Synthetic Colors in Wastewater Pose a Threat to Food Chains Worldwide
Synthetic Colors in Wastewater Pose a Threat to Food Chains ... Lab Manager Magazine
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Synthetic Colors in Wastewater Pose a Threat to Food Chains Worldwide
Dyes widely used in the textile, food, and pharmaceutical industries pose a pressing threat to plant, animal, and human health, as well as natural environments around the world, a new study has found.
Billions of tons of dye-containing wastewater enter water systems every year, and a group of researchers from the UK, China, Korea, and Belgium say that new sustainable technologies including new membrane-based nano-scale filtration are needed to solve the issue, adding that legislation is needed to compel industrial producers to eliminate colorants before they reach public sewage systems or waterways.
Published Study Highlights
- Published in Nature Reviews Earth & Environment, the study “Environmental impacts and remediation of dye-containing wastewater” was written by academics from the University of Bath, the Chinese Academy of Sciences, the Fujian Agriculture and Forestry University, the Korea Institute of Energy Technology (KENTECH), and KU Leuven, Belgium.
The research highlights that currently, up to 80 percent of dye-containing industrial wastewaters created in low- and middle-income countries are released untreated into waterways or used directly for irrigation. The authors say this poses a wide range of direct and indirect threats to human, animal, and plant health.
Despite these “severe” threats to health and ecosystems, the authors underscored that there is inadequate infrastructure, investment, and regulatory effort for making dye usage more sustainable, or for treatment of dye-containing wastewater.
Dr. Ming Xie, a lecturer in the Department of Chemical Engineering at the University of Bath (UK), believes that a multi-pronged approach is needed to combat the issue. He says: “Dyes create several problems when they reach water systems, from stopping light reaching the microorganisms that are the bedrock of our food chains, preventing their reproduction and growth, to more direct consequences like the toxic effects on plants, soils, animals, and humans.
“There are several potential ways to remove dyes from water including chemical, biological, and membrane-based techniques, but different dyes required different approaches, and once they reach wastewater systems treatment processes can be highly energy intensive. A worldwide regulatory effort is needed to stop dyes reaching wastewater or other water systems such as irrigation. Given the complexity of treating dye-containing wastewater, one solution would be to shift from the concept of centralized or regional treatment methods, to decentralized and site-specific treatment at source, by compelling industries to remove dyes from the wastewater they create before it reaches public water systems.”
Textile Industry is the Biggest Dye Consumer
Mauveine, the first organic synthetic dye, was discovered in 1865, spurring the creation of the global dye industry. Since then, more than 10,000 different types of dyes have been synthesized, with annual global production today estimated at 1 million tons.
Dyes are used in the rubber, leather tanning, paper, food, pharmaceuticals, and cosmetic industries, while the biggest user, the textile business, consumes 80 percent of produced synthetic dyes and generates about 70 billion tons of dye-containing wastewater annually.
China, India, and Bangladesh combined discharge around 3.5 billion tons of textile wastewater each year. Water contamination is aggravated by synthetic dyes, which in light of water scarcity issues, makes dyes a fundamental environmental and sustainable development issue.
Untreated dyes cause coloration of water bodies, reducing the degree of visible light that passes through the surface layer—hindering photosynthesis for aquatic plants and creating impacts along the food chain.
Microalgae, which form the foundation of the aquatic food chain, are most sensitive to photosynthesis reduction, suffering growth inhibition and cell deformation when exposed to a synthetic dye. This effect, and the knock-on suppressed transfer of energy and nutrients up the food chain, could lead to breakdown of entire aquatic ecosystems.
The effects have also been observed in fish. Dyes can deposit in fishes’ gills, lateral lines, or brains, leading to toxicological effects such as uncoordinated movement, respiratory distress, liver damage, and kidney dysfunction. These effects not only reduce the nutritional value of the fish to predators, but also lower their reproductive rates. Toxic dyes can also bioaccumulate in the fishes’ fatty tissue, presenting health risks to humans and animals throughout the food chain.
Negative impacts of dyes are also found on land—where they disturb the balance of microbial communities in soil—and in humans. Exposure to dyes can trigger allergies, asthma, and diseases including dermatitis and central nervous system disorders, as well as organ dysfunction and increased cancer risk.
No Single Treatment Offers a Solution
The review explores the variety of remediation technologies for dye-containing wastewater, including chemical, biological, physical, and emerging advanced membrane-based techniques. The authors found that no single technique presents a “silver bullet” for removing dyes, while several promising methods are not yet technologically ready at scale.
In light of this, they suggest a collective effort, led by policymakers, to increase the adoption of advanced remediation technologies and change textile processing methods to minimize the use of the most toxic dyes.
The authors also highlight a potential commercial impetus—the scope for industries to create new revenue streams from the processing, separation, and reuse of wastewater materials.
