The government of Quebec has reported finding high levels of pollution from plastic microbeads in its waterways.
A team of researchers from McGill University found the beads widely distributed across the bottom of the St Lawrence River - the first time such pollutants have been found in freshwater sediments.
Researchers lowered a steel grab from a boat to collect sediment from ten locations along a 320km section of the river from Lake St Francis to Quebec City. Microbeads were sieved from the sediment and then sorted and counted under a microscope.
"We found them in nearly every grab sample taken,” said Rowshyra Castañeda, the lead author of the study. “The perfect multi-coloured spheres stood out from natural sediment, even though they were the size of grains of sand."
In some locations, the researchers measured over a 1,000 microbeads per litre of sediment, a level that rivals the world's most contaminated ocean sediments.
"We were surprised to find such concentrations at the bottom of a river," said McGill professor Anthony Ricciardi, who supervised the study. "It was previously assumed that floating microplastics are flushed through rivers to the sea. Now we have evidence that rivers can act as a sink for this pollution."
