated that groundwater samples from Abeokuta Metropolis (i.e., basement complex terrain) had fluoride content in the range of 0.65?±?0.21 and 1.20?±?0.14. These values were found to be lower than the fluoride contents in the groundwater samples from Ewekoro peri-urban and Lagos metropolis where the values ranged between 1.10?±?0.14-1.45?±?0.07 and 0.15?±?0.07-2.20?±?1.41?mg/l, respectively. The fluoride contents in almost all locations were generally higher than the WHO recommended 0.6?mg/l. Analysis of Duncan multiple range test indicated that there is similarity in the level of significance of fluoride contents between different locations of same geological terrain at p?≤?0.05. It was also observed that fluoride distribution of groundwater samples from the different geological terrain was more dependent on factors like pH and TDS than on temperature. The result of the analyzed social demographic characteristics of the residents indicated that the adults (between the age of 20 and >40?years) showed dental decay than the adolescent (<20?years). This signifies incidence of dental fluorosis by the high fluoride content in the drinking water of the populace. Further investigation on all sources of drinking water and other causes of tooth decay in the area is suggested.     

A study of biochemical parameters among individuals residing in a fluoride endemic area in India

Fluoride (Fl) exerts an inhibitory effect on many metabolic enzymes of various tissues. A study was carried out among individuals residing in a Fl-affected area in India. The biochemical parameters including serum enzyme activities of alkaline phosphatase (ALKP), glutamic pyruvic transaminase (SGPT), lactate dehydrogenase (LDH), and serum creatinine (CRTN) were estimated in 259 subjects compared to 233 controls. The results showed that among the Fl-exposed population, ALKP and SGPT were significantly increased compared to control. The CRTN levels were also significantly increased compared to the control subjects. LDH levels were not markedly altered. Data suggest that Fl exposure affects renal and hepatic functions in endemic areas of India.     

Evaluation of acidity in late Permian outcrop coals and its association with endemic fluorosis in the border area of Yunnan,Guizhou, and Sichuan in China

The junction area of Yunnan, Guizhou, and Sichuan provinces is the heaviest coal-burning endemic fluorosis zones in China. To better understand the pathogenicity of endemic fluorosis in this area, 87 coal samples from the late Permian outcrop or semi-outcrop coal seams were collected in eight counties of the junction area of Yunnan, Guizhou, and Sichuan provinces. The total fluorine and sulfate content, etc. in the coal was determined using combustion-hydrolysis/fluoride-ion-selective electrode method and ion chromatography, respectively. The results show that the total fluorine concentrations in the samples ranged from 44 to 382 µg g^?1, with an average of 127 µg g^?1. The average pH of the coals is 5.03 (1.86–8.62), and the sulfate content varied from 249 to 64,706 µg g^?1 (average 7127 µg g^?1). In addition, the coals were medium- and high-sulfur coals, with sulfur mass fraction ranging from 0.08 to 13.41%. By heating the outcrop coals, HF release from the coal was verified quantitatively without exception, while simulated combustion directly confirmed the release of sulfuric acid (H₂SO₄). The acid in coal may be in the form of acidic sulfate (\({\text{HSO}}_{4}^{ - }\)/H₂SO₄) because of a positive relationship between pH and \(p\left( {{\text{SO}}_{4}^{2 - } } \right)\) in the acidic coal. The possible reaction mechanism would be that a chemical reaction between the acid (H₂SO₄ or \({\text{HSO}}_{4}^{ - }\)) and fluorine in the coal occurred, thereby producing hydrogen fluoride (HF), which would be the chemical form of fluorine released from coal under relatively mild conditions. The unique chemical and physical property of HF may bring new insight into the pathogenic mechanism of coal-burning endemic fluorosis. The phenomenon of coal-burning fluorosis is not limited to the study area, but is common in southwest China and elsewhere. Further investigation is needed to determine whether other endemic fluorosis areas are affected by this phenomenon.     

