If we’re taking about hypothetical effects on hypothetical generations of life that can never be reversed, anything you can worry about probably meets that threshold and so picking any given thing is arbitrary. Gaza and the Ukraine conflicts are the results of choices made by the generation before, which are in turn the result of choices made by the generation before that, which in turn are… and so on. Consider Gaza on its own. You could probably trace a pretty clear line from this conflict back to decisions made in the earliest records we have of Judaism. How many generations and people has that impacted? How many of these chemicals you’re specifically worried about are the consequences of actions taken in this and the prior conflicts? The total global impact of the decision of one Jewish sect to crucify the leader of another sect is probably conceivably larger than anything PFAS have done or even will do for quite a long while considering we’re still dealing with the consequences of that decision even now.