Professor Richard Thompson, Plymouth University
This week the UK government pledged to ban the use of microbeads in cleaning products and cosmetics like toothpastes and facial scrubs by 2017. Given that a single shower with a microbead gel can result in 100,000 plastic particles entering the ocean, the ban is aiming to reduce the amount of plastic in our seas. But what exactly are microbeads, what damage do they do, and will the ban actually make a difference? Kat Arney caught up with Richard Thompson, Professor of Marine Biology at Plymouth University, at the British Science Festival in Swansea for the answers.
Richard - Well, microbeads are very small pieces of plastic. Theyíre part of a wider problem, if you like, of small pieces of plastic in the environment - pieces that are described as microplastic and that captures any piece thatís less than 5mm or so in size. And we know that these really tiny parts are widely distributed in the ocean, that a wide range of creatures are ingesting them, and thereís evidence from laboratory studies of harm. But itís important to understand that microbeads from cosmetics are just one source to this wider picture of microplastics.
Kat - What do we know about the kind of harms that they're causing and the kind of organisms that theyíre harming?
Richard - We know that a wide range of organisms will ingest microplastics and that includes creatures with a range of different feeding strategies: filter feeders, deposit feeders, detritivores, fish, birds, invertebrates, and weíve got that information from the natural environment.
The evidence about harm largely comes from laboratory studies where thereís evidence of physical disruption thatís caused by ingesting these microscopic particles.
Kat - So it actually kind of stuffs them up or causes them physical problems?
Richard - What it seems to do it compromise their ability to put on weight, if you like, and weíre not completely sure what the mechanism behind that is, but invertebrates in treatments with microplastics present, didnít fare as well as those in terms of where the microplastics were absent in terms of putting on weight.
Kat - And what about evidence of larger animals that itís causing problems?
Richard - Thereís very little evidence of harm to larger creatures. We know that a wide range of creatures will ingest microplastic including, potentially, some larger organism, but the picture of harm in respect to larger organisms is just not clear.
Kat - The ban on these microbeads has been because of fears that maybe they could get into the food chain and we could end up eating them. Is that a problem or do we need more evidence for that?
Richard - My view is that, at the moment, there isnít a cause for concern from a point of view of human consumption of fish or shellfish. But let's not forget that plastics are persistent contaminants in the environment, the abundance of them is increasing, theyíre not going to degrade so, if we were conducting this interview in 10 or 20 years time and weíd carried on with business as usual with emissions of plastics to the ocean, that might be a different story in terms of the quantities that are in seafood but, at the moment, I donít perceive that as being the driver behind the ban.
I think that the ban comes from two perspectives really - one is itís not clear to me or to others what the societal benefit is of trying to cleanse ourselves with millions of small particles of plastic. It seems to us an avoidable source of contamination and there are alternatives that can be used. And, at the same time, thereís considerable concern about the accumulation of plastic litter in the environment and thereís growing evidence about the harm that particularly small particles can cause.
Now weíre still trying to understand that the full range, the full potential of environmental impacts of very small particles but, if weíve got an unnecessary source of contamination, it seems to me appropriate to thinks about legislation to reduce that.
Kat - Proportionally speaking, how big a problem are microbeads?
Richards - Microbeads are a relatively small contributor; even at the highest estimate suggests that there could be somewhere, 1-4% of all of the litter entering the oceans. The reason we have that uncertainty is because we really donít have a clear picture of exactly how much litter is entering the oceans annually, we only have estimates.
We know that in the UK 680 tons of microbeads are used annually and thatís a reasonably precise figure that comes from industry. Now thatís a substantial quantity; itís considerably more than all of the litter thatís collected on our beaches in voluntary cleanups by Marine Conservation Society. Itís equivalent to 20 or 30 articulated lorries full of microscopic plastic beads. Itís not a trivial amount, itís an amount thatís worth us taking action about but, if we try to set that into context to the wider picture of litter, yes microbeads are a small element. But, to me, that highlights the scale of the problem that we face in terms of solving the overall picture. Itís not a reason that we would not want to take action on unnecessary sources like microbeads, it sets the rest of the problem into context.