Fluoride contents in groundwaters and the main consumed foods (dates and tea) in Southern Algeria region

Changes in Metabolism and Content of Chlorophyll in Common Duckweed (Lemna minor L.) Caused by Environmental Contamination with Fluorides

The impact of fluorine on plants remains poorly understood. We examined duckweed growth in extracts of soil contaminated with fluorine leached from chicken manure. Additionally, fluorine levels were analyzed in fresh manure, outdoor-stored manure, and soil samples at varying distances from the manure pile. Fresh manure contained 37-48 mg F- × kg-1, while soil extracts contained 2.1 to 4.9 mg F- × kg-1. We evaluated the physiological effects of fluorine on duckweed cultured on soil extracts or in 50% Murashige-Skoog (MS) medium supplemented with fluorine concentrations matching those in soil samples (2.1 to 4.9 mg F- × L-1), as well as at 0, 4, and 210 mg × L-1. Duckweed exposed to fluorine displayed similar toxicity symptoms whether in soil extracts or supplemented medium. Fluoride at concentrations of 2.1 to 4.9 mg F- × L-1 reduced the intact chlorophyll content, binding the porphyrin ring at position 32 without affecting Mg2+. This reaction resulted in chlorophyll a absorption peak shifted towards shorter wavelengths and formation of a new band of the F--chlorophyll a complex at λ = 421 nm. Moreover, plants exposed to low concentrations of fluorine exhibited increased activities of aminolevulinic acid dehydratase and chlorophyllase, whereas the activities of both enzymes sharply declined when the fluoride concentration exceeded 4.9 mg × L-1. Consequently, fluorine damages chlorophyll a, disrupts the activity of chlorophyll-metabolizing enzymes, and diminishes the plant growth rate, even when the effects of these disruptions are too subtle to be discerned by the naked human eye.

A review on fluoride contamination in groundwater and human health implications and its remediation: A sustainable approaches

Contamination of drinking water due to fluoride (F-) is a major concern worldwide. Although fluoride is an essential trace element required for humans, it has severe human health implications if levels exceed 1.5 mg. L-1 in groundwater. Several treatment technologies have been adopted to remove fluoride and reduce the exposure risk. The present article highlights the source, geochemistry, spatial distribution, and health implications of high fluoride in groundwater. Also, it discusses the underlying mechanisms and controlling factors of fluoride contamination. The problem of fluoride-contaminated water is more severe in India's arid and semiarid regions than in other Asian countries. Treatment technologies like adsorption, ion exchange, precipitation, electrolysis, electrocoagulation, nanofiltration, coagulation-precipitation, and bioremediation have been summarized along with case studies to look for suitable technology for fluoride exposure reduction. Although present technologies are efficient enough to remove fluoride, they have specific limitations regarding cost, labour intensity, and regeneration requirements.

The performance of water-soluble fluoride transformation in soil-tea-tea infusion chain system and the potential health risk assessment

BACKGROUND

Water-soluble fluoride (WS-F) can be absorbed directly by tea plants from soil and comprises a major source of dietary F in tea consumers. To reveal the WS-F accumulation in tea leaves and assess WS-F health risks, 70 sets of samples including tea leaves at three maturity stages and corresponding topsoil were collected from Xinyang, China. The WS-F contents in tea samples and pH values in soil samples were determined.

RESULTS

The contents of WS-F in tea leaves exhibited a positive correlation with leaf maturity. The contents of WS-F in tea leaves showed a positive correlation with WS-F contents in the soil as the soil pH value exceeds 5. All the bud with two leaves samples, 84.29% of the third to sixth leaves samples, and 78.57% mature leaves samples in 5-min infusion tend to be no health threat. The leaching characteristics of WS-F from tea leaves were influenced by the leaf maturity and soaking time.

CONCLUSION

Taking measures to control pH and WS-F concentration of plantations soil, as well as drinking tea infusion made from young leaves or reducing soaking time could decrease the WS-F health risk. © 2021 Society of Chemical Industry.

Fluoride concentration in bottled drinking water from a fluoride endemic area: A market-based survey

Drinking water is the primary source of fluoride intake for humans around the world. In southern Algeria, dental fluorosis is considered an epidemic that is spreading among the population by health professionals. Thus, the consumption of bottled water is important because it is considered safer for health.

OBJECTIVES

This study aims to determine the fluoride concentrations of bottled water commercially available in southern Algeria and report the non-carcinogenic health risk via daily human intake.

MATERIAL AND METHODS

By 2021, 28 commercial brands were obtained from different supermarkets in Ouargla, Algeria. Fluoride was measured using a validated spectrophotometric method. The fluoride risk quotient (HQ) and the estimated daily intake (EDI) were calculated.

