Depleting Groundwater Levels and Increasing Fluoride
Concentration in Villages of Surajpur District,
Chhattisgarh, India: Cost to Economy and Health.
Dr. Manish Upadhyay,
Dr. C.V.
Raman University, Kargi Road, Kota, Bilaspur (C.G)
ABSTRACT:
Although
fluoride was once considered an essential nutrient, the U.S. National Research Council
has since removed this designation due to the lack of studies showing it is
essential for human growth, though still considering fluoride a
"beneficial element" due to its positive impact on oral health. The
U.S. specifies the optimal level of fluoride to range from 0.7 to 1.2 mg/L
(milligrams per liter, equivalent to parts per
million), depending on the average maximum daily air temperature;
the optimal level is lower in warmer climates, where people drink more water,
and is higher in cooler climates The U.S. standard, adopted in 1962, is not
appropriate for all parts of the world and is based on assumptions that have
become obsolete with the rise of air
conditioning and increased use of soft drinks,
processed
food, and other sources of fluorides. In 1994 a World Health
Organization expert committee on fluoride use stated that 1.0 mg/L should
be an absolute upper bound, even in cold climates, and that 0.5 mg/L may
be an appropriate lower limit A 2007 Australian systematic review recommended a
range from 0.6 to 1.1 mg/L.
A
2000 systematic review found that water fluoridation
was statistically associated with a decreased
proportion of children with cavities (the median of mean decreases was 14.6%,
the range −5 to 64%), and with a decrease in
decayed, missing,
and filled primary teeth
(the median of mean decreases was 2.25 teeth, the range
0.5–4.4 teeth), which is roughly equivalent to preventing 40% of cavities.
The review found that the evidence was of moderate quality: many studies did
not attempt to reduce observer bias, control for confounding factors, report variance measures,
or use appropriate analysis. Although no major differences between natural and
artificial fluoridation were apparent, the evidence was inadequate to reach a
conclusion about any differences. Fluoride also prevents cavities in adults of
all ages. There are fewer studies in adults however, and the design of water
fluoridation studies in adults is inferior to that of studies of self- or
clinically applied fluoride. A 2007 meta-analysis
found that water fluoridation prevented an estimated 27% of cavities in adults
(95% confidence interval [CI] 19–34%), about the
same fraction as prevented by exposure to any delivery method of fluoride (29%
average, 95% CI: 16–42%). A 2002 systematic review found strong evidence that
water fluoridation is effective at reducing overall tooth decay in communities.
Fluoride's
adverse effects depend on total fluoride dosage from all sources. At the
commonly recommended dosage, the only clear adverse effect is dental fluorosis, which can alter the appearance of
children's teeth during tooth development; this is mostly mild and is
unlikely to represent any real effect on aesthetic appearance or on public
health.[10]
The critical period of exposure is between ages one and four years, with the
risk ending around age eight.
Fluorosis can be prevented by monitoring all sources of
fluoride, with fluoridated water directly or indirectly responsible for an
estimated 40% of risk and other sources, notably toothpaste, responsible for
the remaining 60%..
Compared to water naturally fluoridated at 0.4 mg/L, fluoridation to
1 mg/L is estimated to cause additional fluorosis
in one of every 6 people (95% CI 4–21 people), and to cause additional fluorosis of aesthetic concern in one of every 22 people
(95% CI 13.6–∞ people). Here, aesthetic concern is a term used in
a standardized scale based on what adolescents would find unacceptable, as
measured by a 1996 study of British 14-year-olds In
many industrialized countries the prevalence
of fluorosis is increasing even in unfluoridated communities, mostly because of fluoride from
swallowed toothpaste. A 2009 systematic review indicated that fluorosis is associated with consumption of infant
formula or of water added to reconstitute the formula, that the
evidence was distorted by publication
bias, and that the evidence that the formula's fluoride caused the fluorosis was weak.. In the U.S.
