Tittabawassee River Watch  www.trwnews.net
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Dow distortions and half truths about dioxin

"In November 2004, Dow distributed a Community Update filled with distortions and half truths about dioxin. It was one of Dow's most blatant efforts to date to minimize the risks associated with dioxin. We were told by DEQ management that a response was being prepared but it never came to fruition. The last we heard it was sent to the Governor's communications people and never returned. It is with absolute impunity and with no apparent fear of reprisal from the state that Dow continues to shamefully put communities and our natural resources at risk."   Michelle Hurd Riddick, Lone Tree Council     

The MDEQ analysis comments where evidently leaked and posted on a list-server, TRW did not receive an actual copy of the MDEQ document and we have no information concerning the author's or how the document was obtained.   The chart below, prepared by TRW, provides a direct comparison between the Dow publication statements and the alleged MDEQ analysis which points out the distortions and half truths of the Dow PR machine..

  Dow Newsletter November 2004 Dow Statements MDEQ Analysis of Dow statements
1 Page 1, Column 1, Paragraph 2 This analytical work is important because dioxins and furans are perhaps the most frequently studied compounds, yet the findings about their toxicity – especially in humans – are inconclusive. Despite the claims of some, the overwhelming weight of scientific evidence does not support the fact that dioxin/furan exposure at low levels is cause for serious concern This is an overly generalized and ambiguous statement. The Environmental Protection Agency, International Agency for Research on Cancer (IARC), U.S. Department of Health and Human Services, and other government organizations recognize 2,3,7,8-TCDD as a known human carcinogen and dioxin mixtures (toxic equivalence or TEQ) as suspected or probable human carcinogen.
2 Page 1, Columns 2 and 3 Topics:  Dow Releases Results of Current Worker Study Blood Levels Elevated, Still Below CDC Level for Cancer Concern ...No Indication of Health Effects...People More Resistant

 

It is difficult to review this section because Dow would not provide the actual study results or even a copy of the Powerpoint presentation given to staff of the Departments of Community Health (DCH) and Environmental Quality on November 3, 2004. DCH staff requested this information on November 4, 2004. Dr. Michael Carson of Dow declined to provide the requested information
3 Page 1, Column 2, Paragraph 3: Heading: No Indication of Health Effects

Text: “Given these new study findings, we are more confident than ever about our health conclusions that, other than chloracne among highly exposed workers, we find little indication of any health effect related to dioxin exposure in our chlorophenol workers,” said Dow Medical Director, Dr. Mike Carson...

The heading of this section states “No Indication of Health Effects” and the text indicates that Dow finds “little indication of any health effect related to dioxin exposure in our chlorophenol workers
4 Page 1, Columns 2 and 3, Paragraph 6 No worker in the Dow study had these high levels of dioto 176 ppt TCDD.xin in their blood. The range for Dow employees was 2 In 2004, this is the range Dow reports. Dioxin is eliminated from the body with a half life of approximately seven years. If the Dow reported levels are corrected for elimination via half life, this range would be much higher. It is not accurate to compare the 2004 Dow data to the levels reported by the Centers for Disease Control which are the estimated highest serum levels at the time of last exposure.
5 Page 1, Columns 3, Paragraph 2 People More Resistant:
The CDC also states: “Although dioxin is extremely toxic in some animals, humans appear to be more resistant to its toxicologic effects than most animals in which it has been tested. The primary clinical health effects that have been observed in humans exposed to high levels of dioxin through occupational or accidental exposures have been chloracne and transient mild hepatotoxicity. Various types of cancer and non-cancer health effects also have been associated with exposure to dioxin in some studies. However, study results have been inconsistent in demonstrating these effects.”
The section, “People More Resistant,” is misleading. The statement cited is not proven for all adverse effects that have been associated with dioxin exposure. For example, for effects that have been clearly associated with dioxin exposure, such as chloracne and the induction of liver enzymes, humans and animals respond at similar body burdens. For some effects, humans are more sensitive than certain other mammalian species (e.g., chloracne in mice, cancer in hamsters, decreased testosterone in rats).
6 Page 2, Column1, Paragraph 4 To date, the studies show that Dow workers with high levels of dioxin exposure do have an increased risk of chloracne, a skin condition known to be caused by such exposure. However, other than chloracne, no other increased risk of disease, including cancer, was found related to dioxin exposures. These results are consistent with recent observations published by the U.S. Agency for Toxic Substances and Disease Registry and the national Centers for Disease Control. The more comprehensive studies by National Institute for Occupational Safety and Health (NIOSH) and IARC do show increased risk of disease (cancer, ischemic heart disease). These results were reaffirmed in 2004. Dow should cite the study to which they referred.
7 Page 2, Column 2, Paragraph 4 Bioavailability Study. Dow also is conducting a pilot bioavailability study. Bioavailability refers to the ability of the human body to absorb any compound. This study will help find out how much dioxin can be absorbed into the body if it is attached to soil. Since dioxins firmly bond to soil particles and are not readily absorbed into the bloodstream, it is important to understand this process. ... What’s more, a German study found the level to be as low as 15 percent. ... The bioavailability study design has not been approved by the DEQ. An independent peer review by Toxicology Excellence in Risk Assessment (TERA) indicates that there are major problems with the study design. In addition, it has not been demonstrated at this location that dioxins are “firmly bound” to soil and are not readily absorbed into the blood. In fact, based on Dow’s wild game study and Michigan State University’s (MSU) ecological risk studies, dioxins in the Tittabawassee River floodplain appear to be very bioavailable.  The German study referred to in this discussion may not be relevant as bioavailability varies based, in part, on soil type and contamination.
8 Page 3, Columns 2 and 3 Studies Will Clarify Models
Several studies help in our understanding of the validity of the models being used to assess potential risk of exposure to dioxins and furans. Dow’s recent study of the levels of dioxins in wild game such as deer, turkey, and squirrels from the flood plain area

