Hello fellow readers, we are back with another post! As we have covered a lot about the pollution caused by the acquiring of raw materials to make fabric (see here and here for cotton, here for nylon, and here for viscose), we want to move on to discuss the environmental and health hazards of fabric manufacturing. Specifically, today I am here to talk about the wasteful world of fabric dyeing.
We have been dyeing our clothes for a long, long time. Historical records have been found of the use of natural dyes extracted from vegetables, fruits, flowers, insects, and even fish dating back to 12th Millenium BC (1). However, these natural dyes could only offer a few handfuls of (often muted) colors – it would be almost impossible to produce the vibrant, colorful clothes we have now with natural dyes. This all changed when William Henry Perkin accidentally made the first-ever synthetic dye when trying to produce malaria-treating chemical – a purple hue he called "mauveine". Sensing a business opportunity, Perkin quickly opened his own dye shop and created a multitude of new colors made available to the masses. From then on, almost all of textile-dyeing uses synthetic colors.
But why is it so bad for the environment?
Well, when you apply dye to fabric, it is hard to make everything stick. Because of this, the textile industry wastes up to 200,000 tons of dyes in wastewater each year because of the inefficiency of the coloring cycle (2). This is a big environmental concern because dyes are virtually immune to chemical, physical, and biological treatments due to their chemical structure – moreover, many colors, due to their complex structure and synthetic origin, are difficult to decolorize (3). This wastewater does not only contain dyes, but they also contain other chemicals used in the dyeing process, such as metals and acid salts, finishing agents, and many more (5). Hence, treating wastewater from textile plants is difficult, and coupled with the amount of wastewater, the textile industry inevitably contributes to the water pollution problem.
The pollution produced by the textile-dyeing process is particularly dangerous to aquatic ecosystems. This is because when the colored wastewater ends up in water bodies, it could prevent the penetration of light to the depths of aquatic environments and thereby reduces the ability for aquatic flora to conduct photosynthesis – this could cause ecological imbalance by disrupting the food chain (4, 5). Moreover, studies found that the wastewater from textile dyeing could cause physiological problems to aquatic fauna, including hypertension and kidney damage (5).
Is it also bad for human health?
Textile dyes pose two kinds of health concerns: acute toxicity and genotoxicity (5). The former refers to adverse effects that occur as a result of oral or dermal exposure of a substance, either from a single exposure or multiple exposures in a short amount of time. Acute toxicity as a result of the exposure to textile dyes includes contact dermatitis, asthma, rhinitis, and other allergic reactions (5). The latter, genotoxicity, can pose more serious risks to human health – it can be defined as the destructive effect on a cell's genetic material, and with regards to textile dyes, it has been found to be carcinogenic and mutagenic. Studies have linked exposure to textile dyes to several cancers, prominently bladder cancer and lung cancer, but also breast cancer, colon cancer, and rectum cancer, all of which presents an occupational hazard for those working in the textile industry (6). Some have also cited that synthetic dyes, specifically azo dyes containing benzene, have mutagenic properties on bacteria and thus also introduce health risks to human tissues (7, 8). This genotoxic feature in synthetic dyes occurs after the degradation process, as the dyes release aromatic amines. Aside from being an occupational hazard, a drinking water source in Brazil has been found to be polluted with wastewater from a nearby plant, posing dangerous risks to those that consume it (9).
So are there any alternatives to synthetic dyes??
At the industry level, it may be hard for industries to switch to non-synthetic dyes as synthetic dyes can produce maximum color payoff, and virtually any color can be made from mixing synthetic dyes. But, if you're bored with your clothes but don't want to buy new ones because you don't want to contribute to fashion's pollution problem, you can try dyeing your own clothes using food scraps!
Textile dyed with Streptomyces coelicolor. Source: Faber Futures
Furthermore, scientists have found a way to dye fabric that requires less water and produces less waste – they do this by using bacteria. Particularly, the bacteria Streptomyces coelicolor. How it works is that the bacteria can be directly cultured on fabric such as silk to generate an even color or even patterns! What's more, the scientists that developed this project is also working to scale this method in textile-dyeing so that it can be used at the industry level. If this could be done, the impact would be revolutionary – so let's all hope the future of the fashion industry would be cleaner and greener. If you want to find out more about this project, check out this link and the ted talk video below.
I hope this post has been interesting for you! If you're really interested in this topic and want to know more, look out for our next post – Bremen will be talking about a case study that illustrates the dangers of the textile dyeing industry. Until next time!
Yours truly,
Katya
References
Bechtold, T., & Mussak, R. (2009). Handbook of natural colorants. Chichester, U.K: Wiley.
Ogugbue CJ, Sawidis T. (2011). Bioremediation and Detoxification of Synthetic Wastewater Containing Triarylmethane Dyes by Aeromonas hydrophila Isolated from Industrial Effluent. Biotechnology Research International. DOI: 10.4061/2011/967925
Ben Mansour, H., Houas, I., Montassar, F., Ghedira, K., Barillier, D., Mosrati, R., & Chekir-Ghedira, L. (2012;2011;). Alteration of in vitro and acute in vivo toxicity of textile dyeing wastewater after chemical and biological remediation.Environmental Science and Pollution Research International,19(7), 2634-2643. DOI:10.1007/s11356-012-0802-7
Berradi, M., Hsissou, R., Khudhair, M., Assouag, M., Cherkaoui, O., Bachiri, A. E., & Harfi, A. E. (2019). Textile finishing dyes and their impact on aquatic environs. Heliyon, 5(11). DOI:10.1016/j.heliyon.2019.e02711
Yusuf, M. (2019). Synthetic dyes: A threat to the environment and water ecosystem in Textiles and Clothing (pp. 11-26). Hoboken, NJ, USA: John Wiley & Sons, Inc. DOI:10.1002/9781119526599.ch2
Singh, Z., & Chadha, P. (2016). Textile industry and occupational cancer. Journal of Occupational Medicine and Toxicology (London, England),11(1), 39. DOI:10.1186/s12995-016-0128-3
Esancy, J. F., Freeman, H. S., & Claxton, L. D. (1990). The effect of alkoxy substituents on the mutagenicity of some aminoazobenzene dyes and their reductive-cleavage products. Mutation Research, 238(1), 1.
de Aragão Umbuzeiro, G., Freeman, H., Warren, S. H., Kummrow, F., & Claxton, L. D. (2005). Mutagenicity evaluation of the commercial product CI disperse blue 291 using different protocols of the salmonella assay. Food and Chemical Toxicology, 43(1), 49-56. DOI:10.1016/j.fct.2004.08.011
Alves de Lima, Rodrigo Otávio, Bazo, A. P., Salvadori, D. M. F., Rech, C. M., de Palma Oliveira, D., & de Aragão Umbuzeiro, G. (2007). Mutagenic and carcinogenic potential of a textile azo dye processing plant effluent that impacts a drinking water source. Mutation Research. Genetic Toxicology and Environmental Mutagenesis,626(1-2), 53-60. DOI:10.1016/j.mrgentox.2006.08.002
Comments