Fluoride in groundwater, dates and wheat: Estimated exposure dose in the population of Bushehr, Iran

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.

Fluoride occurrence in environment, regulations, and remediation methods for soil: A comprehensive review

Fluoride, a naturally occurring chemical element, is largely insoluble in soils. More than 90% of the fluoride in soil is bound to soil particles and is unable to be dissolved. As part of the soil, fluoride is predominantly located in the colloid or clay fraction of the soil, and the movement of fluoride is strongly affected by the sorption capacity of the soil, which is affected by pH, the type of soil sorbent present, and the salinity. The Canadian Council of Ministers of the Environment soil quality guideline for fluoride in soils under a residential/parkland land use scenario is 400 mg/kg. In this review, we focus on fluoride contamination in soil and subsurface environments, and the various sources of fluorides are discussed in detail. The average fluoride concentration in soil in different countries and their regulations for soil and water are comprehensively reviewed. In this article, the latest advances in defluoridation methods are highlighted and the importance of further research addressing efficient and cost-effective methods to remediate fluoride contamination in soil is critically discussed. Methods used to mitigate fluoride risks by removing fluoride from the soil are presented. We strongly recommend that regulators and soil chemists in all countries explore opportunities to improve defluoridation methods and consider adopting more stringent regulations for fluoride in soil depending on geologic conditions.

Re-evaluating fluoride intake from food and drinking water: Effect of boiling and fluoride adsorption on food

Although drinking water is the main source of fluoride intake, recent studies reported that fluoride intake from foods could also be high, depending on cooking methods. In this study, we quantified the fluoride accumulation in foods soaked or boiled in fluoride-containing water and assessed the fluoride intake in different age groups from food and drinking water. We observed that, in the case of rice soaked in fluoride-containing water, more fluoride was accumulated in the rice than previously estimated. Fluoride interferes with the iodine staining process of rice, indicating fluoride adsorption. Fluoride accumulation in rice and vegetables increased when the soaking temperature was raised to 100 °C due to the gelatinization of rice grains and softening of vegetables. Ingesting foods boiled in fluoride-containing water increased the fluoride intake per body weight of infants more significantly than that in children and adults due to their low body weight. These results indicate that soaking and boiling foods in fluoride-containing water significantly increases fluoride intake compared to previous estimations. Therefore, it is necessary to re-evaluate the fluoride intake from food and drinking water considering the methods used for cooking food in each country and region.

Plaster board waste (PBW) - A potential fluoride leaching source in soil/water environments and, fluoride immobilization studies using soils

Plaster board waste generated from industries, usually contains major proportion of calcium as calcium sulfate. In addition, fluoride is remarkably one among the constituents of this waste material which leaches off into the soil and aquatic environments and causes fluoride pollution. In order to simulate how the dumping of PBW causes fluoride contamination in soil and water sources, shaking and stirring based batch-mode leaching studies were conducted. These studies explored the leaching of fluoride as a function of particle size, agitation time, pH of the leaching solvent (distilled water), L/S (water: PBW) ratio, temperature and electrolytes. It was explored that 1 g of plaster board waste contains18.54 mg F per gram of PBP. High leaching of 3.72 mg F per liter was studied at pH 6.02 with Ca²⁺ and TDS contents of 1050 mg L^-1 and1640 mg L^-1 respectively. The influence of sodium electrolytes such as chloride, nitrate, hydrogen carbonate, carbonate, sulfate, borate, phosphate and acetate on the leaching of fluoride from PBW was studied. The influence of fluoride leaching by sodium phosphate recorded a high value of 12.75 mg L^-1 with no detectable amount of calcium ions. The influence of eight electrolytic mixtures each containing five sodium electrolytes on fluoride leaching corroborated the highest leaching in mixtures containing phosphate followed by hydrogen carbonate/carbonate. Solutions of calcium and aluminium chloride and their mixture were used to measure the rate of leachable fluoride in solution. Furthermore, the fluoride leaching at different temperatures and acids was studied. Naturally occurring soils when blended with PBW were observed to immobilize fluoride and lessened the amount of leaching fluoride in water. Various characterization studies such as FTIR, Raman, FESEM (with EDS), XRD and XPS were carried out for PBW and its treated samples using different electrolytes. Fluoride leaching proportionate to the precipitation of carbonate and phosphate was recorded in the case of appropriate electrolyte and mixtures.

