Kathie Marchlewski, Midland Daily News 07/14/2005
Michigan Department of Community Health officials acknowledge that results of a pilot dioxin exposure study are not an indicator of regional exposure, but a survey of the worst first. Because the study included only 20 people living on 15 properties in the dioxin-contaminated Tittabawassee River flood plain, the state cautions against reaching broad conclusions, but announced it did find higher-than average levels of dioxin in the bodies of people who were tested.
"The results aren't surprising to us," MDCH spokesman T.J. Bucholz said. The department specifically sought properties and people expected to have the highest levels of contamination, based on previous soil sampling conducted by the Michigan Department of Environmental Quality.
But the primary goal of the study was to test study design and feasibility. The report released Wednesday includes a plan forward: a public action plan suggesting the possible development of a comprehensive, MDCH-conducted exposure study. It also discusses the possibility of a health outcome study that would determine if there are increased rates of disease for people living in or near the flood plain.
"It's too soon to tell what we might do next," Bucholz said.
"First we need to determine if there's a need (for further study)," he said. "It's going to be dependent on public comment."
The public has 60 days, until Sept. 11, to comment on the pilot investigation.
Another dioxin exposure study is under way by the University of Michigan, funded by a grant from The Dow Chemical Co., but Bucholz said he doesn't know if it suits MDCH needs.
"This is a study that, while conducted by an outside agency, is funded by Dow," Bucholz said. "We're interested in results, but that doesn't preclude us from doing our own (study)."
He said the departments don't know where the money to conduct such studies would be found.
Dr. David Garabrant, who is leading the $15 million U-M study, said he doesn't think an additional study at additional expense is necessary. "Ours will be conclusive," he said. Already on-task with results expected in 2007, dioxin exposure study scientists are looking at soil, household dust and blood levels from properties and people in the flood plain, in the Tri-City area and in Jackson and Calhoun counties. "When the results are ready, they will allow us to make inferences about whether averages are the same or different," Garabrant said.
The goal is to provide a basis for determining whether a full-blown health investigation needs to take place. If dioxin levels found in people in the flood plain are not higher than levels in people who don't live on contaminated soil, there would be no evidence of unusual exposure or a need for further study.
The U-M study uses a methodology similar to that used in the MDCH pilot study, but is far broader. Garabrant said he would be cautious about interpreting the results of the preliminary state study. "It's a highly biased sample," he said.
MDCH acknowledges the same. Along with testing protocol, its purpose was to learn levels of dioxin in the bodies of a limited number of people.
What it found was that while all levels were above the average expected, all fell between the lowest and highest levels for people with no known exposure to dioxin beyond what generally occurs.
Of the 20 participants, some had levels higher than what would be expected in 90 percent of the population and some higher than what would be expected in 95 percent of the population. The average expected for people aged 45 to 59 is 16.9 parts per trillion, while the average for the age group within the MDCH study was 26.8 ppt.
The background expected for the general population of people over the age of 60 is 36.1 parts per trillion. In the MDCH group, the average for that age was 40.2 ppt.
The Pilot Exposure Investigation Report is titled "Dioxin Exposure in Adults Living in the Tittabawassee River Flood Plain" and is available on the MDCH website, www.michigan.gov/mdch-toxics, or by calling (800) 648-6942. Reports are also available locally at the Grace A. Dow Memorial Library and the Midland County Health Department.
Comments should be addressed to Dr. Linda Dykema, MDCH, Division of Environmental and Occupational Epidemiology, 3423 North Martin Luther King Jr. Blvd., P.O. Box 30195, Lansing, MI 48909. People also may call (800) 648-6942. Comments must be received by Sept. 11.
©Midland Daily News 2005
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