Back in the late 1960's, when I was a student at Oxford Polytechnic (Now Oxford Brookes University) studying for an HNC in Applied Biology, one of the modules (on which apparently the National Council for Academic Awards (NCAA) insisted) was 'General Studies', i.e., anything which broadened our education away from the narrowness of a specialised subject, such as Applied Biology.
Part of that was an assignment to investigate an aspect of man-made environmental pollution, Rachal Carson's 'Silent Spring' being a recent publication and a nascent green movement beginning to emerge. The subject I decided on was to investigate what happened to the millions of tons of vulcanized rubber from road vehicle tyres that needed to be replaced annually because tyres wore away on the roads. It stood to reason that that rubber either entered the atmospheres as dust, or, more likely, got washed off the roads and into road-side ditches and eventually into the waterways and from there to the sea.
The question was, what effect did this fine rubber dust have on the environment and how much of it ended up in the food chain?
I was shocked to discover, after several days searching the literature available to me in the college library (if only we had had the Internet in those days!) that there was not a scrap of scientific data on the subject. There were no published papers on the question whatsoever. Either no-one had thought it worth investigating, no-one had identified the problem, or no-one was prepared to fund the research. And yet millions of tons of vulcanized rubber were being turned into tyres and from then into rubber dust on our roads, and it was all going somewhere, but no-one knew where!
In desperation, and with a project to complete, I abandoned my research and instead looked at the environmental effects of DDT, then extensively used as an insecticide, and about which some alarming news was emerging - extermination of brown pelicans in American lakes treated with DDT to kill mosquitoes, because DDT is adsorbed onto particulate matter which is ingested by the small organisms eaten by fish and so concentrated up the food chain, at the apex of which were brown pelicans; loss of peregrine falcons because DDT reduced egg shell thickness, leading to a loss of broods, again the result of DDT being concentrated up the food chain and killing the apex predators.
So, news that, some 54 years later, researchers at Griffin University, Australia, have published a paper in Environmental Science & Technology, dealing with a closely related problem - the problem of microplastics and tire [sic] wear products in urban stormwater.
Sadly, the research paper is behind a paywall, but a Griffin University news release explains the research and its significance:
In urban stormwater, particles from tyre wear were the most prevalent microplastic a new Griffith-led study has found.
Published in Environmental Science & Technology, the study showed that in stormwater runoff during rain approximately 19 out of every 20 microplastics collected were tyre wear particles with anywhere from 2 to 59 particles per litre of water.
Pollution of our waterways by microplastics is an emerging environmental concern due to their persistence and accumulation in aquatic organisms and ecosystems. Stormwater runoff which contains a mixture of sediment, chemical, organic and physical pollutants, is a critical pathway for microplastics to washed off from urban environments during rain and into local aquatic habitats. But to date, our knowledge of the amount of microplastics in urban stormwater, particularly tyre wear particles, is limited, as is the potential strategies we can use to minimise this source.
Due to the analytical challenges in measuring this source of microplastics in stormwater, research to date often lacks information about the actual number of tyre wear particles water samples.
Microplastics that enter constructed wetlands for stormwater drainage systems settle in the sediment and form a biofilm, leading to their accumulation over time, removing them from stormwater runoff. Urban stormwater runoff typically requires treatment for the removal of suspended solids and nutrients such as nitrogen and phosphorus in many jurisdictions in Australia, with some also requiring the removal of gross pollutants. However, regulations are lagging behind when it comes to microplastics and tyre wear particles.
Our findings show that both constructed wetlands and the stormwater capture device are strategies that could be potentially used to prevent or at least decrease the amount of microplastics tyre wear particles being transported from stormwater into our waterways.
Dr Shima Ziajahromi, lead author
Australian Rivers Institute
School of Environment and Science
Griffith University, Southport, Gold Coast, QLD, AustraliaTyre rubber contains up to 2500 chemicals with the contaminants that leach from tyres considered more toxic to bacteria and microalgae than other plastic polymers.
Quantitative information of this type is crucial to improve our understanding of the amount of tyre wear particles in stormwater, assess the risk to the environment, and to develop management strategies.
Sediment samples collected from the inlet and outlet of a constructed stormwater wetland contained between 1450 to 4740 particles in every kilogram of sediment, with more microplastics in the sediment at the inlet than the outlet, indicating the wetland’s ability to remove them from stormwater.Our study quantified and characterize microplastics and tyre wear particles in both stormwater runoff and sediment of stormwater drainage systems in Queensland. We also assessed the effectiveness of a stormwater treatment device to capture and remove these contaminants from stormwater and evaluated the role of a constructed stormwater wetland for capturing microplastics in the sediment, removing it from stormwater runoff. The device is a bag made of 0.2 millimetre mesh which can be retrofitted to stormwater drains. Although originally designed to capture gross pollutants, sediment, litter and oil and grease, it significantly reduced microplastics from raw runoff, with up to 88% less microplastics in treated water which had passed through the device.
Professor Fred Leusch, co-author
Australian Rivers Institute
School of Environment and Science
Griffith University, Southport, Gold Coast, QLD, Australia
Perhaps I should have followed my instincts in 1969 and pursued the subject further. Maybe I could even have got a PhD out of it, but the important message then seemed to be that we were doing all sorts of things to our planet, but no-one knew what, exactly. Now our seas are full of microplastics, thousands of species are red-listed and on the verge of extinction and our only home in the cosmos is in danger of overheating, making life on it impossible.
Welcome to the Anthropocene.
Reference:
No comments:
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.