scholarly journals Bioaccumulation of Fluoride in Plants and Its Microbially Assisted Remediation: A Review of Biological Processes and Technological Performance

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2154
Author(s):  
Rakesh Kumar ◽  
Rama Sinha ◽  
Pushpa Kumari Sharma ◽  
Nishita Ivy ◽  
Pawan Kumar ◽  
...  
Keyword(s):  
Review Paper ◽  
Dental Fluorosis ◽  
Water Systems ◽  
Fluoride Removal ◽  
Biological Processes ◽  
Neurological Damage ◽  
Fluoride Ions ◽  
Technological Performance ◽  
Fluoride Accumulation ◽  
Microbial Bioremediation

Fluoride is widely found in soil–water systems due to anthropogenic and geogenic activities that affect millions worldwide. Fluoride ingestion results in chronic and acute toxicity, including skeletal and dental fluorosis, neurological damage, and bone softening in humans. Therefore, this review paper summarizes biological processes for fluoride remediation, i.e., bioaccumulation in plants and microbially assisted systems. Bioremediation approaches for fluoride removal have recently gained prominence in removing fluoride ions. Plants are vulnerable to fluoride accumulation in soil, and their growth and development can be negatively affected, even with low fluoride content in the soil. The microbial bioremediation processes involve bioaccumulation, biotransformation, and biosorption. Bacterial, fungal, and algal biomass are ecologically efficient bioremediators. Most bioremediation techniques are laboratory-scale based on contaminated solutions; however, treatment of fluoride-contaminated wastewater at an industrial scale is yet to be investigated. Therefore, this review recommends the practical applicability and sustainability of microbial bioremediation of fluoride in different environments.

Development and Comparative Analysis of Aluminosilicate Based Ceramic Filters for Ground Water Defluoridation

2014 ◽  
Vol 936 ◽  
pp. 822-828 ◽  
Author(s):  
Johnson Kwame Efavi ◽  
Abu Yaya ◽  
Solomon Adeborna ◽  
Julius Fobil
Keyword(s):  
Ground Water ◽  
Contact Time ◽  
Dental Fluorosis ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Ceramic Filters ◽  
Low Levels ◽  
Filter Thickness ◽  
Time Required

Low levels of fluoride in drinking water is healthy for the teeth enamel, however, higher concentrations result in dental fluorosis with prolonged exposures leading to skeletal fluorosis. Fluoride removal capacities of ceramic filters using aluminosilicates (Anfoega clay, Kibi kaolin, Laterite soil and Termitaria earth) samples from Ghana Geological Survey Department have been investigated and analysed for possible application in the Bongo District of Ghana noted forhavinghigh fluoride concentration in its ground water. Batch sorption studies conducted revealed that the amount of fluoride ions removed increased proportionally with increasing filter thickness, temperature and contact time to an optimum value. Using particle size ranges of <355μm and 1cm filter thickness at room temperature, the percentage of fluoride removed by the samples reached an optimum value after 70mins. Increases in filter thickness, contact time or temperatureincreased the amount of fluoride ions removedand the time required to reach the optimum value reduced significantly.

Diseases Prevention by Water Defluoridation Using Hydrotalcites as Decontaminant Materials

2017 ◽  
Vol 68 (1) ◽  
pp. 168-171 ◽  
Author(s):  
Letitia Doina Duceac ◽  
Cristina Elena Dobre ◽  
Ioana Pavaleanu ◽  
Gabriela Calin ◽  
Simona Nichitus ◽  
...  
Keyword(s):  
Dental Fluorosis ◽  
Precipitation Method ◽  
Original Structure ◽  
Fluoride Removal ◽  
Major Goal ◽  
Bone Stiffness ◽  
Morphological Aspects ◽  
Adsorption Capacities ◽  
Interlayer Structure ◽  
Co Precipitation

Preventing diseases is deemed to be the major goal of our century especially when an excessive fluoride in drinking water can cause dental fluorosis, bone stiffness, rheumatism and skeletal fluorosis. Fluoride uptake from groundwater implies a worldwide multidisciplinary effort in order to develop renewable, cheap, human friendly materials. Among other materials, hydrotalcites could be good candidates for an efficient fluoride removal from water due to their adsorption, anion exchange and reconstruction properties. These nanostructured materials were synthesized using co-precipitation method in controlled conditions. Presence of anions in the interlayer structure and morphological aspects were performed by FTIR and SEM techniques. Thermal treatment of hydrotalcites showed good adsorption capacities for water defluoridation mostly due to their tendency to restore the original structure.

