An afternoon cup of tea is a comforting ritual around the world. But this common practice may be exposing people to millions of microplastics. A 2024 study found that using polypropylene plastic tea bags released up to 1.2 billion pieces of plastic per milliliter of tea. Tea bags are just one of the many ways that microplastics can enter people’s bodies and ecosystems.
What are microplastics?
Microplastics are plastic particles that range in size between five millimeters to just one nanometer. Over time, these can degrade into even smaller nanoplastics, which are smaller than one micrometer and undetectable to the human eye. On average, people consume between 39,000 to 52,000 particles of microplastics annually. Of the thousands of plastic compounds used across the world today, more than 20% have been classified by the European Union as of concern due to factors such as their persistence, accumulation in fatty tissues and toxicity.
What are the primary sources of microplastics?
Primary microplastics are deliberately manufactured in small sizes for use in industries such as cosmetics or biomedical products. Secondary microplastics derive from the breakdown of larger plastic materials such as food wrappings like tea bags, tires or synthetic textiles.
How do microplastics affect the water supply?
Microplastics primarily enter the water system from two sources: run-off from land-based sources and wastewater overflow. The land-based sources include landfills, the breakdown of road-marking paint, debris from tires, synthetic products such as footwear or astroturf and agricultural runoff. Wastewater overflow produces microplastics from washing synthetic clothes, cosmetic micro-beads and fragments of products that are flushed down the toilet instead of disposing them safely, such as sanitary pads and wet wipes.
Microplastics impact aquatic ecosystems as well. Fish, mussels and other aquatic organisms may consume the particles, either by mistaking them for food or through the ingestion of other materials contaminated with microplastics. They also have the potential to carry pollutants in the water or release chemicals that are harmful to aquatic ecosystems. Previous studies have found that microplastics can contain chemicals that harm animals’ development, reproduction and immunity to disease.
What are the effects of microplastics on human health?
The impact of microplastics on human health is still emerging, and the effects could vary depending on their characteristics such as type, size, shape and concentration. They can enter human’s blood and tissue through food, water and air. Hazards associated with microplastics generally come in three forms: physical hazards from the microplastics themselves, chemical hazards from the plastics’ properties and microbial hazards where microbial organisms attach themselves to the particles.
In 2022, the World Health Organization (WHO) published a report that found that there is limited good evidence to support that microplastics in drinking food or water pose a significant threat to human health, and that significantly more research and harmonization is needed on the topic. Their diverse nature may also cause them to have different effects on human health. More recent research, meanwhile, has found that the body’s immune cells may recognize microplastics as foreign, leading to inflammation, which could explain links to chronic diseases such as inflammatory bowel disease, cardiovascular disease and cancer.
How can people reduce the amount of microplastics released?
The first action point should be to address the amount of macroplastics produced due to the harm they pose by themselves to life, infrastructure and landscapes. With time, macroplastics will degrade to become microplastics. People can make behavioral changes like increasing plastic recycling and reducing the use of single use plastics and plastic products to minimize the amount of microplastics consumed. In addition to these changes, it is also important to consider how plastics are designed, consumed and disposed of; systemic changes must take place that reduce the use and misuse of microplastics. For example, changing the fashion industry to become more sustainable by creating clothes that shed fewer fibers or mandating washing machines have built in filters could help reduce the number of microfibers that reach the water supply.
How can we address the issue of microplastics in water?
An efficient way of reducing microplastics in the water supply is treating wastewater and drinking water. Managing plastics at their source is the most effective way of preventing them from entering water systems. These solutions include treatment units that can be used in households to remove microplastics from effluents and designing textiles to reduce microfibers released from washing.
Technologies to treat wastewater and run-off before they reach a treatment plant are also essential to minimize the amount of microplastics in the water system. The most commonly used technique globally to remove plastics is using a regular urban clean-up service to avoid accumulation of plastic waste. However, this method is time and labor intensive, which makes it difficult to implement regularly. Setting up infrastructure that operates by itself to capture plastic waste such as booms, deflectors or meshes can effectively aid the removal of plastics from waterways.
In many cases, decision-makers will need to select a sustainable combination of solutions instead of selecting single solutions. For example, to achieve a desired maximum number of microplastics in drinking water a secondary wastewater treatment (upstream) and a conventional drinking water treatment (downstream) could be combined.
Water is one of the primary mediums for the transportation of microplastics. Preventing microplastics from impacting human health and ecosystems will not be possible until control over the discharge of plastics into water systems is achieved.