September 5, 2006
EPA Questions Applicability Of Key Dioxin Study To Michigan
EPA Region V is questioning the applicability of a recent landmark dioxin exposure study to a contentious dioxin cleanup near Dow Chemical Co.’s headquarters in Michigan, saying the study did not thoroughly target susceptible subpopulations and is not the type of information that forms the basis of remediation decisions.
University of Michigan scientists released preliminary results from the research, The University of Michigan Dioxin Exposure Study, last month, which showed residents in a dioxin-contaminated area near the Dow facility have higher levels of dioxin in their blood, but the study also found that age, weight and gender more greatly influenced those levels rather than a person’s proximity to the contaminated site.
While the researches did not draw any conclusions about health risks or cleanup policies, one of the authors said the study—which found the highest dioxin blood levels in older, heavier males—would provide “valuable data [to regulators and the community] in determining how best to manage this problem.”
Dow officials, who have long fought both Michigan and EPA proposed cleanup levels and efforts to demand extensive surveys of dioxin contamination stemming from the facility, cited the study as important information to take into account as EPA prepares a cleanup plan for the site. Dow’s Midland, MI, headquarters has dioxin levels as high as 2,000 parts per trillion (ppt), with an average of almost 1,000 ppt at the site. The site spread contamination to the Tittabawassee River, which has deposited contaminated sediments on the shores of the river via frequent flooding and continues to do so. The area along the river has farms and residences, among other uses.
EPA Region V officials, however, are raising a number of questions about the study, noting that its results are preliminary; that it did not specifically target susceptible populations like children, hunters, fishermen and pregnant and nursing women; and that it is not the type of health effects study that could be used to determine health risks from exposure to the contamination.
Moreover, EPA says that because background levels of dioxin—a suspected carcinogen—found in human blood are high enough to pose health risks, the elevated levels found in the study are of concern, since residents near the Dow site had 28 percent higher dioxin levels than the control group. “EPA is concerned about the dioxin blood levels in some local residents,” one Region V source says, since “a number of studies have confirmed a relationship between background levels [of dioxin in humans] and adverse health effects” such as diabetes, endometriosis, thyroid disorders, immune disorders and neurological impairments.
The source also says EPA is concerned about highly exposed subpopulations, like hunters and fishermen, who consume a significant amount of dioxin-contaminated fish and game. “There wasn’t an attempt upfront to include highly exposed groups,” one EPA source says. Another regional source notes that both subsistence fishermen from environmental justice populations along with recreational fishermen and hunters get a significant portion of their protein intake from fish and game in the area, which are likely to be contaminated with dioxin. The first EPA source also notes that the study only evaluated people over age 18, excluding infants, children and pregnant or nursing women, who would be considered at higher risk than the populations studied.
The second EPA source adds that the Michigan study would only be one of many types of information the agency will consider as it develops its cleanup plan, but it will not be a major factor because it does not draw any conclusions about health. To do so, EPA will develop a risk assessment and combine that information with data that are currently being collected and will be collected over the next few years on levels of contamination in the flood plain near the Dow facility.
Dow is currently collecting samples along the first six miles of the Tittabawassee River and will do more sampling over the next several years based on the results of the initial sampling. EPA says its remedial options include removing contaminants if there are “hotspots,” but if contamination is spread evenly, that would make cleanup more difficult.
Source: Lone Tree Council / TRW
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 source organization's web site link is listed above. The Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.