A new study shows one-third of America’s rivers have changed color since 1984.
Wednesday’s study says much of that is rivers getting greener. Scientists say generally that’s not good. It often means nasty and sometimes toxic algae blooms.
That’s happening most in the North and West. Other river segments are getting more yellow, a sign of more soil in the water which isn’t necessarily a sign of ill health. Only about 5% of U.S. river segments are considered blue.
Scientists say much of the color changes come from fertilizer run-off, dams, efforts to prevent soil erosion and climate change.