Environmental Factor, January 2011, National Institute of Environmental Health Sciences
Miller presents study on erionite exposure and mesothelioma
By Matt Goad
The erionite study is an outgrowth of Miller's work with asbestos contamination in Libby, Mont., which he discussed during a talk(http://www.niehs.nih.gov/news/newsletter/2010/february/spotlight-miller.cfm) at NIEHS last year. (Photo courtesy of Steve McCaw)
In Cappadocia, Turkey, it is too late for generations of victims of mesothelioma in so-called cancer villages, where up to half of the villagers die from the rare lung cancer. But a collaborative program in the United States, including work by NIEHS Senior Medical Adviser Aubrey Miller, M.D.(http://www.niehs.nih.gov/about/od/advisor/miller.cfm), may be able to save lives here before the problem of erionite exposure has the same effect.
Miller presented a study that compared levels of erionite, a mineral fiber similar to asbestos, and perhaps even a more potent carcinogen, in Dunn County, N.D., and the Turkish villages. Miller co-authored the study with Michele Carbone, M.D., Ph.D., director of the University of Hawaii Cancer Center. They presented the results of the study Dec. 9 at the Chicago Multidisciplinary Symposium in Thoracic Oncology(https://www.astro.org/Meetings-and-Events/2010-Thoracic/Index.aspx) (view slides).
Contaminated school bus routes
According to Miller, gravel that is contaminated with erionite is the only gravel readily available in Dunn County, N.D., and, over the past two to three decades, about 300 miles of road have been paved with erionite gravel, including more than 30 miles of school bus routes. The comparison with Turkey showed that levels of erionite in the air equaled and even exceeded levels measured in the town of Boyali, where 6.2 percent of all deaths are caused by mesothelioma, but were generally lower than those found in Turkish villages where mesothelioma-related deaths ranged from 20 to 50 percent of all deaths. Miller said researchers also found in North Dakota that people riding bicycles or riding inside of cars and school buses driving on the gravel roads could be exposed to markedly elevated airborne levels of erionite.
"This is a continuing project," Miller said. "There have been a number of questions about what are we going to do from a public health perspective, so the first element was to understand the exposures and characterize the exposures here in the United States, at least in North Dakota."
No current regulations
Erionite is not regulated in the United States, but federal, state, and local agencies are working to reduce current use of erionite, with an eye toward dealing with the erionite gravel already in place. Erionite deposits are present in several U.S. states, including California, Oregon, North and South Dakota, Arizona, and Nevada.
There is a latency period for mesothelioma of up to 50 years, Carbone said, so the dangers of erionite may have been discovered in time to greatly reduce the risks in the U.S. No spike in mesothelioma-related deaths has yet been identified in North Dakota. However, a recent radiographicby researchers from the University of Cincinnati identified bilateral pleural plaques in two of 15 road workers with no history of asbestos exposure.
Also involved in various aspects of the study have been researchers from Hacettepe University in Ankara, Turkey; the Department of Geophysical Sciences at the University of Chicago; the Department of Chemical and Biochemical Engineering at the University of Iowa; the Department of Environmental Health at the University of Cincinnati; the Centers for Disease Control and Prevention Agency for Toxic Substances and Disease Registry; the U.S. Geological Survey; and the U.S. Environmental Protection Agency, Denver office.
(Matt Goad is a contract writer with the NIEHS Office of Communications and Public Liaison.)