Scientists have discovered a disturbing river of plastic trash flowing through London along the bottom of the Thames River and have raised concerns about the harm it will do to aquatic wildlife.
Scientists from the Royal Holloway, University of London and the Natural History Museum set out to study invasive Chinese mitten crabs and eels in the river using small fyke nets, but began documenting the amount of trash that was collected during a three month period at seven locations and published their findings in the Marine Pollution Bulletin.
They picked up 8,490 submerged plastic items, that had been anchored to the river bed, in the nets. Items included packages, food wrappers and cups, but 20 percent of the trash was made up of sanitary products that scientists believe were flushed down toilets, according to the Natural History Museum.
Scientists worry that what they found is only the tip of the iceberg, because larger objects would likely have been missed by the nets, and that people are underestimating the amount of pollution in the river, which has generally been considered clean.
“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 and co-author of the study.
“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.”
The Thames flows into the North Sea via the Thames Estuary, which are both home to numerous species ranging from fish and birds to seals and bottlenose dolphins.
Dr. Paul Clark, a researcher at the Natural History Museum and co-author of the study explained how this can cause problems for marine species:
“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.”
The problem of plastic pollution in marine environments clearly isn’t limited to the Pacific Gyre or our oceans. A growing number of studies have pointed to the problems with both plastic trash and microplastics in freshwater environments and their harmful effects on the species who live there and pass them through the food chain.
The Guardian notes that this study comes on the heels of others documenting the issue of plastics, including one that found as many microplastic particles in Italy’s lake Garda as are found in beach sediment and another that found plastic pollutants at higher concentrations in the Great Lakes in the U.S. than any other body of water on earth.
In the hope of changing policies and consumer habits, the Natural History Museum is hosting a Plastic Awareness Weekend on January 4-5 to help educate people about the problems associated with plastic.
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