Environ Geochem Health DOI 10.1007/s10653-015-9743-7
ORIGINAL PAPER
Inferring the fluoride hydrogeochemistry and effect of consuming fluoride-contaminated drinking water on human health in some endemic areas of Birbhum district, West Bengal D. Mondal . G. Dutta . S. Gupta
Received: 6 November 2014 / Accepted: 3 July 2015 Ó Springer Science+Business Media Dordrecht 2015
Abstract This research work is carried out to evaluate fluoride (F) hydrogeochemistry and its effect on the population of two endemic villages of Birbhum district, West Bengal. Fluoride concentration in drinking water varies from 0.33 to 18.08 mg/L. Hydrogeochemical evolution suggests that ion-exchange mechanism is the major controlling factor for releasing F in the groundwater. Most of the groundwater samples are undersaturated with respect to calcite and fluorite. Health survey shows that out of 235 people, 142 people suffer from dental fluorosis. According to fluoride impact severity, almost 80 and 94 % people in an age group of 11–20 and 41–50 suffer from dental and skeletal fluorosis, respectively. Statistically drinking water F has a positive correlation with dental and skeletal fluorosis. Bone mineral density test reveals that 33 and 45 % of the studied population suffer from osteopenic and osteoporosis disease. IQ test also signifies that F has a bearing on the intelligence development of the study area school children. The existence of significant linear relationship (R2 = 0.77) between drinking water F and urinary F suggests that consumption of F-contaminated drinking water has a major control over urinary F (0.39–20.1 mg/L) excretion.
D. Mondal G. Dutta S. Gupta (&) Department of Environmental Science, The University of Burdwan, Burdwan, India e-mail:
[email protected]
Keywords Fluoride hydrogeochemistry Dental and skeletal fluorosis Bone mineral density IQ level Urinary F
Introduction Fluoride (F) concentration is an important aspect of hydrogeochemistry because of its impact on human health (Shaji et al. 2007). Its concentration in the environment is variable and is often dependent on the presence of particular types of rocks, minerals or water. For example, endemic dental and/or skeletal fluorosis has been reported in the East African Rift Valley associated with volcanic rock types and thermal waters (Frencken et al. 1990). The concentration of F in most waters is controlled by the solubility of the main F-bearing mineral fluorite (CaF2); hence, waters that are sodium (Na), potassium (K) and chloride (Cl) rich and calcium (Ca) poor tend to contain high F concentration. In general, groundwater contains more F than surface water resources due to greater contact time with F-bearing minerals in rock–water interactions. In addition to natural sources, man disperses F into the environment via aluminum and coal industries, fertilizer use and manufacturing processes (Fordyce et al. 2007). Studies carried out in the USA and Europe in the 1940s demonstrated a link between improved dental health and the introduction of fluoridated toothpaste and fluoridated drinking water to local communities
123
Environ Geochem Health
(Fordyce et al. 2007). Approximately, India has *14 % of total F deposits on the earth’s crust. It is not surprising, therefore, that the fluorosis is endemic in 17 states of India (Hussain et al. 2010). Naturally occurring elements like F can enter the human body via inhalation of air and ingestion of food and water and affect health (WHO 1996). Scientists are still uncertain whether F is essential to human health, but the mechanisms of dental benefaction are thought to be twofold. During the pre-eruptive stage (i.e., during tooth formation in children up to 12 years old), F is thought to accelerate the mineralization process and can enter the mineral lattice forming fluorapatite, which is stronger (less soluble) than hydroxylapatite. Experiments on rats have also demonstrated that the activation of mineralization increases dental cement growth in animals receiving higher F concentrations. Secondly, F acts as an anti-bacterial agent in the mouth, helping to minimize acid attack on teeth (Jenkins 1967; Brown and Konig 1977; Pashayev et al. 1990; Petrovich et al. 1995). It has been shown that F concentration between 0 and 0.5 mg/L favors dental caries development (WHO 1996), whereas concentration between 1.5 and 5 mg/L can result in adverse effect like dental fluorosis. Ingestion of 5–40 mg/day of F via drinking water can produce skeletal deformities, and knock knees (genu valgum) have been reported in adolescents receiving [10 mg/day in water, accumulated from birth. As per (WHO 1997), permissible limit of F in drinking water is 1.0 mg/L. The Bureau of Indian Standards (BIS) prescribed a limit between 1.0 and 1.5 mg/L for F in drinking water for a region depending on its climatic conditions, because the amount of water consumed and consequently the amount of F ingested are being influenced primarily by the air temperature (Heyroth 1953). Accordingly, the maximum allowable concentration for F in drinking water in Indian conditions comes to 1.4 mg/L, while as per Indian standard, it is 1.5 mg/L (BIS 1991). There is also evidence that the adverse health effects of F are enhanced by a lack of Ca, vitamins and protein in the diet (Zheng et al. 1999). Subsequent investigations reveal that F also affects the human skeletal structure as it is a powerful calciumseeking element. Endemic skeletal fluorosis is a chronic metabolic bone and joint disease caused by intake of large amounts of F either through water or rarely from foods/air in endemic areas. Human and other animal bones are composed of hydroxylapatite,
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but this mineral and fluorapatite are end-members in the apatite solid solution series and therefore F exchanges readily with the OH ion in the apatite structure, increasing the brittleness and decreasing the solubility of the bone structure (Dissanayake and Chandrajith 1999; Skinner 2000). The bones of the human body are constantly resorbed and redeposited during a lifetime, and high F intakes increase the accretion, resorption and Ca turnover rates of bone tissue, affecting the homeostasis of bone mineral metabolism (Krishnamachari 1986). Calcification of soft tissues such as ligaments can also occur. It has been also reported that most of the people in the F endemic areas suffer from osteoporosis and osteopenia. Fluoride can penetrate the fatal blood–brain barrier and accumulate in cerebral tissue before birth, thereby apparently affecting children’s intelligence (He et al. 1989; Cheng 1991). Although approximately 80 % of F entering the body is excreted mainly through urine, the remainder is absorbed into body tissues from where it is released very slowly (WHO 1996). Urinary F is regarded as the best indicator of exposure to fluorine compounds, and usually it correlates well with the level of F in drinking water (Czarnowski et al. 1996). Repeated or continuous exposure to F therefore causes accumulation of F in the body. Hence, F is a cumulative toxin, and although skeletal fluorosis commonly affects older people following long years of exposure, crippling forms of the disease are also seen in children in endemic areas (WHO 1996). Two adjacent villages namely Junidpur (24° 060 07.500 N and 87° 460 54.700 E) and Nowapara (24° 060 18.000 N and 87° 470 02.000 E) of Atla mouja, Rampurhat-I block of Birbhum district, having an aerial coverage of 1.5 km2 were selected for the present study. The area under study forms a part of the Dwarka River flood plain (Fig. 1). The alluvial sediments of the Dwarka basin have been classified as recent alluvium which is exposed and subsurface older alluvium of Holocene in age. The later consists of sediments that are formed in distant past and are partly undergoing denudation, while the former is under its process of formation. The recent alluvium is yellowcolored sand and clay and poor in calcareous matter. The older alluvium is made up of typical brown and gray sand intercalated with sticky yellowish and grayish clay. The study area is a flat alluvial tract with soil exhibiting a wide variance: sandy on the
