Universal pollution is escalating due to natural and anthropogenic activities leading to contamination of various terrestrial and aquatic ecosystems with heavy metals, inorganic and organic compounds and radionuclides. According to some researchers environmental pollution is nothing but a misplaced resource and it is a major issue of twenty first century. Controlled and uncontrolled discharge of solid and liquid wastes, accidental spillages, use of agriculture fertilizers, herbicides, insecticides and pesticides, sewage disposal, explosives and tar are some of the main contributors of terrifyingly increased content of various contaminants in the biosphere.
With rapid industrialization (development) all over the world, pollution is on the increase, and India is no exception. Among the most concerned environmental pollutions that threatening our biodiversity, water pollution is major one where effluents from dye-based industries serve as principle source. India is a developing country; it is accounted among most populous countries of the world, having a population of more than one billion. In order to expand its market, India requires establishment of new industries. Due to unplanned industrial growth, much of the land and nearby water bodies is polluted by unsystematic dumping of solid and liquid wastes generated by these industries. Increased levels of metal ions and organic pollutants in the environment are either due to absence of laws for various industries to treat their wastes, or, if there are laws there is no strict enforcement by Ministry of Environment and other regulatory authorities in India. Heavy metal contaminated land and water bodies are increasingly becoming an environmental, health, economic and planning issue in India. The rapid increase in population, together with the unplanned disposal of effluent from textile industries has increased the threat of water and soil pollution in India.
Today we are facing a major environmental problem in the form of increasing pollution. Production of textile involves bleaching, mercerizing, carbonizing and dying, etc. Polyvinyl, alcohol, gums, PCP, cellulose materials, dyes and other substances are present in textile effluent. Azo and reactive dyes constitute the largest class of dyes used commercially in textile industries for dying nylon, wool, silk, cotton, etc. Dyes are recalcitrant molecules difficult to be degraded biologically. Heavy metals as cadmium, chromium, copper, lead, zinc are present in the dyes. Black et. al,. (1980) have demonstrated that aniline dyes could be mutagenic and carcinogenic to biota.
Sources and causes of Generation of Textile Runoff
Textile industry involves wide range of raw materials, machineries and processes to engineer the required shape and properties of the final product. Waste stream generated in this industry is essentially based on water-based effluent generated in the various activities of wet processing in textiles. In 2004 C. N.Sivramakrishnan said that the main cause behind the generation of this effluent is the use of massive volume of water either in the actual chemical processing or during reprocessing in preparatory, dyeing, printing and finishing. In fact, in a practical estimate, it has been found that 45% material in preparatory processing, 33% in dyeing and 22% are re-processed in finishing. The effluent generated in the different steps is well beyond the standard and thus it is highly polluted and dangerous. J. R. Easton in 1995 anticipated that about 10-15% of the total production of colorants is lost during their synthesis and dyeing processes. Whereas, in, 2004, Lee and Pavlosthis stated that in the case of reactive dyes almost 50% of the initial dye load is found in the dye bath effluents. The recalcitrance of azo dyes has been credited to the presence of sulfonate groups and azo bonds, two features generally considered as xenobiotic.
Status of textile industries in India
The textile industries occupies a inimitable place in India, one of the most primitive to come into existence accounts for 14% of the total industrial production, contributes to nearly 20% of the total export, being the largest foreign exchange earner, accounting for more than 5% of GDB and providing direct employment to around 40 million people, primary the weaker sections, it is the second most important sector only after agriculture.
The number one exporter of textiles, China, has a share of more than 10% followed by Korea with 8.1%, India however has 3.5-4% in clothing export. Indiaâ€™s share may look small but in monitory terms it is large.
Although the development of textile sector was earlier taking place in terms of general policies, in recognition of the importance of the sector, for the first time a separate policy statement was made in 1985 in regard to development of textile sector. Another textile policy 2000 aims to provide cloths of acceptable quality at reasonable prices for the vast majority of the population of the country, to increasingly contribute to the provision of sustainable employment and the economic growth of the nation, and compete with confidence for an increasing share of the global market.
Indiaâ€™s textile industry comprises mostly small scale, non-integrated, spinning, weaving, finishing and apparel marketing enterprises. In India, like other countries of the world, the level of metal pollution of fresh water bodies, especially the rivers, is no longer within safe limits for human consumption. Earlier baseline studies have identified elevated levels of certain trace metals in local fresh water system, especially rivers and lakes, arising mainly from agricultural and industrial processes. Million gallons of waste water is being discharged daily into the water bodies from industrial sector, resulting in surface and ground water contamination in industrial areas. Environmental protection agency studies (EPA 1990) have shown that industrial effluent from electroplating and tannery industries containing toxic metals such as Cr, Ni, As, Hg, Cu and Pt, etc. have contaminated soil and biota of these area by such metal.
Jaipur is included among the top textile industries in India. Export of textiles forms the major share of the total export. Jaipur is especially known for cotton based textile industries. In 1992, Spadaro et al., has classified fabric industry into cotton, woolen and synthetic fiber sectors. Textile manufacture consists of a series of processes starting from raw cotton to finished products, comprising pretreatment, dyeing, printing, finishing and treatment of fibers. Marks and Del.co, in 1997 stated that all these textile processing requires bulk amount of water and a variety of chemical and metal complexed dyes. Effluent from textile industry varies in its strength, flow rate and waste concentrations, because a variety of processing systems are involved, depending upon the fabric profiles. In 2001, McMullan et. al, reported that textile effluent is mostly discharged into the surroundings after none, or minimal pretreatment, with a high amount of pollutants. In 2007, Mutambanengwe et al., stated that textile industry consumes over 7 X 105 tons of dyes annually and uses one litre of water for ine kilogram of dye, and are the largest pollutants of the environment.
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