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By PETER W. HOLM Guest columnist Monday, May 4, 2009 2:05 PM CDT.
In October 2008, it became apparent that there was going to be a sand processing plant built in the city of Chippewa Falls, and a large sand mine dug in the town of Howard. Many of our patients had questions concerning potential health effects that the mine and plant might present. Concerns included increased traffic from trucks, pollution from diesel fumes, damage to roadways, destruction of scenic beauty, potential damage to the aquifer due to blasting and possible leaching of toxic chemicals into the groundwater.
We believe that each of these concerns can and should be addressed. However, due to time constraints, we have focused on only one health concern. This column is not meant as a condemnation of anyone involved in the process of approval of this plan, but rather an objective appraisal of one of the issues that might be a serious health concern to the citizens in and around the plant and mine. The question we addressed was particulate levels, especially as they pertain to crystalline silica levels in and around the plant. Dust and silica can cause and aggravate respiratory diseases, heart disease and, over a period of chronic exposure, may even be carcinogenic. We would like to see an objective collection of data, which would either alleviate or cause further concern for people regarding this potential health risk. Learning about silica exposure and disease has been a huge education for us. In reviewing data, as physicians, we are reminded time and time again to view with a very skeptical eye literature that is supported financially by those industries (especially the drug industries) which have vested financial interests in the results. Accordingly, we have approached the examination of silica health risks — to try to find the most objective and rational approach to assess silica-related health risks from the sand processing facility. In an attempt to learn more, we contacted the DNR in Wisconsin, and particularly those members of the DNR who were involved with approval of the plant and mining site. The DNR was very helpful to us and our pursuit of this issue, making no attempt to obscure from view the data they used to compile their reports. We also contacted Dr. Crispin Pierce, a toxicologist who shared information about possible health effects from the sand facility at a public forum Feb. 19. The International Agency for Research on Cancer and the state of California (through Proposition 65 listing) have determined that crystalline silica is a human carcinogen. However, in reviewing studies from the DNR and the EPA we learned, much to our distress, that according to the principal DNR author of the sand plant permit, “neither the EPA nor the DNR had developed air-quality standards for crystalline silica.” We therefore realized that neither the DNR nor the EPA had to ensure air-quality safety for this dangerous pollutant in Wisconsin. The California Office of Environmental Health Hazard Assessment has established a chronic Reference Exposure Level for inhalation of silica for industrial workers of 3 micrograms/m3 of respirable dust, which applies to an eight-hour per day exposure period. Since the REL applied to industrial workers exposed over an eight-hour workday, we felt it could serve as a  baseline for safe levels for the citizens populating the area around the plant. We also learned that, in considering the particulate emissions from the plant, not all potential sources of dust or silica were considered. In the DNR study of the plant alone, only a portion of the particulate sources had to be  considered. Those sources were the sand dryers, the building dust collecting system and the product storage silos. Not considered as particulate sources were the huge sand pile next to the plant, 12 conveyor belts capable of  moving 1,000 tons of sand per hour, semi trailer trucks carrying 20 tons, two 800-ton/hour truck receiving stations, railroad cars capable of moving 80 tons of sand at a time, road dust and the mining site itself. The representatives of the mining plant state that these sources of dust are not concerns, as they will take precautions to keep the sand wet and they will have to monitor particulate levels from the stacks. However, studies of other similar facilities indicate that these fugitive sources significantly contribute to particulate emissions. According to the principal DNR author of the sand plant permit, considering only the sources listed in the DNR report (not including fugitive sources), silica levels at the maximum point of exposure would be 4 micrograms/m3. Using similar calculations given to us by toxicologist Dr. Crispin Pierce, the maximum silica level would be about 7 micrograms/m3. Both of these levels are above the 3 microgram/m3 standard for workers listed above. When Dr. Pierce adjusted for continuous exposure (not just an 8-hour workday), the predicted exposure level rose to about five times the occupational standard. There are computer models that may or may not accurately take into consideration the air drift of silica, but we could not determine if they did based upon the difference of opinions between experts. While the DNR AERMOD (wind drift) modeling suggests a return to nearly ambient conditions within 100 meters of the facility center, it may be that their computer model simulation of particulate matter is not well-suited to the characteristics of crystalline silica. For example, a published study by Trzepla-Nabaglo et al. in 2006 found that “the patterns suggest little net   settling out of airborne PM10 occurred between 65 and 745 meters from the Main Plant” in a California facility. And all of this still does not take into consideration the fugitive sources of dust, or the dust and silica at the mine site itself (which in one study found crystalline silica levels of about 60           micrograms/m3 near a sand gravel facility). Because of the above data and the lack of consensus concerning its potential for harm, we as concerned physicians ask that any further work on either the plant or the mine be postponed until the following analysis is carried out. This would include (but not be limited to): -- Use or collection of any specific measurements of the crystalline silica concentration in the sand to be mined in the town of Howard. -- Estimation of the particulate emissions of the sources from fugitive dust and areas around the plant. -- Evaluation of whether the AERMOD model used by the DNR adequately predicts crystalline silica distribution, and if not, use another model. -- Determination of a reasonable fraction of PM 10, which is silica (the DNR and Dr. Pierce have mentioned a range from 6 percent to 27 percent; the Howard sand may or may not be in this range). -- Use of PM10 particulate modeling results from the DNR and the fraction which is silica to predict silica exposures. -- Deciding whether to regulate silica exposures — cancer-causing or not — determining whether the predicted emissions would violate the 3 microgram/m3 or other appropriate standard. While our position may at first seem onerous, we have an oath as physicians to “first, do no harm.” We hope to stand by this oath. We also realize that an analysis of silica risks may take some time. However, approximately a year was used by our city and county officials to process permits prior to the announcement of the building of the sand plant and the mine to the public in a meaningful way. We feel a comparable amount of time would not be inappropriate when it concerns the health of our citizens for the next 50 years. After the analysis that we propose above, our community will be closer to knowing whether the sand processing facility does indeed pose a health risk. Taking time to complete such an analysis would also allow us to further investigate other concerns in terms of traffic, diesel fumes, possible contamination of groundwater, and the implications of building a resin plant to treat the sand. Peter W. Holm has lived and worked in Chippewa Falls for the past 28 years. He wrote this with the support of the following doctors: Jeffrey Brown, M.D., Steven Cook, M.D., Kristie Gering, M.D., George Fleming, M.D., Sandra Frohling, M.D., Steven Hansen, M.D., Les Harrison, M.D., Bernard Herzog, M.D., Paul Ippel, M.D., Mary Landwehr, M.D., Terrence McCanna, M.D., William McDougall, M.D., Steven aulson, M.D., Steven Steinmetz, M.D., and Aaron Topliff, M.D.