Toxic mercury, cattail-feeding phosphorus and other pollutants continue to plague the Everglades, despite the billions of dollars spent so far on cleanup and restoration efforts, federal scientists reported today.

The study by the U.S. Environmental Protection Agency found some declines in pollution, including a sizable drop in mercury during the past decade in the tissues of fish. But it also concluded that fish mercury levels remain unacceptably high.

Meanwhile, the Everglades shows no signs of reversing the massive loss of peat soil it experienced because of drainage in the 20th century.

And while phosphorus has declined in the Everglades' water, a larger swath of the marsh's soils had excessive levels of the pollutant than in the mid-1990s, the EPA reported. Phosphorus from farm runoff, suburbs and Lake Okeechobee is the main target of Florida's Everglades cleanup program, which has provoked a nearly 20-year-long court battle among the state, the feds, sugar growers and environmental groups.

The report may mean that "things aren't getting any worse," said Mark Kraus, vice president of the not-for-profit Everglades Foundation, after reading some of the findings. But he added, "Things are really horrible and we need to do something about it." EPA representatives said the state's cleanup efforts appear to be having some success - for instance, in limiting the phosphorus-laden compounds that wash into the Everglades. But they said the report points to the need to continue the state and federal governments' restoration programs, which congressional auditors have said will likely cost more than $20 billion.

People should not interpret the shortcomings as signs of failure, the EPA officials said.

"Everyone recognizes that there's more to be done here," said James Giattina, director of the agency's water management division in Atlanta.

Leaders of the South Florida Water Management District agreed with that statement. "It took decades to get us where we are," said Chip Merriam, a district deputy executive director. The district estimates that Florida has spent almost $4 billion on Everglades cleanup and restoration programs.

But veteran Everglades researcher Ron Jones said the main conclusion he draws is the continuing harm the Everglades is suffering from polluted runoff. He noted that the district's massive filter marshes south of Lake Okeechobee still don't meet the state's strict phosphorus limit of 10 parts per billion.

The report "puts some spin on the water getting a little bit better, but in the next sentence they say the Everglades is going down the tubes," said Jones, a professor at Portland State University in Oregon. Jones, who led an earlier version of the EPA study in the 1990s, also has assisted the Miccosukee Indian tribe in its Everglades pollution lawsuits against the state.

The new report points to some enduring mysteries and paradoxes in the Everglades, which spreads from Wellington's fringes to Florida Bay.

For instance, the scientists found that mercury levels in water were highest in the northern Everglades, including the Arthur R. Marshall Loxahatchee National Wildlife Refuge in Palm Beach County. But in the tissues of fish, the highest mercury levels occurred much farther south, including inside Everglades National Park.

State regulators had already noted sharp declines in mercury levels in fish and the feathers of wading birds. But they're still concerned about high levels of mercury's most toxic form, a neurotoxin that accumulates as it moves up the food chain. Scientists are still debating the causes of that buildup.

Health officials advise people to limit the consumption of largemouth bass and other fish caught in the Everglades because of mercury. In some cases, they say, people should avoid the fish altogether.