the decline in tooth decay was accompanied by increased fluorosis
in both fluoridated and unfluoridated communities;
accordingly, fluoride has been reduced in various ways worldwide in infant
formulas, children's toothpaste, water, and fluoride-supplement schedules
KEYWORDS: Word Fluoridation, dosage, fluorosis,
aesthetic, consumption
INTRODUCTION:
Safe drinking water is essential to humans and other
life forms. Access to safe drinking water has improved over the last decades in
almost every part of the world, but approximately one billion people still lack
access to safe water and over 2.5 billion lack access
to adequate sanitation. There is a clear correlation between access to safe
water and GDP per capita. However, some observers have estimated that by 2025
more than half of the world population will be facing water-based
vulnerability. A recent report (November 2009) suggests that by 2030, in some
developing regions of the world, water demand will exceed supply by 50%.Water
plays an important role in the world economy, as it functions as a solvent for
a wide variety of chemical substances and facilitates industrial cooling and
transportation. Approximately 70% of the fresh water used by humans goes to agriculture
.Water is the chemical substance with chemical formula H2O:
one molecule of water has two hydrogen atoms covalently bonded to a single oxygen
atom.Water appears in nature in all three common
states of matter and may take many different forms on Earth: water vapor and
clouds in the sky; seawater and icebergs in the polar oceans; glaciers and rivers
in the mountains; and the liquid in aquifers in the ground.At
high temperatures and pressures, such as in the interior of giant planets, it
is argued that water exists as ionic water in which the molecules break down
into a soup of hydrogen and oxygen ions, and at even higher pressures as superionic water in which the oxygen crystallises
but the hydrogen ions float around freely within the oxygen lattice. Fluoride's
effects depend on the total daily intake of fluoride from all sources. About
70–90% of ingested fluoride is absorbed into
the blood, where it distributes throughout the body. In infants 80–90% of
absorbed fluoride is retained, with the rest excreted, mostly via urine; in adults about 60% is retained. About 99% of retained
fluoride is stored in bone, teeth, and other calcium-rich areas, where excess
quantities can cause fluorosis. Drinking water is typically
the largest source of fluoride. In many industrialized countries swallowed
toothpaste is the main source of fluoride exposure in unfluoridated
communities. Other sources include dental products other than toothpaste; air
pollution from fluoride-containing coal or from phosphate fertilizers; trona, used to tenderize meat in Tanzania; and tea leaves, particularly the tea bricks favored in parts of China. High fluoride levels have been
found in other foods, including barley, cassava, corn, rice, taro, yams, and
fish protein concentrate. The U.S. Institute of Medicine
has established Dietary Reference Intakes for fluoride: Adequate Intake values range from
0.01 mg/day for infants aged 6 months or less, to 4 mg/day for
men aged 19 years and up; and the Tolerable Upper Intake Level is
0.10 mg/kg/day for infants and children through age 8 years, and
10 mg/day thereafter.
OBJECTIVES OF
THE PRESENT WORK:
The
quality of water is of vital concern for mankind since it is directly linked
with human welfare. It is matter of history that faecal
pollution of drinking water caused water bourne
diseases which wiped out entire population of cities.
The
aim of this study was to determine the amount of fluoride in drinking water of
Five villages of Premnagar Block of
Surajpur dist.
Polluted
water is the culprit in all such cases. The major sources of water pollution
are domestic waste from urban and rural areas, and industrial wastes which are
discharged in to natural water bodies.For this Physico-chemical analysis of drinking water samples will be
taken from different Five villages of block Premnagar
and awares to
avoid all problem which come from more fluoride.
Because
presence of large amount of fluoride is associated with
# Dental and skeletal fluorosis and inadequate amount with dental carries.
# U S public health services has stated that fluoride makes the bone more brittle.
# Mottling of teeth disease causes permanent damage to the
enamel.
Skeletal
fluorosis followed by pain and stiffless of
the joints.Osteoporosis found children below age of 10 years also
affected. In female faces infertility
problem.
Introduction of selected area
Surajpur (newly formed dist. of Sarguja division), with an area of 16034.4 Sq.kms with 54
percent of tribal population is one of the under developed districts in
Chhattisgarh. About 36% of area encompasses reserved and protected forest land.
Ambikapur is the district headquarters. The total
population of the district is 1970661 (2001) census, out of which 93.03 % is
rural population. The net irrigated area is 31968 ha. out
of which 6077ha. (19 percent only) is irrigated by ground water
Sarguja district is a great table land of
numerous hills and plateau. The two important Physiographic features of the
district are the Mainpat plateau and the Jamirpat plateau.The former is
28.8 km long and 12.8 km wide and rises to a maximum height of 1152.45 meters.
It forms the southern boundary with Raigarh district.
The Jamirpat is about 3km wide. It forms the eastern
boundary of Sarguja with Jharkhand State. The maximum
elevation of Jamirpat is 1219.2 meters. The principal
rivers of the district are the Kanhar, the Rihand, the Morna, the Mahan, the
Geur, the Geger, the Neur, and the Gej. There are two
distinct drainage system in the district. One is northernly and the other is southerly.
