$15 Million U-M Michigan Dioxin Exposure Study Released

Aug 15: People living in parts of Midland and Saginaw counties, near the Dow Chemical Co. plant have higher levels of dioxins in their bodies than a control group of people elsewhere in Michigan, according to a University of Michigan study released August 15, 2006. The $15 million U-M Dioxin Exposure Study was financed by a grant from Dow Chemical and was controlled and conducted entirely by U-M researchers. Research decisions were reviewed by an independent scientific advisory board. U-M researchers spent two years studying residents in five geographic areas.

The report indicates that in the Tittabawassee River floodplain near Dow, one of the geographic areas studied, people had 28 percent higher median levels of total dioxin-like chemicals in their blood than people in a control group in Jackson and Calhoun counties. Dioxins are toxic chemicals. They had 32 parts of dioxins for every trillion parts of blood, compared to 25 in people living in Jackson and Calhoun counties.

The Jackson/Calhoun region was used as a comparison because it is similar to Midland/Saginaw but is more than 100 miles away from the Dow plant. Dioxin levels in Jackson/Calhoun residents are close to the national median level. According to a release, much of the increased amount of dioxins in Midland/Saginaw residents was related to age. Nationally, older people have higher dioxins levels. People in Midland/Saginaw tend to be older than people in Jackson/Calhoun. Some of the increase was associated with eating certain foods such as fish from local waters contaminated by Dow and other sources, engaging in recreational activities on or near contaminated waters, or having worked at the Dow plant from 1940 to 1959. A small portion of the increase was related to living on soil contaminated by Dow, the study found.

U-M scientists studied levels of dioxins in people’s property soil, household dust and blood samples, and interviewed residents about their age, body mass, dietary habits, land use, occupation, and other personal details. A total of 695 Midland/Saginaw residents and 251 Jackson/Calhoun residents gave blood samples. Participants in the study were at least 18 years old. The researchers found that the median level of dioxins in soil in Jackson/Calhoun, the control area, was 4 parts per trillion -- 4 parts of dioxins for every trillion parts of soil. The median levels in Midland/Saginaw ranged from 4 parts per trillion in the near-floodplain area to 13 in the floodplain and 59 in the area downwind of Dow. The researchers found that people who lived in Midland/Saginaw on property with contaminated soil had higher median levels of dioxins in their blood. If the dioxins in their soil increased by 1,000 parts per trillion, the dioxins in their blood increased by about 0.7 parts per trillion (a 2 percent increase over the average level of blood dioxin for most people).

Access a release (click here). Access the U-M Dioxin website for the complete report, handouts, presentations, information on meetings and background information (click here). Access the WIMS-EcoBizPort Special Report on Midland Area Dioxin Issues for further background information and links to additional resources (click here). [*MIToxics]