Environ Geochem Health
Fig. 1 Map of study area
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Environ Geochem Health
elevated locations, clayey in the topographical lows and loamy on the flat surfaces. General trend of Dwarka River is southwest to northeast. The area also shows low regional surface gradient from southwest to northeast, varying from 10 to 30 cm/km. The prevailing temperature and the rainfall pattern indicate that the semi-arid climate occurs in the study area. Annual average rainfall varies from 600 to 1200 mm, and average potential evapotranspiration is much higher, i.e., 1400 mm (measured at district agricultural seed firm, Nalhati-1). Most of the aquifers in the study lie within 20–30 m depth. The aquifer material is fine- to medium-grained unoxidized organic-rich gray-colored sand (organic carbon *1 %) and generally micaceous in nature, and under semi-confined condition, however, storage coefficient (0.5 9 10-1) reflects the water table condition of the aquifer. Pre-monsoon water level varies from 3 to 8 m bgl (below ground level). Average yield of the tube well is in the tune of 15 m3/h, whereas hydraulic conductivity (K) and transmissivity (T) values of the aquifer are 4 9 10-5 m/s and 200 to 300 m2/day, respectively (CGWB Technical report 1985). Both the villages are endemic with respect to fluorosis since last 6–8 years. From management point of view, presently various NGOs in collaboration with local gram panchayats have started to supply smallscale filters (activated Al2O3) based for domestic use, particularly for drinking purposes. Another community-level water treatment plant has already been installed at Nowapara on behalf of Bengal Engineering University, Shibpur, in 2009. But, most of the time, it gets out of order due to lack of periodical maintenance. In spite of various measures taken by local authority and NGOs, large fraction of villagers are still using F-contaminated groundwater from tube wells for their drinking purposes, due to lack of awareness and lack of confidence in filtration technologies. Both the villages under its administration have been economically and socially backward, as farming is main occupation and there is no industrial enterprise. So far, very limited research works have been executed in the study area in the aspect of hydrogeochemistry and prevalence of dental and skeletal fluorosis and that too also in an isolated manner (Ghosh et al. 2010; Majumdar 2011), but in this research work, an in-depth analysis is carried out in both the aspects along with an additional emphasis on
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the effect of F on intelligence and urinary level of study area population by means of clinical and nonclinical survey.
Materials and methods Sampling and analysis of groundwater samples Altogether, 37 groundwater samples were collected from two villages along the central flood plain of Dwarka River during pre-monsoon (March–April) and post-monsoon (November–December) season of 2012–2013. Samples were obtained from bore wells tapping the Quaternary sediments at a depth of 20–30 m. Samples were stored in 300-mL polyethylene bottles which were acid-washed and had been rinsed twice with deionized water before sampling. Electrical conductance (EC), pH and total dissolved solids (TDS) of the water samples were measured using the Consort C533 portable multi-parameter analyzer. Carbonate alkalinity was measured by titration (APHA-AWWA-WPCF 1980). Other anions and cations were measured using a Dionex Ion Chromatograph. As the ion chromatography is working on conductivity principle, no sample processing is required. In total, 0.5 mL of filtered raw sample was used for the injection. An AS-14A Ion Pac was used with 8.0 mM sodium carbonate and 1.0 mM bicarbonate as eluent and H2SO4 as regenerant to measure the anions, and CS-17 column with 6 mM methanesulfonic acid as eluent to measure the cations. Primary standards were procured from Merck, Germany, and mixed standard of F, Cl, NO2, Br, NO3, PO4 and SO4 for anions and Li, Na, K, Mg and Ca for cations made as per the ion ratios present in the groundwater. Every day, after stabilizing the instrument, blank and three standards of different concentrations were measured before the actual sample measurements. Instrument provides the sample values against the three known standard values. A standard and blank were measured at the end of the day to check the instrument stability. Each water sample was analyzed two times in different runs to check the reproducibility. Instrument precession/error calculated based on the repeated injection of same sample/standard in a single run and also in different runs, has a precision of ±5 % of the total value. Finally, the data quality was checked with ionic charge balances, which is within 5 %.
Environ Geochem Health
Statistical interpretations
of age group consisting of 50.64 % male and 49.36 % female (Table 1).
Pearson correlations (r) and test of significance (p) were performed between analyzed parameter of the water samples and also between drinking water F and prevalence of dental and skeletal fluorosis. Parametric Z test was performed to evaluate the effect of F on the intelligence level of the children. The test statistic is given by ðl l2 DÞ Z ¼ p1 ffiffiffiffiffiffiffiffiffiffiffiffiffi r 1=n1 þ1=n1 where n1 and n2 are the no. of observation, l1 and l2 are mean of the population, r = standard deviation, and D is the assumed difference between the means. The Z statistic follows a normal distribution.Entire statistical calculations were done in XLSTAT 2015 software. Study population The study population was comprised of 235 residents. For collection of data pertaining to evidence, prevalence and severity of dental and skeletal fluorosis, a study was conducted in both the villages (Junidpur and Nowapara) having 0.33–18.08 mg/L F in drinking water. For the survey, a questionnaire was designed consisting of information regarding age, sex, and dietary habits of individuals. Both dental and skeletal fluorosis survey were confined within 2–10; 11–20; 21–30; 31–40; 41–50; 51–60; 61–70; and 71–80 years
Clinical examination for dental fluorosis For dental fluorosis, teeth of individual and nutritional habits of different age groups and sex were carefully examined by a qualified dentist and hygienist in proper daylight. A precaution was taken in diagnosis of dental fluorosis, since it is often mistaken with the stains imposed on teeth by chewing tobacco and smoking. Each tooth in the mouth was rated according to one of the six categories of Dean’s index (Table 2), and the individual’s dental fluorosis score was arrived at based on the severest form recorded for two or more teeth. Community fluorosis index (CFI) It was calculated to identify whether dental fluorosis has been a common public health problem in that area. CFI was computed by summing up the scores of individual grades of dental fluorosis as described by Dean and dividing the sum by the total sample size. Community fluorosis index ðCFI) P ðscores no: in each score groupÞ ¼ number of cases examined The scores represent a particular value given to the various degree of fluorosis. It is 0 for normal, 0.5 for questionable, 1.0 for very mild, 2.0 for mild, 3.0 for moderate and 4.0 for severe. The public health significance of CFI values is represented in Table 3.
Table 1 Percentage of male and female among the studied population according to classified age group Age in years
Total No.
Male Percentage
No.
Total percentage Percentage
Female No.