scholarly journals Dental Fluorosis in Children from Aguascalientes, Mexico: A Persistent Public Health Problem

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1125
Author(s):  
Osiel González Dávila
Keyword(s):  
Public Health ◽  
Health Problem ◽  
Dental Fluorosis ◽  
Tap Water ◽  
Public Health Problem ◽  
Normal Weight ◽  
Fluoride Removal ◽  
Public Elementary Schools ◽  
Ordered Logistic Regression ◽  
Guideline Value

This paper estimates the prevalence and severity of dental fluorosis among participants in the first wave of The Aguascalientes Longitudinal Study of Child Development (EDNA). The analytical sample includes 1052 children in 100 public elementary schools. Dental fluorosis is determined using the Modified Dean’s Index. There is a 43% general dental fluorosis prevalence, and the estimated Community Fluorosis Index is 0.99. Five municipalities report average groundwater fluoride concentrations above the official Mexican guideline value of 1.5 mg/L. In those municipalities, there is a 50% average dental fluorosis prevalence. An ordered logistic regression analysis indicates that obesity in participants increases the likelihood of suffering more severe dental fluorosis symptoms compared with normal-weight participants (OR = 1.62, p < 0.05). Households consuming tap water are more likely to have children suffering more severe dental fluorosis symptoms (OR = 1.63, p < 0.05). Children aged 8 years are more likely to present more severe dental fluorosis symptoms than their peers aged 7 years (OR = 1.37, p < 0.05). Dental fluorosis will persist as a public health problem in Aguascalientes State unless appropriate technologies for fluoride removal from water are installed and operated.

scholarly journals Characterisation of smectite-rich clay soil: Implication for groundwater defluoridation

2016 ◽  
Vol Volume 112 (Number 11/12) ◽  
Author(s):  
Rabelani Mudzielwana ◽  
Mugera W. Gitari ◽  
Titus A.M. Msagati ◽  
◽  
◽  
...  
Keyword(s):  
South Africa ◽  
Rural Areas ◽  
Contact Time ◽  
Clay Soil ◽  
Dental Fluorosis ◽  
Fluoride Concentration ◽  
Limpopo Province ◽  
World Health ◽  
Fluoride Removal ◽  
X Ray

Abstract Groundwater is a widely used and affordable source of drinking water in most of the rural areas of South Africa. Several studies have indicated that groundwater in some boreholes in South Africa has a fluoride concentration above the level recommended by the World Health Organization (1.5 mg/L). Fluoride concentrations above the permissible limit (>1.5 mg/L) lead to dental fluorosis, with even higher concentrations leading to skeletal fluorosis. In the present work, we evaluate the application of smectite-rich clay soil from Mukondeni (Limpopo Province, South Africa) in defluoridation of groundwater. The clay soil was characterised by mineralogy using X-ray diffraction, by elemental composition using X-ray fluorescence and by morphology using scanning electron microscopy. Surface area and pore volume was determined by the Brunauer–Emmett–Teller surface analysis method. Cation exchange capacity and pHpzc of the soil were also evaluated using standard laboratory methods. Batch experiments were conducted to evaluate and optimise various operational parameters such as contact time, adsorbent dose, pH and initial adsorbate concentration. It was observed that 0.8 g/100 mL of smectite-rich clay soil removed up to 92% of fluoride from the initial concentration of 3 mg/L at a pH of 2 with a contact time of 30 min. The experimental data fitted well to a Langmuir adsorption isotherm and followed pseudo second order reaction kinetics. Smectite-rich clay soil showed 52% fluoride removal from field groundwater with an initial fluoride concentration of 5.4 mg/L at an initial pH of 2 and 44% removal at a natural pH of 7.8. Therefore smectite-rich clay soil from Mukondeni has potential for application in defluoridation of groundwater. Chemical modification is recommended to improve the defluoridation capacity.

scholarly journals Biosorption of Fluoride from Synthetic and Ground Water Using Chlorella vulgaris Immobilized in Calcium Alginate Beads in an Upflow Packed Bed Column

2017 ◽  
Vol 61 (3) ◽  
pp. 188 ◽  
Author(s):  
Poornima G. Hiremath ◽  
Thomas Theodore
Keyword(s):  
Experimental Data ◽  
Ground Water ◽  
Chlorella Vulgaris ◽  
Water Samples ◽  
Packed Column ◽  
Fluoride Concentration ◽  
Fixed Bed ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Fluoride Adsorption

