Project 2: Mobility and Fate of Asbestos Particles in the Environment
Significance
Hear from Project Leader Dr. Doug Jerolmack. What continues to inspire him to do this work?
Minimizing the threat that asbestos disposal sites present to surrounding communities requires containment; preventing offsite migration is of paramount importance. Because asbestos fibers are most hazardous when inhaled, research has focused on airborne transport. However, there is now ample empirical evidence that aqueous transport – in groundwater and rivers – is a significant pathway for spreading of asbestos, and such transport has threatened drinking water supplies in some areas.
Asbestos particles have a large specific surface area and surface charge effects are strong, which presumably influence their mobility and interaction with the environment. In particular, asbestos fibers rarely exist in isolation but rather form aggregates; however, little is known regarding the mechanisms controlling aggregate formation. In addition, the unusually large aspect ratio of asbestos is expected to exert a strong control on the migration and trapping of particles in groundwater transport through soil; however no studies have examined aqueous transport in the laboratory.
Hypothesis
The hypothesis of Project 2 is that aggregate size exerts the primary control on the rate of trapping of asbestos particles in soil, and that such trapping (“straining”) may reverse under changing water chemistry.
Project 2 will test these hypotheses with three Specific Aims:
- To elucidate the physico-chemical processes controlling asbestos aggregate formation and mobility.
- Determine mobility and straining of asbestos in groundwater, through laboratory experiments and theory.
- To identify the extent of groundwater transport, and the size distribution of aggregates, for asbestos particles at the Ambler Superfund site; and make recommendations for containment of asbestos to limit aqueous transport.
Our key innovations are to:
- Probe the dynamics of asbestos at the fiber scale using real-time electron-microscopy observations;
- Perform innovative soil column experiments that allow us to image the internal granular pore structure; and
- Apply experimentally-validated theories to field observations at a Superfund site to make scientifically-informed recommendations for improving containment strategies of asbestos.
We believe that the proposed research will directly inform policy for asbestos containment at Superfund and Brownfields sites, while bringing immediate benefit to the community surrounding the Ambler asbestos piles.
Project 2 integrates strongly with Project 1, as remediation of asbestos in the environment requires an understanding of the state of the fibers, their position in the soil and their interaction with water. In addition, a collaborative experiment will involve examining how asbestos fibers altered by fungi (in Project 1) change their size and settling patterns in water. This project will work closely with Project 3, as community exposure to asbestos in Ambler (and other areas) is strongly determined by the transport pathways of asbestos fibers in the environment. It will interact with the Community Engagement Core to ensure that local knowledge of the Ambler sites is used to inform field work. Postdoctoral researchers leading Project 2 will be a part of the Interdisciplinary Training Core, and so will contribute to the diversity of scientific expertise while taking part in research and seminars that promote cross-disciplinary interactions.
Project 2 will work closely with the Research Translation Core on two fronts:
- Results will be used to make site-specific (to Ambler) and general (Superfund and Brownfields sites) recommendations for enhanced containment of asbestos based on sound science, and we will ensure that these are effectively communicated to the EPA; and
- Some aspects of the unique laboratory apparatus built for this research may subject to patent and commercialization opportunities.
Laboratory experimental design, and data analysis, will be coordinated with the Biostatistics Research Support Core to ensure appropriate hypothesis testing. The Administrative Core will provide overall direction and financial oversight to the project.
Project Leaders
Douglas J. Jerolmack, PhD, Project Leader
Associate Professor, Department of Earth and Environmental Science, School of Arts and Sciences, University of Pennsylvania
sediment@sas.upenn.edu
Reto Gieré, PhD, Co-Project Leader
Professor and Chair, Department of Earth and Environmental Science, School of Arts and Sciences, University of Pennsylvania giere@sas.upenn.edu
Publications
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