New analyses of birth outcomes and rates of cancer in south Washington County released by the Minnesota Department of Health this week show that there may not be higher instances in the east metro, after all.
MDH scientists found that rates of cancer, low birth rates and premature births in Washington and Dakota counties are in line with other areas of the metro, the department announced Feb. 7.
Residents in Washington County have long worried that perfluorochemicals groundwater pollution in the area has caused higher rates of cancer or other adverse health effects.
The new analyses began in the fall, assistant commissioner Paul Allwood said, based on those concerns. Allwood said concerns increased after new files were submitted as court materials for the trial in which Attorney General Lori Swanson is seeking $5 billion in damages from 3M.
Materials submitted in November for the trial set to begin Feb. 13 included a study that points to a higher incidence of infertility in women and lower birth weights in Oakdale, which hosted one of three dump sites 3M used decades ago and were polluted by PFCs.
Swanson's expert witness, a natural resources economist David Sunding at the University of California-Berkley, found mothers 34 percent more likely to deliver underweight babies compared to other parts of Washington County between 2001 and 2006 after reviewing birth and death records. After the city switched to non-contaminated water in 2006, low birth rates declined by 13 percent, Sunding found.
"In response to the concerns ... we reviewed data available to us that would indicate whether there were higher (rates) or not," Allwood said. "(It's a) newer look at what's happening in the community."
MDH scientists used 25 years of data from the Minnesota Cancer Reporting System and birth records from three time periods between 2001 to 2015. The department reported that those reports do not specifically link PFCs to adverse health effects.
The areas included in the analyses were Cottage Grove, Hastings, Lake Elmo, Newport, Oakdale, St. Paul Park, South Saint Paul and two zip code areas within Woodbury, and compared those areas to the rest of the seven-county metro area. The birth outcome analysis also compared the region to the 18 other zip code areas in Washington County.
Allwood said there has not been "any kind of systematic review of birth outcomes and PFC contamination" before.
The birth outcomes analysis found that people of color and native Americans have higher rates of low birth weights and premature births, results that are common in other studies, MDH Epidemiologist Jessie Shmool said.
"There's no way to link these health outcomes to PFC exposures," she said.
Among all the data, though Shmool said though there is "lot of variation" it's not out of line with the rest of the metro.
"What we found is that trends over time and across the communities we compared were all very similar," she said. "We did not see any trends in the nine zip codes within the PFC plume."
The MDH and Pollution Control Agency announced new health-based recommendations last May for PFC compounds PFOA and PFOS, lowering them from 70 parts per trillion to 35 parts per trillion for PFOA and 27 parts per trillion for PFOS. The federal Environmental Protection Agency recommendation remains 70 parts per trillion.
Environmental Health Manager Jim Kelly, who helped announce the new lowered values last summer, said after the new analyses the MDH is confident that the levels are "protective based on the most vulnerable populations."
Cottage Grove is in early stages for a water treatment facility to ensure all city water will be below the health-based values. There are currently two temporary treatment facilities operating to keep the water below the values.
In the past, studies have found that PFCs may increase the risk of thyroid disease, lowered immune responses, liver and kidney function and testicular cancer. The MDH will not be conducting their own studies on those, Allwood said.
"What we're doing is that we are monitoring the science very, very carefully," he said. "And then we provide protective recommendations ... based on these analyses. We think the recommendations are having a good effect."
"But that doesn't mean PFCs are not a health risk," he added. "They are."