Skip to main content
U.S. flag

An official website of the United States government

The Chesapeake Bay gets some good news

November 5, 2019

EARTH Magazine — by Mary Caperton Morton — November 4, 2019

"The Chesapeake Bay watershed is the largest on the Atlantic seaboard, encompassing most of Maryland and Virginia, along with parts of Delaware, New York, Pennsylvania and West Virginia. More than 150 rivers flow into the system, carrying pollution and nutrient runoff from a 160,000-square-kilometer area into the bay ecosystem. A new study tracking long-term effects of the Clean Air Act has some good news about the often-poor water quality in some areas of the Chesapeake Bay watershed, but the overall picture may be complicated by hydrology.

Initially passed in 1963, the Clean Air Act was designed to reduce air pollution by requiring the Environmental Protection Agency (EPA) to enforce regulations limiting airborne contaminants. In 1990, amendments were passed to regulate the impact of stationary sources of air pollution, namely coal-fired power plants, to reduce the sulfur dioxide and nitrogen oxide associated with acid rain. According to the EPA, total human-caused nitrogen oxide emissions on the East Coast declined 32 percent between 1997 and 2005.

To study the effects of reduced nitrogen input on the Chesapeake Bay watershed, a team led by Keith Eshleman at the University of Maryland Center for Environmental Science tracked nitrogen levels in the waterways of nine forested areas in Maryland, Pennsylvania and Virginia over a 23-year period and found that water quality in at least some areas of the Chesapeake Bay watershed has improved since 1990.

That the Clean Air Act “brought such obvious improvements in surface water quality” was an unanticipated “side benefit,” Eshleman says.

In their study, published in Environmental Science & Technology, Eshleman and colleagues suggest that reducing the amount of nitrogen oxide being put into the atmosphere also cut down on the amount of nitrogen oxide particles landing on the forested regions in their sample area — a pollutant pathway known as atmospheric deposition — ultimately improving water quality."


Read the full article at EARTH Magazine


« Return to Chesapeake Bay Activities — News