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HYDERABAD,
June 7 (APP): Thar Desert area of Sindh province is among Pakistan’s areas which
are experiencing endemic fluorosis on regional scale. Muhammad
Tahir Rafique, Senior Scientific Officer, Pakistan Council of Scientific
Industrial Research (PCSIR) Karachi said here Friday defending his Ph.D thesis
“Occurrence, Distribution and Origin of Fluoride-Rich Groundwater in the Thar
Desert, Pakistan,” here at a seminar.
The
research was carried out by him in the National Center of Excellence in
Analytical Chemistry, University of Sindh (SU) under a joint venture project
with Pakistan Council for Scientific and Industrial Research (PCSIR) and
Department of Geology, University of Karachi (KU).
The seminar
was attended by a large number of faculty members from various teaching
institutes and departments and also research scholars enrolled for M.Phil and
Ph.D research programme.
In his
presentation, research scholar Muhammad Tahir Rafique said the present study
confirms high fluoride in the groundwater of study area.
He
said through research it was found that 78.77% of the analysed groundwater
samples have fluoride values exceeding the limit of 1.5 mg/L proposed by the WHO.
He pointed
out that distribution patterns show that high fluoride groundwater is
concentrated along the north and northeastern side of Thar Desert especially in
Chahchro and Umarkot areas, whereas localised enrichments have also been
investigated in Mithi, Islamkot and Nagarparkar areas.
He said
Fluoride- bearing granite rocks provide source of dissolved fluoride in
groundwater resources of Thar Desert.
Scholar
Tahir Rafique said the elevated fluoride levels have been investigated in almost
all parts of the study areas whereas local population is consuming water with
fluoride concentration as high as 5-30 mg/L and added that consequently,
fluorosis problem can be visualised at various intensity levels in the study
area from dental fluorosis to skeletal fluorosis, and non-skeletal
manifestations to premature ageing.
The scholar
said Fluoride is considered beneficial to human health if taken in limited
quantity (0.5 to 1.5 mg/L) and added that it is also known to cause dental and
skeletal fluorosis, osteoscalerosis, thyroid, and kidney problems if its
concentration exceeds 1.5 mg/L in drinking water.
The scholar
further said the chronic intake of excessive fluoride leads to severe and
permanent bone and joint deformations in skeletal fluorosis, for which early
symptoms include sporadic pain and stiffness of joints and finally the spine,
major joints and muscles and the nervous system are damaged.
He said
severe forms of fluorosis typically develop only when the fluoride concentration
of drinking water is greater than 5 to 10 mg/L. However, symptoms of this
disease can develop with regular ingestion of water containing fluoride
concentrations as low as 1 to 2 mg/L. Whether, dental or skeletal, fluorosis is
irreversible and no remedy and treatment so far exists, the only remedy is
prevention by keeping fluoride intake within the safe limits, he added.
The
research scholar said the occurrence of high fluoride concentrations in
groundwater and the risk of fluorosis, associated with using such type of water
for human consumption, is a serious problem faced by many countries in the
world.
He said
India, China, Mexico, the Rift Valley countries in East Africa have been
identified as the worst affected countries.
The scholar
pointed out that according to WHO there are more than 29 developed and
developing nations that are endemic for fluorosis across the globe and added
that many of these areas are arid and alternative sources of water are not
available.
He pointed
out that the main source of fluorine in groundwater is basically the minerals
present in granitic rocks through which the groundwater percolates under
variable temperature conditions and added that when fluoride- rich minerals,
present in these rocks and soils, come in contact with water of high alkalinity,
they release fluoride into groundwater through hydrolysis replacing hydroxyl
(OH) ion.
According
to the scholar fluoride- bearing granite rocks provide the source of dissolved
fluoride in groundwater resources of Thar Desert. He added that elevated
fluoride levels have been investigated in almost all parts of the study areas
whereas local population is consuming water with fluoride concentration as high
as 5-30 mg/L.
He said a
detailed hydrochemical investigation of 425 groundwater samples collected from
Umarkot, Mithi, Chachro, Diplo and Nagarparkar sub-districts of Thar Desert have
been carried out for the major ions as well as trace metals’ analyses.
He further
said the correlations between these elements and fluoride ion have been
evaluated, and as a result full speciation calculations have been performed on
these analyses.
In his
concluding comments the scholar said according to the present study, the
groundwater of study area is not suitable for drinking purpose.
He said the
grave situation established through this study requires immediate remedial
actions including the installation of defluoridation and desalination plants by
the concerned authorities.
The scholar
said the results of the present study point to the need for public authorities
to plan and implement comprehensive preventive measures to control the adverse
affects of groundwater consumption and to adopt a policy of information and
advisory services to increase the awareness about the problem.
Vice
Chancellor University of Sindh (SU) Mazhar-ul- Haq Siddiqui who presided over
the seminar, highly appreciated the research work carried out by the scholar
and said the work of the scholar was of pure applied nature and meant for the
betterment of people.
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