Knowledge Level and Consumption Behavior of Native Plants, Meats, and Drinking Waters with High Fluoride Concentrations about the Relation to the Potential Health Risk of Fluoride in Lamphun Province Thailand: A Case Study

Fluoride exposure from natural, agricultural, and industrial sources has harmed people living in fluoride-affected areas. Fluoride accumulates in the human body after being exposed to it through the food chain. The population consisted of 371 community health volunteers who were surveyed and chosen based on personal fluoride information. Only 39 residents were chosen to be interviewed and take part in the trial, which involved drinking fluoride-containing groundwater (>1.5 part per million: ppm) and urine testing that revealed urine fluoride level (>0.7 ppm). In addition, 47 biological samples and eight commercially bottled water specimens were examined. The information was gathered in four ways: (1) a questionnaire-based survey of fluoride knowledge, (2) food consumption behavior with locally grown vegetables, fruits, poultry, and meat, and commercially bottled water produced by groundwater in fluoride-affected areas, (3) a semi-food frequency questionnaire, and (4) fluoride content measurements using an ion-selective electrode. According to the analyses, the participants ranged in age from 51 to 60 years, with approximately 60.38% of them female and born and raised in polluted areas. The majority of subjects had a low level of fluoride knowledge (65.23%). The respondents’ primary source of drinking water (100.00%) was commercially bottled water; they chewed camellia sinensis 11.56% of the time (1 to 5 years) and they drank tea 9.16% of the time (during 1 to 5 years). Sus scrofa domesticus was responsible for the intake of vegetables and fruits, whereas Brassica chinensis, Jusl var para-chinensis (Bailey), and Tsen and Lee were responsible for the intake of poultry and animal flesh. They were all purchased at a local farm. The hazard quotient was greater than one, and the fluoride concentration (ppm) ranged between 75.00% (0.29–5.20), 57.14% (0.01–0.46), 88.89% (0.07–0.91), 100.00% (0.43–3.07), 100.00% (0.58–0.77), 42.86% (0.12–0.62 ppm.), 60.00% (0.11–1.44), and 33.33% (0.10–0.80) in drinking water, fruit, young and mature plants. Fluoride ingestion may pose a health concern. Under the 95th percentile condition, 74.47% consumed water with a high fluoride level, vegetables and fruits, and poultry and meats.

Increase in fluoride concentration in mine water in Shendong mining area, Northwest China: Insights from isotopic and geochemical signatures

Mine water poses severe threats to the quality of the water supply and ecological environment of the Shendong mining areas owing to its excessive fluoride (F^-) content. However, the geochemical behaviours and enrichment mechanisms responsible for F⁻ enrichment during mining activities are not fully understood. In total, 18 Yanan groundwater and 45 mine water samples were collected to analyse the spatial distribution, hydrogeochemical behaviours, and formation mechanisms related to elevated F^- levels by analysing the stable isotopes and water-rock interactions. In this study, F^- concentrations in mine water samples varied from 0.16 to 12.75 mg/L, with a mean value of 6.10 mg/L, and 77.78% of the mine water samples had a concentration that exceeded China's national standards (1.00 mg/L) for drinking water. The F^- concentration was markedly high in the mine water samples, with the mean F^- concentration being 1.58 times of that in the Yanan groundwater samples. The results of stable isotopes (¹⁸O_H2O, D, ³⁴S_SO4, and ¹⁸O_SO4) and water-rock interaction analyses suggested that cation exchange and competitive effects were the dominant factors responsible for elevated F^- concentration in mine water during mining activities. Thus, the weathering of F-bearing minerals, agriculture, and domestic activities do not play a significant role in the secondary enrichment of F^- concentration.

