The article does state though that 'Many studies, including ours, are demonstrating that the toxicity of micro- and nanoplastics is highly linked to the level of exposure'. But it doesn't provide evidence that the amount being ingested is enough to cause harm, so the bit about killing kidney cells seems to be fear mongering (I'm sure there are lots of things babies eat that would kill kidney cells if you instead injected them). What would be more interesting if there was detectable levels of microplastics in blood streams, or how the levels compare to things already studied such as bottled water.