Co-author Dr. Dong Han Seo, from the KENTECH Energy Materials and Devices/Environmental and Climate Technology Track, says: “Dye containing wastewater is one of the most challenging wastewater streams, which impacts lives and the environment in several countries. Our review provides the latest insight on how we can effectively manage the challenge from the perspective of circular economy, effectively recycling dyes from wastewaters using treatment strategies such as advanced membrane-based separation to recover both useful dyes as well as clean water.”
Dr. Jiuyang Lin, from the Chinese Academy of Sciences, adds: “This review provides the examples on how we can reduce the dye footprints from production stages using new dyeing techniques. Guidance on effective solutions to dye containing wastewaters could be used to treat other challenging wastewater streams, safeguarding lives and the environment for future generations.”
– This press release was originally published on the
SDGs, Targets, and Indicators
| SDGs | Targets | Indicators |
|---|---|---|
| SDG 6: Clean Water and Sanitation | 6.3: Improve water quality by reducing pollution, eliminating dumping, and minimizing the release of hazardous chemicals and materials | – Percentage of dye-containing industrial wastewaters treated before being released into waterways – Percentage of dye-containing industrial wastewaters treated before being used for irrigation |
| SDG 14: Life Below Water | 14.1: Prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution | – Degree of coloration of water bodies caused by untreated dyes – Impact on aquatic ecosystems due to reduced photosynthesis in microalgae |
| SDG 15: Life on Land | 15.1: Ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains, and drylands, in line with obligations under international agreements | – Impact on microbial communities in soil due to dyes – Impact on land ecosystems and biodiversity |
| SDG 3: Good Health and Well-being | 3.9: Substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination | – Health effects on humans due to exposure to dyes – Increased cancer risk |
| SDG 12: Responsible Consumption and Production | 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle, in accordance with agreed international frameworks, and significantly reduce their release to air, water, and soil in order to minimize their adverse impacts on human health and the environment | – Adoption of advanced remediation technologies for dye-containing wastewater – Reduction of toxic dyes in textile processing methods |
1. Which SDGs are addressed or connected to the issues highlighted in the article?
SDG 6: Clean Water and Sanitation
This SDG is directly connected to the issue of dye-containing wastewater entering water systems and the need for sustainable technologies to solve the problem.
SDG 14: Life Below Water
This SDG is relevant because untreated dyes cause coloration of water bodies, reducing the degree of visible light that passes through the surface layer, hindering photosynthesis for aquatic plants and creating impacts along the food chain.
SDG 15: Life on Land
This SDG is connected to the issue because dyes can disturb the balance of microbial communities in soil and have negative impacts on land ecosystems.
SDG 3: Good Health and Well-being
This SDG is addressed because exposure to dyes can trigger allergies, asthma, dermatitis, central nervous system disorders, and increased cancer risk, affecting human health.
SDG 12: Responsible Consumption and Production
This SDG is relevant because the article highlights the need to change textile processing methods to minimize the use of toxic dyes and adopt advanced remediation technologies for dye-containing wastewater.
2. What specific targets under those SDGs can be identified based on the article’s content?
Target 6.3: Improve water quality by reducing pollution, eliminating dumping, and minimizing the release of hazardous chemicals and materials
The article emphasizes the need to treat dye-containing industrial wastewaters before they are released into waterways or used for irrigation.
Target 14.1: Prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution
The article highlights the impact of untreated dyes on aquatic ecosystems, including reduced photosynthesis in microalgae, which can lead to the breakdown of entire aquatic ecosystems.
Target 15.1: Ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems and their services
The article mentions the disturbance of microbial communities in soil caused by dyes, indicating the need to ensure the conservation and sustainable use of land ecosystems.
Target 3.9: Substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination
The article discusses the health effects on humans due to exposure to dyes, including allergies, asthma, dermatitis, central nervous system disorders, and increased cancer risk.
Target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle
The article suggests the adoption of advanced remediation technologies and changes in textile processing methods to minimize the use of toxic dyes and effectively manage dye-containing wastewater.
3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?
The following indicators can be used to measure progress towards the identified targets:
– Percentage of dye-containing industrial wastewaters treated before being released into waterways
– Percentage of dye-containing industrial wastewaters treated before being used for irrigation
– Degree of coloration of water bodies caused by untreated dyes
– Impact on aquatic ecosystems due to reduced photosynthesis in microalgae
– Impact on microbial communities in soil due to dyes
– Health effects on humans due to exposure to dyes
– Increased cancer risk
– Adoption of advanced remediation technologies for dye-containing wastewater
– Reduction of toxic dyes in textile processing methods
These indicators can help track the progress in improving water quality, preventing marine pollution, conserving land ecosystems, ensuring good health and well-being, and promoting responsible consumption and production.
SDGs, Targets, and Indicators
| SDGs | Targets | Indicators |
|---|---|---|
| SDG 6: Clean Water and Sanitation | 6.3: Improve water quality by reducing pollution, eliminating dumping, and minimizing the release of hazardous chemicals and materials | – Percentage of dye-containing industrial wastewaters treated before being released into waterways – Percentage of dye-containing industrial wastewaters treated before being used for irrigation |
| SDG 14: Life Below Water |
