26 July 2024
In the textile industry, a wide variety of chemicals are used for different purposes. These range from common substances like sodium chloride (kitchen salt) and sodium sulphate (Glauber’s salt), to hydrogen peroxide, reactive dyes, vat dyes, sulphur dyes, PFAS, and complex coating formulations. While some chemicals are well-known, many are:
1. Pre-mixed in proprietary formulations
2. Not fully purified
3. Of unknown composition; often only indicating the main component or its function
This lack of transparency creates significant challenges in accurately assessing chemical impacts. According to bAwear, this raises concerns about which specific chemicals are utilized in textile processes. Suppliers provide information on composition and toxicological effects through Safety Data Sheets (SDS), which include crucial sections like Section 3 (composition/information on ingredients), Section 11 (toxicological information), and Section 12 (ecological information).
The limitations of safety data sheets (SDS)
While Safety Data Sheets are intended to provide crucial information about chemical compositions and toxicological effects, they often fall short. Key sections such as composition details, toxicological information, and ecological data are frequently incomplete or entirely absent.
The dynamic nature of chemical interactions
In daily practice, the input of chemicals is just one aspect to consider. Chemical behavior in textile processes is far from static. Consider these factors:
- Some chemicals are solely used to extend shelf life
- Others remain on textiles post-production
- Many undergo transformations during processing
For example, hydrogen peroxide converts to water but may oxidize other chemicals in the process. As another example, consider reactive dyes. These dyes can behave in several ways: they may react with the textile and become an integral part of the textile product. Other dye molecules may be hydrolyzed, losing their reactive groups and becoming substantive dyes with poor fixation properties. A small portion of the dyes might be oxidized, where amino functionalities are changed into nitro groups. Additionally, some dyes may form poorly soluble dye complexes in the presence of metal ions. What exactly happens in practice is largely unknown and depends on many situational factors. It is very difficult, if not impossible, to predict the effect on (eco-)toxicity parameters.
Post-production chemical fate
The journey of chemicals doesn't end with the manufacturing of the product/materials. Chemicals that leave the process with the textile materials will be dried in a stenter. Some of these chemicals might evaporate and become airborne particles, while others might be incinerated when they are fed to the burners in the circulating air. Simple carbohydrates will turn into water and carbon dioxide, but chemicals containing nitrogen and sulphur may produce more complex byproducts, such as nitrogen and sulphur oxides. Additionally, some chemicals will exit the system through the wastewater. The fate of these chemicals is largely determined by the wastewater treatment system and the environment where the water is discharged.
Wastewater treatment further complicates matters, as chemicals may be:
- Removed unchanged (in coagulation/flocculation) and discharged with the sludge.
- Biodegraded into smaller molecules of unknown composition; depending on the nature of the biological treatment (aerobic or anaerobic wastewater treatment).
- Transformed through various treatment processes.
The shortcomings of current eco-toxicity models
Eco-toxicity models, like USEtox, use chemical structures to predict the impact on (eco-)toxicity. Since these structures are not known, bAwear believes these models cannot be used to calculate the impact adequately.
Conclusion: bAwear Score's stance on chemical toxicity reporting
Due to these facts and the unknown and unpredictable changes the chemicals might undergo, bAwear believes it is not possible to accurately calculate the impact of the chemicals used in textile processing. Reporting values that could be 10 to 100 times too low or too high would do more harm than good. This is why bAwear does not include certain impact categories related to toxicity and eco-effects in its impact calculations.
Sources:
https://www.diva-portal.org/smash/get/diva2:850089/FULLTEXT02.pdf
https://medcraveonline.com/JTEFT/green-chemistry-and-textile-industry.html
https://www.ijcmas.com/vol-3-3/R.Shyamala%20Gowri,%20et%20al.pdf
