Influences of charcoal and bamboo charcoal amendment on soil-fluoride fractions and bioaccumulation of fluoride in tea plants

High levels of fluoride in tea plants pose a potential health risk to humans who drink tea. It has been demonstrated that tea plant fluoride is closely related to the available fluoride in soil. But approaches that could be used to regulate the availability of fluoride in soil have been rarely seen. This study aims to investigate how the addition of charcoal and bamboo charcoal affected soil fluoride availability and bioaccumulation of fluoride in tea plants. In a microcosm experiment, tea plants were grown in the tea garden soil mixed with different amounts of charcoal and bamboo charcoal [that is, 0.5, 1.0, 2.5, and 5.0?% (w/w)]. Soil-fluoride fractions and fluoride accumulated in tea plants were determined using the sequential extraction and ion selective electrode method. Obtained results showed that both charcoal and bamboo charcoal additions significantly enhanced the concentrations of Fe/Mn oxide-bound fluoride, but significantly reduced the concentrations of water-soluble and exchangeable fluoride (p?相似文献   

源于大气的氟在水稻不同器官的分布及对糙米含氟量的影响

用开顶式熏气罩熏气的方法,研究了气源氟在水稻不同器官的分布及对糙米含氟量的影响。结果表明:气源氟主要分布于水稻叶片中,根含氟量不受气源氟的影响;籽粒含氟量取决于籽粒器官形成后空气氟浓度,与籽粒器官形成前的空气氟浓度无关;糙米氟含量与水稻抽穗齐穗后所暴露的氟剂量间呈极显著线性相关关系。     

Retarding fluoride accumulation in Amaranthes viridis through liming and implications of phosphorous treatment

With an objective to retard fluoride being taken up by the plants from soil, a study was carried out on Amaranthes viridis. Four groups of treatment were carried out vis-à-vis fluoride alone, fluoride and calcium, fluoride and phosphorous and fluoride, calcium and phosphorous together at three different concentration levels vis-à-vis 1, 10 and 25 mg/kg soil of each. Sampling was carried out first on day 45 and at the end of reproductive phase on leaf and seed for accumulation of fluoride in the plants. It was observed that fluoride accumulation in plants could be averted through soil amendment by calcium treatment in the form of calcium carbonate thereby reducing the risk of human and livestock exposure to abnormal levels of fluoride through food chain other than protecting plants from getting affected. At the same time, fertilizing the soil contaminated with fluoride by superphosphate would aggravate fluoride accumulation and exacerbate fluorosis problem in human and livestock through food chain. Therefore it is recommended to use acid water-soluble orthophosphate or anhydrous dicalcium phosphate or soluble pyrophosphate fertilizers as an alternative.     

Utility of check dams in dilution of fluoride concentration in ground water and the resultant analysis of blood serum and urine of villagers,Anantapur District,Andhra Pradesh,India

High levels of fluoride (beyond 1.5 ppm) in ground water as source of drinking water are common in many parts of Andhra Pradesh, India, causing fluorosis. The study carried out in endemic Nalgonda District, Andhra Pradesh, has indicated that the fluoride-rich ground water present in the wells located down stream and close to the surface water bodies is getting diluted by the low-fluoride surface water. Encouraged by this result, check dams were constructed upstream of the identified marginally high fluoride bearing ground water zones in Anantapur District to reduce fluoride levels as an alternate solution for safe drinking water.In this paper, an attempt is made to study the utility and effect of these check dams in dilution of fluoride concentration in drinking water and its resultant impact on the health aspects of certain villagers of Anantapur District through the analysis of their blood serum and urine. Ground water samples from three fluoride-affected villages, blood and urine of males and females from the same villages were collected and analyzed for fluoride using ion selective electrode method. The results indicated that the fluoride levels in blood serum and urine of males in the age group of 5–11 years are found to be the highest. The concentration of fluoride in ground water is directly proportional to the concentration of fluoride in blood serum and urine. The concentration of fluoride in ground water with depth of the aquifer is a function of lithology, amount and duration of rainfall, rate of infiltration, level of ground water exploitation in the area etc. The construction of check dams upstream of the identified marginally high fluoride waters will not only cause additional recharge of ground water but also reduces the fluoride concentration eventually improving the health of the villagers.     

