Microplastics, the environment and us with Fay Couceiro

Professor Fay Couceiro gave ERA members and friends a fascinating and, much of the time, concerning talk on microplastics and related matters, providing many startling statistics.

When introducing herself, Fay told us she has worked on many aspects of pollution, including: nutrients, metals, hydrocarbons, underwater noise as well as microplastics. At Portsmouth University she works as part of the Revolution Plastics Institute to address the global plastics crisis. Interestingly, it was at Portsmouth University that the first work was carried out on enzymes that ‘eat’ plastics, returning them to monomers that can then be used to create new plastics.

Plastic pollution can be classified by size: >20mm - Macroplastics; 20mm<x>5mm - Mesoplastics; 5mm<x>1µm - Microplastics; <1µm - Nanoplastics. The last two now being ubiquitous. Plastic pollution that is still at the size it was manufactured (such a nurdles or the plastic microbeads found in personal care products) are classed as being Primary, those that have broken down to a smaller size than they were manufactured at are classed as Secondary. Fay drew our attention to The Great Nurdle Hunt  an activity any of us can take part in when in a suitable location! Nurdles are the plastic pellets used in plastic injection moulding to make plastic products.

Two of the main sources for plastic pollution in the environment are tyre wear and plastic from agriculture, so called ‘plasticulture’. On farms plastic is used to protect haystacks, as part of product packaging and plastic is even used as a mulch. 30% of plastic in use in the UK is in agriculture.

Microplastics fall into water bodies from the atmosphere where they can then absorb other pollutants and may subsequently get consumed by the plankton, which are then eaten by organisms further up the food chain. They then bioaccumulate in the larger organism, including in the fish that we might eat. Plastic particles <10 µm remain very difficult to see and measure, meaning we have little idea as to their prevalence.

30% of all tyre wear ends up aerially deposited in the oceans, a lot of it coming down in the rain.

Microplastics also accumulate in the soil. Last year the EU brought in a law to prohibit the amount of microplastics in compost to below 1% but we have no such law in place in the UK. 90% of the microplastics in sewage end up in the sludge which is still being sold to farmers for use as fertilisers. 1% of sludge is microplastics, but as little as 0.1% can have a negative impact on soil.

Studies have shown that increased microplastics in soil will decrease germination success, and impact plant growth and root biomass. In the UK we already have poor soil health due to intensive agriculture. Microplastics in the soil are just compounding the issue.

The artificial surfaces used to create softer sports pitches are predominantly made of shredded tyres, which include synthetic rubber, better known as plastic. These then wear down with use, distributing that plastic far and wide. While in use on vehicles tyres wear down, releasing plastic to the air and leaving it on the road surface to be washed into the wider environment by the next rain storm. (Yet another reason why we have to stop forever accommodating more and more vehicles on our roads!)

Apart from tyre wear leading to microplastics in the air, microplastics are brushed off of our clothes as we move and from our carpets as we walk on them.

Microplastics can act as vectors either absorbing other pollutants of having them adhere to them. Biofilm, the slime that can form on wet surfaces, is a foodstuff to many types of organism. When biofilm forms on microplastics those microplastics can then get mistaken for food and ingested, for example, by oysters.

The three main ways that pollutants enter us humans are by the skin, the gut and the lungs, the latter two being the predominant way that microplastics enter us.

Microplastics in the air are breathed in and have been studied in the sputum of people with respiratory ailments. We spend 90% of our time indoors and that is where there is greatest density of microplastics in the air, having been released from carpets, settees and soft furnishings.   12 – 40% of house dust is plastics.

People often think of fish as being the only way that humans might ingest plastic, but in fact all food types that have so far been investigated have been shown to contain microplastics. Microwaving food in plastic containers, be that ready meals or Tupperware type containers used for food storage, transfers plastic into the food, but is easily avoided by using non-plastic containers. Plastic spoons and spatulas can be replaced with wooden ones.

And why would we care about all this plastic within ourselves? Microplastics have been linked with respiratory disease, oxidative stress, inflammation, cytotoxicity and also impacts on wound healing – and that is only the impacts we have so far discovered!

Fay finished by outlining some of the wide-ranging areas of plastic pollution study currently being undertaken at the University of Portsmouth, involving work here at home and as far away as the Antarctic. Many of these can be read about here.

Fay certainly gave us plenty to think about but she also gave us some ideas to start reducing the amount of microplastic pollution we ourselves are responsible for, such as choosing less man-made fibres in the clothes we buy and replacing plastic kitchen utensils and food storage items. I suggest ERA pools all the steps our different members have already taken to reduce the amount of plastic in their lives so that we can share these ideas and even further reduce the plastic in our lives.