Multiple Assessments and Ancillary Support for the US Army, Aberdeen Proving Ground – Edgewood Arsenal

APG Directorate of Safety, Health, and Environment (under contract to General Physics, Weston Solutions, and Plexus Scientific)

Because of its unique ecological setting and multitude of potentially affected habitats, ecological risk assessments have required biological expertise in estuarine and freshwater ecology as well as upland and wetland vegetative communities.

Overview:

• Avatar has provided human health and ecological risk assessment support for DHSE and AEC
• HHRA support included oversight, review and modification of previously performed assessments as well as screening level and baseline assessments
• Chemicals of concern and potential pathways of exposure to the more exotic of these including perchlorate, explosives, chemical and nerve agents; vapor intrusion and food chain vector
• Project has required significant, ongoing agency regulatory support (EPA Reg / MDE)

Description:

Avatar scientists have worked as both prime contractors and subcontractors for at least 4 Army agencies on Aberdeen Proving Ground (APG), including DSHE, AEC, the USACE – Baltimore, and the CHPPM to investigate impacts of the disposal and historical releases of chemicals at the site. Avatar’s scope of work included:

• 1) Preparation of human health and ecological risk assessments
• 2) Development of risk-based remediation goals
• 3) Support for development of remediation strategies
• 4) Oversight reviews and re-evaluation of risks and remedies as part of 5-year reviews
• 5) Technical support in design of aquatic, wetland, and terrestrial restoration efforts

Avatar risk assessors have performed more than 25 screening and baseline human health and ecological risk assessments at sites on APG. For simpler sites, Avatar scientists performed less costly and less time-consuming screening evaluations. For more complex sites, Avatar scientists performed full baseline risk assessments, some of which included fate and transport modeling and/or sensitive habitat investigations.

Sensitive Habitat Investigations. Because APG and these sites are located adjacent to environmentally sensitive and recreationally/commercially significant natural areas, i.e. Chesapeake Bay and wetlands, Avatar performed the risk assessments with a particular focus on persistent and bioaccummulative chemicals, e.g., mercury and halogenated organic compounds.

Feasibility Study Support. Avatar has been actively involved in developing potential remediation strategies to reduce risk at sites warranting remediation. We reviewed the risk assessments and developed more sophisticated approaches (e.g. spatial analytics, i.e., inverse distance weighting and Thiessen polygons) to reduce uncertainties associated with contaminant distribution and facilitate better decision-making.

5-Year CERCLA Reviews. Avatar also performed oversight reviews and provided modifications to previously performed human health and ecological risk assessments at 5 APG sites (e.g. 5-year CERCLA ROD review).

Ecological Restoration Support. Avatar has provided technical support in the design of aquatic, wetland, and terrestrial restoration/enhancement projects.