The potential of immobilized Chlorella vulgaris to remove fluoride from synthetic and real ground water samples in a fixed bed was investigated. The effect of important kinetic parameters including column bed height, feed flow rate and influent fluoride concentration of solution on fluoride removal was studied. Thomas, Yoon-Nelson, and BDST models were used to analyze the experimental data and understand the influence on biosorption performance. The models’ predictions were in good agreement with the experimental data for all the process parameters studied, indicating that the models were suitable for fixed-bed column design. Fluoride adsorption was reversible. Desorption of fluoride ions was accomplished by pumping 0.1 N HCl solution. The reusability of adsorbent was studied by subjecting column to repeated cycles of fluoride adsorption and desorption. The suitability of immobilized C. vulgaris adsorbent for fluoride removal from ground water samples of Pavagada taluk, Tumakuru district was studied in the packed column.

scholarly journals Fluorides in groundwater, soil and infused black tea and the occurrence of dental fluorosis among school children of the Gaza Strip

2004 ◽  
Vol 2 (1) ◽  
pp. 23-35 ◽  
Author(s):  
B. Shomar ◽  
G. Müller ◽  
A. Yahya ◽  
S. Askar ◽  
R. Sansur
Keyword(s):  
School Children ◽  
Dental Fluorosis ◽  
Gaza Strip ◽  
Linear Regression Analysis ◽  
Age Groups ◽  
Black Tea ◽  
Fluoride Ions ◽  
High Positive Correlation ◽  
The Gaza Strip ◽  
Groundwater Wells

The purpose of this study was to determine the fluoride levels in water, soil and tea, and to identify the major fluoride minerals in soil that supply water with fluoride ions. Another aim was to study the prevalence of dental fluorosis in permanent dentition of the school children of the Gaza Strip. Monitoring of fluoride levels in 73 groundwater wells and 20 topsoil samples for the last three years revealed a general trend of increasing from north to south of the Gaza Strip. A linear regression analysis found a correlation coefficient of r=0.93 between the fluoride concentrations in groundwater and soil for the same geographic areas. However, the X-ray diffraction technique (XRD) results showed that none of the four major fluoride minerals were detected in the tested soil samples; the PHREEQC model showed that fluorite (CaF2) was the main donating mineral of fluoride ions to groundwater.A high positive correlation was found between fluoride concentrations in groundwater and occurrence of dental fluorosis. Among 353 school children of the five geographic areas of the Gaza Strip the prevalence of dental fluorosis was 60%, and 40% had no signs of fluorosis in their permanent dentitions. The highest occurrence, 94%, was in Khan Yunis, followed by 82% in Rafah, 68% in the middle area, 29% in Gaza and the lowest occurrence of 9% was in the northern area. These percentages were directly proportional to the average content of fluoride in groundwater of each area: 2.6, 0.9, 1.7, 1.2, and 0.7 ppm, respectively. The exception was Rafah where people drank from new groundwater wells that have been dug in the last 10 years.The occurrence of the disease was due to intake of high amounts of fluorides in drinking water, tea and fish. Communication with population indicated a heavy intake of tea starting from a very young age; not uncommonly tea is put in nursing bottles. No significant correlation was found between prevalence figures and gender or age groups. This high prevalence indicates a need to examine other sources of F including diet.

scholarly journals Novel Lanthanum Doped Magnetic Teff Straw Biochar Nanocomposite and Optimization Its Efficacy of Defluoridation of Groundwater Using RSM: A Case Study of Hawassa City, Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Temesgen Abeto Amibo ◽  
Surafel Mustafa Beyan ◽  
Tsegaye Markos Damite
Keyword(s):  
Rotational Speed ◽  
Ligand Exchange ◽  
Contact Time ◽  
Adsorption Process ◽  
Quadratic Model ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Removal Capacity ◽  
Mathematical Process

The problem extent of the large concentration of fluoride ions in drinking water is still a central health issue. In the present study, lanthanum doped magnetic Teff straw biochar (LDMTSB) was developed as a novel adsorbent for removing fluoride ions in the groundwater in Rift-Valley regions, especially Hawassa city, Ethiopia. The synthesized LDMTBC was characterized via FTIR, XRD, SEM, and BET. And, this analysis proposed that multiadsorption techniques such as ligand exchange, precipitations, and electrostatic interaction could be evinced throughout the fluoride ions adsorption process by LDMTSB. The constraints that influence the adsorption efficacy, namely, a dosage of LDMTSB, contact time, pH of the solution, and rotational speed, were analyzed and optimized using the response surface methodology approach. Under the optimum situations, LDMTSB dosage: 3.97 g, contact time: 56.36 min, rotational speed: 591.19 rpm, and pH: 3.968 demonstrate high efficacy of LDMTSB with 98.89% fluoride removal capacity. Further, the quadratic model (R2 = 0.9841) was designated for governing the mathematical process. The LDMTSB was successful in the removal of fluoride ions in the groundwater. This study provides a valuable economical solution for the application of Teff straw.

