Environmental Effects Of Azo Dyes

Azo Dyes are the largest class of aromatic dyes having lots of commercial interest. These dyes are mostly used in textile industries. Dyes used in the textile industry are difficult to remove by conventional waste water treatment methods since they are stable to light and oxidizing agents and are resistant to aerobic digestion. These dyes are carcinogenic both for animal and human beings. Biological treatment either by bacteria, fungi or consortia of both have been reported to reduce the toxicity of the dye to the permissible limit of discharge to the environment. This article reviews the importance of microorganisms to reduce these azo dyes and protect the environment from the devastating effect of these dyes.Environmental pollution is one

They are primarily used for colouring cotton, leather, cosmetics, and food items . Azo dyes belong to a group of organic compounds. The azo 14 group of dyes binds to an aromatic ring. Through mineralization, these dyes can be splitted into an aromatic amine, an arylamine that is suspected to be carcinogenic. Most of the azo dyes are water soluble and readily to absorb through skin and intake may lead to the risk of cancer and allergic reactions, an irritant for the eyes and extremely dangerous , if inhaled or consumed (Nikulina et al., 1995). For example, Para-phenylene diamine (PPD) also called 1, 4-diamino benezene or 1,4-phenylene diamine, is an aromatic amine, which is a major component of azo dyes. PPD-containing azo dyes are toxic and cause skin irritation, contact dermatitis, chemosis, lacrimation, exopthamlmose, and permanent blindness. Ingestion of PPD products leads to the rapid development of oedema on face, neck, pharynx, tongue and larynx along with respiratory distress. In some cases, it may cause rhabdomyolysis, acute tubular necrosis supervene, vomiting gastritis, hypertension, and vertigo (Macphec et al., 1975; Young H. and Yu J., 1997). Some azo dyes are carcinogenic and mutagenic. Malachite green causes serious public health hazards and environmental problem. So far through various experimental observations it is revealed that malachite green is a multiorgan toxin; it decreases food intake, growth, fertility rates; and causes damage to liver, spleen, kidney and heart (Werth and Boiteaux, 1967, Culp et al., 1999). In malachite green-fed mice, apoptosis in the transitional epithelium of the urinary bladder and thyroid follicles was observed (Culp et al.,