Microplastics In Our Water: How Polluted Are Our Supplies?

Microplastics are fragments of plastic waste that have been produced by human activities and released into the environment. These tiny plastic particles have been detected in water sources around the globe, from the oceans to freshwater systems, and even in drinking water. The presence of microplastics in our water supplies has raised concerns about potential impacts on human health and the environment. Studies have found microplastics in the digestive tracts of fish and other aquatic organisms, leading to concerns about the contamination of our food chain. With limited data and research on the topic, the long-term health risks of microplastic ingestion remain largely unknown, but it is predicted that there will be negative consequences. As the issue of plastic pollution gains attention, understanding the extent and effects of microplastic pollution in water supplies becomes increasingly urgent.

Microplastics in drinking water

Microplastics are fragments of plastic waste that originate from anthropogenic activities. These tiny plastic particles are released into the environment and can eventually find their way into our water supplies, including drinking water. While the long-term health risks of ingesting microplastics are still unknown, their presence in our water systems is a growing concern.

A 2022 study found that microplastics accumulate in freshwater systems, particularly at the source of rivers or streams, where the slow-moving water favours the piling up of microplastics. This contamination has been found in natural freshwater systems worldwide, including wetlands, lakes, and rivers. The concentration of microplastics varies, with developing nations facing a more severe problem. For example, the surface water of lakes in China and Saudi Arabia has been found to be much more contaminated than water bodies in other countries.

Microplastics can enter the water environment through various means. One way is through wastewater, as tiny plastic microfibers from synthetic clothing shed during washing and eventually make their way back into our drinking water supplies. Agricultural products, such as fertiliser and mulch, can also contain plastic particles that can quickly contaminate groundwater systems. Additionally, plastic pollution in the environment can contribute to microplastic infiltration in waterways, with North American waterways being some of the most heavily polluted.

The presence of microplastics in drinking water has been confirmed by various studies, and it is predicted that there will be negative impacts on human health. Limited data from animal studies suggest that microplastics may accumulate and cause particle toxicity by inducing an immune response or chemical toxicity due to leaching of plastic-associated chemicals. Plastic particles also provide a breeding ground for harmful biofilms made of bacteria, viruses, and other contaminants. However, more research is needed to fully understand the exposure levels and potential hazards associated with microplastics in drinking water.

While there is no standardised method for testing microplastic removal rates, several measures can be taken to reduce exposure. These include running the tap before sampling and using filters to remove plastics from drinking water. It is essential to continue studying microplastics in drinking water to address this unseen threat to human health and the environment effectively.

Microplastics in bottled water

Microplastics have been found in natural freshwater systems, including wetlands, lakes, and rivers around the world. A 2022 study found that microplastics accumulate in freshwater systems, especially at the source of a river or stream, where the flow of water is relatively low. This allows pollutants to reside for longer, increasing the risk of ingestion by marine animals and other organisms.

Bottled water is not immune to this issue. A recent study by researchers at the National Institutes of Health (NIH) found that a liter of bottled water contained about 240,000 tiny pieces of plastic, with nanoplastics accounting for 90% of these fragments. Polyethylene terephthalate (PET), a type of plastic commonly used in beverage bottles, was detected in high amounts. Other plastics identified included polyamide, polyvinyl chloride, polymethyl methacrylate, and polystyrene.

The presence of microplastics in bottled water is influenced by various factors. The longer a bottle sits, the more time plastic has to break down into micro- and nanoplastics through processes like heat, photochemical reactions, and oxidation. External factors, such as temperature, can also play a role. For example, water in a bottle left in a hot car is likely to contain more plastic than one stored at a controlled temperature.

The potential health impacts of consuming micro- and nanoplastics are still being studied. Limited data from animal studies suggest that ingestion or inhalation of microplastics may lead to particle toxicity and chemical toxicity due to the leaching of plastic-associated chemicals. Bisphenol A (BPA), a chemical used in plastic water bottles, has been linked to adverse reproductive effects at very low doses.