Fluoride concentrations in the pineal gland,brain and bone of goosander (Mergus merganser) and its prey in Odra River estuary in Poland

The aim of the study was to investigate fluoride concentrations in bone, brain and pineal gland of goosander Mergus merganser wintering in the Odra estuary (Poland) as well as in fish originating from its digestive tract. The fluoride concentrations were determined with potentiometric method. Medians of concentrations in goosander had the highest and the lowest values in pineal gland and brain (>760 and <190 mg/kg, respectively). Fluoride concentration in the pineal gland was significantly greater than in the bone and the brain of the duck. In fish, the fluoride concentration ranged from 37 to 640 mg/kg and significant correlation was revealed between the fluoride concentration and fish weight and length. Based on own results and data of other authors, a daily fluoride intake by the goosander in the Odra estuary was estimated at 15 mg. So high fluoride concentrations like in the duck have not been found in mammal brains.     

The determination of fluoride in water in the presence of organic acids and iron using a fluoride-selective electrode

Surface waters in Scotland, notably from upland catchment areas, are commonly enriched in iron and organic acids. This study investigated the impact of these species on the direct potentiometric determination of fluoride using a fluoride-selective electrode. As the electrode technique is commonly used to monitor the fluoride content of potable waters, it is important that these effects are evaluated if such waters are to be fluoridated. The determination method used was that defined by Nicholson (1983) and Nicholson and Duff (1981) to minimise errors. This employs the TISAB III-TAC buffer system with the following composition (in 1L): 58.0 g sodium chloride, 57.0 mL glacial acetic acid, 4.0 g CDTA, 243.0 g tri-ammonium citrate adjusted to pH 5.4 with 10 M sodium hydroxide. Experimental solutions of fluoride with organic acid or iron were prepared, and the effect on fluoride concentration determined for each combination. Concentrations used: fluoride: 0.1, 1.0 mg L⁻¹; humic acid: 5, 10, 100, 1000, 10,000 mg L⁻¹; oxalic acid: 5, 10, 100, 1000, 10,000 mg L⁻¹; iron(III): 1, 10, 100, 500 mg L⁻¹; Humic acid (HA) concentrations had no impact on the determination of fluoride at the 1.0 mg L⁻¹ level. However, with 0.1 mg L⁻¹; F⁻, an increase in the apparent fluoride concentration was observed when HA > 1,000 mg L⁻¹; this increased with increasing HA content to a maximum of ∼600%. Oxalic acid (OA) generally had no impact on the fluoride determinations at the 1.0 mg L⁻¹; level, but at an OA concentration of 10,000 mg L⁻¹; fluoride concentrations were reduced by ∼50%. At 0.1 mg L⁻¹ F⁻, increasing OA concentrations produce a steady increase in the fluoride concentration of up to 200% with 1,000 mg L⁻¹; OA, greater OA contents produce a fall in the fluoride content. Iron had no effect on the fluoride determinations at both the 0.1 and 1.0 mg L⁻¹ levels. The causes of the apparent increases in fluoride concentration have not been determined, although fluoride contamination by the reagents has been ruled-out. However, the results demonstrate that the defined method and buffer system is suitable for the determination of fluoride in the presence of iron and organic acids at naturally occurring levels, and that fluoride will not be masked from detection.     

Distribution and Risk Assessment of Fluoride in Drinking Water in the West Plain Region of Jilin Province, China

The west plain region of Jilin province of northeast China is one of the typical endemic fluorosis areas caused by drinking water for many years. Investigations of hydrogeological and ecoenvironmental conditions as well as endemic fluorosis were conducted in 1998. Results show that the ground water, especially, the water in the unconfined aquifer is the main source of drinking water for local residents. The fluoride concentration in groundwater in the unconfined aquifers is higher than that in the confined aquifer in the west plain of Jilin province. The fluoride concentration in the unconfined aquifer can be used to classify the plain into fluoride deficient area, optimum area and excess area, which trend from west to east. High fluoride (>1.0 mg L(-1)) in drinking water resulted in dental and skeletal fluorosis in local residents (children and pregnant women). There exists a positive correlation between fluoride concentration in the drinking water and the morbidities of endemic fluorosis disease (r1 = 0.781, r2 = 0.872). Health risks associated with fluoride concentration in drinking water are assessed. It has been determined that fluoride concentration in excess of 1.0 mg L(-1) exposes residents to high health risks based on risk identification. The study area is classified into five health risk classes as shown in Figure 4. The risk indexes of this area more than 1.0 are accounted for 68% of the total west plain region.     