A medical geology study of an arsenic-contaminated area in Kouhsorkh, NE Iran

High concentrations of arsenic were determined in sediments from the Kouhsorkh area, Khorasan province, NE Iran. The main rock formations in the area consist of Tertiary volcanic rocks as Tuffaceous sandstone, polymictic conglomerate and andesite. Furthermore, some As–Sb–Au mineralization occurred in this area. Concentrations of arsenic in sediments were determined to range between 4.2 and 268.2 ppm, exceeding US EPA (2004) limits. It seems that young volcanic activity is one of the most important factors for arsenic contamination in this area. The first stage of this medical geology study was done at 2 villages in the Kouhsorkh area in which the arsenic concentration in water is high. People in this residential area suffer from skin diseases including hyperpigmentation, hypopigmentation, keratosis on head, hands, and feet. The 24-h urine specimens were tested for arsenic, the level of total arsenic in urine were determined to range between 13.66 and 75.92 μg/l day, exceeding permissible limits from 5 to 40 μg/day. More systematic studies are needed to determine the link between As exposure and its related diseases.     

Haematological changes in fluorotic adults and children in fluoride endemic regions of Gaya district,Bihar, India

Groundwater used for drinking and cooking was analysed for fluoride (F), and health surveys were conducted in Bodh Gaya, Amas and Bankebazaar blocks of the Gaya district, Bihar, India. Amas and Bankebazaar blocks were F endemic areas with mean F = 2.36 ± 0.23 mg/L (N = 27). Bodh Gaya was considered as control area with mean F = 0.59 ± 0.03 mg/L (N = 11). Health survey showed that more than 50 % of adults and more than 55 % of children had complaints of gastro-intestinal (GI) disturbances in the F endemic areas, while less than 20 % of adults and less than 10 % of children complained of GI problems in the control areas. Haematological analyses were conducted on age- and sex-matched fluorotic subjects (N = 93) of F endemic areas, and non-fluorotic subjects (N = 52) of control area showed lowered haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration in the fluorotic subjects, suggesting the occurrence of anaemia in the fluorotic subjects.     

Dental fluorosis associated with drinking water from hot springs in Choma district in southern province,Zambia

This study was conducted to investigate the high incidence of mottled teeth among residents of an area with hot springs in the Choma District of the Southern Province of Zambia. A survey involving 128 pupils was conducted at a Basic School to collect data on pupil’s backgrounds and their main sources of drinking water between birth and age 7. A dental specialist examined the pupils’ teeth and samples of drinking water were collected from locations where the majority of the pupils lived. It was analysed for fluorides and other drinking water quality parameters. Results of the survey showed a highly significant (P < 0.001) association between pupils’ main sources of drinking water between birth and age 7 and the incidence of discoloured teeth. All (100%) pupils who drank water from hot springs before age 7 had moderate to severe fluorosis, while the majority (96.7%) of the pupils who drank water from other sources had no dental fluorosis. Fluoride concentrations ranged from 5.95 to 10.09 mg/l in water from hot springs, and from 0.03 to 0.6 mg/l in water from other sources. Fluoride levels in water from hot spring water samples exceeded the 1.5 mg/l WHO guideline value for drinking water, while those in water from other sources were significantly (P < 0.05) lower than this. We conclude that the high prevalence of mottled teeth among residents of the study area is a case of endemic dental fluorosis associated with drinking water from hot springs containing high concentrations of fluoride.     

Distribution,geochemistry, and mineralogy of aerosols in the Angouran Mine area,northwest Iran

