A grave need to reduce plastic pollution
Contamination of the River Thames with microplastics, wet wipes and potential Covid-19 related pollution include masks and gloves has become a “major issue”, according to new research.
As many as 94,000 pieces of microplastics are estimated to now flow down the river per second, highlighting the "grave need for the reduction of plastic input into the freshwater environment".
The study from Royal Holloway, University of London was designed to generate baseline data for microplastics in the River Thames, which is potentially feeding the contamination to the North Sea, , as a significant input.
Researcher Katherine McCoy said: “With the potential threats of plastic pollution to both human and ecosystem health, it is of great importance that the input of plastic into marine and freshwater environments is reduced.”
“Massive wet wipe reefs”
In collaboration with river clean-up charity, Thames21, McCoy also looked at wet wipes as a source of pollution in the river.
They found “flushable” and “non-flushable” wet wipes in sewage effluent are deposited in large numbers on the foreshore of the south bank, creating “massive wet wipe reefs”.
The study found evidence of synthetic polymers, which may have originated from the wet wipe reefs, in nearby clams.
Shocking” findings in invasive crabs
A separate study looked at how two resident estuarine species of crab, namely the native shore care and invasive Chinese mitten crab, are ingesting microplastics.
Researchers from Royal Holloway, University of London found that 95 per cent of the mitten crabs had ingested plastics.
Dominated by fibres, this tangled material also included fragments of other microplastics, including sanitary pads, balloons, elastic bands and carrier bags.
Typically, ingesting microplastics has been seen as low in many species, so this discovery was seen as “shocking” by Masters Student, Alex McGoran, supported by the Fishmongers Company Charitable Trust.
What are the sources of the microplastics?
The study revealed that plastic fibres commonly came from washing machine outflows and “potentially” from sewage outfalls.
However, fragments from the breakup of larger plastics, such as packaging items, were the most abundant in the water.
Previous studies have shown that the “trapping efficiency” of wastewater treatment plants varies, although some reach levels of 99 per cent.
Professor Dave Morritt from the Department of Biological Sciences at Royal Holloway, said: “Taken together these studies show how many different types of plastic, from microplastics in the water through to larger items of debris physically altering the foreshore, can potentially affect a wide range of organisms in the River Thames.”
The professor added that Covid-related contamination may make the contamination worse.
“The increased use of single-use plastic items, and the inappropriate disposal of such items, including masks and gloves, along with plastic-containing cleaning products, during the current Covid-19 pandemic, may well exacerbate this problem,” he said.