The district has subtropical climate
characterised by hot summer and monsoon rainfall
followed by dry and cold winter season. The normal rainfall of the district is
1600.9 mm. The annual temperature varies from 39.6°C to 43°C in summer and 8.6°
to 23.9°8C in winter.
Hydrogeology
The major geological formations in
the district are rocks belonging to Archean, Gondwanas, Lametas and Deccan
trap group of rocks overlain by sub Recent to Recent alluvial sediments. Ground
water occurs under phreatic and semi confined to
confined conditions in the intergrannular pore spaces
in the shallow weathered rocks and in the fractured system at deeper levels
respectively. The ground water levels in the phreatic aquifer varies from 3.66 to 16.5 mbgl and from 1.59 to 10.37 mbgl
during pre monsoon and post monsoon period respectivly.
Long term trend analysis of ground water level in the district reveals that
13.15% of the wells in pre monsoon and none of the wells in post monsoon period
show a significant (20 cm/year) falling trend.
Under the exploration programme, the Central Ground Water Board (CGWB) has
drilled 30 exploratory in the Sarguja district to
assess the aquifer system and their potential. The data from these boreholes
has indicated that the aquifers vary from few metres
to 70 mbgl. Tube wells in Gondwanas
range from 27 to 76 mbgl. with
discharge between 5 to 3 m3/hr.The ground
water in the district is mainly developed by dug wells for domestic and
irrigation purposes. The dug cum bore wells are also used for irrigation. These
structures tap ground water down to a depth of 6 to 20 mbgl.
The borewells fitted with hand pumps are used for the
rural drinking water supply requirements of the village community.
Quality
The quality of ground water in the
district is generally suitable for both drinking and irrigation and is within
the permissible limits as per Indian Standards.
Ground Water Resources
Ground water resource figures
presented below are as per the estimations carried out jointly by CGWB, Govt.
of India and Ground Water Survey Circle, Govt. of Chhattisgarh. The figures
pertain to the year 2004.All the blocks in the district have been categorised as safe from ground water development point
of view.
Water Table Condition
Decadal (1995-2005) Average of Pre-monsoon (May) Water
Level in m
|
Annual
Available Ground Water Resources (ha m) |
154455 |
|
Allocation for
Domestic Use in the year 2025 (ha m) |
7302 |
|
Gross Draft
for Irrigation (ha m) |
26326 |
|
Balance Ground
Water Availability for Future Irrigation (ha m) |
120827 |
|
Stage of
Ground Water Development (%) |
20.05 |
|
Additional
Area that can be Brought Under Irrigation (ha) |
73550 (4.3 %
of the geographical area) |
MATERIAL AND METHOD:
Samples
were collected and analysed as per procedure laid down in the standard
methods for examination of water and waste water of American public Health Association (APHA) compsite
sampling method was adopted for collection of samples of water from five location of village Sample for chemical analysis were collected
in polyethylene container's. Samples
collected for metal contents were acitified (1.0 ml
HNO3 per liter samples). Some of the parameter like PH Temperature, conductivity, dissolve oxygen T.D.S. were analysed on site using portable water analysis kit. The other parameter were analysed
at laboratory.
Method: SPADNS
SPECTROPHOTOMETRIC
Apparatus
a. Distillation apparatus: 1L round bottom long neck, borosilicate glass boiling
flask, thermometer adapter, connecting tube and an efficient condenser, with
thermometer adapter and a thermometer reading up to 200oC, The
apparatus is shown in the Figure.
Alternative types of distillation apparatus may be
used.
b. Spectrophotometer for use at 570nm. It must provide a light path of at least 1 cm or a
spectrophotometer with a greenish yellow filter (550 to 580nm).
Reagents
Reagents
a. Sulphuric acid, H2SO4, conc., reagent grade
b. Silver sulphate, Ag2SO4, crystals, reagent grade
c. Stock fluoride solution. Dissolve 221.0mg anhydrous sodium fluoride, NaF, in distilled water and dilute to 1000 mL; 1 mL = 100μg Fd.
Standard fluoride solution. Dilute
100 mL stock fluoride solution to 1000 mL with distilled water; 1 mL =
10μg Fe.
