Summary: we could have considerable extra time to figure out how to not pollute everything and ourselves with microplastic. Systematic flaws in several microplastic studies point towards human body fat mimicking the signature of polyethylene, leading to serious overestimation of how far microplastic can penetrate:

“One of the team behind the letter was blunt. “The brain microplastic paper is a joke,” said Dr Dušan Materić, at the Helmholtz Centre for Environmental Research in Germany. “Fat is known to make false-positives for polyethylene. The brain has [approximately] 60% fat.” Materić and his colleagues suggested rising obesity levels could be an alternative explanation for the trend reported in the study.”