Total percentage Percentage
2–10
11
4.68
7
63.64
4
36.36
11–20
30
12.77
14
46.67
16
53.33
21–30
35
14.89
20
57.14
15
42.86
31–40
44
18.72
16
36.36
28
63.64
41–50
61
25.96
26
42.62
35
57.38
51–60
35
14.89
21
60
14
40
61–70
15
6.38
13
86.67
71–80 Total
4 235
1.7 100
2 119
50
50.64
2
13.33
2
50
49.36
116
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Environ Geochem Health Table 2 Dean’s (1942) classification for dental fluorosis Normal (0)
The enamel presents translucent, semi-vitriform type of structure. The surface is smooth, glossy and usually pale creamy white color
Questionable (0.5)
Seen in area of relatively high endemicity, occasional cases are borderline and one would hesitate to classify them as apparently normal or very mild
Very mild (1)
Small, opaque paper-white area seen, scattering irregularly over the labial and buccal tooth surfaces
Mild (2)
The white opaque areas involve at least half of the tooth surface and faint brown stains are sometimes apparent
Moderately (3)
Generally all tooth surfaces are involved and minute pitting is often present on the labial and buccal surfaces. Brown stain are frequently a disfiguring complication
Severe (4)
The severe hypeoplasic affect the form of the teeth and stains are wide spread, and vary in intensity from deep brown to black
Table 3 Value range of CFI CFI value range
Public health significance
0.0–0.4
Negative
0.4–0.6
Borderline
0.6–1.0 1.0–2.0
Slight Medium
2.0–3.0
Marked
3.0–4.0
Very marked
Skeletal fluorosis survey by means of fluoride impact severity (FIS) The study area population were asked for the FIS symptoms (mentioned below), and the visible symptoms and deformities were checked out. Simultaneously, bending or movements of different parts of the body were also observed for their easiness in movements or bending in suspected cases of skeletal fluorosis and such was done among all the studied population. Severity of fluorosis among the affected people living in the affected area was determined on the basis of eight (8) symptoms. These symptoms are (a) dental fluorosis (FIS-1), (b) unable to walk (FIS-2), (c) can’t touch chest with chin (FIS-3), (d) can’t bend forward easily (FIS-4), (e) can’t do sit-up (FIS-5), (f) can’t touch back of the head with hands (FIS-6), (g) pain in knee joints (FIS-7) and (h) pain in hip joint (FIS-8) (Indu et al. 2007). Score ‘1’ is set for each of the 8 symptoms mentioned above. So, full score is 8 for eight above-mentioned symptoms. It is added according to the presence of ‘anyone of these symptoms’ in a person and not in any serial order or not in any ordinal value for the severity. It is a simple scoring approach, the higher the score, the higher the severity considered. Except these physical symptoms, we have
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not used any other clinical/psychological symptoms in these FIS survey here. Bone mineral density (BMD) test A bone mineral density test measures how much calcium and other types of minerals are in an area of bone. Inherent strength of bone depends upon a host of multi-factorial components, the amount of mineralized matrix being a major factor. In the study area, BMD test was carried out by means of Ultrasound Bone Densitometer CM-200. The measurement results tend to vary depending on heel temperature. CM-200 provides highly accurate measurement by temperature correction with the heel temperature sensor. Normal, osteopenic and osteoporosis conditions of the studied population were evaluated by means T-score. The criterion of World Health Organization (WHO 2003) for T-score is as follows: normal is a T-score of -1.0 or higher; osteopenia is defined as between -1.0 and -2.5; and osteoporosis is defined as -2.5 or lower. Intelligence test An intelligence test was conducted among 40 children selected 20 each from endemic villages (Nowapara and Junidpur) and nearby non-fluorosis villages (Bilaspur, Mohula and Bhalian) considering similar food habit and economic status of the family. The collective testing of intellectual ability was conducted using the Raven Standard Theoretical Intelligence Test (Raven et al. 2003) developed by the Psychology Department of Beijing Normal University; a sample of children 10–14 years old were selected and the intelligence quotient (IQ) was measured by using a 60-item
Environ Geochem Health Table 4 Criteria for intelligence rankings
Level
IQ evaluation standard
1
IQ score in the 95 % or higher range
High intelligence
2
IQ score in the 75–94 % range
Good
3
IQ score in the 25–74 % range
Average
4
IQ score in the 5–24 % range
Below average
5
IQ score in the 4 % or lower range
Intellectual deficit
questionnaire. A base score was calculated in comparison with standard answers, and then the final IQ was calculated (Wang et al. 2008). Criteria for intelligence ranking have been represented in Table 4.
Rank
prescribed specifications of (WHO 1997) and Indian standard for drinking water, i.e., IS-10500 (BIS 1991). Comparison shows that except F, all other hydrochemical parameters are well within the prescribed limit.
