that is how it often is with water. in fact when you study desert survival you learn not to drink out of anything that does not have algae or other aquatic plants growing in it.

you will also find that the higher you go on rocky mt rivers like the animas in colorado and they become basically fishless as you get high into the really pristine waters that look like they would be the best. reason is you are geting closer to all of the mining tailings with there heavy metals and seperation chemicals still leaching out of them

and of course when you are on the mighty coulmbia you notice how beautiful it is but you dont actually SEE that it is the most radioactive river inthe WORLD.

when you study "green" economies that grow like a tree (strongly rooted, sustainable) and compare them to "open market" economies that grow like a fire thru rapacious consumpion you find that our natural resources are about 50 times more economically valuable undeveloped rather than developed.

for instance take the profits from a wetland that is filled in and developed. it will cost society 50 times more over time from increased flooding/decreased habitait etc than if it was left alone or used in a sustainable manner

there is not one ounce of truth in the jobs vs the environment theory pushed so hard by the right wing