evidence: Tea drinkers have been urged to avoid plastic tea bags after tests found that a single bag sheds billions of particles of microplastic into each cup. A Canadian team found that steeping a plastic tea bag at a brewing temperature of 95°C releases around 11.6 billion microplastics – tiny pieces of plastic between 100 nanometres and 5 millimetres in size – into a single cup. That is several orders of magnitude higher than other foods and drinks. [...] While microplastics are increasingly found in drinking water, the World Health Organization says there is no evidence of a health risk for humans. To test the potential toxicity of the particles released by plastic tea bags, Tufenkji and her colleagues exposed water fleas to the contaminated water.