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Leather produces some environmental impact, most notably due to:

  • Use of chemicals in the tanning process (e.g., Cr, formic acid, Hg and solvents)
  • Air pollution due to the transformation process (H2S during dehairing and NH3 during deliming, solvent vapors)

Leather biodegrades slowly—taking 25 to 40 years to decompose.Script error However, vinyl and petro-chemical derived materials take 500 or more years to decompose.Script error

One ton of hide or skin generally produces 20 to 80 m3 of waste water, including chromium levels of 100–400 mg/L, sulfide levels of 200–800 mg/L, high levels of fat and other solid wastes, and notable pathogen contamination. Producers often add pesticides to protect hides during transport. With solid wastes representing up to 70% of the wet weight of the original hides, the tanning process represents a considerable strain on water treatment installations.[1]

Tanning is especially polluting in countries where environmental regulations are lax, such as in India, the world's third-largest producer and exporter of leather. To give an example of an efficient pollution prevention system, chromium loads per produced tonne are generally abated from 8 kg to 1.5 kg. VOC emissions are typically reduced from 30 kg/t to 2 kg/t in a properly managed facility. A review of the total pollution load decrease achievable according to the United Nations Industrial Development Organization[2] posts precise data on the abatement achievable through industrially proven low-waste advanced methods, while noting that "even though the chrome pollution load can be decreased by 94% on introducing advanced technologies, the minimum residual load 0.15 kg/t raw hide can still cause difficulties when using landfills and composting sludge from wastewater treatment on account of the regulations currently in force in some countries."

In Kanpur, the self-proclaimed "Leather City of World"—with 10,000 tanneries as of 2011 and a city of three million on the banks of the Ganges—pollution levels were so high that, despite an industry crisis, the pollution control board decided to shut down 49 high-polluting tanneries out of 404 in July 2009.[3] In 2003 for instance, the main tanneries' effluent disposal unit was dumping 22 tonnes of Cr-laden solid waste per day in the open.[4] Scientists at the Central Leather Research Institute in India have developed biological methods for pretanning as well as better chromium management.

In the Hazaribagh neighborhood of Dhaka in Bangladesh, chemicals from tanneries end up in Dhaka's main river. Besides the environmental damage, the health of both local factory workers and the end consumer is also negatively affected. Besides local sales of products made with leather from the Hazaribagh neighborhood of Dhaka, the leather is also bought by huge Western companies and sold in the developed world.[5][6]

The higher cost associated with the treatment of effluents than to untreated effluent discharging leads to illegal dumping to save on costs. For instance, in Croatia in 2001, proper pollution abatement cost USD$70–100 per ton of raw hides processed against USD$43/t for irresponsible behavior.[7]

No general study seems to exist, but recent media reports are rife with examples.Script error In November 2009, for example, one of Uganda's main leather companies was caught directly dumping waste water into a wetland adjacent to Lake Victoria.[1]

it takes 4,384,000 gallons of H2O to make one ton of leather

See alsoEdit

Wikimedia Commons has media related to:
Types
Substitutes
Fabrication
Other

ReferencesEdit

  1. Script error

External linksEdit

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