scholarly journals In Situ Synthesis of Structural Hierarchy Flowerlike Zeolite and Its Application for Fluoride Removal in Aqueous Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Zhihan Tian ◽  
Yiqun Gan
Keyword(s):  
Ph Value ◽  
Three Dimensional ◽  
Adsorption Properties ◽  
Aluminum Silicate ◽  
Fluoride Removal ◽  
Fluoride Ions ◽  
Structural Hierarchy ◽  
Hydrated Aluminum ◽  
Pseudo Second Order ◽  
Ft Ir

A three-dimensional hierarchically structured flowerlike zeolite was synthesized using naturally occurring nanohalloysite (HNT) by hydrothermal methods. Halloysite a hydrated aluminum silicate with nanohollow morphology, microporosity, and environmentally friendly properties was chosen to be the sole precursor. The morphology and structure of the composite that was prepared was characterized using XRD, FT-IR, BET, TG, SEM, HRTEM, and NMR. SEM and HRTEM images indicated that the synthesized zeolite has a flowerlike hierarchical structure, with well-defined edges and uniform pore channels. FT-IR and NMR spectra indicated that different species of silicon and aluminum were present in the synthesized zeolite. The zeolite was applied in fluoride (F-) removal from aqueous solutions. Single-factor studies, including the initial concentration of F-, initial adsorbent concentration, and the effect of pH value on the adsorption properties, were investigated to evaluate the removal behavior of F- by the zeolite. The zeolite exhibited strong adsorption properties for fluoride ions (F-), with an adsorption capacity up to 161 mg g-1. The pseudo-second-order kinetics and Freundlich models were the best fit to the kinetics and isotherm experimental data, respectively.

scholarly journals Basic Roles of Sex Steroid Hormones in Wound Repair with Focus on Estrogens (A Review)

2016 ◽  
Vol 60 (1) ◽  
pp. 41-46
Author(s):  
Z. Čriepoková ◽  
L’. Lenhardt ◽  
P. Gál
Keyword(s):  
Postmenopausal Women ◽  
Steroid Hormones ◽  
Tissue Repair ◽  
Wound Repair ◽  
Review Paper ◽  
Therapeutic Option ◽  
Hormone Replacement ◽  
Sex Steroid ◽  
Biological Processes ◽  
Tissue Repair And Regeneration

Abstract Previously, it has been shown that sex hormones, in particular estrogens, play an important role in the regulation of biological processes involved in tissue repair and regeneration. Accordingly, several studies have supported the beneficial properties of hormone replacement therapies (HRT) in postmenopausal models. The present review paper explores the potential for targeted sex steroid HRT as a new therapeutic option for the surgical management of wounds in postmenopausal women and animals.

Fluoride removal from drinking water in Senegal: laboratory and pilot experimentation on bone char-based treatment

2011 ◽  
Vol 1 (4) ◽  
pp. 213-223 ◽  
Author(s):  
Sabrina Sorlini ◽  
Daniela Palazzini ◽  
Carlo Collivignarelli
Keyword(s):  
Drinking Water ◽  
Dental Fluorosis ◽  
Low Cost ◽  
Fluoride Concentration ◽  
Pilot Scale ◽  
Appropriate Technology ◽  
World Health ◽  
Fluoride Removal ◽  
Process Conditions ◽  
Bone Char

In Senegal there are four regions where fluoride concentration in drinking water exceeds the World Health Organization guide value of 1.5 mg/L. This generates permanent damages to the teeth (dental fluorosis) and to the skeleton (skeletal fluorosis). A safe, efficient, simple and low-cost effective defluoridation technique is not available yet and needs to be developed in order to prevent the occurrence of fluorosis. This experimental research was carried out in order to define an appropriate technology for fluoride removal from groundwater in Senegal. Batch tests and filtration tests at laboratory and pilot scale were carried out using animal bone char as adsorbent material for fluoride removal. Possible influencing parameters, such as specific ions in Senegalese drinking water, were investigated and the best process conditions were defined for the application in Senegal. The results attest to the efficacy of bone char in removing fluoride from Senegalese water: at pilot scale the mean specific adsorption was 2.7 mg F−/g of bone char, corresponding to a total treated volume of 4,000 L and a filter life of nearly three months.

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