Estimation of urinary F Urine samples were also collected from 235 individuals of both the villages. Urine samples were collected in sterilized plastic containers and preserved in deep freezer at -20 °C before the analysis. Fluoride concentrations in urine were measured in the field itself with the F-specific electrode (Orion ion meter) after dilution of each sample (1:1) with the total ionic strength adjustment buffer (Singh et al. 2007).
Results and discussion Groundwater chemistry Average (pre- and post-monsoon) analytical data of the water samples along with descriptive statistics and water type are represented in Table 5. Overall, the groundwater is neutral to alkaline in nature having mean pH values ranging from 6.72 to 7.91. On the contrary, Eh of the groundwater is moderately low ranging from -93 to -24 mV. Electrical conductivity ranges from 334.50 to 975 lS/cm. The TDS values of all the groundwater samples are less than 500 mg/L. The relative abundance of ions, represented by Schoeller (1965) diagram, is in the sequence of Na [[ Ca [ Mg [ K and HCO3 [[ SO4 [ Cl (Fig. 2). Trace amount of NO3 (mean range of 0.10–1.00 mg/L) and PO4 (mean range of 0.01–0.49 mg/L) has also been noted from the chemical analysis. To assess the suitability for drinking and public health purposes, the hydrochemical parameters of the study area groundwater are compared with the
Fluoride hydrogeochemistry and statistical interpretation of analyzed data Mean F concentration in the study area varies from 0.32 to 13.29 mg/L. Out of 37 samples, 40.54 % samples have F concentrations \1.5 mg/L, while 59.46 % samples have F concentrations [1.5 mg/L. High-F groundwater in other parts of the world are often associated with low Ca concentrations and neutral to alkaline pH values. Most of the groundwater in the study area having F [ 1.5 mg/L shows water type of NaHCO3 (Fig. 3). Several studies demonstrate that in high-F groundwater, F has positive correlations with HCO3 and Na and inverse relationship with Ca (Handa 1975; Kundu et al. 2001; Wang and Cheng 2001; Smedley et al. 2005; Guo et al. 2007). High-F groundwater in the study area also follows exactly the similar relationship as suggested by the various researchers. Groundwater from study area has significant (p \ 0.05) positive correlations (Table 6) with pH, EC, TDS, Na, K, HCO3 and Cl, whereas a significant (p \ 0.05) negative relationship exists with Eh, Ca and Mg. Ion-exchange capacity The relationship between F and Ca in the study area groundwater is rather poor (R2 = -0.519). The poor relationship between these two parameters does not preclude F enrichment due to the dissolution of fluorite in the aquifers (Apambire et al. 1997; Subba Rao 2003). This is because of the other complex processes such as cation exchange and silicate mineral weathering, which have a bearing on the concentration of Ca
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7.81 ± 0.93
7.37 ± 0.95
7.19 ± 0.77
7.66 ± 0.98
7.19 ± 0.74
7.37 ± 0.74
7.21 ± 1.02
6.72 ± 0.66
7.26 ± 1.17
7.50 ± 1.02
7.28 ± 0.89
7.41 ± 1.26
6.99 ± 0.39
7.39 ± 0.98
7.77 ± 0.76
7.23 ± 0.71
7.43 ± 0.78
7.56 ± 0.66
7.61 ± 0.78
7.56 ± 0.78
7.65 ± 0.78
7.62 ± 0.87
7.35 ± 0.73
7.52 ± 0.78
7.66 ± 0.72
7.79 ± 0.72
7.87 ± 0.91
7.19 ± 0.76
7.77 ± 0.71
7.83 ± 0.75
7.00 ± 0.14
7.91 ± 0.76
7.63 ± 0.33
7.10 ± 0.43
7.79 ± 0.59
J1
J2
J3
J4
J5
J6
J7
J8
J9
J10
J11
J12
J13
J14
J15
J16
J17
J18
J19
J20
J21
J22
J23
N1
N2
N3
N4
N5
N6
N7
N8
N9
N10
N11
N12
pH
Sample No
123
-85.50 ± 34.65
-46.50 ± 23.33
-76 ± 18.38
-90 ± 39.60
-40.50 ± 6.36
-85.50 ± 38.89
-82 ± 36.77
-50.50 ± 38.89
-87.50 ± 47.38
-82.50 ± 37.48
-76 ± 36.77
-68.50 ± 40.31
-58 ± 36.77
-73.50 ± 44.55
-75.50 ± 40.31
-71 ± 41.01
-72.50 ± 40.31
-71 ± 33.94
-63.50 ± 40.31
-52.50 ± 36.06
-81.50 ± 38.89
-60.50 ± 51.2
-38 ± 18.38
-62 ± 66.47
-55 ± 45.25
-67.50 ± 53.03
-54.50 ± 61.52
-24 ± 32.53
-51 ± 53.74
-60 ± 36.77
-49.50 ± 37.48
-76.50 ± 51.62
-50 ± 39.60
-60 ± 50.91
-93 ± 35.36
Eh
642.50 ± 44.55
446.5 ± 16.26
687 ± 25.46
756.50 ± 31.82
434 ± 9.90
738 ± 26.87
873 ± 122.33
638 ± 66.47
559 ± 16.97
553 ± 32.53
728 ± 39.60
668 ± 144.25
404 ± 32.53
427 ± 11.31
522.50 ± 31.82
352.50 ± 19.09
483.50 ± 31.82
723 ± 141.42
561 ± 59.40
463.50 ± 51.62
697.5 ± 113.84
425.50 ± 24.75
418 ± 7.07
366 ± 22.63
420.00 ± 29.70
387.50 ± 53.03
346.50 ± 13.44
334.50 ± 50.20
507.50 ± 45.96
672 ± 22.63
439.5 ± 36.06
533 ± 32.53
347 ± 14.14
366 ± 4.95
975 ± 148.49
EC
Table 5 Physicochemical analysis of groundwater samples
342 ± 24.04
237.50 ± 9.19
365.50 ± 13.44
402.50 ± 16.26
230.50 ± 4.95
393.50 ± 14.85
469.50 ± 71.42
339 ± 35.36
298 ± 8.49
294 ± 16.97
377 ± 35.36
356 ± 76.37
215 ± 16.97
227 ± 5.66
278 ± 16.97
186.50 ± 12.2
257 ± 16.97
385.5 ± 77.07
298.5 ± 31.82
247 ± 26.87
370 ± 59.40
226.5 ± 13.44
223 ± 4.24
195 ± 12.73
224 ± 16.97
206.50 ± 28.9
184 ± 7.07
178.50 ± 27.8
270 ± 24.04
360 ± 14.14
232.50 ± 7.8
283.50 ± 17.8
184.50 ± 7.78
195.50 ± 2.12
481.5 ± 139.3
TDS
119.73 ± 36.25
84.16 ± 6.85
149.04 ± 0.09
163.89 ± 2.41
84.48 ± 2.72
155.83 ± 2.31
172.32 ± 5.21
