Asbestos is an environmental contaminant commonly encountered at previously developed sites. When asbestos is found within buildings, current regulations are clear on how it is to be handled and removed prior to renovation or construction projects. But asbestos is also often encountered in the soil, in and around buried pipes and boilers, in improperly disposed-of debris, and as unconsolidated fibers in the soil. Because it is hazardous when inhaled, asbestos in soil is regulated, along with other potential site contaminants, by the Department of Environmental Protection (DEP)’s Bureau of Waste Site Cleanup under the Massachusetts Contingency Plan (MCP). Local municipalities can impose additional regulations. For example, the Cambridge Asbestos Ordinance managed by the Cambridge Public Health Department further regulates asbestos fibers in soil.
Prior to the new proposed regulations and guidelines, asbestos in soil has posed an expensive proposition for many construction projects, real estate transactions, and spill sites due to confusing notification requirements, analytical limitations, and the lack of a clearly defined clean-up level. For other regulated pollutants covered under the MCP, there are minimum clean-up concentrations in place (based on extensive field study) that present a clearer picture. Concentrations below these threshold values generally present no significant risk and site development can continue. However, asbestos has no threshold value in place for soil, and any level found often results in handling under MCP Method 3 risk characterization rules. Method 3 constitutes a very involved risk assessment study, and a significant cost addition to the project.
The new policy changes for asbestos are intended to promote responsible management of the majority of projects involving low levels of asbestos contamination, and free up regulatory resources to cope with situations that pose the greatest risk to public health. In addition to standardized procedures for the handling and removing of asbestos containing materials in the ground, the new policy defines new notification requirements that reduce the number of conditions for asbestos in soil that require reporting under the MCP. In addition, guidance has been provided for defining clean-up levels.
Environmental Health & Engineering, Inc. (EH&E) recently completed extensive site assessment, risk characterization, and remediation projects involving asbestos (and other contaminants) in soil, and our experience resulted in some practical insights for managing project costs and timelines when asbestos is involved. Additionally, EH&E was first to successfully manage a site through the stringent requirements of the Cambridge Asbestos Ordinance, and achieve “delisting” status for the property. This means that redevelopment at that site is currently moving forward with no further restrictions under the ordinance.
On-site Experiences and Insights
The first challenge we encountered in the site evaluation process was the characterization of asbestos in soil. Few standard analytical methods exist for measuring asbestos in soil. The best analytical methods for analysis use polarized light microscopy (PLM) and transmission electron microscopy (TEM), but are semi-quantitative at best primarily due to a limited sample size. As a result, we recommend that this type of analysis be used in conjunction with other information, such as site history and in some cases a measurement of the site-specific respirable dust concentration. One such method, the “Modified Elutriator Method for the Determination of Asbestos in Soils and Bulk Materials” is well suited for this determination in bulk samples (and is recommended in new DEP guidance). This analytical method simulates the release of the asbestos in the soil that is disturbed by construction. We have found this method to be a cost-effective approach for many sites, as the number of composite samples required to satisfy a reasonable site size can be relatively small.
The new proposed MCP policy changes also provide alternatives for site closure using several criteria. Closure options include elimination of exposure pathways (for example using capping technologies), demonstration that site conditions represent background level conditions for the local area, or demonstration of a condition of “No Significant Risk”. The DEP currently recommends the use of exposure modeling in conjunction with the Elutriator Method analytical results to demonstrate “No Significant Risk” and develop site clean-up concentrations.
A Good First Step
The new changes to asbestos regulations in soil provide a much needed opportunity to characterize this pollutant using techniques similar to those employed with other contaminants. However, the nuances associated with testing and characterizing the risks associated with asbestos will continue to pose a challenge for property owners and developers until the process for characterizing and evaluating sites for asbestos has been tested a bit more through experience. Obtaining the proper advice early in the assessment process from an experienced source still provides the best opportunity to successfully (and cost effectively) navigate this obstacle.
For additional information on environmental site assessment, risk characterization, remediation, and compliance with the evolving regulations for management of asbestos in soil, contact the author.
Cynthia D. Campisano, M.S.,P.G., C.H.M.M., is a Senior Associate at EH&E with expertise in the areas of hydrogeology and site assessment / remediation. Her current work also involves exposure assessments and risk characterization.