SPADNS solution:
Dissolve 958mg SPADNS, sodium 2 - (parasulphophenylazo)-1,8 dihydroxy-3,6-naphthalenedisulphonate, in distilled water
and dilute to 500 mL; protect from light - stable for
1 year.
f. Zirconyl-acid reagent: Dissolve 133mg zirconyl
chloride octahydrate, ZrOCl2.8H2O, in about 25 mL distilled water, add 350 mL conc HCl and dilute to 500 mL.
g. Mixed acid zirconyl-SPADNS
reagent: Mix equal volumes of SPADNS
solution and zirconyl-acid reagent - stable for 2
years.
h. Reference solution: Add 10 mL SPADNS solution to
100 mL distilled water. Dilute 7 mLconc
HCl to 10 mL with distilled
water and add to SPADNS solution - stable for 1 year. Set the instrument to
zero with this solution.
i. Sodium arsenite
solution: Dissolve 5g NaAsO2 and dilute to
1L with distilled water
Procedure
a. Distillation:
Distillation is necessary for samples containing high concentration of
dissolved solids, see Table. Proceed to step d if distillation is not required.
To 400 Ml distilled water in the distillation flask, with magnetic stirrer
operating, add 200 mL conc.
H2SO4 and a few glass beads. Connect the apparatus as shown in the figure and
heat to Laboratory Manual ID: 1.11 Version: 2 Page: 2/3
180°C
Prevent overheating by stopping heating when temperature reaches 178oC.
Discard
distillate.
b. Cool the
acid mixture remaining in the flask to 80oC and add 300 mL
sample. With stirrer operating, distil until the temperature reaches 180oC
(again stop heating at 178oC to prevent overheating), turn off heat; retain the
distillate for analysis.
c. Add AgSO4
to the distilling flask at the rate of 5mg/mg Cl- to
avoid Cl- interference.H2SO4 solution in the flask
can be used repeatedly until contaminant from samples accumulates to such an
extent that recovery is affected. This can be ascertained by distilling a known
standard and determining recovery.
d. Standard
Curve Preparation: Take the following volumes of standard fluoride solution and
dilute to 50 mL with distilled water and note down
the temperature:
Standard
F-solution, mL 0 0.1 0.2 0.5 1.0 2.0 3.0 5.0 7.0
μg F- 0 1.0 2.0 5.0 10.0 20.0 30.0 50.0 70.0
e. Pipette
10.00 mL of mixed acid-zirconyl-SPADNS
reagent to each standard and mix well. Avoid contamination. Set photometer to
zero absorbance with the reference solution and obtain absorbance readings of
standards (at 570nm). Plot a curve of mg F- versus absorbance. Prepare a new
standard curve whenever a fresh reagent or a different standard temperature is
used.
RESULT AND DISSCUSSION:
Village I Baraul
A
Total number of six samples were collected and tested for their fluoride concentration . Three samples represent surface water
collected from river/nallah and represented as s1-sw1,
s2-sw2,s3-sw3 while the remaining samples were collected
from under-ground water / tube wells s4-sw4, s5-sw5,s6-sw6
.All the six samples were colourless . odourless, and free from solid
suspension. The result of absorbance have been
compiled below for the se samples:-
Table I- Fluoride Concentration of water samples
in village Baraul
|
Samples |
Fluoride in mg/l |
|
s1-sw1 |
2.40 |
|
s1-sw2 |
2.80 |
|
s1-sw3 |
3.50 |
|
s1-sw4 |
2.50 |
|
s1-sw5 |
3.0 |
|
s1-sw6 |
3.0 |
WATER SAMPLES
Table II- Fluoride Concentration of water samples
in village Ramtirath
|
Samples |
Fluoride in mg/l |
|
S2-sw1 |
2.44 |
|
S2-sw2 |
2.60 |
|
S2-sw3 |
3.0 |
|
S2-sw4 |
2.50 |
|
S2-sw5 |
2.50 |
|
S2-sw6 |
2.16 |
Water samples
Village II Ramtirath
A
Total number of six samples were collected and tested for their fluoride
concentration. Three samples represent surface water collected from river/nallah and represented as s1-sw1, s2-sw2,s3-sw3
while the remaining samples were
collected from under-ground water / tube wells s4-sw4, s5-sw5,s6-sw6
.All the six samples were colourless. odourless, and free from solid
suspension. The result of absorbance have been compiled
below for these samples:-
Village III-BANAPATTI
A
Total number of six samples were collected and tested for their fluoride concentration . Three samples represent surface water