RESULTS

All the brands did not mention the fluoride content on the label. The mean level was 0.40 ± 0.42 mg/L, and a wide range was found [0.00-1.65 mg/L]. The average was below the WHO standard. Most samples (75%, n = 21) contained less than 0.50 mg/L, which can cause dental caries. The HQ values average were less than 1, suggesting no health risk associated with drinking bottled water.

CONCLUSION

With the increasing consumption of bottled water, this work is important for primary prevention programs for dental caries. The main contribution is the constitution of a database concerning the fluoride levels in bottled water marketed in southern Algeria. Labelling of fluoride concentrations by manufacturers should be mandatory.

Fluoride concentrations in drinking water and health risk assessment in the south of Algeria

Drinking water is the primary source of fluoride intake by humans worldwide. Algeria, Africa's largest country, has been reported to have moderate to high fluoride levels in the water, particularly in the Southern and Saharan regions. In the south of Algeria, dental fluorosis is considered an epidemic that is spreading within the population by health professionals. This study aimed to determine fluoride concentrations in drinking water consumed by Ouargla population (south-east of Algeria) in 2021, assess non-carcinogenic health risk via daily human intake, and calculate the upper acceptable fluoride concentration in drinking water by Galgan and Vermillion formula. Forty-two water samples were collected during the spring season. The fluoride was measured using a validated spectrophotometric method. Hazard quotient of fluoride (HQ) and estimated daily intake (EDI) were calculated. The results reveal a mean fluoride level of 1.07 ± 0.38 mg/L, below WHO recommendation. Fluoride concentrations in water were higher in rural areas than in the central city (p = 0.05). HQ values were less than one for adults but greater than 1 for infants and children, suggesting health risks associated with water consumption for these vulnerable groups (p = 0.007). The main contribution of this study is the establishment of a database concerning fluoride levels and hazard quotient in the south of Algeria. Monitoring drinking water and control fluorosis is essential to avoid potential health risks.

Biological approaches of fluoride remediation: potential for environmental clean-up

Fluoride (F), anion of fluorine which is naturally present in soil and water, behaves as toxic inorganic pollutant even at lower concentration and needs immediate attention. Its interaction with flora, fauna and other forms of life, such as microbes, adversely affect various physiochemical parameters by interfering with several metabolic pathways. Conventional methods of F remediation are time-consuming, laborious and cost intensive, which renders them uneconomical for sustainable agriculture. The solution lies in cracking down this environmental contaminant by adopting economic, eco-friendly, cost-effective and modern technologies. Biological processes, viz. bioremediation involving the use of bacteria, fungi, algae and higher plants that holds promising alternative to manage F pollution, recover contaminated soil and improve vegetation. The efficiency of indigenous natural agents may be enhanced, improved and selected over the hazardous chemicals in sustainable agriculture. This review article emphasizes on various biological approaches for the remediation of F-contaminated environment, and exploring their potential applications in environmental clean-up. It further focuses on thorough systemic study of modern biotechnological approaches such as gene editing and gene manipulation techniques for enhancing the plant-microbe interactions for F degradation, drawing attention towards latest progresses in the field of microbial assisted treatment of F-contaminated ecosystems. Future research and understanding of the molecular mechanisms of F bioremediation would add on to the possibilities of the application of more competent strains showing striking results under diverse ecological conditions.

Oral and Dental Status of Lebanese and Syrian Refugees Living in Proximity to Deir Kanoun Ras El Ain Dump in Lebanon

Aims:

In this study, we aimed at investigating the oral and dental health conditions of Lebanese and Syrian refugees living in proximity to Deir Kanoun Ras El Ain dump whereby its leachates influx into a canal used for irrigation and drinking purposes.

Materials and Methods:

This observational study involved oral and dental examinations of 589 Lebanese and Syrian Refugees participants living in the three villages: Deir Kanoun Ras El Ain, Klayleh, and Smaiyeh. Differences in oral and dental examination results were analyzed between different villages, sexes, nationalities, and age groups. Correlation tests were conducted between dental fluorosis, staining, papilla swelling, and several sociodemographic factors.

Results:

Dental fluorosis, staining, and papilla swelling were the most prominent problems among total participants. The highest percentages of individuals with the studied diseases were shown to be in Klayleh village, among females, and individuals aged between 21 and 40 years. Significant associations were observed between dental fluorosis and nationality; between dental staining and gender, nationality, age, and smoking; as well as between papilla swelling and age, smoking, and diabetes.

Conclusions:

Our study investigated and highlighted the prevalence of several oral and dental diseases among Lebanese and Syrian inhabitants that are related to environmental, social, and economic determinants and not just by individual behaviors. It also showed gaps of oral and dental health knowledge that recommend implementing health systems that focus on preventing oral diseases.

