The following is a "guest post" by my esteemed colleague Peter B in Australia:
http://www.care2.com/causes/u-s-waters-polluted-by-10-million-tons-of-dog-poop.html
Dog
Waste Threatens Public Health
“Dog
waste is an environmental pollutant. In 1991, it was placed in the same health
category as oil and toxic chemicals by the Environmental Protection Agency,”
explains Virginia-based pet waste removal company
Doody Calls in a press release. “The longer dog waste stays on
the ground, the greater a contamination becomes. Bacteria, worms and other
parasites thrive in waste until it’s washed away into the water
supply.”