The Angouran Mine, located in northwest Iran, is the largest Zn–Pb producer in the Middle East. This study was designed to investigate the distribution, geochemistry, and mineralogy of the aerosols in the mining area and to assess their likely health impacts on the local residents. For this purpose, 36 aerosol samples were collected from 2014 to 2015 at nine sites located in mine district and upwind and downwind directions. The concentration of potentially toxic elements in the aerosols was determined using AAS instrument. Size, morphology, and mineralogy of the particles were studied using SEM and EDX spectra. The results indicate that the amount of total suspended particles in upwind, mine district, and downwind sites is 95.5, 463.4 and 287.5 µg/m³, respectively. The concentrations of PM_2.5 in the three locations are 8.9, 134.7, and 51.8 µg/m³, whereas the PM₁₀ contents are 2.9, 74.4, and 15.5 µg/m³, respectively. These observations point to the impact of mining activities on the concentration of aerosols in the local atmosphere. The values of air quality index also show the probable effects of the mining activities on the health of the local populations, especially for allergic peoples. The average concentration of Zn in the samples collected from the mining district (290 µg/kg) is much higher than its value in the upwind sites (27 µg/kg). The highest concentration of As (70 µg/kg), Cd (10 µg/kg), and Pb (3 µg/kg) is in downwind sites, which shows the negative impact of mining activities on the local air quality. Temporally, the highest concentration of the studied elements is recorded in spring season, especially for PM_2.5 collected in downwind stations. Based on the results of SEM and EDX spectra, three groups of minerals, i.e., carbonates, silicates, and sulfides, are present in the aerosol particles, confirming the local source for the aerosols. SEM analyses showed that the aerosol particles with dissimilar chemical composition have different morphologies such as irregular, rounded, elongated, and angular. On the basis of the results, the mining activities in the Angouran Zn–Pb Mine may have various short- and long-term consequences on the public health, especially due to high amount of the finer particles (PM_2.5) and the higher concentration of the potentially toxic elements in PM_2.5 which can penetrate into the lungs.

     

Monitoring,mapping and health risk assessment of fluoride in drinking water supplies in rural areas of Maku and Poldasht,Iran

The aim of this study was to investigate and determine fluoride concentrations in drinking water supplies in rural areas of Maku and Poldasht in West Azerbaijan Province, the northwest of Iran. Fluorosis risk assessment and characterization was also investigated. Fluoride concentrations mapping was accomplished by using the GIS system. Totally, 356 water samples, including one sample in each season, were collected from 89 water supplies providing water for 95 and 61 rural areas of Maku and Poldasht, respectively. According to the results, in Maku and Poldasht, 25 and 30 rural areas had contaminated water sources, respectively. Average annual fluoride concentrations ranged from 3.04 to 7.31 mg/l in the contaminated villages of Maku, which is about 2–4.8 times higher than the maximum standard level of the Iranian drinking water standard, and 4.52–8.21 mg/l in the contaminated areas of Poldasht, which is about 3–5.47 times higher than the maximum standard level. The maximum fluoride level was determined 11.12 mg/l and 10.98 mg/l in one of villages of Maku and Poldasht Counties in summer, respectively. Neither in Maku nor in Poldasht, water resources showed dental cavity risk, while dental fluorosis risk and skeletal fluorosis risk were very significant in some villages of both cities. Children were at most risk of fluorosis. New alternative water supplies for the contaminated villages if possible, consumption of bottled water and application of reverse osmosis are recommended as remedial actions in the contaminated areas.

     

Source identification of particulate matter and associated intake of elements through inhalation in an industrial area of Odisha,India

Particulate matter concentrations were measured in an industrial region in the Ganjam district of Odisha. The average levels of suspended particulate matter (SPM) were measured to be 142 ± 8 and PM₁₀ of particulate matter with a size of less than 10 micrometers (PM₁₀) to be 50 ± 15 μg m^?3. Out of the 14 elements determined, Ca, Na, Mg, Fe, and K contributed more than 95% of the total weight. In enrichment factors, the trace elements, i.e., Zn, Pb, Cd, and Hg were observed to be highly enriched in the SPM and PM₁₀. Factor analysis indicates that more than 75% of the variance was due to five component factors, which have eigenvalues greater than 1. Intake of elements through inhalation route to adults has been estimated.     