Geological sources of fluoride and acceptable intake of fluoride in an endemic fluorosis area, southern Iran

The present study is the first attempt to put forward possible source(s) of fluoride in the Dashtestan area, Bushehr Province, southern Iran. In response to reports on the high incidence of dental fluorosis, 35 surface and groundwater samples were collected and analysed for fluoride. The results indicate that dissolved fluoride in the study area is above the maximum permissible limit recommended by the World Health Organization (WHO). An additional 35 soil and rock samples were also collected and analysed for fluoride, and rock samples were subjected to petrographic investigations and X-ray diffraction. The results of these analyses show that the most likely source for fluoride in the groundwater is from clay minerals (chlorite) and micas (muscovite, sericite, and biotite) in the soils and rocks in the area. We also note that due to the high average temperatures all year round and excessive water consumption in the area, the optimum fluoride dose level should be lower than that recommended by the WHO.     

Study of fluoride content in groundwater of Nawa Tehsil in Nagaur, Rajasthan

There is a severe fluoride problem in Nawa tehsil of Nagaur district. Villagers are suffering from dental fluorosis and skeletal fluorosis. So an extensive geochemical study of 27 villages of eastern, south-eastern and southern zone of Nawa tehsil was done. Total 46 ground water samples were collected and analyzed for various physicochemical parameters as well as fluoride content. The ground water samples collected in clean polyethylene plastic containers were analyzed for pH, electrical conductivity, total dissolved salts, calcium, magnesium, total hardness, chloride and alkalinity. The fluoride concentration in the three different zones ranged from 0.64 to 14.62 mg l(-1) where 13.04% samples were found within permissible limit while 86.96% had fluoride beyond permissible limit (> 1.5 mg l(-1)). It was found that among the three different zones south-eastern zone was under serious fluoride contamination where fluoride concentration ranged between 1.10 to 14.62 mg l(-1). In the eastern zone fluoride concentration was recorded from 1.52 to 5.13 mg l(-1) whereas in the southern zone it was found between 0.64 to 3.63 mg l(-1).     

Occurrence and problems of high fluoride waters in Turkey: an overview

Endemic dental fluorosis was first observed in Turkey in Isparta Province, located in the SW of Anatolia, with mottled enamel related to the high levels of fluoride (1.5–4.0 ppm) in drinking waters, about 55 years ago. The origin of fluoride was attributed to the contents of minerals in volcanic rocks, consisting of pyroxene, hornblende, biotite, fluorapatite and glassy groundmass minerals. It was also reported about 35 years ago that severe dental and skeletal fluorosis has been observed in human beings and livestock in Dogubeyaz?t and Caldiran areas, located around Tendurek Volcano in eastern Turkey, where natural waters contained fluoride levels between 2.5 and 12.5 ppm. It was hypothesised that fluoride, which might be transported by fumaroles or escaped from devitrified lavas, could be held on the surface of some minerals and then exchanged with OH^- in ground waters with high pH at the foothills of the young Tendurek Volcano. Endemic dental and skeletal fluorosis was also observed in the inhabitants in Kizilcaoren Village of Beylikova Town in Eski?ehir Province situated in the midwest of Turkey, where the fluoride content of the drinking waters ranged from 3.9 to 4.8 ppm. The origin of high fluoride in the natural waters was related to the fluorspar deposits, occurring in the catchment area near the village. During the survey in the Güllü Village of Esme-Usak, located in south-midwest of Turkey, it was observed that most of the inhabitants born and raised in the village and aged between 10 and 30 years, showed mild to moderate levels of mottled enamel. The fluoride contents of the deep well waters used for drinking in the village, varied from 0.7 to 2.0 ppm. Amorphous microscopic fluorite existing in the Pliocene lake limestones was considered as a possible origin of fluoride in the waters.     

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.     

