Bountiful populations of fish and oysters and underwater grasses may never return to the Chesapeake Bay unless leaders of the bay cleanup consider involving more states and making more drastic cuts in air pollution.
An interstate panel, convened this year to evaluate how the bay cleanup has worked since a 1987 agreement by Virginia, Maryland, Pennsylvania and the District of Columbia, will meet tomorrow to give its preliminary report.
What is becoming clear, scientists and environmental regulators say, is that the amount of pollutants from New York, West Virginia and Delaware is far greater than was imagined in 1987.
The Susquehanna River, for example, carries more nitrogen into Maryland waters of the bay than farm fields and sewage treatment plants in this state, according to Maryland Environment Secretary Robert Perciasepe, who heads the interstate panel.
The good news, Mr. Perciasepe said, is that no apparent mistakes were made in spending hundreds of millions of dollars on farms, sewage plants and industry to reduce the two major bay pollutants, nitrogen and phosphorus, that rob the water of oxygen.
But, he said, new information coming from a computer model and scientific studies "is sobering news in that to do what we want, we will be pushing the limits of [environmental] technology."
While the amount of phosphorus going into the bay has been reduced, particularly from sewage plants, the amount of the second pollutant, nitrogen, is still on the rise. "I think many of us think we may need to get more reduction [in nitrogen]. . . . What we will propose is that we expand the playing field," he said.
New York, Delaware and West Virginia share no borders with the Chesapeake Bay, but the rainfall in those states trickles into streams and rivers that feed the bay. Without help from those states, cleaning up the bay could require cuts in pollution closer to home that would be unrealistic.
For instance, Maryland might have to reduce pollution from sewage treatment plants to nearly nothing during the next decade, at a time when the state is expected to add nearly a half-million residents.
Whether other states will help remains to be seen. New York's environmental commissioner, Tom Jorling, has said he is not yet convinced that his state's contribution of nitrogen into the Susquehanna is significant.
However, he said, "what is clear is that regional cooperation is essential to protect these treasured resources." He also noted that reducing the amount of fertilizers on farm fields in New York would make good economic and environmental sense for his state, whether or not it affects the Chesapeake Bay.
Several cleanup officials are saying they must now attack the regional air pollution problem because it contributes nearly 30 percent of the nitrogen entering the estuary. If the public recognizes that the problem is key to restoring the bay, state legislatures will feel more pressure to pass a California-style bill that requires cars sold in Maryland to pollute less by the end of the century, Mr. Perciasepe said.
The interstate panel also will look at new technology that might help reduce bay pollution. For instance, many farmers around the bay still pour more fertilizers on their fields than can be used by crops, and the excess chokes the bay. New farming techniques, particularly in Pennsylvania's heavily agricultural Lancaster County, would reduce the nitrogen loads dumped into the Susquehanna.
Besides reducing pollution that reaches the bay, said Michael F. Hirshfield, a senior science adviser at the Chesapeake Bay Foundation, the panel should be considering the role of the bay's natural systems -- its oysters and wetlands -- in helping to improve water quality. Increasing the oyster population and ensuring that wetlands are not lost to development could make a difference.
Several scientific advancements over the past few years will help direct the restoration. Scientists now understand that the bay's bottom muds, a rich repository of pollutants, can be turned off like a tap if the amount of oxygen in the water is increased. And they have further refined their knowledge of the conditions in which underwater grasses flourish, and they can set more effective water quality standards.
In addition, a unique computer model has been developed over the past five years that attempts to simulate how the bay works.
Preliminary results from the model show that if the states meet the goal of reducing nitrogen and phosphorus pollution by 40 percent, they will reduce the volume of anoxia, or water without oxygen, in the main stem of the bay by 10 percent.
While those figures could change as researchers in Mississippi and New York begin to fine-tune the model, it is becoming clear that when the governors of the bay states meet in August to reassess the cleanup campaign, they will be confronted with some difficult choices.