Caffeine: A Direct Correlation To Sewage

In this article, they speak to a direct correlation of the amount of caffeine in water and the amount the bacteria in water. This means that---especially in urban areas---water pollution is at a rise and it's directly caused by substances found in human sewage.

http://www.macroevolution.net/sewage-and-caffeine.html#.TugUXdUrUqM