While filtration can help remove microplastics, not all filters are effective, and only a few remove nanoplastics. Adsorbents, which bind to nanoplastics, can be a solution, but most consumer water filters do not utilize this method. Boiling water is ineffective in removing microplastics, as it does not target plastic particles.

Microplastics in natural freshwater systems

The presence of microplastics in natural freshwater systems is a growing concern for environmental scientists. Microplastics, defined as plastic fragments smaller than 5mm, have been found in natural freshwater systems worldwide, including wetlands, lakes, and rivers. The sources of these microplastics are both land- and ocean-based, with terrestrial sources contributing 80% of plastic debris in marine environments. These sources include personal care products, the air-blasting process, improperly disposed plastics, and leachates from landfills.

The continuous increase in synthetic plastic production and poor management of plastic waste have led to a significant increase in plastic dumping into natural water systems. Once released into these systems, microplastics can accumulate, especially at the source of a river or stream, where the relatively low speed of water flow favours the piling up of microplastics. This accumulation has been observed in natural freshwater systems across the globe, with Lake Superior in North America, Swiss lakes in Europe, and Lake Taihu in China found to contain large amounts of microplastics.

The presence of microplastics in these freshwater systems poses a threat to the organisms that reside there. Similar to marine life in oceans, freshwater organisms face the risk of entanglement and ingestion of microplastics. A 2016-2017 study by Loyola University Chicago biologists found that 85% of sampled fish from three rivers in the Midwestern United States had microplastics in their digestive tracts. These plastics can cause particle toxicity and chemical toxicity due to the leaching of plastic-associated chemicals and adsorbed toxins. The potential health effects of microplastics on freshwater organisms are not yet fully understood, and more research is needed to assess their impact on biodiversity and movement through the food chain.

The behaviour of microplastics in aquatic ecosystems is another area that requires further study. While it is known that factors such as density, shape, and size affect their transportation and distribution patterns, the understanding of their environmental fate and fragmentation rates is still evolving. Generating comprehensive monitoring data on the abundance of microplastics in freshwater systems is crucial to address these knowledge gaps and develop effective management policies and legislation to mitigate the impact of microplastic pollution.

Microplastics in the human body

Microplastics have been found in human blood, organs, tissues, lungs, and even the placentas of unborn babies. The exact entry routes are unclear, but inhalation and ingestion through food and water are the likely primary routes of entry.

The presence of microplastics in the human body is a growing concern, and more research is needed to fully understand the potential health risks associated with their accumulation in the body and their ability to transport toxic chemicals to various organs.

While the science is still developing, there are ways to reduce exposure to microplastics. These include avoiding drinking from disposable plastic water bottles, filtering your water, dusting and vacuuming regularly to reduce microplastic fibers in household dust, and avoiding plastic containers for microwaving food.

Microplastics in the food chain

Microplastics have been detected in the human and animal food chain, and are now found in the human body, including the blood, lungs, liver, lower limb joints, and even the brain. The versatility of plastic materials has led to their widespread use, but this has also resulted in contamination of the environment with microplastics, which is endangering animal life and, in turn, the food chain and public health.

Microplastics can enter the human food chain through direct exposure to the environment or indirectly by the transfer of MPs within the ecosystem. Marine and terrestrial organisms ingest microplastics, which can then be consumed by humans. A 2022 study found microplastics in blue mussels off the Australian coast, with research concluding that "if you eat mussels, you eat microplastics". Microplastics have also been found in 98.9% of seafood samples in the US state of Oregon, and in foodstuffs such as honey, tea, sugar, fruit, and vegetables.

Microplastics can also make their way onto farmland through sewage sludge used as fertilizer, which can then end up in waterways as a result of runoff from the top layer of soil. A 2022 study also found that microplastics accumulate within freshwater systems, especially at the source of rivers or streams, where pollutants usually reside the longest due to the low speed of water flow. This can affect the entire food chain, as well as access to food and food security.

The health impacts of microplastics are not yet fully understood, but studies indicate that they can increase the likelihood of heart attack, stroke, or death, and can cause intestinal damage, immune problems, and neurotoxicity. They can also carry other toxic chemicals and microorganisms, which can affect human health.

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