15 July, 2022

Marine plastic waste is one of the most significant environmental problems globally. As plastic waste continues to grow, another problem has emerged; microplastic pollution. To mark Plastic Free July, we discuss microplastics; where they are found and what dangers they might pose to the environment and to our health, including our risk of breast cancer. 

What’s the problem with plastic? 

Most plastics are manufactured using crude oil. They are lightweight, cheap to produce and have many different structures and uses. Most plastics are durable and it’s difficult for microorganisms to break them down. This is a benefit to the user – but a disaster for the environment and a potential threat to human health. 

 In 2020, global plastic production was around 367 million metric tons, generating approximately 29 million tons of plastic waste. Around 9% of this waste is recycled. 12% incinerated and the rest goes to landfill or is dumped directly into the environment. Over time, plastics disintegrate into smaller and smaller pieces known as microplastics. 

 How are microplastics defined? 

 Microplastics are plastic pieces less than 5 mm in size which are found in the environment. They are insoluble in water and may take centuries to break down. They arise following the environmental breakdown of plastics or they are intentionally produced.  

 Examples of intentionally produced microplastics include microfibres used to make synthetic textiles, microbeads used in toothpaste and paint, glitter and nurdles – small plastic pellets that are the raw material for manufacturing many plastic products.  

The most common use for microplastics is as plastic coatings for slow-release fertilisers and pesticides used on soil and crops. Particles of paint account for over half of all the microplastics that end up in the world’s oceans and waterways every year. 

 Microplastics are everywhere, including inside us 

 Microplastics are found all around the globe, including newly fallen snow in Antarctica.  

The majority of microplastics are found in the oceans, where most rubbish ends up. Hundreds of thousands of tonnes of microplastics are now floating on the global sea surface. Microplastics are increasingly accumulating in agricultural soil. This directly introduces them into the environment and potentially into our food supply.  

 Microplastics are also present in the air and food, such as sugar, salt, honey, beer and seafood. Most urban tap water worldwide is reported to be contaminated with microplastics. 

Microplastics can fragment into even smaller particles known as nanoplastics (less than 1/1000 mm). These have been detected in animal organs including brains of fish and the liver and kidneys of mice.  

They have also been found in humans, including the placenta and lungs. A recent Dutch study found 17 out of 22 human blood samples contained microplastics.  

 How do microplastics enter our bodies? 

 Microplastics mainly enter our bodies from food and drinking water, or indirectly from food packaging materials. Plastic tea bags and water bottles also release high quantities of microplastics into liquid contents. One study found infant feeding bottles can release millions of microplastic particles per litre into infant formula. 

 We breathe in microplastics from microfibres released from textiles, erosion of car tyres and dust.  

Microplastics may enter our bodies through skin contact, for example through the application of sunscreen. 

 How do microplastics impact human health and the environment? 

 Microplastics pose a serious threat to the environment and our health. They remain in the environment for a long time, may be potentially toxic and can adsorb environmental contaminants and microorganisms that cause disease. In addition, the raw materials and chemical additives which are incorporated into plastics when they are manufactured may be later released into the environment.  

 Examples of additives include plasticisers used to soften plastics, UV filters used to help prevent degradation, flame-retardants, sealants and dyes. Many of these are persistent organic pollutants and/or endocrine-disrupting chemicals (EDCs) that interfere with hormone function and so may be detrimental to animal or human health. 

 Microplastics can bind to chemical pollutants found in the environment. If marine organisms such as fish ingest these, they are getting a strong dose of toxic chemicals, which may be passed on to any fish-eater – including humans. 

 Nutrients and organic matter adsorbed from surroundings by microplastics can enable microbial communities (known as biofilms) to stick to their surface. These often harbour food poisoning bacteria, which can be ingested by marine organisms such as fish, oysters, and scallops, which may be later consumed by humans. 

 Animal studies have shown ingestion of microplastics can cause inflammation, organ damage, and affect reproduction, metabolism and gut bacteria. Breathing in microplastics may cause inflammation, and chemical toxicity, and introduce pathogens into the body.  

 Microplastics and breast cancer  

Studies have yet to demonstrate a link between microplastics and breast cancer risk, but such a link is feasible. Plastics components such as bisphenols and additives, including phthalates, heavy metals such as cadmium, PFAS or flame retardants, all leach from microplastics. Many are EDCs that can act as oestrogen mimics at low concentrations and so may increase breast cancer risk. 

 Microplastics often contain mixtures of EDCs, which mimic oestrogen. These may be particularly hazardous. Ingestion of microplastics can cause inflammation and irritation. This may potentially lead to DNA damage and promote cancer. They may also affect intestinal microorganisms which can influence cancer risk.  

 Finally, in vitro cell culture studies have shown microplastics are toxic to cells, cause oxidative stress (an imbalance between free radicals and antioxidants in the body) and can trigger an immune response in human cells.  

 What can we do about microplastics? 

 As a start; try to avoid single-use plastics such as those used for bottled water; clothes made from non-natural fibres such as polyester, nylon and acrylic; and glitter. To help reduce your own microplastic intake, drink tap water not bottled and avoid drinking from single-use hot drink cups. Our next blog will focus on alternatives to products containing plastic.  

 Breast Cancer UK collaborates and partners with important NGOs, to share awareness and impact on joint issues such as plastic waste and the impact it has not just on the environment, but on our human health.  

 Green Alliance, said: “Our throwaway culture has real consequences for the environment, both in the production and disposal of single-use items. Cutting them out completely or swapping for reusable alternatives is the best way to reduce our impact and protect the planet.”  

 Fidra, said: “Microplastics are threatening whole ecosystems and are of increasing concern for human health. We must act now to reduce the amount of microplastics entering the environment. Nurdles are one of the largest sources of primary microplastic pollution.  You can help be part of the solution by taking part in a nurdle hunt today to track plastic pellet pollution and hold industry to account.” 

 Chem Trust said: “Plastics contain many chemical additives, some of which are hazardous to human health and the environment. As a society, we, therefore, need to reduce our use of plastics and make sure that the plastics that are produced are free from the most hazardous substances. As a first step, the UK needs to match EU action by introducing a comprehensive restriction on microplastics that have been intentionally added to products, one of the most preventable sources of microplastic pollution.”

Read our other Plastic Free July blog for great plastic-free alternatives you can incorporate into your daily life.

Or if this blog has inspired you, please consider making a donation to help prevent breast cancer. Your donation can provide vital funds for our animal-free research into breast cancer prevention.



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