Dietary high fluorine induces apoptosis and alters Bcl-2, Bax, and caspase-3 protein expression in the cecal tonsil lymphocytes of broilers

Long-term excessive fluoride intake is known to be toxic and can lead to fluorosis and bone pathologies. However, the cellular mechanisms underlying sodium fluoride-induced cytotoxicity in the cecal tonsil lymphocytes are not well understood. The aims of this study were to investigate the effects of high dietary fluorine on apoptosis and the expression of the Bcl-2, Bax, and caspase-3 in the cecal tonsil lymphocytes of broilers. The broilers were fed on high-fluorine diets containing 0, 400, 800, and 1,200 mg/kg fluorine. As measured by flow cytometry, the percentage of apoptotic lymphocytes was significantly increased in the high-fluorine groups II and III when compared with those in the control group. Meanwhile, immunohistochemical tests showed that the Bcl-2 protein expression decreased, and the Bax and caspase-3 protein expression increased in the high-fluorine groups II and III. In conclusion, dietary fluorine in the range of 800-1,200 mg/kg increased lymphocyte apoptosis in the cecal tonsil of broilers, suggesting that the lymphocyte apoptosis in the cecal tonsil was mediated by direct effects of fluoride on the expression of Bcl-2, Bax, and caspase-3.

Spatial distribution and temporal variation of high fluoride contents in groundwater and prevalence of fluorosis in humans in Yuanmou County, Southwest China

Successive surveys conducted in 1984, 2006 and 2007, of all villages in Yuanmou County, China, highlighted 40 villages with groundwater fluoride levels higher than 1.0mg/L and related cases of human fluorosis. Using the data from these surveys and by employing geographic information system (GIS) techniques, high fluoride levels and fluorosis cases were mapped. The results show high fluoride concentrations and fluorosis hotspots were found to be predominately located in the lowlands of central Yuanmou County. Spatial distribution of high fluoride levels was found to be primarily determined by geology, arid climate, and topography. Both dental and skeletal fluorosis had dramatically decreased due to a program of low-fluoride drinking water supply supported by local governments. The prevalence of dental fluorosis in children had dropped from 43.26% in 1984 to 21.97% in 2006, and the number of skeletal fluorosis cases had decreased from 327 in 1984 to 148 in 2006, respectively. Despite a decline in fluorosis cases, the emergence of fluorosis in new areas indicates the need for both continuous monitoring of drinking water in affected areas and increased public awareness.

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.

The pollution control of fluorine and arsenic in roasted corn in "coal-burning" fluorosis area Yunnan, China

Pilot experiments were carried out to reduce the fluorine (F) and arsenic (As) pollution of roasted corn dried by open ovens in "coal-burning" fluorosis area Yunnan, China. The results indicated that the average emission amount of F and As in briquettes in experimental group were 29.20mg/kg and 0.76 mg/kg in Xiaolongdong, and 46.8 mg/kg and 0.54 mg/kg in Mangbu respectively. The results also indicated that the fixing rate of F and As in briquettes in experimental group was more than 4 times and 1.2 times of that in control group respectively. The average concentration of F and As in roasted corn in experimental group were 3.86 mg/kg and 13.23 μg/kg in Xiaolongdong, and 4.77 mg/kg and 122.96 μg/kg in Mangbu respectively, which reduced by more than 65% and 75% respectively compared with that in control group. Adding local natural calcium-based materials in briquettes can reduce the emission of F and As and their pollution on roasted corn largely, and thus will reduce the risk of fluorosis for residents greatly in "coal-burning" fluorosis area of southwestern China.

Assessment of water contribution on total fluoride intake of various age groups of people in fluoride endemic and non-endemic areas of Dindigul District, Tamil Nadu, South India

The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through water. It is necessary to determine the contribution of water used for drinking and food processing and other diet sources on daily fluoride intake for finding the ways to reduce the excess fluoride intake than the minimum safe level intake of 0.05 mg/kg/day. The main objectives of this study are to determine the quantitative impact of water through drinking and cooking of food and beverages on total fluoride intake as well as to estimate the contribution of commonly consumed diet sources on total fluoride intake. Contribution of water on daily fluoride intake and estimation of total fluoride intake through the diet sources were accomplished through analysis of fluoride in drinking water, solid and liquid food items, Infant formulae, tea and coffee infusions using fluoride ion selective electrode. Determination of incidence of fluorosis in different fluoride endemic areas in Dindigul District of Tamil Nadu, South India is achieved through clinical survey. The percentage of daily fluoride intake through water is significantly higher for infants than children, adults and old age groups of people. The percentile scores of fluoride intake through water from drinking and cooking increases with increase of water fluoride level. The rate of prevalence of fluorosis is higher in adolescent girls and females than adolescent boys and males residing in high fluoride endemic areas. More than 60% of the total fluoride intake per day derived from water used for drinking and food processing. Hence the people residing in the fluoride endemic areas in Dindigul District of Tamil Nadu, South India are advised to take serious concern about the fluoride level of water used for drinking and cooking to avoid further fluorosis risks.