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Comparative Study of Fluoride Concentration in Human Serum and Drinking Water in Fluorinated Endemic and Non Endemic Areas of Pakistan.


Summary: For comparing the human blood serum and drinking water fluoride levels of subjects with dental fluorosis and bony deformities, this study is carried out with individuals ranging 8-17 age group fluorinated Sham Ki Bhatiyan, Punjab (endemic) and Queens Road, Lahore, Punjab (non- endemic) areas. Fluoride concentrations were determined using ion selective electrode methodology and statistically compared. Both the groups showed a significant difference (p less than 0.05). Subjects from fluorotic area showed high concentration of fluoride in water and blood serum samples (mean value: 135.587+-77.435 and 2.765+-0.469 umolL-1 in water and blood serum samples respectively) as compared to controls (mean value: 19.509+-2.432 and 2.364+- 0.667 umolL -1). These findings indicate that serum and water fluoride concentrations have a significant positive dose response relationship with the prevalence of dental fluorosis in an area associated with high fluoride level in drinking water.

Keywords: Serum, fluorosis, endemic area, fluoride, drinking water.


Fluoride is one of the trace elements which are widely distributed in the environment. Once it is absorbed from GIT, calcified tissues rapidly incorporate them [1]. One of the serious health problems related to high fluoride content intake results in fluorosis. It is more common in those areas of the world in which the level of fluoride in drinking water is more than 1 ppm. Prevalence of fluorosis in all areas of the world has been reported to be approximately 32 % [2]. The clinical importance of fluoride lies in the fact that it is used for the treatment of Paget's disease as well as for the prevention of dental caries [3]. But the decision to use fluoride for caries prevention has to be taken with lot of caution to balance the risks with the benefits [4]. Fluoride up to the permissible limits is helpful in decreasing dental caries, but at or above 2ppm it can cause dental fluorosis. At 8 ppm, it can cause osteopathies.

In 10% of the subjects changes in thyroid functions can ccur at an intake of 50 ppm in water. At 100 ppm to 125 ppm, disturbances in renal functions and growth retardation can occur. Intake of 2.5 gm of fluoride per person is considered to be the acute lethal dose [5-7].

Contaminated ground water with fluoride above the permissible limit was noted in India, China, Sirilanka, Spain, Italy, West Indies, South and North America [8, 9]. The three main resourcesresponsible for exposure in human subjects are food, water and air [10]. Sixty different types of industries can cause air and water contamination resulting in fluoride intoxication like manufacturing of bricks, phosphate and aluminum fertilizers clay glass enamel metal steel works ceramic industries and magnesium foundries [11]. Though main source of fluoride ingestion is contaminated drinking water, foods prepared with fluoride rich water can make a major contribution to fluoride intake particularly younger age groups [12].

Dietary ingestion has recently been recognized as a route which can cause dental fluorosis however intake of fluoride from food can show great variations [13]. It is not only the food stuff, even table salt, spices and condiments can add to total fluoride content in diet. The fluoride content of tea among the beverages is very high and varies from 122 to 260 ppm in different brands within average of 186 ppm [14]. Certain household products and medicines like mouth rinses and tooth pastes contain fluoride as ingredient. In children less than six years of age the main source of fluoride ingestion can be due to swallowing of fluoride rich toothpastes [15, 16]. On an empty stomach, there is total absorption of the ingested fluoride in tooth paste. Normally tooth paste ingested per brushing is up to 20% [17, 18]. Ingestion of tobacco and Pan Masalah and burning of low quality coal in a primitive way can also lead to fluorosis [19].

The relationship between dental caries and fluoride was observed in early 20th century, when resident of certain areas of USA develop brown stains on their teeth and they were resistant to caries and dental decay [20]. It was discovered in 1930 that the severity and prevalence of this type of mottled enamel was in direct proportion to amount of fluoride in water [21]. Increase intake during the pre-eruptive stage of teeth leads to dental fluorosis and continuous ingestion over the years can finally cause skeletal fluorosis. So, in the present study, concentration of fluoride has been determined in drinking water and human serum of patients of fluorinated endemic area of Pakistan (Sham Ki Bhatiyan, Punjab). For comparing them with non fluorinated area, water and human serum samples from non endemic area (Queens Road, Lahore, Punjab) were collected during same duration of study, i.e. December 2010-May 2011.

Results and Discussion

Concentration of Fluoride in Drinking Water

The problem of fluoride is now becoming a hot issue in endemic areas of Pakistan. Its main source for human beings is drinking water. Normally fluoride concentration is less than 1 ppm in water, but this concentration is varied due to geographical and seasonal variations in various part of the world [22, 23]. So, for comparison study, reference samples of drinking water were collected and analyzed. Their results were listed in Table-1 and 2. The water fluoride level is found to be more than 3 ppm. As it is evident from this data, that average concentration of fluoride in non endemic area drinking water is 19.509 +- 2.432 umolL-1 (0.37 ppm), whereas in endemic area (Table-2), fluoride concentration is increased up to an average value of 135.587 +-77.435 umolL-1 (2.57ppm) with the range of 26.346-268.632 umolL-1 (0.5-5.10 ppm).

