The hidden garbage in the Thames

Plastic garbage is clogging the River Thames, and some of the most commonly discarded items are parts of sanitary pads that have been flushed down the toilet, according to a new study in Marine Pollution Bulletin. Much of this “large unseen volume of submerged plastic” could eventually make its way into the sea, the authors say.

The problem of plastic garbage in the ocean has gotten a lot of attention. Marine animals often end up eating plastic, getting tangled in it, and being exposed to chemicals released from the waste. But the researchers wondered how much rivers contributed to the never-ending stream of junk flowing into the ocean.

The study began as an investigation of an invasive species, the Chinese mitten crab. Several years ago, researchers set up nets in the UK’s River Thames and ended up catching all kinds of plastic rubbish. In 2012, researchers deployed more nets at seven spots in the Thames estuary, then returned every three days for three months to sort and record the contents.

During that 2012 study, the team found 8,490 pieces of garbage. Twenty-one percent of the junk was sanitary pad components, usually the plastic backings of the pads. Food and tobacco packaging made up another 25 percent and 19 percent, respectively. The problem was the worst at sites near sewage treatment plants, the authors report.

People are probably flushing sanitary products down the toilet, even though they’re not supposed to. To reduce this source of pollution, people will need to change their habits or companies will need to make the products more biodegradable, the authors say.

“There is little doubt that significant quantities of litter, especially plastics, are moving down the River Thames and thus providing a major input of such debris to the North Sea,” the researchers write. And they suspect that other rivers around the world harbor hidden junk as well. Roberta Kwok | 14 January 2014

Source: Morritt, D. et al. 2014. Plastic in the Thames: A river runs through it. Marine Pollution Bulletin doi: 10.1016/j.marpolbul.2013.10.035.

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