Last updated March 13, 2018 at 10:03 am
It’s not just the oceans that are being destroyed by our addiction to plastics.
Sections of some rivers in the UK near urban areas can carry as much as 517,000 micro-plastic particles per square metre, researchers have found.
While the issue of micro-plastics in the ocean has been well studied, their presence in fresh water sources has been largely overlooked.
Now research led by geographer Rachel Hurley from the University of Manchester, UK, has found that it is very likely every watercourse in England, even the smallest, are contaminated.
In a paper published in the journal Nature Geoscience, Hurley and colleagues report sampling 40 freshwater sources in north-western England and finding all of them carrying heavy loads of micro-plastics.
And while that situation is plainly troubling, the researchers found that from one perspective it periodically gets worse.
Picture 43 billion particles of plastic
Unlike oceans, rivers can be subject to natural flushing systems – floods.
Hurley’s team made its initial measurements three or four years ago. Then, in 2015-2016, the area experienced above-average rainfall and significant flooding.
After the water levels decreased again, the team resampled its target rivers and streams. The results were dramatic. Micro-plastic levels had decreased at 28 of the sites – 20 of them by an entire order of magnitude. Seven sites were completely free of particles.
Hurley and her colleagues estimated that a hefty 70 per cent of the micro-plastic load – around 43 billion particles, weighing almost a tonne – had been cleared from the river systems.
This, on one hand, was good news, with the researchers confirming that periodic flooding acts as an efficient way to flush micro-plastics from flowing rivers and streams.
On the other hand, however, the discovery is concerning: the billions of flushed particles were pushed, inexorably, into the already-contaminated sea.