Water is among the basic necessities of life which plays a vital role in a healthy society. Contamination in water is a major concern at local, regional, and global levels due to its impact on public health. The present study evaluates the environmental impact of leather tanneries and the industrial wastes over water and life. Leather industry is the second largest contributor in the national economy of Pakistan in terms of GDP growth while more than 500,000 people are directly and indirectly employed in this sector. At the same time a serious concern about this industry is its adverse effects on environment and particularly on water due to the toxic industrial wastewater. A considerable amount of toxic industrial wastewater is discharged from tanneries in the surrounding water resources which is not only contaminating the water and making it unfit for use due to toxic chemicals but it is also endangering the surrounding environment including human population, animals, birds and aquatic life. The agricultural soil and underground water are also badly affected due to this.
Leather and leather products manufactured in the District Kasur of Pakistan are famous all over the world due to high quality and wide range of products. This industry is providing significant means for living of hundreds of families directly and indirectly but contrary to this, the population is also being negatively affected due to the wastewater discharged from the leather tanneries. Since there is no proper infrastructure developed for disposal of industrial wastewater in developing countries like Pakistan therefore it is discharged with common sanitation system and other nearby water.
A big reason for water contamination and excess use of water in tanneries is lack of modern technology for leather processing. Most of the tanneries are still using the centuries old traditional procedures whereby more chemicals are required and on average 40-70% more water is consumed as compare to technological procedures. Consequently, the wastewater ratio is also high with the excess use of water and so are the environmental effects.
The major cause of water contamination is the chemicals used in the tanneries for leather processing. Reportedly these chemicals are over 170 which include calcium oxide, sodium chloride, sodium sulphate, sodium bicarbonate, sodium bisulphate, chromium sulphate, sulphuric acid, ammonium, ammonium sulphate, ammonium chloride, sodium chloride, sodium hypochlorite, formic acid, fat, fat emulsion, lime, soda ash, bactericides, non-ionic wetting agents, syntans, formaldehydes, polyurethane, various dyes and vegetable tannins. Large amount of water is used in the processing which containing the chemicals are then discharged from the tanneries.
The environment on this planet earth is polluted by various factors which are directly or indirectly resulting from different events and factors of our daily life. According to different studies, the industrial wastes are proven to be the major, most common and dangerous source of water pollution and unfortunately with the growing industrialization the water pollution is also growing every year globally.
Leather tanneries in District Kasur are causing devastating effects to the environment particularly water resources. In this context, the presence of toxic chemicals in groundwater at Kalalanwala, District Kasur were for the first time reported in July 2000 after a newspaper reported about a mysterious deformity of bones in the local residents (22nd July, 2000 Dawn, Jang & The News). The facts about water and environmental conditions in Kasur and its impact over public health and other environmental factors are later proved by many studies. The presence of highly toxic and devastating chemicals in water is the major cause and potential threat of several diseases and environmental instability in the region.
The leather processing tanneries use water, different dyes and chemicals during the whole process. These chemicals and dyes later on cause serious threat by contaminating water bodies and making it polluted and unfit for aquatic life as well as for the human use. The industrial waste water can affect the underground water as well and at the same time the fertility of the soil around the toxic contaminated water is also affected.
Leather processing tanneries consume water in huge quantities during different stages of converting raw hides into finished leather while many chemicals are part of this process. In this scenario, this whole process generates highly contaminated wastewater in considerable amount which actually is the point of concern in this study. The processing of raw hide to leather conversion requires large amounts of water i.e. 4000 liters per ton. It is a big concern for an agriculture country like Pakistan where a major portion of population is already suffering due to scarcity of water. In this context, leather processing is another direct threat to the water resources which is not only consuming huge amounts of water but also contaminating the remaining water reservoirs.
A large number of chemicals are used and drained out of tanneries every day which is contaminating the water resources like streams, ponds, rivers and even the underground water. According to research, the devastating effects of an average tannery can badly impact on human beings, animals, birds and aquatic life in an area of around 7-8 Km radius. The contaminated ground water can cause many diseases out of which some very common are stomach problems, respiratory problems, ulcer, hypertension, kidney stones, genetic mutations, cardiac arrest, heart, kidney and liver diseases.
The organic matter dissolved in tannery wastewater consumes huge amount of oxygen from the water bodies in the chemical process of microbial breakdown. In this manner, the tanneries wastewater causes a reduction of oxygen in water. Such water fails to fulfil the requirements of aquatic life because fist, plants and other water organisms can’t survive with oxygen in such water.
The tanning affluent contains dyes and chemical extract in great quantities due to which the transparency of water is disturbed since this contamination acts as a barrier against sunlight passing through the water. The dyes and other chemical extracts at the surface of water absorb the infra-red rays of sunlight. Since the light cannot pass through water therefore the aquatic life cycle is interruption leads to further disturbance of other living organisms.
The industrial wastewater should be treated before disposing out of the industrial unit to limit its toxic effects. But the effluent treatment process for discharged wastewater requires significant investments and operational costs to satisfy the requirements of environmental protection authorities even in developed countries. In developing countries like Pakistan, the scenario is totally changed since there is no proper infrastructure developed for disposal of industrial wastewater therefore it is discharged with common sanitation system and other nearby water resources. This is the case with many leather processing units operating in Pakistan and same is the case for leather processing units in District Kasur.
Leather tanneries despite their devastating effects and toxic chemical; are playing a significant role for the community and national economy. In this scenario, its negative effects should be eliminated to enhance its effectiveness by reducing the devastating environmental effects of industrial wastewater.
In this context, public awareness is essential at the first place about the harmful effects of industrial wastewater and also about the excess use of water in leather processing vs the present water crisis because knowingly the concerned persons may not get into such harmful practices endangering the lives of hundreds of people working and living in surrounding areas of tanneries.
The leather tanneries and other similar toxic chemicals discharging industries should be separately categorized by law and established in a separate industrial zone; away from population to reduce negative impacts. In such industrial zones, Effluent Treatment Plant (ETP) should be established for waste water treatment to reduce its negative environmental effects.
The infrastructure should also be developed for proper and separate drainage and disposal of industrial waste. At the same time, introduction and implementation of efficient and effective leather processing techniques and technology should be ensured to reduce water consumption and excess use of chemicals. In addition, formation of suitable policy and legislative framework.