collected from river/nallah and represented as s3-sw1,
s3-sw2,s3-sw3 while
the remaining samples were collected from under-ground water / tube wells s3-sw4,
s3-sw5,s3-sw6 .All the six samples were colourless . odourless,
and free from solid suspension. The result of absorbance have
been compiled below for these samples:-
Table III- Fluoride Concentration of water samples
in village BANAPATTI
|
Samples |
Fluoride in mg/l |
|
S3-sw1 |
2.05 |
|
S3-sw2 |
3.00 |
|
S3-sw3 |
3.10 |
|
S3-sw4 |
3.55 |
|
S3-sw5 |
3.40 |
|
S3-sw6 |
1.90 |
WATER SAMPLES
Village IV- BARWAHI
A
Total number of six samples were collected and tested for their fluoride concentration . Three samples represent surface water
collected from river/nallah and represented as s5-sw1,
s5-sw2,s5-sw3 while the remaining samples were collected
from under-ground water / tube wells s5-sw4, s5-sw5,s5-sw6
.All the six samples were colourless . odourless, and free from solid
suspension. The result of absorbance have been
compiled below for these samples:-
Table IV-
Fluoride Concentration of water samples in village BARWAHI
|
Samples |
Fluoride in mg/l |
|
S5-sw1 |
3.16 |
|
S5-sw2 |
3.18 |
|
S5-sw3 |
2.50 |
|
S5-sw4 |
3.0 |
|
S5-sw5 |
3.50 |
|
S5-sw6 |
3.20 |
Water samples
Village VI- FATEHPUR
A
Total number of six samples were collected and tested for their fluoride concentration . Three samples represent surface water
collected from river/nallah and represented as s1-sw1,
s2-sw2,s3-sw3 while the remaining samples were collected
from under-ground water / tube wells s4-sw4, s5-sw5,s6-sw6
.All the six samples were colourless . odourless, and free from solid
suspension. The result of absorbance have been
compiled below for these samples:-
Table VI- Fluoride Concentration of water samples
in village Fatehpur
|
Samples |
Fluoride in mg/l |
|
S6-sw1 |
2.0 |
|
S6-sw2 |
3.05 |
|
S6-sw3 |
2.30 |
|
S6-sw4 |
3.0 |
|
S6-sw5 |
3.50 |
|
S6-sw6 |
3.18 |
Water samples
Result
of analyses of Water from Five villages of Surajpur
dist. Of Premnagar Block are recorded in table 1,2,3,4 and 5.
In all the five villages each have six sampling station (three were collected from the
surface and three samples were collected from the tube well) of village- BARAUL fluoride was
recorded in the range of 2.40,2.80,
3.50, 2.50, 3.0 and 3.0 mg/l . maximum permissible
limit for fluoride as world Health organization (WHO) is 1.5 mg/l. all six
samples fluoride found excess of
their permissible limit .
Water samples analyses
of Five villages of Surajpur dist. Of Premnagar
Block are recorded in table 1,2,3,4 and 5. In all the five villages each have
six sampling station (three were collected
from the surface and three
samples were collected from
the tube well) of village-
BANAPATTI fluoride was recorded in the range of 2.44,2.44, 3.0, 2.50,
2.50, and 2.16 mg/l . maximum
permissible limit for fluoride as Indian standard (IS) is
0.6 to 1.2 mg/l. all six samples fluoride found
excess of their permissible limit
.
Mximum
permissible limit for fluoride as NEERI manual (1991) is 1.0 mg/l. Water from Five villages of Surajpur
dist. Of Premnagar Block are recorded in table 1,2,3,4 and 5.
In all the five villages each have six sampling station (three were
collected from the surface and
three samples were collected from the tube well) of village- BARWAHI fluoride was recorded in the range of 2.05, 3.00, 3.10, 3.55,
3.40 and 1.90 mg/l. all six samples fluoride found
excess of their permissible limit
.
The
concentration of
fluoride from Five villages
are recorded in table . In all the five villages each have six sampling
station (three were collected from the
surface and three samples were collected from the tube well) of village- DHODHAGAON fluoride was recorded in the range of 3.16, 3.18, 2.50, 3.0, 3.50 and 3.20
mg/l. all six samples fluoride
found excess of their permissible limit .Maximum permissible
limit for fluoride as NEERI manual
(1991) is 1.0 mg/l and maximum permissible limit for fluoride as world Health
organization (WHO) is 1.5 mg/l.
