Researchers assess the damage to environment caused by tannery wastewater.
Leather manufacturing is one of the oldest traditions in the world, which still continues to this day. India saw some of the earliest tanneries in the world, with archeological discoveries pointing to tanning being carried out in Mehrgarh (located in modern day Balochistan, Pakistan) between 7000 and 3300 BC. Even today, India remains one of the top producers of leather and products made from it, accounting for around 13 % of the world’s leather production. Kanpur in Uttar Pradesh is considered one of the largest producers of leather, with around a third of all the leather exports going from here. Tanneries- the place where animal skins are processed in to leather, also form an important part of the economic backbone of the country.
Although an ancient practice, the process of producing leather from animal hides still leaves a lot to be desired. One of the major threats to the environment comes from the wastewater produced from tanneries. In their study, the researchers identified and characterized the recalcitrant organic and inorganic pollutants present in the wastewater, and studied its effects on the environment.
The researchers used Gas chromatography–mass spectrometry- where in the sample is separated into its constituent compounds, and the mass of each compound is calculated. Sample wastewater obtained from a common effluent treatment plant in Unnao served as the sample for the studies.
The analysis showed the present of several toxic chemicals, like benzyl chloride, butyl octyl phthalate, 2,6-dihydroxybenzoic acid 3TMS, dibutyl phthalate, benzyl alcohol, benzyl butyl phthalate, dibenzyl phthalate, and nonylphenol etc. were present in the treated tannery wastewater. “Due to endocrine disrupting nature and aquatic toxicity, the U.S. Environmental Protection Agency classified many of these as “priority pollutants” and restricted their use in leather industries” remark the authors. The treated water also contained high chromium and lead content beyond the permissible limits for industrial discharge.
Further, a study of the effect of the treated wastewater on environmental parameters suggests that the tannery wastewater inhibits seed germination and seedling growth of Phaseolus aureus L (Mung Bean). “This indicates that the TWW discharged even after secondary treatment into the environment has very high pollution parameters and may cause a variety of serious health threats in living beings upon exposure” say the researchers. They further believe that this study would be helpful to form proper guidelines for the treatment of tannery wastewater.