Despite early progress reducing Chesapeake Bay pollution, levels of a key pollutant, phosphorus, have not come down in many rivers in the past decade — and are actually rising in several, officials say.
Phosphorus is one of two pollutants blamed for causing algae blooms and "dead zones" in the bay, where fish and shellfish can't get enough oxygen in the water. Plants and animals need phosphorus and nitrogen to live, but the bay is choking on an overdose.
The lack of progress in reducing phosphorus is a particular problem on the Delmarva Peninsula, officials say, where there's evidence it is washing off the many farm fields fertilized with chicken manure. But phosphorus levels also are on the rise in some urban and suburban watersheds, which scientists say may stem from the erosion of stream banks caused by storm runoff from buildings and pavement.
"We're seeing some trends not headed in the right direction," said Rich Batiuk, associate director of the Environmental Protection Agency's bay program office in Annapolis. "We've got to step back and refocus on phosphorus."
Phosphorus levels in the rivers that feed into the bay are still mostly below where they were three decades ago, when the bay restoration effort formally began, officials say. But in the past decade, phosphorus levels have remained unchanged in nearly two-thirds of the rivers and streams routinely monitored by the U.S. Geological Survey, while pollution worsened in 16 percent. Just 21 percent of those waters monitored recorded declines in phosphorus in recent years.
Efforts to reduce phosphorus get only passing mention in a recent draft of a new Chesapeake restoration agreement obtained by The Baltimore Sun. It is to be signed Monday in Annapolis by Gov. Martin O'Malley and representatives of five other bay region states, as well as the EPA. A spokeswoman for the bay program said the final agreement won't be made public until it's signed. But officials involved with the cleanup say they're very aware they need to deal with the declining progress in reducing that key pollutant.
"Phosphorus pollution absolutely has to be on our radar screen," said Ann P. Swanson, executive director of the Chesapeake Bay Commission, which represents state lawmakers from Maryland, Pennsylvania and Virginia. "The progress that we made in the last 25 years is being eclipsed by increases in the last 10, so we're losing ground."
Pollutants in the bay pour into rivers and streams from a variety of sources, including sewage treatment plants, runoff of animal waste and fertilizer from farms and lawns, and from power plants and vehicle exhaust.
The bay cleanup has focused largely on reducing nitrogen, which readily dissolves in water and tends to travel farther downstream, causing more problems. Officials long believed that phosphorus could be dealt with by upgrading sewage treatment plants and controlling erosion, as phosphorus tends to stick to soil particles. But the river and stream monitoring indicates there are holes in the cleanup strategy, some say.
"We are still seeing improvements from wastewater treatment plant upgrades," said Scott Phillips, the geological survey's bay coordinator.
There also appear to be water-quality improvements in agricultural areas where farmers have fenced their livestock away from streams, he said. But in other areas, the increased use of manure as a fertilizer is degrading phosphorous levels, he said. Stormwater runoff is suspected of boosting phosphorus in more developed areas, Phillips added.
"We have to do everything we can to work with the agricultural community and work with our local governments to find solutions to better control phosphorus," Swanson said.
More than half of Maryland's farms have phosphorus running off into waterways, and animal manure accounts for 59 percent of the phosphorus spread on fields to raise crops, Swanson told commission members in a briefing last month.
Poultry litter, a mix of chicken waste and wood shavings, is widely used as fertilizer on the Eastern Shore. Containing both nitrogen and phosphorus, farmers favor it as a cheaper alternative to chemical fertilizer.
The problem is two-fold, experts say. Farmers generally don't till their fields in an effort to prevent soil erosion, so the manure is spread on the surface, where it's more likely to wash off in a rain.
Second, because corn, soybeans and other crops need more nitrogen, the phosphorus from the fertilizer builds up in the ground. After repeated annual applications, phosphorus can become so concentrated that it no longer binds to the soil and dissolves in rainfall runoff or shallow ground water, eventually reaching streams and rivers.
Kenneth W. Staver, a scientist at the University of Maryland's Wye Research and Education Center, said he and others have been saying for nearly two decades that phosphorus as well as nitrogen runoff must be controlled. Only in the last nine years or so haveregulators began requiring farmers to start curtailing how much phosphorus they put on their fields.
A new rule adopted last year should help, Staver said. Under it, Maryland farmers are no longer allowed to leave manure — or sewage sludge — on the surface when fertilizing their fields. They must, in most cases, work it into the soil within 48 hours of applying it.
Dealing with phosphorus buildup in soils is more problematic, and controversial.
Phillips said some rivers and streams may not be showing improvements yet because it can take years for the phosphorus built up in soils to come down. That could be the case in the Eastern Shore's Choptank River, where nutrient pollution levels are higher than they were 30 years ago.
While farmers in the Choptank watershed and elsewhere are planting winter cover crops and taking other steps to curb nutrient loss from their fields, "it could be we're still seeing the [delayed] effects of just overuse of fertilizer," Phillips said.
But on the lower Eastern Shore, he added, "I don't think it's lag time. It's just too much manure being applied."
Poultry industry supporters have argued that chicken manure is not responsible for rising phosphorus levels. They note that the number of chickens raised on the Delmarva Peninsula has declined in recent years, and the birds are fed an enzyme now that reduces the amount of phosphorus in their waste.
But a recent report to the bay program concluded that phosphorus produced by the chicken flocks raised in Maryland has increased. It suggested the birds being raised are larger, producing more waste, and the waste remains in the chicken houses longer before being cleaned out, increasing the concentration.
As part of Maryland's effort to comply with the bay "pollution diet" imposed by the EPA in 2010, the O'Malley administration pledged to tighten standards on where animal manure and sludge could be spread as fertilizer. Last year, the Department of Agriculture proposed new limits, but chicken growers warned they'd be hurt by having to find other ways of disposing of their birds' waste, and farmers said they would have to pay higher costs for chemical fertilizer.
Officials withdrew the rules for revision and the regulation is on hold, pending completion of a study this summer of the economic impact. State officials have said they intend to adopt the regulation by the end of the year, though they plan to phase it in over a period of years.
In the meantime, Swanson said, the EPA has questioned whether Maryland is on track to reach its phosphorus pollution reduction target by 2017.
But Lee Currey, director of science services for the Maryland Department of the Environment, said the state is on track. While it may not reduce farm-related phosphorus as much as the EPA would like, it will more than make up for it with the completion of upgrades to Baltimore's two large sewage treatment plants.
In more developed areas, stormwater runoff is blamed for rising phosphorus levels, but it's not clear what's happening or how to fix it, Phillips said. Federal scientists are analyzing the effectiveness of stormwater pollution measures in Montgomery County, he said, and also conducting a comprehensive study in Fairfax County, Va., to try to better identify how stormwater affects streams.
"Historically, we thought the lion's share of phosphorus is washing off the landscape," said William P. Stack, deputy director of the Center for Watershed Protection. "What we've found is a large percentage of the phosphorus — as much as 50 percent — is actually originating from stream-bank sediments."
Stack said that could mean efforts to control runoff are misdirected.
"If we're really going to put a dent in phosphorus, we really have to look at stream restoration practices," he said.
Alison Prost, Maryland director of the Chesapeake Bay Foundation, said the varying condition of rivers and streams suggests that the state can't rely on reducing phosphorus overall, but needs to address "hot spots" where the nutrient's levels are not declining or even increasing.
"It shows we cannot have a one-size-fits-all approach," she said. "We need to adjust."Copyright © 2015, The Baltimore Sun