DEQ goal: Protect public, environment

Steven E. Chester and Janet Olszewski, Midland Daily News 02/19/2006

A recent forum piece by Dr. Richard Reitz, former toxicologist for Dow Chemical, suggested that the Michigan Department of Environmental Quality (MDEQ) has failed to use science to guide our decisions concerning the cleanup of historic dioxin contamination in the Midland area. This assertion is false, and with the great deal of progress we have made over the past year to move this process forward, it is disappointing to see these misleading statements made.

The MDEQ, along with our partners at the Michigan Department of Community Health (MDCH), have a clear goal in mind: Protecting the environment and the public health of those affected by dioxin contamination. Our combined efforts are the work of some of the top scientists and health experts in the state, all of whom have dedicated their careers to serving the people of Michigan. To suggest that they have used anything but the highest degree of scientific review to guide their work simply demonstrates a lack of understanding as to how our agencies fulfill our commitment to the public.

Dr. Reitz makes a number of misstatements throughout his article, all of which have been refuted by many people time and again, but which warrant additional response here. First, he states that soil samples that have been taken throughout the area have shown inconsistent results, causing us to simply make assumptions on the area of contamination. This is simply not true.

The results from sampling done along the Tittabawassee River have consistently shown elevated levels of dioxin within the March 2004 floodplain area. Dow has acknowledged this in their recently submitted remedial investigation work plans that specifically state, "Éthese results suggest that the 8-year flood boundary may be a good predictor of whether or not TEQ (dioxin & furans concentrations) will fall below 90 parts-per-trillion." This does not suggest that there are not elevated levels of dioxin outside of the floodplain area, however, it clearly shows that existing data provides the basis to make a consistent and reasonable estimate of the scope of contamination.

Dr. Reitz states that scientific experts from around the world disagree with our cleanup criteria for dioxin. Again, this is not correct. He cites the Agency for Toxic Substances and Disease Registry (ATSDR) level of 1,000 ppt for dioxin exposure. The ATSDR 1,000 ppt level is an action level, meaning that they have determined that levels of dioxin in soil should trigger measures to interdict or prevent exposures. The action level of 1,000 ppt is considered protective by ATSDR only when it is combined with site-specific evaluation of levels such as Michigan's 90 ppt, which is a preventative level meant to safeguard the long term health of those living in contaminated areas. A number of other states go well below Michigan's risk level. Oregon, for example, has a residential soil cleanup level for dioxin of 3.9 ppt, while Massachusetts' is 4 ppt.

Dr. Dennis Paustenbach is quoted by Dr. Reitz as concluding that persons living near concentrations of dioxin in soil containing 1,000 ppt have no greater than a 1 in 100,000 chance of contracting cancer due to their exposure. Actual risk evaluations that have been conducted by federal and state agencies for people residing on property with soil concentrations at 1,000 ppt indicate that risk to be far higher; in fact, the U.S. Environmental Protection Agency has estimated that the 1,000 ppt level represents a 2.5 in 10,000 cancer risk. Those numbers certainly can not be overlooked.

As a toxicologist, Dr. Reitz should also understand that the MDEQ and MDCH have acted in accordance to common scientific practice in relying on cancer studies in rats when setting cleanup standards. In fact, we relied on a Dow Chemical Co. rodent study to derive an appropriate soil cleanup criterion for dioxin. This study has been and continues to be widely used while states and other organizations await finalization of the EPA's Dioxin Reassessment, which preliminarily estimates that the cancer potency for dioxin is approximately 10 times higher than previously estimated.

Dr. Reitz also appears to be under the impression that the U of M Dioxin Exposure Study will establish a soil cleanup level, something that it was not designed to do. The U of M study is an exposure investigation that we hope will provide valuable information, however, it is not a health study and is not designed to determine a health risk based on soil concentration.

Perhaps most troubling, however, is Dr. Reitz' claim that the work done by the MDEQ and MDCH does not undergo independent scientific review. Being public agencies, our work goes through extremely thorough public and scientific review on a regular basis. We work very closely with the U.S. EPA, ATSDR and other state and federal agencies, and our scientific processes are consistent with those of the World Health Organization, the International Agency for Research on Cancer, and others. We have in the past, and will continue to have independent scientific reviews conducted through Toxicology Excellence for Risk Assessment (TERA), a peer review organization used by Dow Chemical, among many others in our state.

All of our work is guided by the very best scientific research, methodologies, and processes accepted by the scientific community, and we make great efforts to ensure that we are transparent in how that work is done, and that it is understood by the public.

Our ultimate goal is to develop a remediation plan that is protective of human health, the environment, and local economic needs and interests.

We are requiring Dow to perform the investigations necessary to determine what cleanup alternatives are practical, however we have not reached the point to determine what those alternatives are. The MDEQ and MDCH are making progress in this area, and will continue to work with Dow Chemical to find the answers necessary to guide us toward a reasonable, scientifically-based plan that ensures the health and well-being of those affected by dioxin contamination.

Steven E. Chester is director of the Michigan Department of Environmental Quality.

Janet Olszewsk is director of the Michigan Department of Community Health.

©Midland Daily News 200
 

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 Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The source organization's web site link is listed to the right of the article, visit often for other news in our area. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.