Activity-Based Evaluation Report, August 3, 2012
Asbestos Resource Program
Lincoln County, Montana
By Tony Ward, The University of Montana, and
Steve Ackerlund, Ackerlund, Inc.
As part of the Activity-Based Evaluation Report (August 3, 2012) submitted to Lincoln County Environmental Health, Trihydro Corporation conducted a summary of the available toxicological and activity-based sampling (ABS) findings (draft and final) related to exposures to Libby Amphibole (LA) asbestos. As part of the Trihydro report, it appears that a thorough review was conducted of the existing ABS studies (past and proposed) conducted by EPA, with useful suggestions also provided where appropriate. As the report points out, ABS activities are still occurring throughout Libby and Troy. In addition, the LA asbestos toxicity factor and risk assessment calculations have not yet been finalized by EPA, with the final toxicological review to be completed in 2013. Overall, the report is well written and summarizes the ABS activities conducted to date by EPA. Below are some general thoughts and comments.
This is a very useful report, and it was well prepared. It brings together a large amount of information into a single place in a way that makes it coherent. It is the knowledge needed to understand exposure, risk, possible additional remediation needs, and the interface of the remediation with the emerging Asbestos Resource Program (ARP) at the county. I do think it can serve as an important basis for initiating meaningful public participation regarding the needs of the ARP.
In many of the studies noted, it is not clear if the ABS studies were conducted before or after cleanup. Establishing a “pre-cleanup” baseline is important when evaluating the impact of the cleanup effort, as well as conducting health studies considering historical exposures.
It is important to note if sampling and analytical (PCM vs TEM) protocols/methodologies have remained consistent throughout the periods of ABS and throughout all the studies to date. It is critical to have consistent methodologies in an effort to accurately evaluate the impact of the cleanup activities.
My unanswered questions focus on wanting to know more about positive detections in likely key exposure situations:
What is meant on page 2-17 about “sensitivity issues” in regards to ambient LA measurements conducted between 2000 and 2002? Are there similar sampling/analytical concerns with other studies that were conducted by EPA when carrying out the initial ABS efforts?
Evaluating the cumulative risks across multiple OUs is important.
p. 3-2, section 3.3. What is meant by “…further delineation of asbestos types in comparative ambient air monitoring data may be pertinent”?
A potential future exposure to the Libby population is if a large wildfire burns in the contaminated areas of OU3. This needs to be addressed.
Multiple times throughout the report it states that summer ABS results were higher than ABS results measured in other periods of the year. This is an important point when considering public health practices, and addressing those high-priority issues.
Similarly, the high variability mentioned for many ABS results is not surprising. Moving forward, decisions are likely to be driven by Reasonable Maximum Exposure (RME) estimates as opposed to average levels of exposure in the community. Is there adequate repeatability of measurements to define RME with confidence?
Trihydro does a nice job of summarizing ABS work conducted by EPA. However, there are no mentions of ABS studies conducted by groups outside of EPA. Specifically, The University of Montana and Montana Tech have conducted multiple ABS sampling studies within OU3. As these studies were intended to complement the EPA’s completed and proposed studies, these independent studies should be considered and utilized when moving forward with the formation of the Asbestos Resource Program. The following publications list these studies:
Ward, T.J., Spear, T., Hart, J., Noonan, C., Holian, A., Getman, M., and Webber, J.S., 2006. Amphibole fibers in tree bark. Science of the Total Environment, 367:1, 460-465.
Hart, J.F., Ward, T.J., Spear, T.M., Crispen, K., and Zolnikov, T.R., 2007. Evaluation of asbestos exposures during firewood harvesting simulations in Libby, Montana. Annals of Occupational Hygiene, 51, 8: 1-7.
Ward, T.J., Hart, J.F., Spear, T.M., Meyer, B.J., and Webber, J.S., 2009. Fate of Libby amphibole fibers when burning contaminated firewood. Environmental Science & Technology, 43(8) 2878–2883. PMCID: PMC2688714.
Hart, J.F., Spear, T.M., Ward, T.J., Baldwin, C. E., Salo, M.N., and Elashheb, M.I., 2009. An evaluation of the potential exposure to asbestiform amphiboles near a former vermiculite mine. Journal of Environmental and Public Health, Article ID 189509, 10 pages. PMCID: PMC2799270.
Ward, T.J., Spear, T.M., Hart, J.F., Webber, J.S., and Elashheb, M.I., 2012. Amphibole asbestos in tree bark – a review of findings for this inhalational exposure source in Libby, Montana. Journal of Occupational & Environmental Hygiene, 9, 387–397.
At a general level, I think the report stops short of a critical examination of the available information. To gain proactive entry into EPA’s risk assessment process, which is going to drive remediation and ARP decisions, we need to consider now if the information collected is of adequate quantity and quality for risk assessment use. Perhaps given the extensive data review TriHydro did to prepare this report they might extend on their work to comment on the suitability of the available data to support the risk assessment that is planned for next year? Also, LATAG could members familiar with the community might be able to identify other actitivies not yet studied that should be included in future ABS studies.
Lastly as concerns this report, the Risk Reduction Considerations section appropriately blankets a range of regulatory and voluntary based approaches around which the ARP may be designed. Perhaps it can go further to specifically identify entities that are likely “targets” for the actions. In particular, the last bullet regarding outreach efforts for potentially sensitive populations might identify community leaders who will ultimately become conduits for this information: school administrators, leading contracting business owners, realtors, health care providers, welcoming committee, and so on. The point of this is to begin to identify them and draw them in early to the discussion of what this information is telling us about what the community needs to do to promote health and welfare, via the ARP or otherwise.
Beyond this report, I think some social scientific research is needed to understand the range of ways that people in the community understand exposure and risk in a post remediation community. This information is essential to designing outreach strategies that are effective in changing behavior. I am concerned that even if you were to go hog wild on an ARP program that regulats all risky behavior in the community, participation and enforcement will be limited. My early suspicions are that success in adopting and implementing an ARP will be heavily dependent on an effective risk communication strategy.
Again, this report is extremely valuable. You seem to be off to a good start. Thanks for sharing this report. We hope our thoughts are helpful.