I agree to a point, but these pollutants build up over time. It is like mercury and lead build up in fish, and even higher consentrations in Eagles and Osprey. The same happens to bears and humans that consume a lot of those fish.
Many water pollutant health problems either show up in children affected in the womb or 25 to 30 years later in adults. Yes the world will be here, but why expose people to debilitating health effects? Remember, you could be the next victim.