Pollution Rising In Tributaries of Bay, Data Show

Scientists Cite Suburbs' Growth As a Likely Cause of Backslide

The massive government effort to clean up the Chesapeake Bay is not just falling short of its goals. Now the bay's pollution might actually be taking a turn for the worse.

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New federal research indicates that pollution has crept up in some of the Chesapeake's biggest tributaries this decade, after a slow decline during the 1980s and 1990s. In the Potomac, the Patuxent and other major rivers, the pollutants on the rise include those blamed for low-oxygen "dead zones."

One likely cause for the apparent backslide, scientists say, is suburban development across the bay's watershed. As houses and parking lots replace farms and forests, they say, the result is a new glut of polluted runoff.

The leaders of the Chesapeake cleanup, including the governors of Virginia and Maryland and the mayor of Washington, will hold their annual Chesapeake Executive Council meeting today in Annapolis.

They were supposed to be making environmental history by now, delivering a healthy bay by a 2010 deadline. Instead, the leaders face the danger that the Chesapeake's modest progress might be rolled back.

"Growth in the watershed is starting to overwhelm our restoration efforts," said Frank Dawson, an assistant secretary at Maryland's Department of Natural Resources. Probably because of that growth, Dawson said, "there are certain areas in the bay where we are starting to go back in the wrong direction."

The day-to-day coordinator of the cleanup effort, Environmental Protection Agency official Jeffrey L. Lape, said the increases in pollution are not a sign of failure.

Lape, who is director of the EPA's Chesapeake Bay Program Office, said the new research "just simply [suggests] that the existing actions aren't adequate to keep up with the new sources" of pollution.

The research, published last month by the U.S. Geological Survey, charts the levels of two critical bay pollutants: nitrogen and phosphorus. These two chemicals, found in manure, lawn fertilizer and treated sewage, help fuel the large algae blooms that create dead zones in the bay.

The scientists used equations to remove variations caused by high or low rainfall. They were aiming to isolate the human pollution signature: Were people getting better or worse at keeping these contaminants out of the water?

In many tributaries, the answer was better -- for a while. For instance, measurements taken at Chain Bridge, which connects the District and Virginia, showed that phosphorus levels in the Potomac fell more than 20 percent between 1984 and 1995. In the Patuxent, measured at Bowie, nitrogen fell more than 60 percent between 1984 and 2000.

These declines happened after the first Chesapeake Bay Agreement in 1983, when local and state governments pledged to help the estuary. In the 1980s and 1990s, detergents were purged of a high-phosphorus ingredient, and sewage plants took the first steps to clean up their effluent.