By AMANDA PROSCIA
Capital News Service
LANSING — The air near a mid-Michigan chemical plant that was closed for cleanup nearly 40 years ago because it threatened the environment remains contaminated with chemicals, according to a new study.
The study concludes that people living within six miles of the 54-acre former site of the Velsicol Chemical Co. “are still being subject to relatively high levels of HBB, PBBs, and DDTs in the air they breathe.” It was published in the journal Environmental Science and Technology.
Those are among the chemicals that prompted federal regulators to designate the chemical factory in St. Louis, Mich., a Superfund site in 1982. The cleanup of that site, the nearby Pine River and the city itself has cost millions of dollars and continues.
“People can’t control what they breathe,” said Angela Peverly, lead author on the study at Indiana University, explaining the significance of the research.
The study does not conclude whether the air contamination can cause immediate or long-term harm to human health. However, it could heighten awareness of the contamination and possibly encourage outside help to assess that health threat, said Marcus Cheatham, health officer for the Mid-Michigan District Health Department, which serves Montcalm Clinton and Gratiot counties.
His agency has helped Emory University in Atlanta draw the blood of St. Louis residents who are concerned about the contamination. Emory University is providing toxicology testing.
The health agency is looking for a definitive dangerous threshold of contamination in humans so it can educate area residents about what medical tests are needed and at what levels they should be performed, Cheatham said.
The researchers tested for an alphabet soup of chemicals that the Velsicol plant used to produce. DDT is the pesticide dichlorodiphenyltrichloroethane. PBB refers to the fire retardant polybrominated biphenyls. And HBB is hexabromobiphenyl, a chemical related to PBB. For comparison, they also tested for other chemicals not produced by Velsicol.
“Clearly, the levels of HBB, DDT, and PBBs are elevated close to the manufacturing site with a sharp decrease” after six miles, the study said.
To assess air quality, researchers studied tree bark surrounding the Velsicol site. Bark gives an accurate measurement of atmospheric conditions over three to 10 years, the amount of time the bark is on the tree, she said.
Researchers collected 43 bark samples throughout central Michigan. The large sample area allowed them to check for patterns of concentrations. They tested different trees at each site.
The study found that concentrations of DDT, banned in the United States in 1972, are about 18 times higher in bark collected near the Velsicol site than that from more than half a mile from it.
According to the Centers for Disease Control and Prevention, exposure to DDT “could possibly cause cancer in humans.” Less severe effects of DDT exposure include headache, dizziness, nausea, vomiting, and tremors, with symptoms subsiding once exposure has ended.
The U.S. Environmental Protection Agency is now overseeing the replacement of DDT-contaminated soil in nearly 100 residential yards in St. Louis.
Cleanup experts say that wind blew much of that contamination from the nearby factory site to the yards before the site was cleaned up. That cleanup was sparked in part by the discovery of birds that died from exposure to DDT.
Concentrations of PBB were at least 100 times higher in bark within a half of a mile of the site than in bark 60 miles away, the study reported.
HBB concentrations were about 150 times greater within a half of a mile of the site than those farther away.
PBB exposure has been linked to a number of health problems, but it cannot be fully established that PBB is the sole cause of those problems, according to the federal Agency for Toxic Substances and Disease Registry.
According to the agency, “If you breathe air that contains PBBs, or swallow food, water, or soil contaminated with PBBs, they can enter your body through your lungs and stomach and pass into the bloodstream.” However, little is known about the health of people who are exposed to low levels of PBBs for long periods by eating, breathing, or skin contact.
Jane Keon, secretary of the Pine River Superfund Citizen Task Force, said that even if the highest DDT concentration found in the bark doesn’t adversely affect people, its ecological effects are unknown.
The EPA has been removing trees from the city as part of the cleanup and offering the wood as firewood, she said. Keon said the agency should stop giving it away as firewood.
Instead, the trees should be burned in an incinerator or buried in a hazardous waste disposal area, she said.
The EPA did not respond to requests for comment.
According to the researchers, the new report is the first published study concerning air quality around the Velsicol Superfund site. In 2000, the EPA monitored air quality during attempts to remove contamination but the EPA did not release the data.
The study suggests that there should be air monitoring of all Superfund cleanup sites, especially those sites requiring soil
remediation, Peverly said.
Amanda Proscia writes for Great Lakes Echo
Additional resources for CNS editors:
Study “Air is Still Contaminated 40 Years after the Michigan Chemical Plant Disaster in St. Louis, Michigan,” http://pubs.acs.org/doi/abs/10.1021/es502809f
By AMANDA PROSCIA