Environmental Effects Of Dyes

Water is vital requirement of life but today whole world is facing water crises. These water crises are due to unrestricted and huge exploitation of water. Rapid urbanization of natural resources of water such as a huge increase in industries, especially textile industries have threat to water bodies. The discharge effluents from these industries have various harmful and toxic components mainly dye. This deteriorates water and makes it unsafe for further use. Wastewater released is a complex mixture of many polluting substances such as dyes, which induce color coupled and various other organic substances disrupt the total ecological balance of the receiving water system. Dyes contain high concentration of organic compounds and heavy metals.

Color is an obvious indicator of water pollution and presence of dye in it imparts color and blocks sunlight penetration and oxygen dissolution, which are essential for aquatic life. Most of these dyes are harmful and potentially carcinogenic and mutagenic to living organisms may lead to serious health problems and also have acute and chronic effects on aquatic life. Also cause aesthetic problem and can have a negative impact on public health. Their presence cause ecological and sanitary changes in the soil, hydric resources and atmosphere. Their exclusion from wastewaters is a major environmental problem.[4]. ] Of the total amount of dyes that are produced annually, more than 50% of are azo dyes. It has been reported that 50% reactive dyes and 2% basic dyes are released in wastewater. During degradation of these dyes, aromatic amines are produced which are highly mutagenic and carcinogenic [9]. Azo dyes are characterized so because of presence of one or more azo groups (-N=N-), usually in one or four. These are synthesized from aromatic compounds, are not basic in aqueous solution These azo groups are linked to phenyl and naphthyl radicals, which are usually replaced with some combinations of functional groups

amellus showed versatility to considerable extent in decolorizing all the tested dyes. In the initial experiments, 96% decolorization within 60 h was obtained and 95% decolorization was achieved within 48 h. As dye concentration increased to 60 mg per litter in the next cycle the plant died but when the concentration was kept at 40 mg L_1, the plants survived and removed 90% in 50 h and started drying thereafter. Dying of the plant could be because of nutrient deficiency and repeated dye stress as the plants were uprooted. Soil plants were not affected by even concentrations higher than 100 mg per litter. Concentration 20, 40, 60, 80 and 100 mg per littrewere monitored for 60 h, the plants removed 1.92, 3.24, 4.26, 4.8, 5.1 mg of dye respectively. Increase in the number of plants 2, 4, 6, 8 and 10; were monitored up to 60 h, the plants removed 74%, 79%, 84%, 90% and 98% of dye respectively. In the case of textile effluents, removal was found to be 47%, while in case of mixture of dyes it was found to be 62% within 60 h. The mixture of dyes showed more removal than the effluent