For many years, the Pennsylvania Department of Environmental Protection (DEP) prohibited vertical blending of soils as a remedial method. Liberty Environmental recently identified a site where the use of vertical blending was demonstrated to be an attractive remedial option. Liberty proposed to DEP that it reconsider its long-standing policy on vertical blending, which was based on a prohibition on blending in its Management of Fill policy. Liberty argued that 1) the Management of Fill policy is not applicable to remediation of contaminated soil at a cleanup site, and 2) since DEP permits excavation, consolidation and capping of contaminated soil under a site-specific cleanup utilizing pathway elimination, it should allow vertical blending for a site-specific cleanup under a human health risk assessment. In correspondence received on March 2, 2018, DEP acknowledged that no statute or regulation exists to prohibit vertical blending to eliminate a human health risk and attain a cleanup standard under the Land Recycling Program. This is a significant advancement in Pennsylvania site cleanup policy because vertical blending allows for elimination or significant cost reduction of remediation.
What is Vertical Blending?
Vertical blending is a process where mechanical equipment is used to blend shallow contaminated soils with uncontaminated underlying soils, resulting in a reduction of contaminant concentrations throughout the blended soil zone to levels below applicable cleanup standards. Particularly applicable at golf courses and orchards where historical application of pesticides has contaminated very shallow soils (typically 6 to 9 inches), this remedial approach has been applied in other states with great success.
Evaluating Remedial Alternatives
Application of lead arsenate and other arsenic-containing and organic pesticides over many decades has resulted in contaminant concentrations several times higher than cleanup standards on recreational and agricultural sites. The first step in evaluating remedial alternatives on these sites, once the extent of impacts is known, is to perform site-specific studies to determine 1) the leachability of the contaminant in soil which determines whether groundwater is a medium of concern and 2) the bioavailability of contaminants in soil to establish a site-specific contaminant concentration that is protective of human health. By following this type of risk-based approach, it is often possible to substantially increase the acceptable concentration of contaminants in soil when compared to the regulatory agencies’ established cleanup levels, and either eliminate or greatly reduce the cost of remediation.
Strong State Agency Relationships Help Our Clients Achieve Their Site Cleanup Goals
Liberty Environmental is a full-service environmental consulting firm with extensive experience in assessing and remediating sites under numerous cleanup programs. Similar to this policy advancement, Liberty was also successful in petitioning DEP to reconsider its Agricultural Soils Policy, which allowed our client to to enter the Land Recycling Program (Act 2 cleanup program) to develop a former orchard site. Read more here: Pennsylvania Act 2 and Agricultural Soils Policy _Orchard Site Remediation.