Dioxin in Midlanders' blood
08/15/2006
Kathie Marchlewski , Midland Daily News

People whose yards have higher levels of dioxin also have higher levels of dioxin in their bodies.

Specifically, people living in Midland and Saginaw counties near The Dow Chemical Co.'s Midland plant have higher levels of the toxin in their blood than people living in Jackson and Calhoun counties -- where there is no Dow plant and where dioxin levels are similar to levels across the country.

Dr. David Garabrant, University of Michigan professor leading the $15 million Dow-funded study, will release the results of a two-year dioxin exposure study today at a 1 p.m. meeting of more than 100 stakeholders including local government officials, health departments and environmental groups. The public is invited to a 6 p.m. meeting today at Saginaw Valley State University, Curtiss Hall. The study has been available on line since this morning at its homepage, www.umdioxin.org.

The study examined exposure levels only, not potential health effects. Whether the results are good or bad and for whom remains a question.

"Our job was to go out and find facts, and we did find facts," Garabrant said. "I don't know if you'd say it's good or bad for anyone. We found that what's in the environment is contributing to what's in people's bodies, but it's small."

The study shows that people living in the control group in Jackson and Calhoun counties -- chosen for its demographic likeness to Midland and Saginaw counties -- have median levels, the level at which half are above and half below, of 25 parts per trillion of dioxin in their blood. People in the Tittabawassee River floodplain have 32 parts per trillion, people near the floodplain have 29 parts per trillion, and people in Saginaw and Midland but away from expected contamination have a median of 28 parts per trillion. People who live in Midland north and northeast of the Dow plant had a median level of 24 parts per trillion.

In Jackson/Calhoun, 25 percent of people had levels higher than 36 ppt in their blood, but in the floodplain, 35 percent had levels higher than 36. Overall, floodplain residents' levels were 28 percent higher than Jackson/Calhoun's residents.

"The absolute increases were small, but sometimes the percentages were not," Garabrant said.

Fluctuations in dioxin levels across populations are attributed to factors such as age, sex and body mass index, or the amount of fat a person has. But the U-M study identified a variety of factors that contributed to higher dioxin levels in residents here, including recreational activities such as swimming, biking, hiking or picnicking on the Tittabawassee River, the Saginaw River and Saginaw Bay, working at Dow, and gardening.

Eating fish also raised dioxin levels in the blood. That's the case for fish that is store bought, caught elsewhere, or caught from the Tittabawassee River, Saginaw River or Saginaw Bay, but especially the locally contaminated fish. "We can see an overall indication that eating fish contributes to your body burden," Garabrant said.

The study showed that levels increased by 1 to 2 percent for each year a person reported eating fish from the Tittabawassee River, Saginaw River and Saginaw Bay. Eating other wild game, such as deer or turkey, did not appear to affect levels.

One participant who look part in the study -- there were 1,324 in all, 946 of whom gave blood -- had a blood level of 240 parts per trillion, far higher than the around-50 ppt level that would be expected for that person's age. More than a dozen people had levels higher than 100 parts per trillion.

Age is an important factor in dioxin levels, and was in this study. Garabrant said the population in Jackson/Calhoun counties was an average of four years younger than those living on the floodplain. "The longer you live, the longer you are in contact with dioxin," he added.

Older people have higher levels of dioxin in their bodies no matter where they live -- during the 1970s, contamination in the national food supply was at its peak -- but the study found the age factor to be amplified for people who lived in Saginaw and Midland between 1940 and 1959, and attributes the increase to Dow's operations during that time period.

The study's findings are not isolated to the Tittabawassee River or areas of Midland known to be contaminated. People who lived outside of known contamination areas but in the Saginaw Valley region also had higher levels of dioxin in their blood.

Activities, age and eating habits aside, residing on contaminated soil was found to increase levels of dioxin in the blood by about 2 percent. Researchers found that for each 1,000 parts per trillion of dioxin in soil -- the highest level found in this study was over 15,000 -- the level of dioxin in blood increased by 0.7 ppt.

"It looks like a small number in magnitude, but it is statistically significant," said Alfred Franzblau, professor of occupational medicine at U of M.

Statistically significant means the difference is unlikely to be due to chance. What is biologically significant remains a matter of opinion.

Dow officials have said that according to company studies, dioxin has no ill effects on people other than chloracne, a skin disease made widely known by the poisoning of Ukraine President Viktor Yushchenko. Linda Birnbaum, of the Environmental Protection Agency and a world-renowned dioxin expert, however, told Midlanders last year in a presentation that scientific studies show repeated links between dioxin exposure and disease -- even at background levels in the general population. "We have strong and repeated associations in human studies," she said. "We believe they are real."

She acknowledged it is impossible to tell on a case-by-case basis if a health issue is the direct result of dioxin. Cancer is one such example: The risk because of dioxin exposure is slight when compared with the already existing risk for developing the disease. One in three, maybe one in two, people will develop the disease in their lifetimes, Birnbaum said. Dioxin exposure is expected by some to add a nearly invisible additional risk of 1 in 1,000.

But there are host of other health effects associated with dioxin, including reproductive issues, birth defects and diabetes, she said.

Garabrant stressed that the dioxin exposure study is not an indicator of potential health effects. It answers only the question of whether people have dioxin in their bodies as a result of living on dioxin-laced dirt.

Garabrant said the team of researchers plans to present its work at an international conference on dioxin this month, and will return to the Saginaw Valley region beginning this fall to host technical meetings, open to the public, on the findings. A portion of the study analyzing other dioxin congeners is not complete, but will be presented as it is finished.

People's dioxin levels higher in mid-Michigan What: University of Michigan dioxin exposure study shows that living in areas contaminated with dioxin leads to higher levels of the toxin in blood.

How they know: They took blood samples from people, and sampled dust in their homes and soil on their property. They compared those with samples from Jackson and Calhoun counties, where dioxin levels are not elevated.

What it means for your health: That question remains unanswered. The study wasn't a health study, so it doesn't indicate if the levels affect health.

Everyone has dioxins in their bodies, most of it from food they buy in the grocery store. Some scientists believe even background levels are dangerous; some say not.

What's next: Study leader Dr. David Garabrant will share findings at a public meeting, 6 p.m. tonight at Saginaw Valley State University, Curtiss Hall.

Preview online: Review the results at www.umdioxin.org .

©Midland Daily News 2006
 

For additional articles like this one, go to the Tittabawassee River Watch web site www.trwnews.net for complete coverage of the Tittabawassee River Dow Chemical dioxin contamination saga. . The Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The source organization's web site link is listed to the right of the article, visit often for other news in our area. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.