98.41 ± 1.69
111.77 ± 2.02
112.05 ± 0.22
120.21 ± 10.87
68.29 ± 1.27
47.26 ± 1.64
64.45 ± 4.17
79.17 ± 6.12
49.92 ± 0.11
72.95 ± 2.90
101.11 ± 5.22
84.92 ± 1.11
78.72 ± 0.82
121.34 ± 2.78
73.81 ± 0.27
61.44 ± 1.93
52.07 ± 1.51
43.11 ± 1.11
34.26 ± 1.50
32.43 ± 0.24
32.18 ± 1.25
77.65 ± 1.49
108.78 ± 5.25
63.47 ± 0.88
77.44 ± 0.34
50.23 ± 1.52
51.15 ± 2.19
199.60 ± 16.40
Na
1.31 ± 0.59
1.03 ± 0.04
1.97 ± 0.05
2.42 ± 0.11
1.03 ± 0.10
1.92 ± 0.17
2.60 ± 0.15
1.59 ± 0.13
1.40 ± 0.00
1.49 ± 0.26
1.16 ± 0.06
1.45 ± 0.08
1.19 ± 0.02
1.21 ± 0.02
1.64 ± 0.19
1.18 ± 0.68
1.36 ± 0.09
1.17 ± 0.25
1.04 ± 0.06
0.99 ± 0.13
1.47 ± 0.10
0.95 ± 0.21
0.80 ± 0.00
0.97 ± 0.24
1.25 ± 0.07
1.02 ± 0.18
1.16 ± 0.23
0.98 ± 0.11
1.05 ± 0.07
1.52 ± 0.02
0.85 ± 0.21
1.50 ± 0.28
0.89 ± 0.02
0.79 ± 0.02
3.60 ± 0.42
K
3.44 ± 0.62
5.35 ± 0.78
4.26 ± 0.05
5.25 ± 0.06
3.95 ± 0.08
5.79 ± 0.15
7.53 ± 0.04
9.36 ± 1.08
5.06 ± 0.20
4.77 ± 0.10
11.97 ± 0.46
19.62 ± 0.45
8.66 ± 0.23
7.40 ± 0.28
9.81 ± 0.28
6.39 ± 0.13
8.94 ± 0.51
15.43 ± 0.32
10.84 ± 0.06
6.88 ± 0.96
11.88 ± 0.68
5.82 ± 0.31
7.72 ± 0.39
6.44 ± 0.06
9.05 ± 1.63
9.03 ± 0.89
8.35 ± 0.08
7.93 ± 1.74
8.95 ± 0.36
10.84 ± 0.20
8.20 ± 0.84
10.29 ± 0.55
6.17 ± 0.38
6.67 ± 0.32
7.81 ± 0.83
Mg
15.50 ± 4.95
21.42 ± 2.23
20.38 ± 0.18
25.05 ± 0.63
17.09 ± 0.41
26.14 ± 0.52
27.42 ± 14.31
38.08 ± 8.03
22.42 ± 0.04
21.19 ± 1.12
39.17 ± 18.06
27.68 ± 6.82
37.59 ± 1.82
30.41 ± 0.84
34.99 ± 10.45
26.82 ± 1.01
33.50 ± 9.76
24.62 ± 1.53
37.99 ± 12.43
24.90 ± 8.76
28.95 ± 15.21
23.29 ± 2.40
27.43 ± 1.74
26.05 ± 1.07
35.58 ± 6.53
41.79 ± 4.08
35.20 ± 0.57
33.83 ± 5.42
31.63 ± 8.96
38.1 ± 15.75
32.30 ± 4.66
38.31 ± 5.95
25.88 ± 1.95
29.04 ± 1.51
27.4 ± 9.62
Ca
0.04 ± 0.04
0.45 ± 0.07
0.06 ± 0.02
0.07 ± 0.00
0.10 ± 0.01
0.08 ± 0.04
0.03 ± 0.03
0.72 ± 0.46
0.04 ± 0.00
0.04 ± 0.04
0.14 ± 0.11
0.10 ± 0.04
0.09 ± 0.01
0.15 ± 0.17
0.07 ± 0.07
0.09 ± 0.07
0.11 ± 0.09
0.29 ± 0.22
0.10 ± 0.08
0.21 ± 0.25
0.07 ± 0.04
0.53 ± 0.29
2.02 ± 2.62
0.41 ± 0.33
0.40 ± 0.10
0.13 ± 0.13
0.09 ± 0.00
0.07 ± 0.02
0.12 ± 0.07
0.10 ± 0.04
0.06 ± 0.03
0.20 ± 0.17
0.91 ± 0.95
0.56 ± 0.77
0.18 ± 0.18
Fe
288 ± 24.04
239.38 ± 15.03
314.05 ± 4.17
321.75 ± 19.45
221.30 ± 2.40
315.68 ± 15.10
321.98 ± 57.95
208.70 ± 1.84
257.70 ± 15.13
260.70 ± 10.89
292.68 ± 47.62
254.78 ± 118.48
220.90 ± 12.59
220.93 ± 19.69
236.15 ± 36.98
187.63 ± 15.03
244.15 ± 25.67
289.93 ± 94.65
280.50 ± 34.65
230.48 ± 14.81
335.65 ± 68.80
235.03 ± 17.01
186.13 ± 17.15
178.55 ± 14.92
176.95 ± 0.07
198.28 ± 25.84
166.40 ± 6.22
166.40 ± 6.22
236.55 ± 19.16
324.58 ± 23.44
234.98 ± 8.45
265.30 ± 21.64
192.08 ± 0.11
198.13 ± 0.18
324.50 ± 10.61
HCO3
Environ Geochem Health
73.77 ± 0.61
28.10 ± 1.70
79.69 ± 0.98
N7
N9
117.81 ± 0.41
N6
N8
44.21 ± 1.26
40.95 ± 2.62
103.85 ± 15.62
102.70 ± 19.37
N2
N3
N4
91.38 ± 6.53
N1
N5
21.47 ± 5.70
17.82 ± 5.68
J22
J23
12.81 ± 0.44
43.12 ± 4.22
J20
J21
96.05 ± 5.44
45.25 ± 1.20
J17
32.63 ± 5.33
33.46 ± 2.50
J16
J18
65.17 ± 1.80
J15
J19
20.82 ± 1.81
23.82 ± 1.39
J13
25.62 ± 0.82
J12
J14
21.69 ± 3.95
45.94 ± 17.34
J10
J11
24.69 ± 0.87
71.37 ± 2.03
J6
J9
27.14 ± 2.32
J5
47.77 ± 0.24
38.55 ± 1.77
J4
21.99 ± 6.78
13.02 ± 0.18
J3
J7
14.48 ± 1.87
J8
192.32 ± 10.78
J2
0.00 ± 0.00
0.00 ± 0.00
0.30 ± 0.42
0.28 ± 0.03
3.95 ± 0.78
0.00 ± 0.00
0.15 ± 0.21
0.00 ± 0.00
1.10 ± 0.01
8.53 ± 6.61
3.95 ± 0.64
3.39 ± 0.70
2.91 ± 1.86
1.98 ± 0.25
1.50 ± 0.01
1.79 ± 0.57
1.83 ± 2.08
2.46 ± 0.63
2.21 ± 0.86
22.79 ± 21.93
0.20 ± 0.28
3.20 ± 0.14
0.71 ± 0.29
0.30 ± 0.42
2.22 ± 0.26
1.32 ± 0.82
1.88 ± 0.88
0.77 ± 0.10
2.18 ± 0.68
1.72 ± 0.59
1.27 ± 0.04
BDL
0.15 ± 0.00
BDL
BDL
0.60 ± 0.00
BDL
BDL
0.11 ± 0.00
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.55 ± 0.00
0.10 ± 0.13
0.40 ± 0.00
1.00 ± 0.00
BDL
0.30 ± 0.00
BDL
BDL
BDL
BDL
BDL
0.55 ± 0.00
BDL
0.25 ± 0.00
BDL
75.56 ± 2.33
67.97 ± 2.59
Na
0.01 ± 0.00
0.02 ± 0.00
BDL
BDL
0.01 ± 0.00
0.01 ± 0.00
0.06 ± 0.00
BDL
BDL
BDL
BDL
BDL
0.14 ± 0.00
0.04 ± 0.00
0.02 ± 0.00
0.02 ± 0.00
0.01 ± 0.00
0.01 ± 0.00
0.01 ± 0.00
BDL
0.01 ± 0.00
0.01 ± 0.00
0.01 ± 0.00
0.19 ± 0.00
0.03 ± 0.00
0.02 ± 0.00
0.01 ± 0.00
0.01 ± 0.00
BDL
0.06 ± 0.00
0.49 ± 0.44
0.01 ± 0.00
PO4
299.50 ± 50.20
329.50 ± 47.38
TDS
0.66 ± 0.77
NO3
564 ± 94.75
619.50 ± 89.80
EC
0.21 ± 0.28
SO4
-74 ± 35.36
-68 ± 32.53
J1
7.58 ± 0.63
N14
Cl
7.48 ± 0.58
N13
Eh
Sample No
pH
Sample No
Table 5 continued
27.72 ± 3.79
31.67 ± 0.24
27.59 ± 2.98
26.69 ± 1.39
28.88 ± 0.32
32.61 ± 1.54
20.48 ± 13.83
32.36 ± 3.02
34.06 ± 3.02
31.99 ± 0.55
32.09 ± 2.28
30.26 ± 2.47
29.60 ± 2.97
25.48 ± 10.72
19.94 ± 16.03
23.35 ± 15.91
34.46 ± 0.36
24.13 ± 16.31
37.37 ± 0.75
22.15 ± 12.66
34.75 ± 17.60
31.67 ± 17.07
30.38 ± 12.98
36.80 ± 17.25
46.35 ± 3.47
26.14 ± 9.38
27.23 ± 10.50
24.13 ± 5.28
27.51 ± 3.69
22.71 ± 7.23
31.88 ± 0.68
29.71 ± 9.48
SiO2
0.99 ± 0.01
1.50 ± 0.15
K
10.96 ± 0.22
4.58 ± 0.11
10.55 ± 0.06
9.25 ± 0.07
2.22 ± 0.25
6.64 ± 0.06
8.04 ± 0.34
2.32 ± 0.26
1.16 ± 0.08
0.85 ± 0.21
2.30 ± 0.14
2.80 ± 0.28
1.73 ± 0.33
2.73 ± 0.32
2.03 ± 0.18
1.42 ± 0.17
0.63 ± 0.19
1.63 ± 0.33
7.28
6.54
4.94
5.96
6.28
2.58
4.98
5.29
3.07
2.47
1.26
2.12
2.26
1.86
