Samir Kumar Sinha | June, 2003

A total of 114 cities spew raw sewage into the Ganga. But in many respects pesticides pose an even greater threat.

While a lot of attention has been directed toward untreated sewage and other sources of point pollution, a far greater pollutant, nay, poison, is in the waters of the Ganga, in its sediment and the fish.

And most certainly in the millions of Indians who consume fish and agricultural produce from the Ganga basin.

We're talking about pesticides, of course. They have the capacity to bio-accumulate and manifest itself in a variety of diseases-even cancer.

The Ganga streams through the heartland of India before meeting its destination at the Bay of Bengal. During this long journey, the surface run-off from agricultural land contains significant quantities of synthetic agro-chemicals, harmful to all.

The Ganga as 'lifeline of millions' is contending to survive amidst several maladies. And the pesticide pollution is the most severe one. This is particularly true of organochlorines that enter the river water body and get accumulated and magnified at every level of the food chain in the river ecosystem.

Deposits we'd rather do without
Extensive farming, even in the riverbed, utilizes varieties of pesticides. Most of these pesticides are organochlorine in nature, which are known for high toxicity and bioaccumulation. Organochlorine pesticides like Hexa-chloro-cyclo-Hexane (HCH) and Dichloro Diphenyl Trichloro Ethane (DDT) account for 2/3rds of the total consumption of pesticides in the country. Though DDT has been banned, it is available off the shelf, and any farmer wishing to use this relatively cheap agent, can do so with impunity. After all, who's to check? Eventually, due to run-offs, rivers become the main inland repositories of pesticide residues.

Toxic pesticide residues end up in the river

DDT is used mainly to control the vectors of Kala-azar and Malaria. Inevitably, traces of DDT reach the river. To control the vector of Kala-azar, the sand fly (Phlebotomus argintepes and P. papatasi) 2191.582 metric tonnes of DDT was sprayed only in Bihar during 1995-98, according to the recent report of Malaria Control Office at Patna. For the financial year 2001-2002, the union government had allotted 850 metric tonnes of DDT for spraying to control Kala-azar in Bihar. The catchment area of Ganga and its tributaries in Bihar are prone to this disease and DDT spraying is the only precautionary measure being taken by the state. The flip side is that a significant quantity of DDT residues ends up in the river.

A study by the Industrial Toxicological Research Centre (ITRC) in Lucknow during 1986-92 shows the presence of DDT in concentrations exceeding the EPA criteria value of 0.001 ppb for freshwater aquatic life in the water of Ganga. (Also see table Organochlorine pesticides in Ganga river system). According to research published in Bulletin of Environmental Contamination Toxicology in 1995, concentration of DDT in water of the of the Ganga was in the range of 0.07 to 143 ppb with mean value of 13 ppb, exceeding the safe limit of 1 ppb proposed by World Health Organisation for drinking water. Water from the Ganga is an important source of drinking water for cities and villages situated on its bank.

The ITRC study also found as much as 0.5671 ppb high concentrations of Endosulfan, another oganochlorine pesticide used in agricultural sector, in the Ganga at Allahabad. Endosulfan on long-term exposure is supposed to affect the reproductive physiology in human beings besides increasing the chances of breast cancer.

A joint study conducted by Environmental Biology Laboratory, Patna University, India; Department of Environment Conservation, Ehime University, Japan and Institute for Environmental Technology, Michigan University, USA in 1998 revealed the presence of Polychlorinated biphenyls (PCBs) and organochlorine pesticide residues in very high concentration in sediment and fishes in the Ganga at various locations. Exceptionally high concentrations of DDT were reported in fishes collected from Haridwar followed by Patna. Maximum concentration of DDT was found to be 3,700 ppb in fishes collected from Haridwar-which is an amazing fact itself. Haridwar is the first large town on the Ganga, and as such, the water is considered almost pristine. It is quite interesting that the pesticides are not extensively used in the stretch of Ganga near Haridwar.

Organochlorine Pesticides in the Ganga river system

	DDT (ppb)		HCH (ppb)
	Fish1	Water2, **	Fish1	Water2, **
Rishikesh	NA	0.00382 - 0.0984	NA	0.00596-0.12428
Haridwar d/s	3700	0.00234- 0.11258	110	0.00414-0.15372
Kannauj d/s	NA	0.00336-0.14948	NA	0.00802-0.15426
Kanpur d/s	300	0.00846-0.17391	77	0.01488-0.35942
Allahabad	120	0.00242-0.13642	57	0.00684-0.2699
Varanasi	NA	0.00308-0.08404	NA	0.0091-0.15616
Patna	1300	0.00472-0.38488	110	0.01092-0.13098
Farakka	60	NA	28	NA
Uluberia	NA	0.0056-0.05742	NA	0.0094-0.1875

NA: Data not available

** : Range of Averages of annual minimum and maximum concentrations during 1986-1992.

1 : Source - K. Senthilkumar et al, 1999, Environmetal Toxicology and Chemistry, Vol. 18, No. 7, pp- 1511-1520.

