Asbestos in Duluth's drinking water remains a concern


I recently received and read the “City of Duluth 2018 Drinking Water Quality Report.” I was shocked to see once again no mention of asbestos concentrations.

In 1974, I was a biology student at the University of Minnesota Duluth and was involved in collecting Lake Superior water samples for the detection of asbestos-like fibers that later were determined to be mostly asbestos fibers. The average concentration of fibers was about 100 billion fibers per liter of water. The asbestos levels in the Duluth drinking water far exceeded all other Minnesota water sources, we determined. The city of Duluth was ordered to use micropore filtration. The problem was that these filters with microscopic pores quickly clogged and ruptured. After just a few months, the city stopped filtering asbestos this way and went back to the sand-pit method of water filtration.

The source of the fibers was generally thought to be from Reserve Mining and its practice, for 16 years, of dumping taconite tailings into Lake Superior. This was just upstream from the city of Duluth’s water intake. The dumping stopped when the Minnesota Supreme Court ordered Reserve Mining to dispose of its tailings on land.

UMD experts estimated that the circulating asbestos fibers, due to their small size and settling rates, would be present in Lake Superior water for thousands of years. They also determined that levels would increase with storms, causing bottom turbidity.

Dr. Irving J. Selikoff, an expert on environmental medicine at Mount Sinai Hospital in New York, showed that the asbestos fibers in Duluth’s water were the same type (amosite) as those implicated in half the deaths among workers in a Paterson, N.J., asbestos plant.


Dr. Lawrence Plumlee, a physician on the staff of the U.S. Environmental Protection Agency, said that limited studies in animals indicated that when asbestos is placed in the stomach, it rapidly enters the bloodstream and is widely distributed to tissues throughout the body.

A greater concern than ingestion may be repeated exposure and inhalation of this water via steam saunas or via water mist from humidifiers.

Having an interest in this topic, I have requested repeatedly for many years — sending inquiries to the city, state EPA, and Save Lake Superior Association — the current levels of asbestos in our drinking water. Year after year, my letters and phone calls have been ignored. Phone calls always resulted in, “We will get back to you.” But no one ever has.

My goal isn’t to cause undue concern. My aim is to get accurate science on both the lake levels of asbestos and the effectiveness of in-home water filtration. If there is even a slight potential of health risk, including gastrointestinal and lung cancers, we should be told how to effectively filter our drinking water.

Thomas Grier of Duluth is a microbiologist and study coordinator for the Dr. Paul Duray Pathology Fellowship.

Related Topics: WATER QUALITY
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