Polyester Safety: Evaluating Toxicity Implications

Polyester is a synthetic polymer highly prized for its strength, resistance to wrinkles or shrinking, and quick-drying properties. Its versatility and cost-effectiveness make it highly popular in the textile industry, and it is used extensively in apparel, home textiles, and various technical applications. 

In recent years, its use has been under public concern, especially regarding its safety and potential health implications. "Is polyester toxic?” or “Is polyester bad for you?" questions have proliferated in both public opinion and the scientific community. 

This article addresses these concerns by evaluating the existing polyester toxicity studies, debunking prevalent myths, and presenting current research about its implications on human health.

Is Polyester Harmful? Debunking Myths

Whether polyester is toxic or not has had a lot of resonance in recent years, promoting the circulation of a series of myths about its use and effects on human health. Some of the apprehension is based on the chemical composition of polyester and the potential for microplastic fibers to be released during its lifecycle. The concern about its composition regards its production process, which involves petrochemicals, a group of substances that have been irrespectively stigmatized by public opinion as harmful to health, often without scientific evidence. 

A significant area of investigation is represented by the release of microplastics into the environment, which has legitimately raised questions about ecotoxicology and systemic health effects. Polyester garments can shed microplastics when washed or dried, which may enter the food chain and into the human body through ingestion or inhalation. Additionally, there are concerns about skin sensitivity and the possibility of polyester to trap moisture against the skin, creating a breeding ground for bacteria. A 1995 study by Hatch K. and Maibach H. linked synthetic fibers to skin irritation and allergic reactions for the first time, but their findings have yet to be sufficiently confirmed by the following studies.

Nevertheless, it is crucial to differentiate between chemicals' presence and their actual risk. Most polyester fabrics undergo rigorous toxicity studies to ensure they meet safety standards that limit the presence of any toxic substances to safe levels for human contact. Furthermore, the belief that polyester clothing directly leads to health issues lacks scientific backing. Studies focusing on the "polyester toxic" hypothesis have not found conclusive evidence to support a direct link between polyester fabric exposure and health issues.

Moreover, the durability and stability of polyester mitigate the risk of chemical leaching under normal conditions of use and wear. While the environmental impact of polyester, particularly regarding microfiber pollution, is a valid concern, this does not directly translate to toxicity in the context of human health. Thus, the myth that polyester is inherently toxic to humans is unfounded, mainly considering the current regulatory status.

Polyester and Health: What Research Says

The discourse around synthetic fabrics and cancer has fueled concerns, with debates such as "Do polyesters affect any pathway involved in oncology processes?" gaining prominence. These concerns mainly arise from the chemicals used for processing its fibers after polyester manufacturing, some of which are known to be carcinogenic.

A key document in this context is the polyester toxicity study conducted by various health organizations to establish its carcinogenic potential. According to the International Agency for Research on Cancer (IARC) and other health institutions, there is insufficient evidence to classify the chemicals used in polyester production as carcinogens. These polyester toxicity studies consider exposure levels, routes, and the inherent properties of substances to determine their potential health risks.

Moreover, it is important to note that the level and duration of exposure significantly influence the risk of any adverse health outcome. In the case of polyester, the typical consumer exposure through clothing is minimal, with most studies indicating no direct causal relationship between polyester fabric wear and cancer development. This perspective is supported by a comprehensive review of occupational exposure studies among workers in polyester manufacturing plants, where no consistent increase in carcinogenic risk has been observed.

Nevertheless, it is prudent to continue monitoring and researching as manufacturing processes evolve and new data emerge, especially for prolonged exposures and later effects. Ongoing research efforts aim to elucidate any potential health implications of polyester, focusing on long-term exposure and the cumulative effect of various chemicals. It is also worth mentioning that advancements in textile technology are continuously improving the safety profile of polyester by reducing the need for potentially harmful chemicals and enhancing the sustainability of production processes.

In summary, the debate on polyester’s safety involves analyzing its chemical safety, the environmental and health impacts of microplastic pollution, and the potential carcinogenic properties of chemicals involved in its manufacturing process. Despite these concerns, definitive answers to questions like "Is polyester toxic?" require further research and contextual understanding of exposure levels and toxicity mechanism of actions.

Studying the Impact of Microplastics with Ecotoxicity Assays

Microplastics released by washing or drying polyester can enter water systems through domestic washing, ending up in rivers, lakes, and oceans. Once in the environment, they contribute to the broader problem of microplastic pollution, one of the most investigated topics of recent years.

Zebrafish are a freshwater species, highly suitable for studying pollution toxicity in aquatic ecosystems, and included in the OECD Guidelines for aquatic toxicity.  Zebrafish embryos are transparent, and this visual accessibility provides direct evidence of how microplastics interact with living organisms at various developmental stages.

The use of zebrafish in toxicity testing is supported by guidelines from regulatory bodies like the OECD (Organization for Economic Co-operation and Development) and the EPA (Environmental Protection Agency). Biobide has developed several assays following OECD Guidelines in aquatic models, such as Zebrafish, Algae and Daphnia. In the case of the Zebrafish, Biobide offers two strategies for acute assays. The first one is the Acutetox Assay, a simplified version of the OECD TG 236 Guideline that can be implemented to elucidate lead compounds in a High-Content Screening platform using a cost-effective and time-saving alternative assay. The second one is the Fish Embryo Acute Toxicity Test, which follows the OECD TG Nº 236 strictly under Good Laboratory Practices (GLPs). 

Furthermore, Biobide offers other time and cost-effective screening assays to assess the aquatic toxicity of chemicals, like the Daphnia Immobilization and the Miniaturized Alga Growth-Inhibition assays, following OECD Guidelines 201 and 202, respectively. Algae and Daphnia magna are extensively used in several ecotoxicity assays; in particular, the Daphnia Immobilization assay is performed to comply with regulatory requirements or support environmentally acceptable product label claims. It is suitable for High-Content Screening of test items, as well as the Miniaturized Alga Growth-Inhibition assay.

Sources

Bhagat J, Zang L, Nishimura N, Shimada Y. Zebrafish: An emerging model to study microplastic and nanoplastic toxicity. Science of The Total Environment. 2020;728:138707.

Chen, G, Patel, MK. Evaluating the Carcinogenic Potential of Polyester-Based Textiles: An Occupational Health Study. Industrial Health. 2019; 57(4), 490-500.

International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Chemicals Used in Textile Manufacturing. Lyon: World Health Organization; 2018. 

Lee MH, Park, SY, Kim, SJ. A Review on the Toxicological Aspects of Polyester Microfibers: Environmental Health Perspectives." Toxicology Reports. 2020;7, 1256-1263.

Schwarzer M, Brehm J, Vollmer M, Jasinski J, Xu C, Zainuddin S, et al. Shape, size, and polymer dependent effects of microplastics on Daphnia magna. Journal of Hazardous Materials. 2022;426:128136.

Smith JL, Johnson AB. Assessment of Chemical Exposure Risks from Polyester Clothing. Int. J. Environ. Res. Public Health. 2022; 14(3), 255-267.

U.S. Environmental Protection Agency. Assessment of Chemical Substances Used in Polyester Fabric Production. Washington, DC: U.S. EPA; 2021.