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River Yamuna
India consumes about 86,311 tonnes (t) of technical-grade
insecticides annually to cover 182.5 million hectare of its
land. Most Indian rivers pass through agricultural areas that
use pesticides. This makes leaching from agricultural fields
the most serious non-point — unspecified, and therefore,
not measurable accurately — source of pollution to the
aquatic environment. And now there’s a 1995 study that’s
found traces of isomers (a carcinogenic organochlorine) in
Indian rivers, including the Yamuna.
About 57 million people depend on Yamuna waters. With an
annual flow of about 10,000 cubic metres (cum) and usage of
4,400 cum (of which irrigation constitutes 96 per cent), the
river accounts for more than 70 per cent of Delhi’s water
supplies. Available water treatment facilities are not capable
of removing the pesticide traces. Waterworks laboratories
cannot even detect them. Worse, Yamuna leaves Delhi as a sewer,
laden with the city’s biological and chemical wastes.
Downstream, at Agra, this becomes the main municipal drinking
water source. Here too, existing treatment facilities are
no match for the poisons. Thus, consumers in Delhi and Agra
ingest unknown amounts of toxic pesticide residues each time
they drink water.
The Central Pollution Control Board (CPCB), on its part, had
found endosulphan residues — alpha and beta isomers —
in the Yamuna in 1991. An earlier study by H C Agarwal (Delhi
University) had traced ddt residues amounting to 3,400 nanogram
per litre (ng/l). However, later cpcb studies showed reduced
ddt levels. To gauge the immensity of the threat, it is necessary
to trace the river’s flow — divided in five segments
on the basis of hydro-geomorphological and ecological characteristics
— down to its final reaches.
Upper
segment
HARYANA FACTOR: Yamuna’s
pollution starts from Tajewala in the upper segment. Here two
canals, the Western Yamuna Canal (WYC) and the Eastern Yamuna
Canal (EYC), divert river waters — save in the three monsoon
months — into Haryana and Uttar Pradesh (UP). The WYC crosses
Yamuna Nagar, Karnal and Panipat before reaching the Haiderpur
treatment plant (which supplies part of Delhi’s water),
receiving wastewater from Yamuna Nagar and Panipat.
Drain Nos ii and viii branch off the WYC augment the water in
the river. Another augmentation canal branches out of the WYC
at Yamuna Nagar, and rejoins the canal about 80 km downstream
at Karnal. All domestic and industrial discharges from Yamuna
Nagar are let out into this canal. Water from the augmentation
canal is used for irrigation. However, when excess water from
the wyc is let into it, pollutants are flushed into the wyc
downstream at Karnal. Thus, a few times a year, there is a sudden
and massive increase in pollution loads when the water reaches
Haiderpur.
Furthermore, at Panipat, discharges from the Panipat sugar mill
and distillery are let out into a disused canal, which has a
kutcha dam across it. Sometimes, when the effluents cross
the dam, it results in a major increase in biological oxygen
demand (BOD) loads in the WYC. A CPCB inspection report estimated
that there were 1,00,000 cum of effluents in the disused canal,
having a bod level of 1,380 mg/l. According to the report, when
this water enters the WYC, it carries with it a total of 125
t of BOD and the BOD levels reach 17 mg/l at Haiderpur; the
acceptable bod levels for raw water meant for treatment are
three mg/l.
Haryana’s vast agricultural fields are also significant
contributors to pollution. The consumption of pesticides in
Haryana in the years 1995-96 was to the tune of 5,100 t. Out
of this, benzene hexachlorides (BHC) accounted for 600.24 t,
malathion 831.48 t and endosulphan, 263.16 t. The state department
of agriculture estimates that 12.5 per cent of the Yamuna basin
has forest cover, 27.5 is wastelands, 53 per cent is agricultural
land; the rest are villages, towns, cities and roads. There
are plans to bring 27.5 per cent more under agriculture: this
means more abstraction from the river and also greater use and
subsequent runoff of fertilisers and pesticides.
Delhi
: Biggest Culprit
Yamuna enters Delhi at Palla village 15 km upstream of Wazirabad
barrage, which acts as a reservoir for Delhi. Delhi generates
1,900 million litre per day (mld) of sewage, against an installed
wastewater treatment capacity of 1,270 mld. Thus, 630 mld of
untreated and a significant amount of partially treated sewage
enter the river every day. The Wazirabad barrage lets out very
little water into the river. In summer months especially, the
only flow downstream of Wazirabad is of industrial and sewage
effluents. Lesser discharge means lesser river flow and thus,
greater levels of pollution. From the Okhla barrage, which is
the exit point for the river in Delhi, the Agra canal branches
out from Yamuna. During the dry months, almost no water is released
from this barrage to downstream Yamuna. Instead, discharges
from the Shahadara drain join the river downstream of the barrage,
bringing effluents from east Delhi and Noida into the river.
This is the second largest polluter of the river after the Najafgarh
drain.
The main problem lies in undetected and untreated pesticide
residues. Waterworks officials in Delhi and Agra point out that
pesticide traces cannot be removed with conventional treatment.
"Organic substances can be assimilated in freshwater, provided
there is enough freshwater in the river," states R Dalwani,
scientist, ministry of environment and forests (MEF). "But
for micropollutants such as pesticides, only more freshwater
can reduce the percentage of traces in water. These cannot be
dissolved or assimilated, but certainly can be diluted to an
extent." The river has a dilution requirement of 75 per
cent, which implies that for every 100 litres of wastewater,
75 litres of freshwater is required. Scientists state that with
the flow of water, pollutants (especially organic pollutants)
degrade to a large extent. But at every step, this purified
water is abstracted, and ever larger loads of pollution make
their way into the river.
Treatment technologies
: Not Cheap
Water treatment technologies in practice in the West are expensive,
something which India can ill-afford. Besides, it is now widely
acknowledged that conventional water treatment processes, based
on chemical coagulation and filtration or biological slow sand
filtration, have little capacity to remove water-soluble pesticides.
Western researchers are coming to the conclusion that protecting
the catchment from chemical contamination — by switching
to organic or biological farming methods and curtailing the
use of pesticides and fertilisers — is possibly the best
way to deal with the problem. According to Centre for Science
and Environment researcher Sangeeta Agarwal, who spoke to officials
of the Sacramento department of utilities, at California, US,
which faced problems with pesticide contamination from rice
fields upstream: "The problem was resolved by persuading
polluting farmers to use pesticides in such a manner that it
does not enter surface water."
What
now?
In India, public opinion over the issue is growing. Numerous
public interest litigations have forced the MEF into an alien
arena: that of accountability. This has made the CPCB, the Haryana
SPCB and other agencies take note of what is getting into the
river and the ways and means of lessening such entry. Several
polluting units which discharge into the river, and the canals
and drains that lead to it, have been forced to instal water
treatment facilities. However, cpcb officials admit that high
operational and maintenance costs of the facilities and the
apathy of individual units limit their usage.
Another issue is that of appropriate property rights. Maybe
things will change when the people of Delhi get the right to
sue Haryana for polluting their drinking water and the people
of Agra get the right to sue both Haryana and Delhi together.
Perhaps much-needed and urgent change will come if the one who
consumes the dread water — Delhi’s citizens or indeed
Agra’s — refuses to ingest such deadly poisons, and
demands the legitimate right to clean drinking water. Who does
the Yamuna belong to, after all? |
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