U.S. sprawl takes toll on environment

To save money and limit growth, individual septic tanks are being required instead of municipalities installing sewer lines in some suburbs, but they are more responsible than previously thought for the nitrogen runoff into the nation's waterways, USA Today reported Wednesday.

"Nitrogen causes algae blooms, fishery declines and low water quality," Lawrence Band, a professor of geography at the University of North Carolina, told a meeting of the American Geophysical Union.

"We were surprised to find that areas zoned to be low-density to protect watersheds had the highest nitrogen levels."

Lush, green suburban lawns require lots of water and fertilizer, which is also contributing to the runoff problem.

Grass is now the largest irrigated crop in the United States, according to Jennifer Jenkins, a professor of environmental economics at the University of Vermont.

Copyright 2005 by United Press International