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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.
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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.
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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."
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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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