2.18
4.11
2.24
3.16
4.19
3.17
2.24
2.00
1.21
0.82
0.92
0.95
2.45
2.85
1.97
2.02
1.94
1.76
0.31
0.61
0.35
0.23
0.37
0.51
0.52
0.38
0.30
2.11
1.42
0.81
2.09
1.03
0.26
0.84
0.74
0.44
0.98
1.32
1.02
0.77
1.93
1.43
1.54
0.66
0.53
1.19
0.99
1.99
2.01
0.14
Ca/Cl
0.11 ± 0.04
0.20 ± 0.10
Fe
Na/Ca
34.40 ± 13.86
50.24 ± 25.80
Ca
0.47 ± ± 0.04
0.74 ± 0.06
0.39 ± 0.02
0.39 ± 0.02
0.41 ± 0.02
0.32 ± 0.02
0.34 ± 0.06
0.68 ± 0.03
3.17 ± 0.18
0.86 ± 0.06
2.94 ± 0.08
1.62 ± 0.25
1.50 ± 0.14
11.40 ± 0.28
F
11.98 ± 0.03
16.71 ± 0.84
Mg
-0.59
-0.52
-0.59
-0.60
-0.56
-0.52
-0.72
-0.52
-0.49
-0.52
-0.52
-0.55
-0.56
-0.62
-0.73
-0.66
-0.49
-0.64
-0.45
-0.68
-0.49
-0.52
-0.54
-0.46
-0.36
-0.61
-0.59
-0.64
-0.59
-0.67
-0.52
-0.55
SISiO2(a)
219.75 ± 77.43
227.25 ± 66.82
HCO3
Environ Geochem Health
123
-0.55
123
* SISiO2(a) = saturation index for silica, calculated using PHREEQ (Parkhurst and Appelo 1999)
BDL Blow detectable limit
All the units are expressed in mg/L except pH; Eh in mV; EC in ls/cm; and Na/Ca and cation/Cl in meq/L
-0.55 0.55
0.47 2.20
1.35 1.55 ± 0.21
1.24 ± 0.06 30.24 ± 1.76
30.23 ± 2.08 0.01 ± 0.00
0.01 ± 0.00 BDL
BDL 0.45 ± 0.07 91.96 ± 10.53
72.92 ± 3.94
N13
N14
0.30 ± 0.42
-0.63
-0.59 0.33 7.72 13.29 ± 0.44 27.32 ± 2.58 0.06 ± 0.00 BDL 46.37 ± 7.46 N12
0.00 ± 0.00
-0.69 0.35
0.93 3.93
7.31 12.76 ± 0.05
4.04 ± 0.06 24.82 ± 0.87
21.52 ± 6.96 BDL
0.05 ± 0.00 0.40 ± 0.00
BDL 0.08 ± 0.11
0.94 ± 0.93
58.58 ± 0.26
23.05 ± 2.05
N10
N11
Cl Sample No
Table 5 continued
SO4
NO3
PO4
SiO2
F
Na/Ca
Ca/Cl
SISiO2(a)
Environ Geochem Health
in the medium. Similar type of cation exchange phenomenon has also been noted as a major hydrochemical process within alluvial aquifers of other parts of the world by various researchers (Yidana and Yidana 2009; Guo and Wang 2010; Currell et al. 2011; Li et al. 2012). In order to investigate the occurrence of cation exchange reaction in the groundwater, [(Ca ? Mg)(HCO3 ? SO4)] (meq/L) is plotted against [(Na ? K)-Cl] (meq/L) (Fig. 4). Since calcite, dolomite, gypsum and anhydrite are the most likely additional sources that Ca and Mg could enter in the groundwater apart from cation exchange. By plotting these parameters, possible contributions of Ca and Mg from calcite, dolomite, gypsum and anhydrite dissolution to lithogenic Ca and Mg in the groundwater are accounted for, by subtracting the equivalent concentrations of HCO3 and SO4 (McLean and Jankowski 2000). Similarly, to account for lithogenic Na available for exchange, it is assumed that Na contribution from meteoric origin will be balanced by equivalent concentration of Cl; therefore, equivalent Cl concentration is subtracted from that of Na (Nkotagu 1996; McLean and Jankowski 2000). If the two indices vary inversely with a slope close to -1, with the data plotting away from the origin, cation exchange activity is most probably significant in the hydrochemistry (Jalali 2007). In Fig. 5, a large percentage (89.19 %) of the water samples are away from the origin of the X-axis and fall significantly R2 ¼ 0:89 along a line with gradient of -1.347 suggesting that ion exchange plays a major role in contributing Na? in the groundwater system. The presence of negative correlation between Na and dissolved silica concentrations in both the seasons (r = -0.09) indicates that weathering of albite is probably not a major control on Na concentrations in the groundwater, given that all samples are undersaturated with respect to amorphous silica [mean saturation index (SI) value is -0.57], which rules out buffering of dissolved Si concentrations by amorphous silica precipitation. High molar Na/Cl ratios (e.g.,[2) and low Ca/Cl ratios (e.g.,\1) in groundwater are also consistent with cation exchange being a major control on Na and Ca concentrations (Table 5). The mean Na/ Ca ratio in Nowapara (4.62) groundwater is much higher than Junidpur (2.39), thereby indicating dominant role of cation exchange capacity, leading to greater mobilization of F.
Environ Geochem Health Fig. 2 Schoeller (1965) diagram showing relative abundances of cations and anions
The saturation indices
Effect of F on human health
The solubility limits for fluorite and calcite provide a natural control on water composition in a view that Ca, F and CO3 activities are interdependent (Kundu et al. 2001). The saturation indices (SI) of fluorite (CaF2) and calcite (CaCO3) in the groundwater samples are calculated using PHREEQCI version 2 (Parkhurst and Appelo 1999) and are plotted in Fig. 5 which shows that the most of the samples are undersaturated with respect to calcite and fluorite. This situation of solubility control on the higher concentration of F can be explained by the fact that F ions in groundwater can be increased as a result of precipitation of CaCO3 at high pH, which removes Ca from solution (increased F/Ca ratio of solution) allowing more fluorite to dissolve. Figure 5 represents that SI of F is greater than calcite in some sampling stations of Nowapara [i.e., N13(26), N10(29), N6(33), N3(36)] giving higher dissolution of F in that groundwater.