This severe increase in fluoride level lead to fluorosis, in which dental and skeletal fluorosis is observed in the patients of fluorotic endemic area

Concentration of Fluoride in Human Blood Serum

In Pakistan, I.S.E (Ion selective electrode) method is not so common on clinical scale for fluoride determination. In this study, it is noted that this method can be easily used for monitoring fluoride levels in patients. In blood serum, concentration of fluoride in individuals of non endemic area was an average of 2.364 +- 0.667 umolL-1 (0.045 ppm), but in endemic region, this level is increased to 2.765 +- 0.0.469 umolL-1 (0.053 ppm) with the range of 2.126-3.623 umolL-1 (0.04-0.06 ppm).


Selection of Subjects

Two areas about 60-80 Km apart namely Sham Ki Bhattiyan and Queens Road, Lahore, Punjab were selected for study. Sham Ki Bhattiyan is located on a severe endemic fluorosis area, with reported mottling of teeth and sporadic pains and stiffness of joints in the affected population. Queens Road, Lahore is a non-endemic area and the subjects were referred to as control group. A total of 60 young individual ranging from the age of 8 to 17 years were selected from both the localities on the basis of presence or absence of dental fluorosis along with bony deformities as shown in Fig. 1 and 2. All of the subjects from the endemic areas had dental fluorosis, 15 had grade IV dental fluorosis i.e. brown to black

Chemical Reagents and Instrumentation

Fluoride stock solution (Jenway 025 087),Ion selective electrode (ISE-Jenway ISAB-025 107, detection range: 0.02 - 1900 mgL), plain and gel vacuum tubes (sample tubes) and TISAB (total ionic strength adjustment buffer is a buffer solution for fluoride- HANNA instruments) were used. Benefits of using I.S.E method are: (i) less expensive than other analytical techniques like AAS or Ion Chromatography, (ii) simple, robust and durable to apply and measurement is fast, (iii) large range of applications and can be used over a wide concentration range, (iv) accuracy and precision levels of +- 2% for some ions compare favorably with analytical techniques which require more complex and expensive instrumentation.

Sampling and testing

Water samples

The samples of drinking water were collected from each subject's household tap and were kept in clean polythene bottles. They were labeled as W.1 to W.60 and analyzed for fluoride concentration using ion selective electrode methodology.

Blood Sample

A fasting venous blood sample (5-10 mL) was obtained from each individual and preserved in clean gel tubes. They were labeled as S.1 to S. 60 and centrifuged at 4000 rpm for 10 minutes. The serum was removed in another clean sample tube, and refrigerated for next day analysis.

Sample Preparation

Water Samples

To 7.0 mL portion of sample, 3.0 mL of fluoride TISAB were added. Fluoride standard solutions range for their analysis is kept in range of 0.1-10.0 mgL-1.

For accuracy of results and validation of applied method, recoveries after spiking tap water with standard fluoride solutions were recorded in the range of 0.01 to 1 mgL-1 and found to be in order of 94-103 %.

Human Blood Serum Sample

Fluoride standard solutions range for their analysis is kept in range of 0.01-0.04 mgL-1. Samples were prepared similarly using 0.7 mL serum and 0.3 mL TISAB. Then they were analyzed with ion selective electrode.

For accuracy of results and validation of applied method, recoveries after spiking serum samples with standard fluoride solutions were determined in 0.01 to 0.04 mgL-1 range and found to be in order of 93-107 %.

Statistical Analysis

For comparing the concentration of fluoride in water and serum samples of endemic and non endemic area subjects, Student 't' test was applied for data analysis using SPSS 12 software. 95% confidence interval was applied. P value of [?] 0.05 was considered to be statistically significant.


From this study, it is evident that concentration of fluoride in fluorinated endemic areas is very high. So, preventive measures like: water purification, use of calcium, vitamin D and vitamin C supplements should be adopted for controlling this higher concentration of fluoride, because it, in turns destroy human health, by leading to dental and skeletal fluorosis.


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Article Details
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Author:Qayyum, Muniza; Ahmad, Bashir; Ahmad, Maqsood; Waheed-Uz-Zaman; Rehman, Rabia
Publication:Journal of the Chemical Society of Pakistan
Article Type:Report
Geographic Code:9PAKI
Date:Jun 30, 2013
Previous Article:Statistical Analysis of Fluoride Levels in Human Urine and Drinking Water Samples of Fluorinated Area of Punjab (Pakistan).
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