Assessment of Carbon Contribution to the East Kolkata Wetland Ecosystem (Ramsar Site: 1208) by Leather Producing Units of the Calcutta Leather Complex: Part I

In the context of addition of carbon to East Kolkata Wetland (EKW) ecosystem, an attempt has been made to provide a comprehensive computation of carbon input by raw hides-skins and different chemicals; and carbon output by various solid and liquid waste from the leather industry. The calculations are based on the conventional operations of nine tanneries of which three produce bag leather, three gloves and three shoe uppers. The amount of carbon that enters into the leather industry depends upon the selection of raw hides and skins, percentage of chemicals used and purity of chemicals. In case of bag leather and shoe upper manufacturing units the carbon value changes depending on the tannery specific finishing recipe, spray types and number of coats. Besides this the carbon value also changes with the customeris required finish. Whereas the carbon value of solid and liquid wastes changes depending upon the carbon input, mechanical operations and the binding of chemicals with hides and skins. The analysis of large samples from nine selected tanneries has permitted us to calculate that 396.1 +/- 11.67kg carbon are present in one tonne raw cattle hides or skins. The processing of this one tonne cattle raw hides and skins results in 65.54 +/- 13.06kg carbon being incorporated with chemicals and, from which 320.75 +/- 16.37kg of carbon are discharged in the EKW area through different solid and liquid wastes. The tannery agglomerates at the Calcutta Tannery Complex at Bantala, Kolkata are situated on the boundary of the EKW, a Ramsar site, and so this work is thought to be important to assess the carbon-budget of the EKW ecosystem.