The relationship between the levels of F in drinking water and the incidence of dental fluorosis varies from place to place. In the study area, 142 (60.43 %) individuals out of total 235 are affected with various grades of dental fluorosis (Table 7). Maximum occurrence of dental fluorosis is found among 11–20 years of children. Similar kinds of observations are also reported by Baelum et al. 1986. According to various grades of dental fluorosis, 24 (10.21 %), 48 (20.43 %) and 21 (8.94 %) individuals are affected with very mild (Fig. 6a), mild (Fig. 6b) and moderate grade (Fig. 6c) of fluorosis, respectively, whereas 37 (15.74 %) individuals are affected with severe grade (Fig. 6d) of fluorosis (Table 7). With respect to gender-wise distribution, almost 65 % male and 56 % female are affected with dental fluorosis out of 119 male and 116 female, respectively. Community fluorosis index (CFI) of the study area represents
123
Environ Geochem Health
Fig. 3 Piper (1944) trilinear diagram showing water type of the study area
medium value category (1.43) of public health significance (Table 3). Skeletal fluorosis is a bone disease caused by excessive accumulation of F in the bones. The symptoms of skeletal fluorosis in human beings are pains in the body, restricted and painful movements of cervical, dorsolumber spine, pelvic and forearm and leg joints. Some visible deformities such as crippling, kyphosis, can’t bend, genu varum (convergent banding of legs) and genu valgum (divergent bending of leg bones), calcification and can’t not touch head by both hands are also non-clinical symptoms of skeletal fluorosis (WHO 1984). Some of the above-mentioned visible symptoms are also found among the study area population (Fig. 7). Fluoride impact severity (FIS) Most of the population in the study area are found to attend various grades of severity index. Higher occurrence of FIS-1 is mainly restricted to 11–20 years of age limit followed by a decreasing percentage up to 80 years (Fig. 8). Most of the affected person under FIS-2 is gradually increased from 61–70 age to 71–80 age with a minor occurrence of 11–20 age to 51–60 years of age limit (Fig. 8). Maximum occurrence of FIS-3 is found in 61–70 and 71–80 years of age group, whereas FIS-4 is mainly
123
restricted to 11–20 years of age limit followed by an increasing trend up to 71–80 years. Similar to FIS-4, FIS-5 occurs high in the age group of 71–80 years and has an increasing trend with increasing age. Minor percentage (3.4 %) of population is affected by FIS-6 and is mainly restricted to 21–30 years and 61–70 years of age groups. FIS-7 (68.51 %) and FIS-8 (70.21 %) are the most predominant ones among the studied population. Both these symptoms present within early age group (i.e., 2–10 years) and are found maximum in 71–80 years age group. According to symptoms of FIS study, 60.43 % people suffer from dental fluorosis, 22.13 % are unable to walk, 20 % cannot touch chest with chin, 57.45 % cannot bend forward easily, 54.04 % cannot do sit-up 3.4 % cannot touch back of the head with hands, 68.51 % of the studied people suffer from pain in joint like knee and 70.21 % of the studied people suffer from pain in hip joint (Fig. 9). So, it can be concluded that maximum occurrence of FIS-1, i.e., present dental fluorosis, is found in 11–20 years age group, whereas maximum occurrence of FIS-2 and FIS-6, i.e., unable to walk, can’t touch back of the head with hands, is found in 61–70 years age group. FIS-3, FIS-4, FIS-5, FIS-7 and FIS-8, i.e., can’t touch chest with chin, can’t bend forward easily, can’t do sit-up, pain in knee joint, pain in hip joint, are found maximum in 71–80 years age group. From the FIS study, it is also revealed that male is more affected with FIS-1 and FIS-3 (except 11–20 years in case of FIS-1) than female. Regarding FIS-4, female is more affected than male in early and middle age group, but after 60 years, both male and female are equally affected. In case of FIS-5, female is more affected than male, but after 60 years, male is more affected than female. In case of FIS-6, FIS-7 and FIS-8, female is more affected with increasing age than male. Most of these symptoms are found to occur predominantly in 60? age group because of the incidence of calcium metabolism disorder such as osteoporosis or hypercalcemia (too much calcium in the blood) and genetic or autoimmune disorders that affect the skeletal system and connective tissues. Maximum numbers of male and female suffer from FIS-7 and FIS-8 because skeletal fluorosis causes bony outgrowths (i.e., osteophytes), degradation and calcification of cartilage, osteosclerosis and reduced space between the joint conditions, thereby enhancing pain in hip and knee joints (Rui et al. 2012). With respect to total FIS score of 8, maximum percentage of
-0.446
Fe
-0.103
-0.295
PO43
SiO2
-0.275
0.240 -0.072
-0.633
0.289
0.102
0.376
0.377
0.654
-0.332
-0.327
-0.025
-0.259
0.653
-0.346
-0.333
-0.054
-0.259
0.893
0.881
-0.280
0.247 -0.074
0.790
0.904
1
TDS
0.835
-0.372
-0.268
0.034
-0.265
0.744
0.881
-0.243
-0.166 -0.347
0.823
1
Na
1
0.715
-0.142
-0.235
0.008
-0.236
0.789
0.649
-0.285
-0.041 -0.082
K
Values in bold are different from 0 with a significance level alpha = 0.05
0.603
-0.410
NO3
F
0.451
-0.362
Cl
SO4
*
0.447
-0.022 0.129
0.810
0.909
0.912
0.024 -0.122
Mg Ca
-0.636
-0.671
-0.502
0.590
K
0.998
1
0.873
0.642
Na
-0.667
EC
-0.681
0.641
TDS
-0.669
1
Eh
0.672
0.638
EC
HCO3
-0.995*
1
pH
Eh
pH
Variables
Table 6 Pearson correlation coefficient among different parameters
-0.456
0.018
-0.166
-0.143
0.021
0.381
0.070
-0.071
1 0.605
Mg
-0.519
0.185
-0.075
-0.116
0.087
0.109
-0.203
-0.055
1
Ca
-0.273
-0.187
0.097
0.693
0.786
-0.188
-0.383
1
Fe
0.669
-0.454
-0.302
-0.163
-0.295
0.627
1
HCO3
0.443
-0.137
-0.284
0.106
-0.244
1
Cl
-0.291
-0.139
-0.095
0.551
1
SO4
-0.114
-0.112
-0.154
1
NO3
-0.112
0.121
1
PO4
-0.321
1
SiO2
1
F
Environ Geochem Health
123
Environ Geochem Health
Pearson correlation coefficient reveals that both dental (r = 0.165) and skeletal fluorosis (r = 0.070) are positively correlated with drinking water F. With respect to FIS symptoms, FIS-1, 3, 6, 7 and 8 are positively correlated with drinking water F (r = 0.215, 0.248, 0.147, 0.090 and 0.041, respectively) as well as urinary F (r = 0.148, 0.313, 0.163, 0.149 and 0.170, respectively). Bone mineral density 2?
2?
)–(HCO3-–SO42-)
Fig. 4 Bivariate plot of (Ca ? Mg versus (Na? ? K?)–Cl- of the groundwater sample in both pre- and post-monsoon seasons
Fig. 5 Spatial distribution of SIcalcite versus SIfluorite
population, i.e., 13.62, 17.87 and 19.15 % are found to score 3/8, 4/8 and 5/8, respectively. Moderate percentages of population, i.e., 9.79, 10.21 and 11.06 % score 1/8, 2/8 and 6/8, respectively, whereas very small fraction of studied population, i.e., 5.53 and 0.43 % score maximum of 7/8 and 8/8, respectively.