Sensitive assessment of groundwater-associated, multi-exposure health hazards in a fluoride-enriched region of West Bengal, India

Ninety groundwater samples were collected from Khayrasole and Rajnagar blocks of Birbhum district, West Bengal, India, during pre-monsoon and post-monsoon in 2016 to assess the hazards of fluoride in groundwater. Fluoride concentration fluctuated from 0.3 to 17.6 mg/L, with 70% of samples reported beyond the modified regional optimal fluoride level (0.7 mg/L) with a statistically significant level of p < 1.7E-24. The average cation and anion concentrations exhibited a descending order of Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃^- > Cl^- > SO₄^2- > NO₃^- > F^-, respectively. Notably, groundwater quality in 50% of the places ranged from poor to unfit for drinking purposes in terms of water quality index. The mean total hazard index (THI) was 1.1 for adults and 1.9 for children, signifying a greater chance of non-carcinogenic threats to both age groups. In calculating the THI, ingestion and dermal pathways accounted for approximately 96% and 3% health hazards, respectively. The Monte Carlo simulation and sensitivity analysis identified that the diurnal water ingestion rate, exposure duration, and fluoride concentration were the significant sensitive variables that triggered most groundwater-associated non-carcinogenic health issues, signifying more risks among children. Further, dental health surveys (N = 746), following Dean's norms for classification based on regional optimal fluoride level, designated the borderline grade of the community dental hazard. The subsequent hydrogeochemical characterization directed that dissolution from fluoride-bearing minerals and water-rock interaction, such as halite dissolution and calcite-dolomite precipitation, were the governing factors for F^- enrichment in groundwater. This study will serve as baseline data for delineating fluoride-induced dental and other health hazards through sensitivity and spatial analysis in the GIS platform for hazard zonation and effective groundwater quality management.

Monitoring of Fluoride Content in Drinking Water by Ion Chromatography: A Case Study in the Suzhou Urban Area, China

BACKGROUND

Both deficient and excessive intake of fluoride can lead to adverse health problems.

OBJECTIVE

The aim of this study is to investigate the fluoride content in three types of drinking water in Suzhou urban area.

METHOD

Ion chromatography was employed to conduct the validation of analysis of fluoride ion in water and the method was applied to analyze the concentration of fluoride in 22 drinking water samples, including tap water, purified water, and commercially available bottled water, collected from five municipal districts of Suzhou urban area.

RESULTS

The used method was validated in the range of 0.05 and 2.00 mg/L with good repeatability and accuracy. Results of water analysis indicated that fluoride content in tap water ranged from 0.267 to 0.336 mg/L (average 0.304 mg/L), and the levels of fluoride in purified water and bottled water were 0.068-0.317 mg/L (average 0.134 mg/L) and 0-0.120 mg/L (average 0.080 mg/L), respectively.

CONCLUSION

The amount of fluoride in all samples analyzed were lower than the limit set for fluoride in drinking water according to the China standard (1.0 mg/L). The low fluoride exposure for the population in the studied area was observed, and the replacement of tap water with purified and bottled water could further aggravate the deficient of fluoride intake for local residents.

HIGHLIGHTS

The present study carried out is the first to characterize the fluoride content in these three types of drinking water in Suzhou urban area by ion chromatography.

Fluoride Geochemistry and Exposure Risk Through Groundwater Sources in Northeastern Parts of Rajasthan, India

Exposure to fluoride concentrations above a threshold of 1.5 mg/L can cause joint pains, restricted mobility, skeletal and dental fluorosis. This study aims to determine the hydrochemical evolution of the fluoride-rich groundwater and estimate the risk of fluoride exposure to the residents of semi-arid northeastern part of Rajasthan, India. The methodology involves measurement of fluoride and other ionic concentrations in groundwater using ion chromatography, followed by an estimation of the cumulative density function and fluorosis risk. The fluoride concentration in water samples varied from 0.04 to 8.2 mg/L with 85% samples falling above the permissible limit. The empirical cumulative density function was used to estimate the percentage and degree of health risks associated with the consumption of F^- contaminated water. It is found that 55% of the samples indicate risk of dental fluorosis, 42% indicate risk of deformities to knee and hip bones, and 18% indicate risk of crippling fluorosis. In addition, instances of high nitrate concentrations above the permissible limit of 45 mg/L are also found in 13% of samples. The fluoride rich groundwater is mainly associated with the Na-HCO₃-Cl type water facies while low fluoride groundwater shows varied chemical facies. The saturation index values indicate a high probability of a further increase in F^- concentration in groundwater of this region. The calculated fluoride exposure risk for the general public in the study area is 3-6 times higher than the allowed limit of 0.05 mg/kg/day. Based on the results of this study, a fluorosis index map was prepared for the study area. The northern and northeastern parts are less prone to fluorosis, whereas the south-central and southwestern parts are highly vulnerable to fluorosis. The inferences from this study help to prioritize the regions that need immediate attention for remediation.

