Posted on Thursday 22nd May 2014
Recent reports in the national press have drawn attention to calls for a ban on the use of tiny plastic beads (microbeads) added as exfoliants and abradants to toiletries like cosmetics and toothpaste. This is in response to concerns that after use, such beads pass through sewage filtration systems and escape into the environment. The theory is that such synthetic particles are more effective than their natural counterparts at sorbing chemical pollutants like pesticides, and are subsequently better at transferring such pollutants into aquatic life that consume them. These concerns are compounded further when this aquatic life forms part of our diet. While the scientific evidence for such concerns is real, there are wider issues at play here.
Firstly, the application of plastic microbeads in toiletries constitutes just one source of the ever-growing reservoir of waste plastic circulating in the environment. So while restrictions on these particular uses are to be welcomed, they are akin to (forgive the pun) a drop in the ocean, given evidence of a vast ‘plastic soup’ circulating in the Pacific, of which a significant proportion is composed of particles of degraded plastic, of a size that matches that of the microbeads in our toothpaste.
Likewise, while there is evidence to suggest that such synthetic particles may be more effective than natural particles at sorbing industrial and household chemicals from water, and of subsequently transferring such chemicals to aquatic animals; the real issue surely lies with how we can reduce our use of these chemicals. Put plainly, if such chemicals were not present in the environment in the first instance, their assisted uptake by biota as a consequence of the environmental presence of microplastics (of whatever origin) would be a non-issue.
It is important to emphasise that the uptake of pollutants by biota occurs regardless of the presence of microbeads. Chemical pollutants were present in our food and bodies long before the introduction of microbeads in toiletries and will remain after any ban. Our research on contamination of English lake sediments reveals substantial increases over the last 30 years of chemicals used as plasticisers and flame retardants in our furniture and electronics. Moreover, despite initially responding rapidly to bans on their manufacture in the late 1970s, similar chemicals known as polychlorinated biphenyls (PCBs) even today maintain a stubborn presence in our environment and food. If such chemicals restricted nearly 40 years ago are still causing us problems, then this raises serious questions about what we are storing up for the future by our continued use of similar chemicals.
In short then, banning these specific applications of microbeads – while welcome – fails to tackle the much wider issues both of waste plastic pollution in general, and of our long and growing history of using chemicals in consumer goods that leads to environmental contamination. This particular issue of microbeads in toiletries deserves our attention mainly because it highlights our surprisingly relaxed attitude to the use of synthetic chemicals in our everyday lives. The benefits of modern chemical use are real and many; but as a chemist it would be disingenuous to deny that incomplete understanding sometimes results in inappropriate applications of chemicals and undesirable consequences. By all means outlaw microbeads in toothpaste, but it is crucial we don’t lose sight of the forest for this one particular tree.
Professor of Environmental Chemistry, University of Birmingham