Why we need to do more to understand the dangers posed by microplastics - Jeanette Rotchell

We first started looking for microplastics in mussels. As filter feeders they are often used by scientists to provide a snapshot of the level of contaminants in the marine environment. Our goal was to find out whether the mussels were taking up microplastics from the seawater, where we know levels can be high, as well as via seafood to humans. We found microplastics in every single mussel we tested.

We also went to supermarkets, testing the mussels available to eat. It didn’t matter which supermarket, we found microplastics in all the mussels. This led us to examining various different types of fish and the story was the same – bottom dwellers or pelagic in the water above, it didn’t make a difference, we found microplastics in their gills and digestive systems.

Next we started analysing the air. We conducted a long study inside 20 household’s living rooms, collecting the settled dust and testing the air for microplastics presence once a month. The levels and types of microplastics differed across the households and the time of year, which raised interesting questions about what types of furnishings or cleaning habits resulted in the higher microplastic levels. Moving our sampling and analysis outdoors, our results detected in the Hull and East Riding area air chimed with other studies around the world finding microplastics in London, Shanghai, and Australia.

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When sea life encountered microplastics in its environment, those microplastics found their way into their bodies. It was logical to ask the same question about ourselves. To do that, we began collaborating with biomedical scientists and surgeons. When these surgeons operated on lungs, they were able to provide small tissue samples for us to analyse. While conducting this work, we also set up blank samples which are used to detect and account for any background levels of microplastics that might be floating in the surrounding air and contaminate any samples we wanted to analyse. We found microplastics in all the human lung tissue samples, and in our next experiment, in a number of human vein samples. We’re in the process of testing blood and urine.

Microplastics have found to be everywhere. PIC: ShutterstockMicroplastics have found to be everywhere. PIC: Shutterstock
Microplastics have found to be everywhere. PIC: Shutterstock

So what? We spend our lives breathing and eating dust and countless tiny particles which don’t seem to do us much harm. There are two answers to this question, both concerning in their own ways.

The first answer details the dangers that we do know, or at least suspect – specifically, inflammation and chemical leaching. Inflammation can be especially hazardous if it exacerbates existing conditions. Take chronic obstructive pulmonary disease (COPD) as an example. COPD is a condition that causes shortness of breath, frequent chest infections, and a persistent cough. It can be life limiting and cannot be cured or reversed. Inflammation makes this regression worse and, remember, we found microplastics in the air we breathe and each of the lung samples we analysed. Similarly in China, preliminary research has connected microplastic levels to inflammation and irritable bowel type conditions.

Chemical leaching happens when the added chemicals involved in plastic production migrate into the tissues around them. Our research found that several of the microplastics detected contained chemical additives, some of them known to be toxic. In human lung samples, we found PTFE, better known as Teflon, which is one of the “forever chemicals” as it is extremely slow to break down. We have no information yet on the levels of these chemicals that are leaching, but, in nature, we’ve found that even very low levels of such chemicals cause hormonal changes in fish, causing conditions such as intersex where fish develop both eggs and sperm rather than one or the other.

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All of this should be taken with a pinch of salt – this is preliminary research and there’s been no robust studies yet on the actual impact of microplastics in humans. Which brings us on to the second, more worrying, answer. We know far too little about the scale of this problem. As far as we know, microplastics are everywhere, but we don’t know how harmful they are to humans or the environment.

We need to stop facing this microplastics dilemma blind and there are two steps we can take right now to fix it.

The first is to improve the quality of our analysis, making it more robust, and moving towards standardised methods.

The second step needs more than academics. We need policy makers, governments on board. We need to actively monitor and regulate the levels of microplastics in our air and water. Human microplastic contamination could be insignificant, it could be seriously impacting us, or it could be somewhere in-between. We just don’t know. And until we start seriously and robustly analysing the levels of microplastics in our environment and bodies, and how it impacts us, we will continue to be the subjects of an experiment over which we have little control.

Jeanette Rotchell is professor in Environmental Toxicology at the University of Hull.