Study documents plastic pollution in Thames

A NASA Earth Observatory shows the discharge of the Thames River into the North Sea. Visit this NASA Earth Observatory page for more information.

Plastic pollution becoming ubiquitous in world’s waterways and oceans

By Summit Voice

FRISCO — In yet another sign that plastic debris has become a ubiquitous form of pollution, researchers in the UK said they recovered thousands of bits of plastic litter from the bottom of the upper Thames Estuary.

In a press release, the researchers with Royal Holloway, University of London and the Natural History Museum said the sheer amount of plastic recovered shows there is an unseen stream of rubbish flowing through London which could be a serious threat to aquatic wildlife.

The findings, published online in Marine Pollution Bulletin, highlight concerns,  for ecosystems around the river and the North Sea, into which the Thames flows.

Using nets designed to catch Chinese mitten crabs, Royal Holloway and the Natural History Museum scientists documented rubbish collected during a three-month trial. More than 8,000 pieces of plastic were collected, including large numbers of cigarette packaging, food wrappers and cups. More than 20 percent of the waste was made up of sanitary products.

“The unusual aspect of the study is that these nets are originally designed to trap fish and crabs moving along the river bed, so we can see that the majority of this litter is hidden below the surface,” said Dr. Dave Morritt, a senior lecturer in Marine Biology at Royal Holloway.

“This underwater litter must be taken into account when predicting the amount of pollution entering our rivers and seas, not just those items that we can see at the surface and washed up on shore. The potential impacts this could have for wildlife are far reaching: not only are the species that live in and around the river affected, but also those in seas that rivers feed into,” Morritt said.

The waste collected for the study is only a small snapshot of the volume of litter which may exist at the bottom of the Thames. Plastic bags and other large items were unlikely to get caught in the small nets so the true extent of the problem is still unknown.

“All of this waste, which was mostly plastic, was hidden underwater so Londoners probably don’t realize that it’s there. Plastic can have a damaging impact on underwater life. Large pieces can trap animals but smaller pieces can be inadvertently eaten,” said Dr. Paul Clark, a researcher at the Natural History Museum.

“This litter moves up and down the river bed depending on tides. The movement causes the pieces of plastic to break down into smaller fragments,” Clark said. “These are small enough to be eaten by even the smallest animals, which are in turn eaten by larger fish and birds. Once digested, plastic can release toxic chemicals which are then passed through the food chain. These toxic chemicals, in high doses, could harm the health of wildlife,” he added.

Scientists are increasingly pressing for changes to both policy and consumer behaviors, as the dangers of plastics become more apparent.

In one recent study, scientists documented how rafts of tiny plastic particles in the ocean can host communities of bacteria, including potentially dangerous pathogens.


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