Fluoride contamination, health problems and remediation methods in Asian groundwater: A comprehensive review

In low concentration, fluoride is considered a necessary compound for human health. Exposure to high concentrations of fluoride is the reason for a serious disease called fluorosis. Fluorosis is categorized as Skeletal and Dental fluorosis. Several Asian countries, such as India, face contamination of water resources with fluoride. In this study, a comprehensive overview on fluoride contamination in Asian water resources has been presented. Since water contamination with fluoride in India is higher than other Asian countries, a separate section was dedicated to review published articles on fluoride contamination in this country. The status of health effects in Asian countries was another topic that was reviewed in this study. The effects of fluoride on human organs/systems such as urinary, renal, endocrine, gastrointestinal, cardiovascular, brain, and reproductive systems were another topic that was reviewed in this study. Different methods to remove fluoride from water such as reverse osmosis, electrocoagulation, nanofiltration, adsorption, ion-exchange and precipitation/coagulation were introduced in this study. Although several studies have been carried out on contamination of water resources with fluoride, the situation of water contamination with fluoride and newly developed technology to remove fluoride from water in Asian countries has not been reviewed. Therefore, this review is focused on these issues: 1) The status of fluoride contamination in Asian countries, 2) health effects of fluoride contamination in drinking water in Asia, and 3) the existing current technologies for defluoridation in Asia.

Age-sex specific disability-adjusted life years (DALYs) attributable to elevated levels of fluoride in drinking water: A national and subnational study in Iran, 2017

National and subnational burden of disease attributable to elevated fluoride levels in drinking water apportioned by sex, age group, province, and community type in Iran, 2017 were quantified based on disability-adjusted life years (DALYs). The attributable burden of disease was estimated using four input data: (1) effect size of elevated drinking water fluoride levels for dental and skeletal fluorosis, (2) population distribution of drinking water fluoride levels, (3) the threshold levels of fluoride in drinking water for contribution in dental and skeletal fluorosis, and (4) age-sex distribution of population. The attributable burden of disease was only related to dental fluorosis, because the fluoride levels were lower than the threshold value for skeletal fluorosis (4.0 mg/L) in all of the cases. The national attributable prevalence (per 100,000 people), DALYs, and DALY rate in 2017 were calculated to be 60 (95% uncertainty interval 48-69), 3443 (1034-6940), and 4.31 (1.29-8.68), respectively. The national attributable burden of disease was not significantly different by sex, but was affected by age and community type in a manner that the highest DALY rate was related to the age group 10-14 y (6.06 [1.82-12.21]) and over 66% of the national attributable DALYs occurred in rural communities. The attributable burden of disease occurred only in 10 out of 31 provinces and about 94% of the attributable DALYs were concentrated in four provinces Fars (1967 [592-3964]), Bushehr (414 [124-836]), West Azarbaijan (400 [120-808]), and Hormozgan (377 [113-761]). Implementation of fluoride-safe drinking water supply schemes in the four leading provinces can prevent most of the national health losses and partly compensate the increasing trend of disease burden from oral conditions at the national level.