2 : Source - Industrial Toxicological Research Centre, Lucknow, Sixth Annual Progress Report ( July 1991-June 1992), Measurements on Ganga water quality - Heavy metal and Pesticides.

The meteorological condition and nature of pesticides favours their accumulation in fish at Haridwar, which is situated at higher altitude with colder condition. The movement of persistent organic pollutants from warmer to colder areas results in such estimates. A phenomenon similar to Haridwar has also been found at higher altitudes in the Alps in Europe.

In a Reuters report from Austria published on April 10, 2000, Mr. Rolland Psenner, a Professor and Limnologist from Innsbruck University, mentioned that the sub-zero temperatures around the Alpine peaks caused accumulation of DDT-, which evaporates over Africa or India- to humidity and fall as precipitation in a process known as "Global Precipitation". According to Psenner, the Persistant Organic Pollutants (POPs) go up into the air, come down with precipitation and hop on further until they get caught in a cold trap. He referred it as "Grasshopper Effect".

Common Knowledge
Dr. Anupma Kumari of Environmental Biology Laboratory at Patna University has worked out the bio-magnification factor of various pesticides in biota of the Ganga in the stretch of Bihar on the basis of her study during 1995-97. Her results are mind-boggling. The bio-magnification factor for DDT that she found in the blubber of the Gangetic dolphin as 3.0 x 107 and 2.6 x 105 in small fish. Bio-magnification factor, she worked out, reflects the ratio of the concentration of pesticides in biota and the concentration in water.

Investigations on pesticide residues in the tissues of Gangetic dolphin (Platanista gangetica) collected from different locations in Bihar confirmed the presence of 64,000 ppb DDT residues in blubber of a calf dolphin, while Poly Chlorinated Biphenyls (PCBs) and HCH were 13000 and 1900 ppb. Gangetic dolphins being at the top of the food chain in the river system accumulate the highest quantity of pesticides due to successive bio-magnification of the pesticides.

After DDT, HCH is another problematic organochlorine pesticide, mainly used in agricultural sector in India. During the mid 80s, annual use of this pesticide totaled 45,000 tonnes. The study of Dr. Kumari reveals higher concentration of HCH in water than DDT, but it was lesser than DDT in fish of commercial importance, reflecting the greater bio-accumulative tendency of DDT in the Ganga river system. "Presence of DDT in the range of 0.019-1.663 ppb in river water and 13.6-1665.9 ppb in fishes as per my study is enough to harm the physiology and endocrine system of people consuming fish caught in the Ganga," says Dr. Kumari. Other studies on pesticides in Gangetic fishes at different sites also show the alarming level of such toxic pesticides.

The World Health Organisation (WHO) has recommended a minimum 11kg fish consumption per capita per annum in India. On the basis of DDT and HCH in big fishes from the river Ganga as found in the study of Dr. Kumari, one could well be imbibing about 16-17 micrograms of these pesticides every day on an average. An effect of accumulation of such a high concentration of pesticides over a prolonged period is a matter that demands thorough investigation.

Hello, anybody listening?
Pesticide pollution of the river Ganga is more critical than the point sources of pollution like domestic and industrial discharge. Ironically, the government and other agencies have taken no steps whatsoever to control pesticide use in the catchment area of the Ganga and its tributaries where pesticide levels in water and biota have increased to a disastrous level.

"Recent time series data of the pesticide residues in water and biota have not been available for important rivers," notes Dr. R.C. Sinha, Chief Executive of the Center for Environment and Nature Conservation, Department of Zoology, Patna University.

"Such important studies need to be made on regular basis like other pollution parameters indicating the industrial and domestic pollution. We have data on pesticides in the river, but they are either very old or collected from discrete segments of the rivers. It is important to collect such important information on regular basis from the entire stretch of the river," adds Dr. Sinha, who is also the former chairman of the Bihar State Pollution Control Board.

Thus the poisons flow freely, into human beings, unhindered by planning or control.


Samir Kumar Sinha is an environmental researcher and freelance writer