for risk should be assessed. Nowadays authorities, scientists and general public is aware to potential risk of production and exposure of synthetic dyes. Textile industries are liable to establish the treatment plants for wastewater before being disposed into the environment. But efficiency of treatment plants, honesty of workers, reliability of industry and implementation by government affect the extent of residual amounts reach to the environment. Export demands associated with low cost labor prevalent in India; determine the existence of small-scale textile factories that clandestinely release toxic dyes into water bodies [129].
The effluent disposal of synthetic dyes in water resources causes bio magnification, effects aquatic life where toxic chemicals enter in their bodies later goes to humans via food chain. Another bitter example of wastewater release from dyeing industry is their uses in irrigation by poor, illiterate, innocent farmers in agriculture enable the harmful chemicals of synthetic dyes reach to both animals and human beings through food chains.
1.13.2 Legislative Regulations for Synthetic Dyes
Though, stringent environmental legislations do exist in most of the countries, the will to implement these laws faithfully is needed to overcome the human health and environmental hazards of synthetic dyes [130]. The ministry of environment and forests, government of India has prohibited the handling of 42 Benzidine based dyes from 1993 onward. In January 1997 the use of Azo dyes was banned in India under the clause of Environmental (Protection) Act 1986. Indian legislation prohibited import ofhazardous Azo-dyes on 31 March 2002. In Europe Sudan I an Azo-dye was banned in 2009. However Sudan I, III and IV have been classifild as category 3 carcinogens. Many Benzidine based dyes are prohibited but Basic Red 9 dye is still in industrial use, which is carcinogenic and genotoxic to humans other mammals and aquatic fauna. As recent research studies showed the harmful effects of Crystal Violet dye on humans, rats and fishes with dangerous carcinogenic disorders. This alarming situation suggests us to ban the use of Crystal Violet dye with immediate effect. Despite of prohibition of many dyes, they are still in use.
1.13.3 Sustainability Aspects of Natural Dyes
Sustainability can be defined as the processes and actions through which mankind avoids the depletion of natural resources to keep an ecological balance so that society’s quality of life doesn’t decrease. Sustainability is the foundation for today’s leading global framework for international cooperation- the 2030 agenda for Sustainable Development Goals (SDGs). The 17 SDGs were adopted by all United Nation Member States in 2015, with 169 targets to reach 2030. International Institute for Sustainable Development (IISD) focus areas are mainly climate, economies, resources and some of the global goals are clean water, economic growth, industry, responsible consumption and production, climate action, life on land and below water etc. Use of natural dyes on large scale leads to Sustainable Development which meets the needs of the present without compromising the ability of future generation to facilitate their own requirements. Three pillars of sustainability are economy, society and environment. Therefore; if we discuss the connection between use of natural dyes and sustainability then we come to the highlight of profit, people and planet the three principles of sustainable development. There are certain precious points of natural dyes for environment, economy and society to combat threats of climate and restoration of sustainability.
i. Environment
The textile industry is the second most polluting industries in the world. Synthetic dyes contribute to a major part of this pollution, with nearly 20% of global water pollution being linked to the textile dyeing processes.
Benefits of natural dyes are as follows
Renewable resources.
Non-hazardous
Biodegradable waste, easily decompose
No negative impact on food supply or water.
ii. Economy
The worst scenario of clothing industry is over consumption and unsafe manufacturing. Hence, the economy can be boosted by use of natural dyes because
Some of the natural dyes are obtained from waste and by-products of plants and vegetables.
They will provide extra source of income for rural farmers.
Natural dyes collection can provide income source for locals.
The process of collection of dyes also requires skilled workers.
iii. Society
Sustainability is also about being socially responsible. And over all, the textile industry isn’t a very responsible one with large scale utilization of synthetic hazardous chemical dyeing and printing. Thus, natural dyeing only can be a safest, everlasting, soothing way of life due to their nature of
Cheap or cost effective
Variety of shades can be obtained from one dye with changing concentrations and combinations.
Non-toxic during the process of production.
No negative health effect on wearing.
Other quality such as antibacterial, UV-Protection, Deodorizing.
1.13.4 Practicality of Natural Dyes
The earlier discussion shows that, the use of synthetic dyes in textile and other industries is hazardous for the life of all organisms and environmental health. Therefore, utilization of natural dyes in large extent is necessary to overcome the toxic effects of synthetic dyes. The advantages of natural dyes are as they come from natural sources therefore, not harmful to the environment, so appealing to the consumers. Natural dyes are obtained from renewable sources, therefore, impose no harm to the environment. When dyes are taken from plant parts, the large scale production of flower crops and other species definitely increase the income of farmers and can generate employability. They give soothing shades and soft hue color pay off to textile so safe and secure for all of us. When fabric is made by natural dyes, it is also protective to the users from harmful rays of sunlight. Antibacterial properties found in the naturally dyed fabric that protect the wearer from diseases.
However, there are some disadvantages of natural dyes as they are expensive, tend to fade quickly, less availability of sources, low sustainability of color and shades etc. Because of these reasons the natural dyes are less popular in use among people. On the other hand natural dyes are vibrant in colors, nontoxic, non-allergic, non-carcinogenic, safer for kids, eco-friendly, lowering human dependence on harmful products, produce no waste due to origin from nature. Thus, the importance of natural dyes is because of their utilitarian uses, aesthetic satisfaction and harmless qualities, demand us to make them popular in society.
The use of natural dyes will make us feel proud to be closely connected with nature and to recognize the importance it plays in our lives. Gradually with the help of organized plantation and farming the cost effective production and dyeing will definitely be possible in future to serve the purpose of large scale trade and commerce. Hence, the application, usage and popularization of natural dyes may be a way to conserve our environment and pay off the obligation of nature.
Acknowledgement
The authors are grateful to University Grants Commission (UGC), Delhi for the Maulana Azad National Fellowship (Taiyaba Nimra Ansari) and Dr. S.T. Silawat, Principal, Govt. Holkar Science College, Indore for providing necessary facilities.
References
1. Kapilraj, N., Keerthanan, S., Sithambaresan, S., Natural plant extracts as acid-base indicator and determination of their pka value, J. Chem., 2019, 6, 2019.