Fluoride in Iranian Drinking Water Resources: a Systematic Review, Meta-analysis and Non-carcinogenic Risk Assessment

A systematic review, meta-analysis, and non-carcinogenic risk considering fluoride content of drinking water resources of 31 provinces of Iran among some international databases such as Science Direct, Scopus, PubMed, and national databases including SID and Irandoc (2011 to July 2017) were conducted. In this context, 10 articles (40 studies) with 1706 samples were included in meta-analyses and risk assessment studies. The pooled concentration of fluoride in the cold, mild, and warm weather provinces were calculated as 0.39 mg/L (95% CI 0.32-0.48 mg/L), 0.52 (95% CI 0.43-0.61 mg/L), and 0.75 (95% CI 0.56-0.94 mg/L), respectively. The pooled concentration of fluoride in Iranian drinking water resources was 0.51 (95% CI 0.45-0.57 mg/L). The minimum and maximum concentrations of fluoride content were related to Kermanshah (0.19 mg/L) and Kerman (1.13 mg/L) provinces, respectively. The HQ of fluoride in the children and adults were 0.462 and 0.077, respectively as children are more vulnerable than adults. The HQ for children and adults was lower than 1 value. Therefore, there is no considerable non-carcinogenic risk for consumers due to drinking water in Iran. Although the non-carcinogenic of fluoride in drinking water was not significant, fluoride entry from other sources, such as food or inhalation, could endanger the health of the residents of Kerman and Bushehr provinces.

Fluoride contamination in groundwater sources in Southwestern Nigeria: Assessment using multivariate statistical approach and human health risk

The present study investigated the ionic and fluoride concentrations in tap water and its associated health risk to local dwellers of Ogun State (Abeokuta south), Nigeria. 63 samples were collected from twenty-one different locations. Results obtained revealed the mean concentration of fluoride (F^-) as 1.23 mg/L. Other water quality parameters such as total dissolved solids (TDS), electrical conductivity (EC), F^-, Fe^2+, and SO₄^2- surpassed the WHO guidance for drinking water. Strong positive correlation was observed between F^- and TDS; F^- and pH; TDS and EC; TDS and Mg²⁺; TDS and SO₄^2-; TDS and HCO₃^-; EC and HCO₃^-; EC and SO₄^2-; Na⁺ and Cl^-; SO₄^2- and Cl^-. In addition, Empirical Bayesian Kriging (EBK) model was employed to spatially distribute the concentration of the analyzed elements within the study region. The chronic daily dose (CDD) and hazard quotient (HQ) were also used to evaluate the health risk associated with F^-, considering dermal and ingestion as pathways. The results revealed that the associated HQ for infants between the age range of 6-12months within about 91% of the study region surpassed the accepted HQ limit. However, the HQ for age categories 11-16years; >65years; 18-21years; 21years; 16-18years within 95.2%, 90.5%, 80.95% and 100% of the study location were less than 1. Conclusively, the HQ values obtained in this study should serve as a baseline information for water management authorities, policymakers and the society at large towards addressing these pollution issues.

Distribution and health risk assessment of natural fluoride of drinking groundwater resources of Isfahan, Iran, using GIS

Fluoride (F) contamination in groundwater can be problematic to human health. This study evaluated the concentration of fluoride in groundwater resources of Isfahan Province, the central plateau of Iran, and its related health issues to the inhabitant populations. For this purpose, 573 drinking groundwater samples were analyzed in 2016 by using the spectrophotometric method. Non-carcinogenic health risks due to F exposure through consumption of drinking water were assessed using the US EPA method. In addition, the associated zoning maps of the obtained results were presented using geographic information system (GIS). The results indicated that F content in drinking water ranged from 0.02 to 2.8 mg/L. The F contents were less than 0.50 mg/L in 63% of the drinking groundwater samples, 0.51-1.5 mg/L in 33.15%, and higher than 1.5 mg/L in 3.85% (Iran and World Health Organization guidelines) of the drinking groundwater samples. The F levels in the west and the south groundwater resources of the study areas were lower than 0.5 mg/L, which is within the recommended values for controlling dental caries (0.50-1.0 mg/L). Therefore, these places require more attention and more research is needed to increase F intake for health benefit. The HQ index for children, teens and male and female adults had health hazards (HQ > 1) in 51, 17, 28, and 18 of samples, respectively. Groundwater resources having a risk of more than one were located in the counties of Nayin, Natanz, and Ardestan. So, in these areas, there are potential risks of dental fluorosis. The most vulnerable groups were children. The F levels must be reduced in this region to decrease endemic fluorosis.

