USACE, Baltimore District

Overview:

• Groundwater Monitoring
• Land Use Control Inspection

Description:

On 1 January 2019, Bluestone acquired Avatar Environmental, LLC. Bluestone (Avatar) was tasked to perform groundwater monitoring and a land use control inspection at Operable Unit 4 – Motor Pool Building 700 at the former Fort Ritchie Army Garrison under contract for the USACE Baltimore district. The former Fort Ritchie Army Garrison is located in Cascade, Washington County, Maryland. Fort Ritchie was selected for Base Realignment and Closure in 1995 and officially closed on 30 September 1998.

When Fort Ritchie was an active installation, the motor pool was located at Building 700, a stone structure built prior to 1941. The Building 700 motor pool served as the maintenance shop and refueling station for the installation. Maintenance of vehicles occurred inside Building 700 until the late 1980s. Chlorinated solvents such as tetrachloroethene (PCE) were commonly used as automotive degreasers during this timeframe. Releases of chlorinated solvents from within or near the maintenance pit near the northwest corner of the building resulted in a dissolved-phase chlorinated solvent plume in underlying groundwater.

The remedy to protect human health and the environment chosen in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Record of Decision for the site is Land Use Controls with Monitoring.

Bluestone performed long-term monitoring and land use control inspection event 8. The purpose of the groundwater monitoring was to evaluate the extent to which contaminants are degrading and/or migrating downgradient. The land use inspection required an inspection of the site to address whether use restrictions and controls were communicated in the deed(s), whether the owners and state and local agencies were notified of the use restrictions and controls affecting the property, and whether use of the property has conformed with such restrictions and controls.

Bluestone collected groundwater samples following low flow sampling protocols consistent with the USEPA low flow sampling procedures. The following indicator field parameters were monitored to confirm stabilization: turbidity, dissolved oxygen, specific conductance, temperature, pH, and oxidation reduction potential. Additionally, samples containing residual permanganate were quenched using sodium thiosulfate. During the land use inspection Avatar conducted a visual inspection of the site and interviews with the current property owner to ensure compliance with the land use control objectives.

Currently, Bluestone is preparing Long-term Monitoring Report 11 to summarize the findings of the groundwater monitoring and land use inspection. Upon finalization of the Long-term monitoring Report, a 5-year review will be conducted to ensure the existing remedial and monitoring system are operating in the most cost-effective manner.