TINA LAM, DETROIT FREE PRESS, AUGUST 16, 2006
Study: Soil close to homes is only partly to blame
A study released Tuesday shows that people who live in contaminated areas of Midland and Saginaw counties near Dow Chemical Co.’s massive manufacturing complex have slightly higher amounts of dioxin — one of the most potent toxic chemicals on earth — in their blood than people who live elsewhere.
But soil near their homes is a source of only a tiny amount of the increased dioxin, researchers said.
The two-year study conducted by University of Michigan researchers found that older people and people who eat fish from the Tittabawassee and Saginaw rivers downstream of the Dow complex had higher levels of the chemical. Dow employees who worked at the plant between 1940 and 1959 also had higher levels.
“There is pollution in some areas of Midland and Saginaw, especially in the floodplain of rivers and downwind from the Dow plant,” said Dr. David Garabrant, who headed the study. But, “Only a small amount of the dioxin that is in people’s blood there is related to that pollution.”
Garabrant said the study did not address the health effects of dioxin in people’s blood, so it’s not known what the increased levels of dioxin will mean to the people living in contaminated areas that were studied.
People who ate fish from the rivers had increases of dioxin of 1%-2% for each year that they ate fish, the study found.
The $15-million study was financed with a grant from Dow. Research decisions were reviewed by an independent scientific advisory board.
The study compared 675 residents of Saginaw and Midland counties who lived near contamination with 251 residents of Jackson and Calhoun counties who have no known direct sources of dioxin contamination.
Dioxins are pervasive in the environment — from incinerators, forest fires and by-products of manufacturing processes. The study was attempting to answer whether dioxins in the environment get into the body and how, Garabrant said.
For decades, Dow’s Midland headquarters released dioxin into the Tittabawassee and into the air. The chemical is now in the soil of the river’s floodplain and in areas downwind from the plant, where the state has issued advisories against eating fish or game.
There are many types of dioxins and some are known to cause cancer or to disrupt hormones, damage fetuses and suppress immune systems. People can get dioxin in their blood from eating fish, meat, dairy products, eggs and fatty animal products. Dioxin is stored in fat.
The researchers found that the median level of dioxins in soil in Jackson and Calhoun counties, the control group, was 4 parts per trillion. The state allows 90 ppt.
The median levels in Midland and Saginaw counties ranged from 4 ppt near the floodplain of contaminated rivers to 13 ppt in the floodplain to 59 ppt downwind from Dow. Some individual properties had more than 1,000 ppt of dioxin.
Environmentalists said the study answered a key question.
“The question is, does dioxin get into people from contaminated soil and the answer is yes,” said Tracey Easthope of the Ecology Center in Ann Arbor.
Contact TINA LAM at 313-222-6421 or tlam@freepress.com.
How dioxins get into our bodies (PDF)

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