KOHIMA — Tests conducted on more than 400
samples of groundwater from Nagaland across the three districts of Kohima,
Dimapur (including the present Chümoukedima district) and Phek showed that they
were safe for drinking.
Nagaland’s Public Health Engineering Department (PHED) had
submitted to the National Green Tribunal (NGT) the action taken report
concerning fluoride contamination in groundwater in Nagaland, particularly in
the three districts, in compliance with a suo moto cognisance filed in 2023.
The NGT had issued notices to the states, including
Nagaland, on the matter of the presence of arsenic and fluoride in groundwater.
In response, the department filed an affidavit mentioning the details of the
action taken report to the Principal Bench of NGT on February 28, 2025.
It submitted that a total of 468 water samples covering 157
villages/habitations were tested, including 110 samples in Dimapur district,
160 samples in Kohima district, and 198 in Phek district.
According to the department, it carried out random analysis
of water samples for the affected districts during pre- and post-monsoon. An
analysis of samples from water sources and delivery points was carried out. The
tests were conducted in 2024 using FTK (Field Testing Kit) and laboratory
tests, it informed.
“The water samples
test reports conclude that there are no active fluoride-affected groundwater
sources in the districts of Dimapur, Kohima and Phek. All the samples tested
are found to be under the desirable limit,” the department stated in its report
to the NGT.
The Annual Ground Water Quality Report 2024, published by
the Central Ground Water Board, indicated that Nagaland and a few other states
are well within the permissible limit as far as fluoride contamination in
groundwater is concerned.
Citing the report, the PHED submitted that Nagaland is
reported to have a “nil number of samples of fluoride (> 1.5 mg/L).”
The Bureau of Indian Standards (IS 10500: 2012) has
recommended an upper desirable limit of 1.0 mg/L of fluoride in drinking water,
which can be extended to 15 mg/L of fluoride in case no alternative source of
water is available.
Water with more than 1.5 mg/L concentration of fluoride is
not suitable for drinking purposes.
An analysis of fluoride concentration in drinking water in
the three districts showed that the highest value detected was 0.97, which is
less than the ‘desirable limit’ of 1.0 ppm (parts per million). Results for
most of the water sample test values showed 0 ppm.
The state PHED submitted that it has established 11 district
laboratories and one state laboratory to analyse water samples across Nagaland
by regularly testing water samples collected from all the sources/delivery
points within the state prior to supply for drinking purposes.
The water samples from the sources and delivery points are
being tested at least twice a year, pre- and post-monsoon, for chemical
parameters, and bacteriological and remedial actions are taken if any
contaminated sources are reported, it added.
The department further stated it would continue conducting
regular analysis of samples from all the districts on random groundwater
sources to ensure that the quality of groundwater is within the permissible
limit.
