|Toxic exposure levels from hazardous-waste sites are typically low, making it difficult to demonstrate a clear health impact.|
The military says these waste-disposal methods were typical because, at the time, the substances were not considered to be particularly hazardous.
Today, Air Force officials say they sympathize with people's concerns, but caution that there's a great deal of misinformation floating around. Although the well on the base was closed in 1985 because it contained harmful chemicals, there is no scientific evidence showing that the pollutants caused any health problems for people who drank the well water, military officials say.
A 1991 study by Boston University researchers suggested that the incidence of cancer in Bourne may be linked to environmental factors, but suspicions don't equal proof, says Robin Wagner, an epidemiologist for the Agency for Toxic Substances and Disease Registry, or ATSDR, a federal agency based in Atlanta.
One impediment to finding a clear connection, say Wagner and the Boston University researchers, is that toxic exposure levels from hazardous-waste sites are typically very low, making it difficult to demonstrate a clear health impact. People exposed to toxic materials may also come into contact with many chemicals simultaneously, complicating the research further, Wagner says.
"There's a lot of uncertainty, and it's very difficult to demonstrate a cause and effect from these low levels of exposure," she says.
But some teachers and principals who have worked in the base schools don't need hard data to convince them that something is awry.
For them, one set of statistics says enough: The incidence of cancer in Bourne was 17 percent higher than what researchers would have expected based on figures for the state as a whole, according to a Massachusetts Department of Public Health study of cancer incidences and rates between 1987 and 1992. Breast-cancer incidences in Bourne were 32 percent higher than in the rest of Massachusetts, and lung-cancer occurrences for women living in Bourne were 78 percent above the state average, said Robert Knorr, an epidemiologist with the state health department.
Many Bourne school employees attach names and faces to those numbers.
|The incidence of cancer in Bourne was 17 percent higher than what researchers would have expected based on figures for the state as a whole.|
"I know several teachers at base schools that have developed cancer, and I worry about what's going to happen down the road," says Jan Kemmitt, who has been a 2nd grade teacher at the Otis Memorial School on the base for 14 years. Kemmitt arrived at the school six years before the military reservation landed on the EPA's national-priorities list of hazardous sites in 1989.
Kemmitt remembers in 1985 when the military closed down one of the wells that supplied drinking water to the Lyle, Otis, and Stone schools after military and local health officials discovered that the water harbored unsafe levels of perchlorethylene, or PCE, a solvent that has been shown to cause cancer in laboratory animals.
When it was closed, the well contained 42 parts of PCE per billion; more than five parts per billion is considered an unacceptable level by the AFCEE.
The schools subsequently were hooked up to another base well with a clean water supply. Although teachers and students are no longer dipping into the polluted water 150 feet beneath them to brew their coffee and wash their hands, the schools' well is still tested each month. Military officials say the schools' water supply is perfectly safe.
"The contamination is well below the school; it's sliding quietly underneath," says Minior, the senior environmental engineer with AFCEE. He adds that it holds no risk for Bourne schoolchildren.
As for the dirt from the Campbell School becoming a toxic cloud, Minior says there is no danger because there's no real exposure. "The [contaminated] dirt is in the soil beneath the grass," he says.
In addition, officials with AFCEE, which assumed control of the cleanup effort from the National Guard last year, say they are taking every precaution to minimize exposure risks.
This month, teams of engineers, construction workers, and hydrogeologists will continue to fan out across the sprawling military installation and several Cape Cod towns affected by the pollution.
Since the cleanup operation began in 1989, the military has installed more than 2,500 monitoring wells on and off base to track the 10 plumes, or streams of contaminated ground water, that flow through the Cape's sandy soil. Air Force workers continually draw samples from these marker wells to enable mapmakers to outline and gauge the movement of the contaminated streams, which so far have polluted 70 billion gallons of ground water, according to AFCEE.
|About 150 parents and teachers are appealing to their neighbors to relocate students to what they consider to be safer ground.|
The military also has erected three water-treatment facilities to extract, filter, and reintroduce clean water into the ground.
"We want to stop these plumes in their tracks to keep them from migrating," says Lee E. Perry, an environmental engineer for AFCEE, touring the facility with several colleagues. Inside the vast building, four huge cylinders of carbon filters tower over workers in hard hats. "We have confidence that the water we pump up will be pumped down clean," Perry says.
Even so, the AFCEE estimates it will take about 50 years to purify all of the contaminated water in the aquifer because the geological complexity of the western edge of the Cape makes the water move fast and in different directions at the same time.
Perry and other engineers involved in the cleanup note that tracking the migration of the plumes is not a precise science. "Nature isn't exact," Perry says. "There's no way to tell what's in the ground everywhere."
Just last month, the state health department found that 27 acres of cranberry bogs in the neighboring town of Mashpee had been contaminated by airplane fuel bubbling up from the aquifer.
Most times, ground water goes in a linear direction, but here it's like spokes of a wheel, says Johanna Hunter, an EPA spokeswoman.
Hunter admits the cleanup effort has moved at a sluggish pace in the past. The military has spent more than $200 million since it began in 1989, and three-quarters of the money has been used for research, according to AFCEE.
Karen Florini, a senior attorney with the Environmental Defense Fund, a Washington-based environmental-research group, contends that the EPA moves most slowly when confronting federal government bureaucracy. "When EPA is dealing with private parties they can say, 'Just shut up and do it,' but when Uncle Sam is wearing two hats it's easier to have arguments," Florini says.
However, Hunter contends that the Air Force has made "significant strides" since it took over cleanup responsibility from the National Guard last year--a move the EPA facilitated.
About 150 parents and teachers nonetheless are appealing to their neighbors to relocate students to what they consider to be safer ground. So far, members of the informal coalition seem to be waging an uphill battle, despite regular reports in the local paper, the Cape Cod Times, about the contamination and the slow pace of the cleanup and a spate of town gossip about what federal, state, and military officials could be hiding.