Dioxin exposure in Saginaw neighborhood has eased, but threats persist

SAGINAW — Residents of one city neighborhood have been exposed to health-damaging levels of dioxin, and although the contamination has been removed though a cleanup effort required by the U.S. Environmental Protection Agency, future flooding is likely to recontaminate the area.

In a report released Tuesday, the Michigan Department of Community Health said that removal of contaminated surface soils, cleaning the inside of the homes and paving Riverside Boulevard in the neighborhood near where the Tittabawassee and Saginaw rivers meet has successfully reduced residents’ dioxin exposure to within safe limits. However, prior to the cleanup some residents were likely exposed to dangerous levels for years.

Dioxin is a by-product of the chemical manufacturing process that is associated with immune system and reproductive problems at very low levels of exposure. It also causes cancer.

The Michigan limit for dioxin contamination of residential areas is 90 parts per trillion. Samples from the propertied in this Saginaw neighborhood ranged as high as 23,000 ppt.

The homes are located along the Tittabawassee River, approximately 22 miles south of Dow Chemical’s Midland complex, the source of the pollution. The dioxin contamination in known to extend for 50 miles from Midland through the Tittabawassee and Saginaw rivers and into Lake Huron’s Saginaw Bay.

As a condition of its Michigan operating license, Dow is required to sample and monitor toxin levels in the watershed.

In 2007, this testing revealed that some areas in and along the Tittabawassee and Saginaw rivers were more highly contaminated than previously thought.

Based on this information the Michigan departments of Community Health and Environmental Quality prepared a list of areas or “exposure units” that should receive top priority for clean up.

The homes along Riverside Boulevard were given top priority, and nearby West Michigan Park, which has also received cleanup under an EPA order, was ranked second.

State and federal officials have declined to share details of any other properties identified as high priority for clean up.

One official said that a list of priority sites could not be released because of confidentiality agreements in ongoing cleanup negotiations between EPA and Dow.

This spring EPA announced that it would supplant the state of Michigan as the primary authority in efforts to pursue cleanup by Dow Chemical.

Linda Dykema, manager of MDCH’s Toxicology and Response section and lead author of the report on the neighborhood in question, said that she was able to determine that the level of contamination in these homes was 16 times higher than the safe-for-children levels established by the World Health Organization.

There are thousands of people living on floodplain properties where dioxin contamination has been documented, but Dykema said that for properties other than 24 parcels along Riverside studied in the report, there is not enough data to be sure of the health risks faced by residents.

Residents of other portions of the contaminated floodplain can take some steps to reduce health risks, Dykema said.

For most people, diet is the major pathway to dioxin exposure, and Dykema urged people to follow the fish advisory which urges severe limits in consumption of local fish.

She said people should also avoid eating chicken, eggs, and other animal products raised on the floodplain.

Other state issued precautions to floodplain residents include, keeping children from playing in yards known to be contaminated, removing shoes before entering a home, wearing a mask when mowing the lawn, and washing hands after outdoor activities.