The
concentration of
fluoride from Five villages
are recorded in table . three were collected from the surface and three samples were
collected from the tube well of
village- FATEHPUR fluoride was
recorded in the range of 2.0, 3.07, 2.30, 3.0, 3.50 and 3.18
mg/l. all six samples fluoride
found excess of their permissible limit .Maximum permissible
limit for fluoride as NEERI manual
(1991) is 1.0 mg/l and maximum permissible limit for fluoride as world Health
organization (WHO) is 1.5 mg/l.
CONCLUSION:
The
preset study has been made to evaluate the Fluoride concentration of water
samples collected from the Five villages of Premnagar Block of surajpur Dist,
Chhattisgarh. Each villages have made six sampling satation
.These samples were analysed for study of fluoride and their effect in surrounding area.
Fluoride
in naturally occurring
in water can be above or
below from recommended levels. Both the excess and deficiency of fluoride in
water produces adverse effects on the health.
Maximum
acceptable limit for fluoride as world Health organization (1985) is 1.5 mg/l.
In present study the fluoride concentration of water samples of all five
villages were found over the permissible limit. Therefore, there was harmful effect of fluoride were found in all
villages
REFERENCES:
1 Burgstahler
AW. Fluoridated bottled water [editorial]. Fluoride 2006;39:252-4.
2 Shivarajashankara
YM, Shivashankara AR, Rao
SH, Bhar PG. Oxidative stress in children
with endemic skeletal fluorosis.
Fluoride 2001;34:103-7.
3 Spittle B. Dyspepsia
associated with fluoridated water. Fluoride 2008;41:89-92
4 Carton RJ. Review of the
2006 United States National Research Council Report: Fluoride in
drinking water. Fluoride 2006;39:163-72.
5 Susheela
AK, Jethanandani P. Circulating testosterone levels
in skeletal fluorosis patients.
J Toxicol
Clin Toxicol 1996;34:183-9.
6 Dobaradaran
S, Mahvi AH, Dehdashti S, Ranjbar Vakil Abadi
D. Drinking water fluoride and
child dental caries in Dashtestan,
Iran. Fluoride 2008;41:220-6.
7 APHA, AWWA, WEF. Standard methods for the examination of water and wastewater.
21st
ed. Washington D.C: AWWA; 2005.
8 Price JK. Workbook applied
math for water plant operators. Lancaster, Pennsylvania:
Technomic Pub. Co; 1991.
9 Chakraborti
D, Chanda CR, Samanta G, Chowdhury UK, Mukherjee SC, Pal
AB, et al.
Fluorosis in Assam, India. Curr Sci 2000;78:1421-3.
10 Karthikeyan
K, Nanthakumar K, Velmurugan
P, Tamilarasi S, Lakshmanaperumalsamy.
Prevalence of certain inorganic constituents in
groundwater samples of Erode district, Tamilnadu
11 Gupta S, Banerjee
S, Saha R, Datta JK, Mondal N. Fluoride geochemistry of groundwater in Nalhati-1 block of the Birbhum
district, West Bengal, India. Fluoride 2006;39:318-20.
12 Karthikeyan
G, Shunmugasundarraj A. Isopleth
mapping and in-situ fluoride dependence on water quality in the Krishnagiri block of Tamil Nadu in South India. Fluoride
2000;33:121- 7.
13 Williams I. Environmental
chemistry. New York: John Wiley and Sons; 2001.
14 Mahvi
AH, Zazoli MA, Younecian M,
Nicpour B, Babapour A. Survey
of fluorideconcentration in drinking water sources
and prevalence of DMFT in the 12 years oldstudents in
Behshahr city. J Med Sci
2006;6:658-61.
15 Nouri
J, Mahvi AH, Babaei A, Ahmadpour E. Regional pattern distribution of groundwater
fluoride in the Shush aquifer of Khuzestan County, Iran. Fluoride 2006;39:321-5.
16 Mahvi
AH, Zazoli MA, Younecian M,
Esfandiari Y. Fluoride content of Iranian black tea
and tea liquor. Fluoride 2006;39:266-8.
17 Hudaykuliyev
Y, Tastekin M, Poyrazoglu
ES, Baspinar E, Veliogu YS.
Variables affecting fluoride in Turkish black tea.
Fluoride 2005;38:38-43.
Received
on 09.06.2012
Modified on 15.06.2012
Accepted on 25.06.2012
© A&V Publication all right reserved
Research
J. Science and Tech. 4(3): May-June 2012: 122-128