There is a controversy regarding the effect of longterm consumption of F on bone mineral density (Kroger et al. 1994; Phipps et al. 1998). Bone mineral density (BMD) test has been done to find out whether a person has osteoporosis or is at risk of developing it. Out of 235 studied individuals, 21.28 % are normal, 33.19 % are osteopenic, and 45.53 % are affected by osteoporosis disease. Generally, osteoporosis disease is found in older women [50 years of age (Abolfazl et al. 2013), because of factors like aging, low body weight, low sex hormones or menopause and some medications. Women start with lower bone density than their male peers, and they lose bone mass more quickly as they age, which leads to osteoporosis in some women. Like osteoporosis, osteopenia occurs more frequently in post-menopausal women as a result of the loss of estrogen. From this study, it is also observed that females are more affected than male by osteoporosis as well as osteopenic disease. In case of these villages, females are affected by osteoporosis in very early age, i.e., after 30 years (Fig. 10).
Table 7 Prevalence and severity of dental fluorosis in the study area with community fluorosis index (CFI) value Age in years
Total population
Grades of dental fluorosis Normal (0)
Questionable (0.5)
Very mild (1)
Mild (2)
Moderate (3)
Affected with fluorosis (%)
CFI
1.43
Severe (4)
2–10
11
9
0
2
0
0
0
*2 (18.18)
11–20
30
6
2
3
6
6
7
24 (80)
21–30
35
16
2
2
6
4
5
19 (54.29)
31–40
44
17
2
5
11
4
5
27 (61.36)
41–50
61
25
6
5
13
4
8
36 (59.02)
51–60 61–70
35 15
11 7
0 0
5 1
8 3
2 1
9 3
24 (68.57) 8 (53.33)
71–80
4
2
0
1
1
0
0
2 (50)
235
93
12
24
48
21
37
142 (60.43)
Total *
Represents the summation of various grades, and within bracket value represents the percentage of dental fluorosis
123
Environ Geochem Health
Fig. 6 Dental fluorosis a Very mild/questionable grade, b Mild grade, c Moderate grade, d Severe grade
Intelligence study among the students This study used the IQ scale to measure intellectual ability, a testing method that minimizes the interference from ethnic, cultural and linguistic factors. Recent research (Shen 2001; Li et al. 2003; Chen and Chen 2002) has demonstrated that excess F uptake can damage the central nervous system and can pass through the placenta and blood–brain barriers to affect the synthesis and excretion of certain neurotransmitters and thus the various stages of child brain development, causing a retardation in the normal development of the nervous system which ultimately affects the intellectual ability of the child. Table 8 represents the descriptive statistics along with the marks regarding age of the students. This study indicates that students exposed to high F (children of Junidpur and Nowapara) show an average IQ of 21.17 ± 6.77 in comparison with low-F exposed
students (children of Bilaspur, Mohula, Bhalian) having an average IQ of 26.41 ± 10.46. Of the studied students, 77.78 % have IQ score in the range of 25–74 %, suggesting the average rank of intelligence (Table 9). Statistical analysis (Z test) demonstrates that there is a significant (Z = 2.59) difference in IQ among the high- and low-F area student. Similar kind of observation has been reported by Chen et al. 2008. Urinary F It is generally accepted that urinary F is normally the best immediate indicator of environmental or occupational exposure to F. Usually higher urinary F levels are found in adults than in children. In adults and children, the fractional urinary excretion is influenced by pH (regulated by diet) and other factors. The data show that urinary F gradually decreases with body weight as well as with age also (Fig. 11). Maximum
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Environ Geochem Health
Fig. 7 Visible symptoms of skeletal fluorosis a kyphosis, b genu-valgum, c swelling of figure joints due to calcification, d can’t touch the head by both hands
concentration of urinary F (9.95 mg/L) is noticed in children of 11–20 years. This may be because most of the children of this age group used to take F-contaminated groundwater after boiling. Therefore, consuming more F enriched drinking water ultimately reflected in the urinary F excretion. Among adults, higher level of F is noticed in 31–40 years age group; thereafter, it gradually decreases. Multiple studies have calculated fractional urinary F excretion in adults and children, with more recent studies calculating
123
fractional urinary F excretion in young healthy adults to be in the range of 78 % (Martinez-Mier 2011). Pearson correlation coefficient (r = 0.88, p \ 0.01) and regression equation reveal that urinary F is significantly correlated with drinking water F (R2 = 0.774) (Fig. 12). So it may be concluded that consumption of F-contaminated drinking water has a major role in urinary F excretion. Similar kind of observation has also been cited by Poureslami and Khazaeli 2010.
Environ Geochem Health
Fig. 8 Percentage of afflicted person with degree of FIS by age and sex in villages
Fig. 9 Fluorosis symptoms in affected community
Fig. 10 Results of bone mineral density test among the affected community
Conclusion Ion-exchange mechanism in the alluvial aquifer of the study area is the major controlling factor for mobilizing F in the groundwater. Fluorosis in this region has
been appeared as an alarming problem. Eighty percentage of children having 11–20 years of age suffer from dental fluorosis. According to visible symptom of skeletal fluorosis, pain in knee joint and hip joint is very common among the majority of the
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Environ Geochem Health Table 8 Descriptive statistics of the standardization’s sample Age
Number
Maximum
Minimum
% of total marks
Mean
SD
SE
Kurtosis
Skewness
10
1
20
20
33.33
17.39
10.93
4.46
0.6
11
7
3
45
34.05
20.08
16.5
6.74
-1.11
-0.16 0.68
12 13
8 11
8 15
37 40
37.92 45.61
20.95 25.33
13.89 14.8
5.67 6.04
-2.26 -1.98
0.45 0.52
14
13
2
40
38.21
21.69
15.05
6.14
-1.52
0.17
Table 9 Comparison of the IQs of 10 to 14-year-old children in the treated and control areas Test areas
No. of children
IQ range
Average IQ ± standard deviation Boys
Girls
Total
High-fluoride area
18
0 8–34
19.83 ± 7.81
21.83 ± 6.45
21.17 ± 6.77
Low-fluoride area
22
0 3–45
30.44 ± 12.81
23.62 ± 7.84
26.41 ± 10.46
Fig. 11 Relation between F in urine with age and body weight in villages
Fig. 12 Linear relationship between drinking water F and urine F
population of the study area. As a whole, prevalence of both dental and skeletal fluorosis is observed to be relatively higher in male in comparison with female. Most of the women having [30 years of age suffer from osteoporosis disease. Moreover, students of the
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study area have less IQ than students of non-contaminated area, demonstrating that consumption of F also has a major role with the intellectual development of children. It also reveals that urinary F has a significant positive correlation with drinking water fluoride. In
Environ Geochem Health
view of the fact that F-contaminated drinking water in the study area is the main culprit for above-mentioned problems, there is an urgent need to improve water supplies and defluoridation of water sources. Apart from alternative source of drinking water supply, more intake of calcium-rich diet will also be very much fruitful in combating fluorosis of the study area population. Acknowledgments The authors are highly grateful to Dr. A. Mallick (Dental and oral hygienist), M/s Aarna systems, Udaipur (supplier of bone densitometer), the local gram panchayat and villagers of the study area for their cooperation and endless support in carrying out health survey. Entire research work is financially supported by the Department of Science and Technology, Govt. of India (SR/S4/ES-547/2010).
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