Geochemical sources, hydrogeochemical behavior, and health risk assessment of fluoride in an endemic fluorosis area, central Iran

The present study is the first attempt to put forward the possible source(s) and health risk assessment of fluoride in Bahabad, central Iran. Fluoride concentrations ranged from 0.22 to 2.35 mg/L and 292-355 mg/kg in the groundwater and soil samples, respectively. Geochemical provenance techniques using major and rare earth elements in soils revealed that local shale is the most probable source rock of fluoride in the area. A two-step chemical fractionation method applied on soil samples demonstrated that residual and water-soluble fractions were the most probable modes of fluoride in soil, whereas exchangeable fraction had a minor role. The coefficient of aqueous migration showed that fluoride in the studied soils behaved as a mobile element. Moreover, the relative mobility indicated that soils played a more important role than rocks in releasing fluoride into groundwater. In groundwater medium, chemical weathering, evaporation, and ion exchange acted as the main geochemical controlling factors of fluoride enrichment. Findings of this study signify that the role of NaCl and NaSO₄-type waters should be considered more to recognize susceptible areas to fluoride contamination in groundwater. People in the study area are exposed to high levels of fluoride intake through drinking water, thus making dental fluorosis a major public health concern in the area. Scanning electron microscopy of the dentin's enamel showed morphological modifications (e.g., cracks and fissures) in residents' enamel structures. The results of this study may lead to suitable management strategies to mitigate the endemic fluorosis problem.

National and sub-national drinking water fluoride concentrations and prevalence of fluorosis and of decayed, missed, and filled teeth in Iran from 1990 to 2015: a systematic review

Fluoride intake, fluorosis, and dental caries could affect quality of life and disease burden worldwide. As a part of the National and Sub-national Burden of Disease Study (NASBOD) in Iran, we conducted a systematic review to evaluate province-year-specific mean drinking water fluoride concentrations and prevalence of fluorosis and of decayed, missed, and filled teeth (DMFT) in Iran from 1990 to December 2015. We did electronic searches of all English and Persian publications on PubMed, ScienceDirect, Google Scholar, and Iranian databases. Results revealed that the weighted mean drinking water fluoride concentration in Iran from 1990 to 2015 has been about 0.65 ± 0.38 mg/l. However, based on the WHO guideline value (1.50 mg/l) and the maximum permissible Iranian national fluoride standard (1.40 to 2.40 mg/l depending on the region's climate), there have been some regions in Iran with non-optimum fluoride concentrations in their drinking water (up to 7.0 mg/l). Overall, concentrations have been higher in southern parts of Iran and in some areas of Azerbaijan-e-Gharbi Province in the northwest and lower in the rest of the northwest and central parts of Iran. In addition, some hotspots have been found in Bushehr Province, southwest of Iran. The highest prevalence of dental flourosis has been reported in normal index while the lowest prevalence has been expressed in severe index. The lowest DMFT (about 0.1) was in Arsanjan City in Fars Province, and the highest (about 6.7) was for Najaf Abad City in Isfahan Province. Prevalence of fluorosis has been rather high in studied areas of Iran (e.g. 100 % in Maku City in Azarbaijan-e-Gharbi Province), and there was discrepancy for DMFT, but a lack of studies renders the results inconclusive. Further studies, health education and promotion plans, and evidence-based nutrition programs are recommended.

Assessment of fluoride intake through food chain and mapping of endemic areas of Gaya district, Bihar, India

Accumulation of Fluoride (F) was found in the soil and vegetation of the F-endemic villages of Gaya district, Bihar, India. The mean F level in the groundwater of F non-endemic (control) area was 0.59 ± 0.03 (n = 11), while that of F-endemic area was 2.36 ± 0.23 (n = 27). Water soluble F (WSF) and total F (TF) in the soil of F-endemic villages were significantly higher as compared to the F non-endemic area. Similarly, WSF and TF in the vegetables and the grain crops (cereals, legumes and oilseeds) of the F-endemic area were significantly higher as compared that of the control area. Leafy vegetables showed higher accumulation of F with WSF and TF in spinach ranging from 3.62 to 4.82 and 9.88-12.88 mg/kg respectively. The WSF and TF in coriander ranged from 9.66 to 10.88 and 23.11-25.73 mg/kg respectively.