杭嘉湖蚕桑区主要大气氟污染源及治理现状

对杭嘉湖蚕桑区大气氟主要污染源——砖瓦厂氟的排放状况及各种含氟烟道废气治理装置的治理效果进行了较为深入的调查分析,认为砖瓦厂含氟废气不经烟道排放较为严重。目前砖瓦厂所采用的各种含氟废气治理装置中,旋流板塔装置除氟效率较佳,可使废气氟的排放浓度降至5mg/m~3以下,基本上能消除下风向300m以远的大气氟污染对蚕桑的严重危害。     

Single and multiple daily dose toxicokinetics of fluoride after oral administration of sodium fluoride along with aluminum sulfate in goats

Our previous study suggested that toxicokinetic parameters of fluoride were significantly changed on the 30th day as compared with 1st day, after repeated oral administration of sodium fluoride alone for 30 days in goats. The purpose of this study was to investigate whether aluminum sulfate has ameliorative effect on the toxicokinetics of fluoride. For this, sodium fluoride (20 mg kg^?1 b. wt.) along with aluminum sulfate (150 mg kg^?1 b. wt.) was administered in goats for 30 days to investigate its effect on toxicokinetics of fluoride on days 1 and 30. The fluoride levels against time were adequately described by one compartment open model. The peak plasma level of fluoride was observed at 2 h. The toxicokinetics data revealed a nonsignificant decrease in β (elimination rate constant) and C _max (the maximum plasma concentration) and increase in t _1/2 K _a (absorption half-lives), t _1/2 β (elimination half-lives), area under the plasma (AUC) concentration versus time curve and mean residence time (MRT) was observed for the last dose from their respective first dose values. On the basis of changes in the toxicokinetic parameters, it was concluded that repeated oral administration has cumulative effect on plasma fluoride level and concurrent oral administration of aluminum sulfate has ameliorative action on the toxicokinetics of fluoride in goats.     

氟对西伯利亚鲟仔鱼的急性毒性及安全浓度评价

为检测氟对鱼类的生态毒性效应,在水温(17±1)℃的条件下,采用半静态式生物毒性试验方法研究了氟离子对西伯利亚鲟初孵仔鱼的急性毒性效应(氟离子浓度梯度设置为0、100、200、300、400、500、600mg·L-1).结果表明,氟暴露后仔鱼出现焦躁不安、失去平衡、呼吸减弱等中毒症状,且随着暴露浓度的升高与暴露时间的延长,死亡率逐渐增加,存在明显的剂量效应关系和时间效应关系.氟对西伯利亚鲟初孵仔鱼48h、72h、96hLC50分别为1014.10mg·L-1、288.28mg·L-1、181.18mg·L-1.经计算得出氟对西伯利亚鲟初孵仔鱼安全质量浓度为1.81mg·L-1,低于我国部分高氟地区地下水、地表水及人为氟污染水域中氟的浓度,应引起高度重视.     

Simultaneous removal of arsenate and fluoride from water by AI-Fe （hydr）oxides

A1-Fe （hydr）oxides with different A1/Fe molar ratios （4：1, 1：1, 1：4, 0：1） were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 ： Fe was superior to other adsorbents for removal of arsenate and fluoride in the pH range of 5.0-9.0. The adsorption capacity of the A1-Fe （hydr）oxides for arsenate and fluoride at pH 6.50.3 increased with increasing A1 content in the adsorbents. The linear relationship between the amount of OH released from the adsorbent and the amount of arsenate or fluoride adsorbent by 4A1 ： Fe indicated that the adsorption of arsenate and fluoride by A1- Fe （hydr）oxides was realized primarily through quantita- tive ligand exchange. Moreover, there was a very good correlation between the surface hydroxyl group densities of A1-Fe （hydr）oxides and their adsorption capacities for arsenate or fluoride. The highest adsorption capacity for arsenate and fluoride by 4A1 ： Fe is mainly ascribed to its highest surface hydroxyl group density besides its largest pHpzc. The dosage of adsorbent necessary to remove arsenate and fluoride to meet the drinking water standard was mainly determined by the presence of fluoride since fluoride was generally present in groundwater at much higher concentration than arsenate.     

