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Social and economic cost of tanneries

By Syed M. Aslam
Oct 23 - 29, 2000

A sinister collusion between tanneries and poultry farmers is posing grave danger to the health and the lives of millions of unsuspecting chicken lovers in Karachi. What you read here may compel you to stop eating chicken meat altogether.

What is putting the lives of millions in peril is an unholy alliance between the tanneries and poultry farmers, to respectively supply and use deadly toxic waste, as poultry feed. The leather tanning waste include such hazardous substances as chromium, sulphides, ammonia and nitrogenous compounds. All of these elements are used during the tanning process to remove the hair and flesh to give quality finish to the raw skins and hides. The resultant waste produced in bulk every single day at the tanneries is seen fit to be used as poultry feed for the benefit of both the poultry farmers and tanneries' operators. It helps the former to buy a cheap feed and the later to make money for an otherwise good-for-nothing waste oblivious to grave dangers which it poses to the human lives.

The highly improper practice for monetary gains is not an stealth or unknown activity. The tanners and the poultry farmers both are well aware of it. Kamal Shahryar, the project director of Environmental Management Project for Korangi Tanneries which houses the biggest cluster of leather treatment plants anywhere in the country, said he was aware of the use of toxic poultry feed. He was answering a question at a discussion held at The British Council here last week on 'The price of leather: social, political and economic costs of tanneries in Karachi.

In his presentation Kamal said that leather tanning is a water-intensive process. A kilogram of skin or hide requires 40 litres of water though many tanneries use as much as 90 litres of water. Highlighting the contribution of cluster of tanneries located in Korangi he said they contribute one-third to the total leather exports of the country. Putting the number of tanneries at Korangi at 170, a figure which is put twice that much by the independent observers, he said that they cumulatively generate a solid waste which fluctuates between 95 tonnes to 200 tonnes a day depending on the season.

While SITE and Shershah areas of Karachi also house tanneries, there they are spread all over like those located in other parts of the country. Much has been written about Korangi tanneries and their adverse effect on the environment and pollution — land, air, surface, underground but the latest disclosure of toxic tannery waste used as chicken feed gives an altogether different human dimension to a problem which has been there all along. Can we ignore to sleep on a problem which puts millions of human lives at grave risks?

Obviously not. It is ironic that while leather plays a vital role in the economy of Pakistan, the tanneries are posing a grave threat to the environment and human lives to the complete indifference of the authorities. In last decade the percentage share of leather in the exports has increased by an average of over 8 per cent which is second only to 60.2 per cent increase registered in cotton commodity group. The production of hides and skins increased from 7.3 million to 7.6 million and 35.3 million to 37.2 million respectively during 1997-98 1999-2000.

The tanning process causes environmental degradation on surface waters, air, land, groundwater and sewerage. It results in rapid deterioration of physical, chemical and biological qualities of surface water causing noxious odors from the decomposition of organic matters such as hair and skin and depletion of dissolved oxygen necessary for the aquatic life. Chromium, sulphides and ammonia cause toxicity while algae growth caused by nitrogenous compounds suffocates aquatic life.

The untreated waste from the tanneries adversely affect the fertility of the soil and causes land pollution due to presence of untreated effluents and sludge. It also affect the quality of groundwater through seepage of water and chemicals polluting it with such deadly combination as chlorides, tannings, chromium, sulphate, sulphides, traces of organic chemicals and solvents as well as high nitrogen level each of which is a health hazard. As groundwater takes a long time to clean itself due to its slow movement and having no contact with air the incessant seepage of tannery waste poses a serious hazard to human health.

The tanning process also results in deposition of solids in the sewers and sewage treatment works. It results in encrustation of calcium carbonate in sewers and excessive sulphides or sulphate level accelerate corrosion and deterioration of concrete or cement of pipes. It also have a direct impact on the quality of air due to sulphide and ammonia emissions during de-hairing and waste treatment process.

With the exception of two the hundreds of tanneries in the Korangi Industrial Area do not have any in-house waste treatment plant. These units use large quantity of water and generate 36 million litres of effluents everyday besides various types of solid wastes creating serious pollution problems particularly those who work or live around the Korangi tanneries.

According to Nuzhat Ahmed of Centre for Molecular Genetics, University of Karachi, significant proportion of the population in the Korangi area is employed as tannery workers. Citing a health survey of tannery workers, she said, indicates a high prevalence of common symptoms like backache, expectorant cough, skin lesions, breathing problems, common cold and watering/red eyes.

But the impact of hazardous pollution in Korangi tanneries is not restricted to its immediate surroundings and area. It poses risks to the lives of millions of unsuspecting people eating chickens fed on toxic feed or vegetable farms irrigated by waters mixed with chemicals: Liquid discharge from Korangi tanneries flow into the drain which runs through the Korangi area and finds its ways into surface waters which is used to irrigate number of vegetable farms.

Whatever awareness and little progress made to improve the working environment of tanneries in Pakistan can be attributed to international pressure. The production of smaller goat and sheep skins and bigger cow and buffalo hides have registered an increase of 14 per cent and 30 per cent during the last decade. The production of skins has increased from 32.7 million to 37.2 million while that of hides has increased from 5.9 million to 7.6 million. The increased production highlights the increased pressure on tanneries to turn skins and hides into quality leather, a process which poses serious environmental problems in the absence of proper treatment methods, both during and after the process at individual and collective levels.

The environmental problems caused by the Korangi tanneries and the grave risks which they pose to the human health should be seen in the broader perspective. If Korangi tanneries are seen it fit to generate extra cash by selling the toxic feed to poultry farmers it would be naive to suggest that other tanneries in Shershah, SITE and other parts of the country are not aware of it. It is time for the Environmental Protection Agency Sindh to investigate an issue which poses serious risks to public health. It is also time for the researchers and professional medical bodies to evaluate the quality of chicken meat available in the market and its impact on human health.

Safety measures

The pollution caused by tanneries could be checked through in-house improvements in better operation and maintenance methods by individual units as well as installation of a collective treatment plant for the effluents. Recovered Chromium costs not only one-third the price of new chromium but is also as good. Similarly, dusted salt is also retrieved for reuse. With better management solid waste can be disposed of in a least polluting manner. Occupational injury, accidents and hazards can be avoided by providing essential personal safety equipment to the tannery workers and industrial safety measures. Diligent management can help to minimise the use of hazardous chemicals.

To promote safety hazardous machines used in the tanneries should be equipped with appropriate protecting devises. Improving the lighting, space, ventilation and work-floor conditions can help reduce accidents and workers should be educated about emergency contingencies. The drainage system should be improved to avoid formation of hydrogen sulphide gas within the premises of a tannery.

Chromium and bio-gas can be recovered from tannery effluents, the later is possible through proper biological treatment. A certain types of solid waste can also be recycled and reused. Some of these wastes including raw hide trimmings, leather trimmings are used in the manufacture of gelatin, leather boards and fertilizers etc.