Daily dietary fluoride intake in rural villages of the Ethiopian Rift Valley

Dental and skeletal fluorosis is widespread in the Ethiopian Rift Valley region. Drinking water has been considered the main reason for the development of fluorosis, but dietary intake may also be a contributor in areas with high concentration of fluoride in water, soil, and biota. The purpose of this study is to assess the total daily dietary fluoride intake by adults in a rural part of the Ethiopian Rift Valley. The food, beverage, and water samples were collected from selected households of three neighboring villages with similar dietary pattern, but with different fluoride content in their water sources. Village A uses water with 1.0 mg L^?1 fluoride, village B uses water with 3.0 mg L^?1 fluoride, and village C uses water with 11.5 mg L^?1 fluoride both for food preparation and for drinking. The level of fluoride was determined in all food ingredients, in the prepared food, beverages, and in the water used for food preparation and drinking. Recipe and food frequency questionnaires were used to gather household food preparation and consumption patterns. An alkali fusion method was used for digestion of food samples and for subsequent determination of fluoride with ion-selective electrode. The daily fluoride intake varied depending on its concentration in the water used for cooking and drinking. In households using water with 1 mg L^?1, 3 mg L^?1, and 11.5 mg L^?1 fluoride, the total personal intake was found to be 10.5, 16.6, and 35.3 mg d^?1, respectively. Contribution of the water to the daily fluoride intake was 33%, 58%, and 86%, respectively. Even in households using water containing fluoride at a concentration of 1 mg L^?1, the daily intake was higher than the recommended safe intake of 1.5–4.0 mg d^?1 for adults, which indicates that the fluoride intake through food may cause health risks. Minimizing the fluoride concentration in water to the lowest possible level will greatly reduce the daily intake. The form of fluorine (organic or inorganic) in the food items and the associated health risk factors need further investigation.     

Geochemical provenance and spatial distribution of fluoride in groundwater of Mayo Tsanaga River Basin, Far North Region, Cameroon: implications for incidence of fluorosis and optimal consumption dose

The 500,000 inhabitants of Mayo Tsanaga River Basin are vulnerable to a “silent” fluorosis from groundwater consumption. For the first time, the groundwater is investigated for the purpose of identifying the provenance of fluoride and estimating an optimal dose of fluoride in the study area. Based on the fluoride content of groundwater, fluorine and major oxides abundances in rocks from the study area, mean annual atmospheric temperature, and on-site diagnosis of fluorosis in children, the following results and conclusions are obtained: Fluoride concentration in groundwater ranges from 0.19 to 15.2 mg/l. Samples with fluoride content of <1.5 mg/l show Ca–HCO₃ signatures, while those with fluoride >1.5 mg/l show a tendency towards Na-HCO₃ type. Fluor-apatite and micas in the granites were identified as the main provenance of fluoride in the groundwater through water-rock interactions in an alkaline medium. The optimal fluoride dose in drinking water of the study area should be 0.7 mg/l, and could be adjusted downward to a level of 0.6 mg/l due to the high consumption rate of groundwater, especially during drier periods.     

Inferring the fluoride hydrogeochemistry and effect of consuming fluoride-contaminated drinking water on human health in some endemic areas of Birbhum district,West Bengal

This research work is carried out to evaluate fluoride (F) hydrogeochemistry and its effect on the population of two endemic villages of Birbhum district, West Bengal. Fluoride concentration in drinking water varies from 0.33 to 18.08 mg/L. Hydrogeochemical evolution suggests that ion-exchange mechanism is the major controlling factor for releasing F in the groundwater. Most of the groundwater samples are undersaturated with respect to calcite and fluorite. Health survey shows that out of 235 people, 142 people suffer from dental fluorosis. According to fluoride impact severity, almost 80 and 94 % people in an age group of 11–20 and 41–50 suffer from dental and skeletal fluorosis, respectively. Statistically drinking water F has a positive correlation with dental and skeletal fluorosis. Bone mineral density test reveals that 33 and 45 % of the studied population suffer from osteopenic and osteoporosis disease. IQ test also signifies that F has a bearing on the intelligence development of the study area school children. The existence of significant linear relationship (R ² = 0.77) between drinking water F and urinary F suggests that consumption of F-contaminated drinking water has a major control over urinary F (0.39–20.1 mg/L) excretion.     

Geological factors controlling occurrence and distribution of arsenic in groundwaters from the southern margin of the Duero Basin,Spain

