The good news about toxic pollutants in the air, soil, and water is that overall levels are coming down. But according to the Environmental Protection Agency some of the most toxic substances - mercury, dioxin, lead, and PCBs - remain an increasing problem.
The recent announcement of another round of military base closures could put more focus on the problem of toxic waste and how to solve it.
The EPA notes significant pollution problems at some 100 military bases, and 34 already-shuttered bases are among the most toxic "Superfund" sites, according to an Associated Press survey. Problems persist with such hard-to-remove contaminants as cleaning solvents, asbestos, radioactive materials, unexploded ordnance, and lead paint. The Pentagon already has spent $8.3 billion cleaning up recently closed military sites, and the total bill could top $12 billion.
All of this makes it difficult for the Pentagon to convert such facilities to state or privately owned properties, the Government Accountability Office (GAO) reported recently. In most cases, it takes years, if not decades, to finish the cleanup. In some places, for example, poisonous chemicals have seeped into groundwater flowing off-base.
According to the GAO, which looked at the previous four rounds of base closures going back to 1988, 28 percent of the total acreage has yet to be transferred "due primarily to the need for environmental cleanup."
While new base closures announced last week will add to that problem, total amounts of toxic pollution in the US environment have edged down.
In its latest annual Toxics Release Inventory, which covers more than 23,000 facilities and about 650 chemicals, the EPA reports that 4.4 billion pounds of toxic chemicals were released in 2003 (the latest available figures), about 6 percent less than the previous year. Most of the decrease was in metal mining and chemical manufacturing. Since 1998, before which fewer chemicals and fewer facilities were reported, toxic releases have gone down 42 percent.
At the same time, EPA officials and environmentalists note the worrisome release of persistent bioaccumulative and toxic chemicals (PBTs), which increased by 50 million pounds or 11 percent in the latest reporting year. These include dioxins, mercury, and polychlorinated biphenyls (PCBs).
"PBT chemicals are of particular concern," reports the EPA, "not only because they are toxic, but also because they remain in the environment for long periods of time and are not readily destroyed (they persist) and build up or accumulate in body tissues (they bioaccumulate)."
In 2003, for example, mercury and mercury-compound releases jumped 41 percent. Mercury is a highly toxic substance that can poison wildlife and cause brain and nervous-system damage in children and fetuses. Unlike most other pollutants, mercury tends to concentrate in dangerous "hot spots."
"Although it is good news that overall releases are back on track, it is a major concern that some of the most hazardous chemicals have increased so dramatically," says Meghan Purvis, an environmental health specialist with US Public Interest Research Group in Washington.
Meanwhile, according to the watchdog group Environmental Integrity Project, the 50 dirtiest among the nation's 359 largest power plants generate as little as 14 percent of the electric power but account for a disproportionately large share of pollution emissions: up to 50 percent of sulfur dioxide emissions, 42 percent of mercury, 40 percent of nitrogen oxides, and 35 percent of carbon dioxide.
"A huge share of these emissions comes from a handful of unnecessarily dirty power plants that have not yet installed modern pollution controls, or which operate inefficiently," says Eric Schaeffer, director of the Environmental Integrity Project and the EPA's former chief of regulatory enforcement.
Others take a longer view of pollution in the United States.
"In reality, the data is very clear," says Scott Segal, director of the Electric Reliability Coordinating Council in Washington, which lobbies on behalf of power plants and utilities around the country. "Power-plant emissions, along with other indicators of air quality in the United States, continue to improve as part of a trend dating back several decades."
"With a decade of compiled research ... we've found that it is nearly impossible to paint a grim, doom-and-gloom picture anymore," says Steven Hayward of the Pacific Research Institute, a free-market think tank in San Francisco that copublishes the "Index of Leading Environmental Indicators" with the American Enterprise Institute in Washington. "The facts speak for themselves, and the facts are hugely encouraging."
Other more recent facts may be less encouraging, however. For example, the Sierra Club reported last month that leaky underground storage tanks "are a growing threat to public health."
In all, there are some 130,000 leaking tanks around the country, including 17,544 needing cleanup in Florida, 15,049 in California, 9,039 in Michigan, and 1,221 in Tennessee.
"More than 100 million people drink groundwater in states where thousands of underground storage tanks are leaking and need cleanups," says Grant Cope, a toxics specialist with the Sierra Club. "These sites include toxics like benzene, toluene, and heavy metals that can quickly pollute groundwater, threaten public health, burden taxpayers with cleanup costs, and hurt real estate values.... A pin-prick sized hole in one fuel tank can leak 400 gallons of contamination a day, and one gallon of gasoline can pollute one million gallons of groundwater."