Dow’s graphs and comparisons are flat out misrepresentations of the actual facts, data, and model for the DEQ’s screening level terrestrial ecological risk assessment (ERA) evaluation.  The DEQ made no estimates of the level of contamination expected to be present in squirrels and turkeys from the Tittabawassee River floodplain. It would have been, and is, inappropriate to use the DEQ’s screening level terrestrial ERA to attempt to make such calculations. The DEQ was, in fact, surprised by the high levels of dioxins found in the portions of squirrels, turkeys, and deer consumed by humans. Higher levels of contamination are expected to be present in portions of animals that are consumed by prey species. The recently released MSU ecological data support the DEQ’s conclusion that ecological risk from dioxins is present in the Tittabawassee River floodplain. Levels of dioxin in small ground dwelling mammals is on the order of 100 times higher than the squirrel data reported by Dow.
9 Page 4, Column 3, Paragraph 1 “This CDC data is important for understanding the connection between age and dioxin levels in the blood,” said Dow Toxicologist Bob Budinsky. “Since everyone has dioxin in their blood, and dioxin breaks down very slowly, the study suggests it is most appropriate to assign guidelines by age.” The “guidelines” referred to in this paragraph are actually concentration ranges. Exposure to these concentration ranges may result in adverse health effects. Some studies in humans have shown adverse health effects associated with background levels of dioxin.
10 Page 5, Columns 1 and 2 Dow is working in cooperation with Saginaw area officials to help improve two Tittabawassee River parks and at the same time take steps to minimize potential exposure to dioxins and furans. Dow and parks officials recently received permit approval for improvement projects at Imerman and Freeland Festival parks. The work is part of the corrective action process by Dow and was proposed as an interim response activity (IRA). The Interim Response Activities (IRAs) referred to in this section have not been approved by the DEQ. This section does not discuss critical components of the IRAs, which include advisory signage to reduce exposure to contaminated soil and fish.
Please note that “permit approval” likely refers to floodplain permits, not Part 111 approval of the IRAs for corrective action purposes as is implied by the wording.
 
11 Page 5, Column 3, Paragraph 1 Other key findings of the study are as follows:
• Some tradesmen who had plant-wide responsibilities, such as pipefitters and mechanics, also had dioxin levels above non-chlorophenol workers.
• Workers with past chloracne had higher blood dioxin levels – five times higher on average than other workers employed in the chlorophenol departments.
• Dioxin exposure estimates used in the previous studies of Dow workers accurately predicted actual, measured dioxin levels.
Based on Dow’s November 3, 2004 presentation to DCH and DEQ staff, chloracne did not predict serum dioxin levels (i.e., some workers with high dioxin levels did not exhibit chloracne).
Dow’s exposure estimates did not predict actual measured dioxin levels as stated in this paragraph. Instead, they predicted relative levels of exposure.
 
12 Page 5, Column  3, Paragraph 7 Results of the study were presented in October at the International Symposium on Epidemiology and Occupational Health in Melbourne, Australia. Dow also met with local health department officials, and has briefed the Michigan Department of Community Health and the Michigan Department of Environmental Quality on the research. Although Dow briefed DCH and DEQ staff on the worker study, Dow declined to provide the actual study results when requested to do so on November 4, 2004.
13 Page 6, Column 2, Paragraph 2 A new cancer study on laboratory animals, recently completed by the U.S. National Toxicology Program, shows that the furan congener 4-PCDF (which makes up about 50 percent of the TEQ in the Tittabawassee River area) is much less potent in laboratory animals than originally thought. A publication of the study cited by Dow supports the TEQ approach, which is an order of magnitude estimate of overall toxic potency (not just cancer). Also, it should be clarified that toxic equivalency factors (TEFs) are developed based on specific toxicity studies of the individual compounds. The TEF for 2,3,4,7,8-PeCDF (not 2,4,7,8-PCDF) estimated from this study were 0.16 to 0.34 for four tumor types, which are within half an order of magnitude of the current TEF of 0.5. The study cited here also verified that the cancer incidence from a mixture of three dioxin-like compounds was adequately predicted by the TEF approach and did not over-predict toxicity as implied by Dow.
14 Page 7, Column 1, Paragraphs 3 and 4 This data will help clarify whether there is a link between dioxins in soil/house dust and in human blood. If dioxin levels are not elevated in residents’ blood, it would indicate there is no increased health risk for area residents. If levels are elevated, additional health studies would be appropriate, to determine if there is a correlation with dioxin exposure. The results also will provide another point of tangible data on which to base decisions about corrective action in Midland and the Tittabawassee River area. Go to http://umdioxin.org for additional information. The University of Michigan Dioxin Exposure Study (UMDES) as designed will not be able to conclusively determine the exposure of the specific population of greatest concern, residents who live on properties that frequently flood. Also, as noted above, even if these residents have dioxin levels within the background range, it does not mean that there will be no increased health risk.
The DEQ will not be able to use the UMDES for corrective action purposes as described here. In addition, it is not appropriate to wait until the study is completed in 2007 to begin to take actions to reduce exposure.