The story changes a little when you get to Lake Michigan, which is more heavy metals, fecal coliform, etc. The heavy metals coming from the steel refineries who periodically have oopsies and dump a few tons of waste into the lake.
The maximum safe concentration of PFAS/PFOA has been reduced in the past years, due to better understanding of health concerns.
As a result and due to more public attention, water surfaces are now seen as harmful up to 10 miles away from the factory. The factory is located right between a medium sized city and a national park. Within a radius of a mile around the factory, people are advised not to grow vegetables.
I think many countries have similar stories and clean up costs are going to be huge.
The stuff is everywhere. At least the raw sewage overflows from Milwaukee/Chicago mostly dilute and turn less toxic in the matter of months versus generations as is the case with PFAS.
Swimming advisories were only in effect for a few hours after the lock was open for nearly 8. Things are getting better but we still have work to do.
Steel mills or petroleum refineries. We have both.
I thought that mercury in the environment came mostly from coal fired power plants. The mills have their share of pollution issues but I think that's more air pollution. Well... There was the issue with killing a bunch of fish a couple years ago. IIRC that was cyanide.