氟离子慢性暴露对中国林蛙蝌蚪生长发育的毒性效应研究

氟元素以不同的结合形式广泛存在于自然界中,适量氟的摄取有益于龋齿预防和骨骼发育,然而过量氟的摄取会对动物及人体健康造成危害。近年来,大量的人类活动导致水环境中氟含量持续升高。为探究水域氟污染对中国林蛙的毒性影响,本研究以中国林蛙(Rana chensinensis)胚胎为试验材料,对卵黄栓期(G12期)胚胎进行了0、0.7、4.2、19.4、42.8 mg·L~(-1)F-慢性水体暴露直至胚胎发育到变态高峰期(G42期)的研究。分别于暴露25 d和40 d后取样测定了蝌蚪全长、体长、体重和发育分期;此外,分析了F-慢性暴露对变态率、G42期蝌蚪的全长、体长、体重和后肢长以及G42期蝌蚪骨骼发育的影响。结果表明:暴露25 d时,4.2 mg·L~(-1)F-处理组促进了林蛙蝌蚪的生长发育,而42.8 mg·L~(-1)F-处理组显著抑制了蝌蚪的生长发育;暴露40 d时,19.4 mg·L~(-1)F-和42.8 mg·L~(-1)F-处理组蝌蚪的生长发育均受到显著抑制。持续进行慢性暴露78 d后,4.2 mg·L~(-1)F-处理组蝌蚪的变态率显著升高,而42.8 mg·L~(-1)F-处理组蝌蚪的变态率受到了显著抑制。此外,42.8 mg·L~(-1)F-处理组G42期蝌蚪形态指标(全长、体长和后肢长)以及骨骼发育均受到抑制。依据G42期中国林蛙蝌蚪的生长发育指标和变态率为观察指标,氟离子慢性暴露对中国林蛙蝌蚪的最低可观察效应浓度(LOEC)为0.7 mg·L~(-1)。研究表明,水环境中高浓度的氟污染会对中国林蛙蝌蚪的生长发育、变态和骨骼发育等造成潜在的不利影响,水体氟污染的生态毒性效应理应引起高度重视。     

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.     

阜阳电厂灰水氟化物浓度的确定及对地下饮用水源污染预测

目前在火电厂环境影响评价中，主要利用类比法和实验法确定灰水中氟化物的浓度。文章提出了一种新的方法－－计算法。该方法以氟的迁移转化规律为基础，以物料平衡原理为依据，充分考虑煤源、煤质、除尘方式、除灰方式、排灰方式及冲灰水水质等影响因素。与类比法和实验法相比，该法简便、可靠、实用、经济。鉴于阜场附近地区地下水饮用水源污染的可能性，影响程度及发生时间。     

Fluorides in groundwater and its impact on health

Fluoride is a naturally occurring toxic mineral present in drinking water and causes yellowing of teeth, tooth problems etc. Fluorspar, Cryolite and Fluorapatite are the naturally occurring minerals, from which fluoride finds its path to groundwater through infiltration. In the present study two groundwater samples, Station I and Station II at Hyderabad megacity, the capital of Andhra Pradesh were investigated for one year from January 2001 to December 2001. The average fluoride values were 1.37 mg/l at Station I and 0.91 mg/l at Station II. The permissible limit given by BIS (1983) 0.6-1.2 mg/l and WHO (1984) 1.5 mg/l for fluoride in drinking water. The groundwaters at Station I exceeded the limit while at Station II it was within the limits. The study indicated that fluoride content of 0.5 mg/l is sufficient to cause yellowing of teeth and dental problems.     

Potential fluoride contamination in the drinking water of Marks Nagar,Unnao district,Uttar Pradesh,India

This study was conducted in the summer season (May, 2007). The fluoride concentration along with other physico-chemical parameters in ground water samples was determined in Marks Nagar of Unnao district, Uttar Pradesh (India), since it is the only source of drinking water for the villagers. The fluoride concentration in the water varied from 0.8 to 13.9 mgl⁻¹ with a mean of 4.02 mgl⁻¹. The correlation analysis revealed that fluoride had a positive correlation with pH, CO₃, HCO₃, and sodium adsorption ratio (SAR), whereas a negative correlation with Ca and Mg was found. A soil profile was also dug in the area to assess depth-wise fluoride content in the soil. The soil samples and underneath calcium carbonate (CaCO₃) concretion were analyzed for fluoride content. The percent of soluble fluoride to total fluoride in the soil varied from 25.15 to 4.76% down the soil profile. The soluble fluoride was found to decrease with the increase in the clay content in the soil. The total leachable fluoride in CaCO₃ concretions was found to be 6.08%. It was inferred from this study that the soil and underneath layer of CaCO₃ concretions may be the potential source of fluoride contamination in the shallow drinking water sources of the area.