EPA, U-M disagree over Dioxin study
 By Tony Lascari tlascari@mdn.net Published: Thursday, October 22, 2009 12:24 PM EDT

U.S. Environmental Protection Agency officials and University of Michigan researchers disagree about the usefulness of the U-M Dioxin Exposure Study.

The two groups explained their positions at a meeting Tuesday night in Saginaw, with the U-M researchers standing behind their work and EPA officials saying it doesn't look at the right populations to measure the risks of exposure.

The U-M study looked at more than 900 people's exposure to dioxin and similar compounds. The contaminants are known to have been released by The Dow Chemical Co. into the Tittabawassee River. They also were released from an incinerator at Dow, resulting in a plume of contamination in Midland.

The study showed factors such as having contaminated soil or household dust were not important contributors to levels of dioxin in a person's blood, but demographic factors such as increased age, dietary choices and being overweight were factors. It found that properties in the Midland area have higher dioxin concentrations in their soil and local people have higher blood levels than a reference area in Jackson and Calhoun counties. Researchers gathered data in 2004-05 through an unrestricted grant from Dow.

Jeff Frithsen, of the EPA's National Center for Environmental Assessment, said the study is the largest of its kind, used sound scientific methods and offers valuable, valid data. But, the EPA doesn't think it answers the questions needed for a risk assessment, which would look at people at high-risk for exposure, such as children, people who fish in the rivers or people who garden in the floodplain.

"The study design may not have completely addressed some of these other factors that contribute to blood serum levels of dioxin," he said.

Frithsen suggested the study should have more properties with soils that are highly contaminated -- not just the 23 it includes with levels above 1,000 parts per trillion.

Dr. David Garabrant, of the U-M School of Public Health, said he and others on the study team are analyzing data on fish consumption and compiling results that should be ready in December.

"We are currently doing exactly what you're asking for," he told the EPA staff at the meeting.

Peter Preuss, director of the EPA's National Center for Environmental Assessment, said information on the population consuming fish would "an important contribution."

Dr. Al Franzblau, who also worked on the U-M study, said with the EPA reviewing its remedial cleanup standards -- and possibly lowering it below the current 1,000 parts per trillion level -- it would make sense to consider the hundreds of properties that include lower quantities of contamination. Even if the EPA doesn't take those into consideration, the 23 highly contaminated properties are important, he said.

"We think 23 properties is enough," he said. "You may disagree."

The EPA also noted the study doesn't address exposure in children. Children were not studied for a valid reason, because the samples required for the study design were too large to take from children, Frithsen said. But, he said it would be important to look at children as part of a risk assessment because they are likely to be in more contact with, and ingest more of, the soils around a property.

Garabrant said it was not possible to study children, and U-M is not aware of any study that does.

"We'd like to include them but we can't because you can't get the amount of blood from a toddler to measure for dioxin," he said.

Frithsen said more data can be analyzed in the study and more sampling could take place to address the EPA's concerns.

"We recognize this is a work in progress," he said, suggesting U-M researchers might want to look at specific at-risk groups.

Garabrant said the study effort, now six years long, includes a lot of data that's still being looked at.

"This has been a huge undertaking, a huge study," he said. "There's no question it's relevant."

Some people in the audience suggested the EPA expedite its processes to resolve the contamination situation so the region can move forward.

Terry Miller, of the Lone Tree Council, said he appreciates the information on the study, but what he really wants to see is cleanup on the river.

"We would like to see the task of cleanup under way," he said. "That's the only way we're going to see this come to an end, is an adequate cleanup."
 

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.