Some still fret over Grace site

A recently released government report has dismissed the long-suspected link between groundwater contamination and cancer rates near the former W.R. Grace & Co. manufacturing site, straddling Acton and Concord, but some local residents and officials are still uneasy.

The federal Agency for Toxic Substances and Disease Registry and the state Department of Public Health last month presented findings that showed no definite link between chemicals from the Superfund site that leaked into the local water supply during the 1970s and a spate of cancers in Acton and Concord.

But weeks after the presentation, not everyone is completely satisfied with the report's findings and suggestions.

Doug Halley, Acton's health director, said he has concerns despite the reassuring tone of the report.

"Within the report," he said, "it seems to indicate no adverse effects, and yet the report recommends actions that are protective of public health. I am a little confused as to how that can be. If there are truly no adverse health effects, why the recommendations?"

The report recommends that the Acton Water District continue to monitor wells and treat its water to remove any volatile organic compounds, including vinyl chloride and benzene. Also recommended was ongoing mitigation of areas with elevated levels of arsenic and manganese, and a moratorium on any new private wells near the site's ground-water plume.

Mary Michelman of the Acton Citizens for Environmental Safety, who has followed the site cleanup closely for years, said she remains wary.

"We look at the details - that is where things matter," she said, noting that the report's conclusion of "no apparent health risk" for local residents does not mean the same as "no health risk."

Michelman said she wants the public as protected as possible. "They are not finding anything blatant or anything they consider apparent, but it doesn't mean people are not at risk," she said, adding that trespassers on the property could still encounter high levels of arsenic and manganese in sediment around Sinking Pond and the North Lagoon Wetland, where cleanup continues.

The town first found that contaminants had been leaking into two of its wells, which supplied 40 percent of its water, in 1978. W.R. Grace, which produced concrete, container sealing compounds, latex products, and paper and plastic battery separators, ceased its on-site waste discharges two years later. In 1983, the property was declared a federal Superfund site, and the cleanup began.

But although local residents have had concerns about high rates of leukemia and bladder, brain and central nervous system, kidney, liver, and lung cancers in the area, and suspected a link to the water contamination, the Department of Public Health concluded they were similar to cancer rates in the general population when all risk factors - smoking, drinking, age, and occupational exposure - were considered.

Suzanne Condon, director of the Department of Public Health's Bureau of Environmental Health, said that two cancer rates stood out, but that their overall emergence patterns point to many possible causes, not the contamination. Brain cancer in Acton and leukemia in Concord in an area close to the Grace site were both elevated in the 1980s through the early 1990s, she said. But since 1994, rates have dropped, she said, indicating other cancer-causing agents not related to the contamination played a role. Because many cancers develop slowly, she says, the reverse pattern would have caused more concern.

"It really looks like it was a mix of different factors," said Condon. "But we will continue to monitor outcomes to see if any patterns reemerge."

Robert Knowles, the lead health assessor for the Agency for Toxic Substances and Disease Registry, an arm of the US Centers for Disease Control and Prevention, said local residents "should be reassured" by the findings in the agency's report. Although residents may have been exposed from 1970 to 1978, Knowles said, the exposure is not considered high enough to cause problems.

"Adverse health effects are not likely," he said.

The Acton Water District today tests and treats the water from five wells near the Grace site for contaminants, which are removed by an air-stripping process before the water is released to the public water supply, and stringent guidelines for water safety are in place, said district manager Chris Allen.

"I am confident that they are taking the necessary steps," he said about the cleanup.

Derrick Golden, remedial project manager for the federal Environmental Protection Agency, said plans for further cleanup are in the design stage and remediation will be slow and steady. Construction of a new ground-water treatment system to remove inorganic chemicals could take up to five years, he said.

The town is compiling comments to respond to the report, and residents are invited to submit questions. The remarks will be recorded and included in the Agency for Toxic Substances and Disease Registry's final health assessment. The final day for submitting comments or questions is Sept. 30.