Microplastic Pollution in Fast Fashion: The Limits of Wastewater Treatment Systems

Introduction

Washing synthetic clothes is a major but often overlooked source of microplastic pollution as a single laundry cycle can release over 700,000 fibres into the environment. The rapid expansion of market size of the fast fashion industry has intensified this problem because of its heavy dependence on synthetic fibers for production. These fibers shed microplastics  during the washing process which seep into water bodies, contributing to nearly 35% of ocean microplastics. Shein’s reliance on synthetic fibres creates an invisible pollution crisis which current wastewater treatment systems are ill-equipped to address.

Scaling Speed, Scaling Harm: Shein’s Polyester Model

Polyester is a petroleum-derived synthetic fiber which is non-biodegradable and contributes to microplastic pollution by shedding fibers throughout its lifecycle. Polyester forms a central part of Shein's material portfolio with its polyester use increasing from  75.7% in 2023 to 81.5% along with cotton’s declining from 9.9% to 6.7%. This shift shows Shein’s growing reliance on synthetic fibers which allows it to produce at a low cost thereby contributing to increasing microplastic output. This reliance on synthetic fibres is not unique to Shein but reflects a broader industry trend within fast fashion.This model allows Shein to produce garments within 10 days by using polyester.  This enables Shein to timely deliver latest designs to consumers at a low cost, allowing it to increase profit margins by providing it a competitive advantage. While the Shein model reduces costs and accelerates trend cycles, it overlooks growing environmental and human body concerns. One such concern is large scale microplastic shedding that happens when synthetic fiber garments are washed.

Microplastic Leakage and the Limits of Wastewater Treatment

Microfibers are released during washing synthetic garments owing to the chemical stresses the clothes undergo in washing machines. However these fibers are not retained in the machines but  rather they are directly discharged with effluents. Additionally, a single laundry load of polyester clothes in a household can discharge as many as 700,000 microplastic fibres.

When scaled across, Shein's global production, this results in cumulative release of microplastics in multiple households every day.

Interestingly Shein’s recycled polyester sheds similar amounts of microplastic as its virgin polyester garments. This challenges the claim of Recycled polyester (rPET) being a more sustainable alternative to virgin polyester.

This suggests that the problem lies in the fiber itself regardless of its form. This raises concerns about whether the existing wastewater management is sufficient to prevent microplastics from seeping into water bodies. The present data shows that current systems are incapable of trapping microplastics as between 200,000 and 500,000 tonnes of microplastics enter the marine environment from the textile industry .  This shows that microplastics used by fast fashion brands form a significant part of 35 percent of microplastics in water bodies. However wastewater treatment plants could partially address this as released microfibers owing to their dimensions and direct reach oceans.

From Water to Body: The Human Cost of Microplastics

The failure of wastewater systems to trap microplastics goes beyond waterbodies as it also impacts human bodies. As microplastics surpass wastewater management they enter the aquatic system, thereby subsequently entering the food chain and human body including brain tissues. Emerging studies have documented the presence of microplastics in the human body including the brain. For instance, a brain sample of the individuals in 2024 showed that microplastics formed  0.5%  of  the brain’s weight. These findings show the extent to which microplastics impact human wellbeing.  In light of these concerns, it is important to examine problems arising from microplastic pollution. Addressing microplastic pollution requires not only changes in garment production and technology, but also a shift in consumer behaviour shaped by the fast fashion model as it plays an important role allowing these models to function. Research shows that some consumers are unwilling to reduce their level of clothing consumption because they enjoy acquiring and accumulating clothing through shopping. Also, the demand for inexpensive and trendy clothes encourages consumers to frequently purchase and dispose of these clothes quickly. This makes sustainability less attractive for both producers and consumers. To address this problem, firstly brands can switch to fabrics which are durable and release fewer microplastics during washing. However, this change will conflict with the fast fashion industry’s idea of fast production at a low cost and will disincentivise investment in high quality materials.  To address this, the government can introduce EPR laws. EPR laws incentivise sustainable design choices by imposing lower fees on eco-friendly materials. So, brands that invest in biodegradable and durable fabrics will benefit from cost saving. Further the government can impose taxes to make disposable clothing more expensive, this will force customers to switch to sustainable brands. Along with this, taxes on second hand clothes should be reduced, thereby effectively providing a subsidy that makes reuse a more affordable and attractive option. Additionally washing machine brands can adopt France's approach, which mandates that all new washing machines should be equipped with microfibre filters at the manufacturing stage.

Conclusion

At the core the problem lies within the fast fashion model which prioritises fast garments production over sustainability. The scale of this model is shown by the data which highlights that global fibre production could reach 160 million tonnes by 2030, up from 124 million tonnes in 2023 .  This is further reinforced by brands like Shein which rely heavily on synthetic fibers, depicting that the fast fashion is moving in the wrong direction by overlooking environmental costs. However, it is not a mere gap in awareness but an outcome which existing mechanisms including wastewater systems, taxes cannot solve alone. Thus, unless incentives for both consumers and producers are fundamentally restructured, microplastic pollution will continue to remain an inevitable consequence of fast fashion industry. ​ [This post has been authored by Shreya Maheshwari, a second-year law student at JGLS]