River of Plastic and Garbage Flows Beneath Thames in London

Scientists studying the Thames River in England have discovered a that a river of garbage is flowing beneath the surface of the Thames. The unseen stream of rubbish could be a serious threat to aquatic wildlife, the scientists report.

A team from Royal Holloway, University of London and the Natural History Museum report on the huge volume of garbage - primarily plastic waste - in the journal Marine Pollution Bulletin.

By using nets designed for crab fishermen, the researchers pulled more than 8,000 pieces of plastic from the river bed of the upper Thames Estuary over three months. Other items in the rubbish stream included cigarette packaging, food wrappers and cups. One-fifth of the waste consisted of sanitary products, the researchers reported.

"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 study co-author Dave Morritt a marine biologist 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."

Because plastic bags and other large items were unlikely to get caught in the nets, the researchers warn that the full extent of the garbage at the bottom of the Thames is not represented by their study and that the true extent of the problem is unknown.

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

Natural History Museum is hosting a Plastic Awareness Weekend on Jan. 4-5, 2014 to highlight the issue of marine litter pollution. Visit the museum's website for more information.