The average brain weighs 1300-1400 grams. If 0.5% of that is plastic by weight, your brain contains 6.5 - 7 grams of plastic. The average plastic credit card weighs 5 grams.
https://www.theguardian.com/environment/article/2024/aug/21/microplastics-brain-pollution-health
While you're at it, make sure you're reducing your energy usage so you can stop climate change. Don't worry about Shell or ExxonMobil, I'm sure they're doing their best. And if we keep politely letting them know that climate change makes us sad I'm sure they'll give up their stranglehold on energy production so we can live happier, healthier lives! /S
In case it wasn't clear, treating huge environmental problems isn't a personal responsibility thing. We need legislation, and that isn't going to happen without drastic action.