m51.    Where do pollutants come from?

Organic chemicals such as gasoline, oil, plastics, pesticides, cleaning solvents, and detergents are a direct result of man dumping these materials. Point sources discharge pollutants from specific places. Non-point sources cannot be traced to any specific discharge point. If cities were required to withdraw their drinking water downstream instead of upstream, water quality would improve. Only 36% of all the streams in the US have been tested. Therefore we know very little about water quality.

e18.    Does water recover from pollution?

e19.    What materials can cause water pollution?  

e20.    What are environmental hazards and risks?

e21.    What are chemical hazards?