Groundwater from springs and boreholes on the southern edge of the Cenozoic Duero Basin (DB) of Spain has concentrations of arsenic (As) which are commonly above the EC drinking-water limit of 10 μg/L and reach observed values up to 241 μg/L. Groundwater compositions within the sedimentary aquifer vary from Ca–HCO₃ type, variably affected by evaporation and agricultural pollution at shallow levels, to Na–HCO₃ compositions in deeper boreholes of the basin. Groundwater conditions are mainly oxidising, but reducing groundwaters exist in sub-basins within the aquifer, localised flow paths likely being influenced by basement structure. Arsenic concentrations are spatially variable, reaching up to 38 μg/L in springs of the Spanish Central System (SCS) basement aquifer and up to 62 μg/L in springs from the DB. Highest As concentrations are associated with the Na–HCO₃ compositions in deep boreholes (200–450 m depth) within the DB. These have high pH values (up to 9.6) which can give rise to associated elevated concentrations of V and U (up to 64 and 30 μg/L, respectively). In the deep borehole waters of the DB, oxidising flows derived from the mineralised igneous–metamorphic basement and discharging via major faults, and are considered the origin of the higher concentrations. Compositions are consistent with desorption of As and other anionic species from metal oxyhydroxides in an oxic environment. Under locally reducing conditions prevalent in some low-flow parts of the DB, an absence of detectable dissolved As is coincident with low or undetectable SO₄ concentrations, and consistent with loss via formation of authigenic sulphide minerals. Mitigation measures are needed urgently in this semi-arid region where provision of alternative sources of safe drinking water is logistically difficult and expensive.     

Characterization and sources of PAHs in an urban river system in Beijing,China

Water samples from 20 locations on rivers in the Tongzhou District of Beijing were collected four times from July 2005 to March 2006. In addition, sediment samples were collected in July 2005. All samples were analyzed for 16 US Environmental Protection Agency (EPA) priority pollutants polycyclic aromatic hydrocarbons (PAHs). The concentration, distribution, seasonal variation, and sources of the 16 PAH compounds identified in the water samples, suspended particles, and surface sediments were then evaluated. The concentrations of PAHs in the water and suspended particle and surface sediment samples ranged from 87.3 to 1,890 ng l⁻¹, 1,330 to 27,700 ng g⁻¹, and 156 to 8,650 ng g⁻¹, respectively. These results demonstrated that rivers in the Tongzhou District of Beijing had a high level of PAH pollution, especially in the suspended particles. The highest and lowest concentrations of PAHs in the water samples were observed in summer and spring. However, the seasonal variations in the concentration of PAHs in the suspended particles were more complicated. The dominant compounds in the water, suspended particle, and surface sediment samples were two-, three- and four-ring PAH compounds, respectively. Ratio analysis illustrated that fuel-burning was the primary source of PAHs in the study area. Gasoline, diesel, coal, and coke oven sources were identified and the contributions of the different fuel-burning sources were then calculated using factor analysis and multiple linear regression. These analyses revealed that coal combustion, gasoline combustion plus coke oven emission, and diesel combustion accounted for 38.8%, 38.5%, and 22.7% of the PAHs in suspended particles, respectively.     

Geochemistry of soil around a fluoride contaminated area in Nayagarh District,Orissa, India: Factor analytical appraisal

Fluoride contamination in soil was studied in the vicinity of a hot spring in Nayagarh district of Orissa. Both bulk soil from 0 to 30 cm depth and profile soils from 0 to 90 cm depth were analyzed for total fluoride (F_t) and 0.01 M CaCl₂ extractable fluoride (F_ca), major elements, pH, EC and Organic Carbon (OC). High concentrations of both F_t and F_ca were observed in the area surrounding the hot spring and the village of Singhpur. Principal factor analysis (PFA) on the parameters of the bulk soils suggests that two major chemical processes due to three factors, control the soil geochemistry of the area. Factor-1 contributes 37.11% of the total variance and is strongly loaded with Al, Si, Fe, F_tand F_ca, and explains the fluoride enrichment of the soil, whereas the second and the third factors contribute 16.6 and 12.2%, respectively and explain the controlling process of carbonate precipitation and soil alkalinity. Multiple regression analysis of the scores of the factors was performed to derive a fluoride contamination index in soil. The magnitude of the factor effect on the contamination index follows the order of Factor-1 > Factor-2 > Factor-3. The spatial distribution of the contamination index is used to classify the area into highly contaminated, moderately contaminated and uncontaminated zones.     

Spatial and temporal variability of fluoride concentrations in groundwater resources of Larestan and Gerash regions in Iran from 2003 to 2010

Environmental Geochemistry and Health - There is discrepancy about intervals of fluoride monitoring in groundwater resources by Iranian authorities. Spatial and temporal variability of fluoride in...