MIDDLE RIVER — Lockheed Martin recently voluntarily sampled 41 existing groundwater wells at the Middle River Complex to determine if per- and polyfluoroalkyl substances (PFAS) are present in the groundwater.
PFAS are a large group of man-made substances that have been used in a variety of industries since the 1940s and were used in the manufacture of commercial products, including stain- and water-resistant fabrics, waxes, paints, and cleaning products. PFAS may have been used historically in metal plating at the Middle River Complex, and aqueous film-forming foam (AFFF), a PFAS product, may have been used in a former firefighting training area at the Complex.
While the samples revealed low-levels of PFAS in 40 of the 41 locations, the combination of PFOA and PFOS (two types of PFAS) at those 40 wells ranged from 0.83 to 62 parts per trillion, which is below the current U.S. Environmental Protection Agency’s (EPA’s) human health advisory level for drinking water of 70 parts per trillion.
Lockheed Martin collected groundwater samples from existing wells that represented different aspects of the site, including background, upgradient, potential source, and downgradient conditions. Samples were taken from 11 wells near the former firefighting training area and former plating location.
An additional 30 wells were sampled near former metal plating areas and near Cow Pen Creek in Blocks G, H, and I. The company is now investigating for PFAS in groundwater at Martin State Airport.
Construction of the Additional Groundwater Cleanup System for Blocks E and F to Begin Soon
Work begins this June to install a second groundwater cleanup system for Blocks E and F at the Middle River Complex. The system will remove contaminants in the groundwater discovered during the construction of the first Block E groundwater cleanup system in 2013.
At that time, Lockheed Martin contractors encountered an abandoned storage tank near the foundation of former D-Building that contained trichloroethene (TCE), historically a solvent commonly used to clean industrial parts.
Lockheed Martin subsequently identified a plume of TCE-contaminated groundwater in the southeastern part of Block E, and after further investigation, in Block F. TCE from the tank is likely the primary source of the TCE in this plume.
A temporary multi-phase extraction system operated from 2014 to 2015 and removed more than 500 pounds of TCE. Plans for the second groundwater cleanup system were first presented to the Maryland Department of the Environment (MDE) in June 2018, and to the Middle River community in October of that year.
MDE approved Lockheed Martin’s final design of the cleanup system in 2019. Lockheed Martin has developed a multipart approach to cleaning up the TCE plume that focuses on groundwater removal and treatment, in situ (meaning in-place) treatment, and monitoring. Groundwater in Block E will be treated using bioremediation as was originally planned; it will be implemented once other treatment systems are in place and Block E soil work is completed.
Bioremediation relies on non-toxic food mixtures injected into the groundwater to stimulate feeding by bacteria that are already present. The stimulated bacteria break down the trichloroethene into nontoxic substances.
Middle River Complex Report on 2019 Groundwater, Surface Water, and Sediment Monitoring
Monitoring the status of groundwater, surface water, and sediments at the Middle River Complex is an essential part of Lockheed Martin’s verification of remediation success.
At the beginning of the cleanup process, groundwater monitoring wells help locate and identify contaminants. Once cleanup gets underway, regular sampling of monitoring wells provides a picture of how effective the remediation approach is in removing contaminants. A commitment to monitoring the wells is part of every remediation plan submitted to the Maryland Department of the Environment (MDE), and, when appropriate, the federal Environmental Protection Agency (EPA).
Lockheed Martin samples groundwater monitoring wells each April. In 2019, 171 wells were sampled, and the results helped guide work for the coming year and beyond. The reports go to the MDE and sometimes to EPA, and project managers brief local officials on the status of the work and monitoring.
MDE has already agreed that no further action is necessary for Block G other than continued groundwater monitoring. Monitoring well samples taken in Block I showed only low levels of TCE in the groundwater. Lockheed Martin has completed remediation in Block I south of one of the main manufacturing buildings (C-Building) using in situ (meaning in-place) bioremediation. The corporation has proposed to the MDE that no further action is needed at Block I, other than continued monitoring, and is awaiting the MDE’s response.
Because the Block I groundwater plume is located partly under C-Building, indoor air in C-Building is monitored routinely to ensure no contaminated vapors have intruded into the building. No contaminated vapor has been found in C-Building in quite some time. A subslab vapor removal system operates in C-basement to prevent indoor impacts from remaining subslab contaminants.
TCE is also present in the Blocks E and F groundwater plume, and Lockheed Martin is engaged in cleanup of those areas (see story on Blocks E and F groundwater remediation on Page 1.) Tom Blackman, Lockheed Martin’s lead project manager for the Middle River Complex, noted that, “because the groundwater at the Middle River Complex is not accessible to the public, and no one is drinking it, there is little to no risk of potential exposure.”
As a result of the 2019 monitoring in newly installed wells, Lockheed Martin is further evaluating the potential for 1,2,4-trichlorobenzene to reach surface water. 1,2,4-trichlorobenzene is a solvent once used with polychlorinated biphenyls (PCBs) in electric transformers and it has been found in soils along with the PCB contamination near former transformer rooms in the former D-Building in Block E.
An initial investigation completed in the fall of 2018 indicated the presence of the compound, and that it may be approaching surface water in Dark Head Cove. A follow-up investigation was initiated this past fall, and Lockheed Martin is now developing an addendum to its groundwater remedial action plan that will present alternatives for addressing 1,2,4-trichlorobenzene in Block F groundwater.
Lockheed Martin samples surface water in Dark Head Cove and Cow Pen Creek three times annually – in April, June, and September – to assess the levels of volatile organic compounds (VOCs), 1,4-dioxane, and polychlorinated biphenyls (PCBs) in the water, and to help assess whether the waters are safe for swimming and the consumption of fish and other aquatic organisms such as crabs.
In 2019’s surface water monitoring results, all VOCs and 1,4-dioxane were below swimming screening levels and levels for human consumption of marine organisms. The levels of PCBs were very low and safe for swimming; however, the levels are above that which is considered safe for consumption of marine organisms. Past monitoring of surface water has periodically shown the presence of PCBs. (Consumption of fish taken in these waters is guided by Maryland Department of the Environment and Maryland Department of Natural Resources fish advisories for the Chesapeake Bay and the Baltimore region, which include the Middle River area.)
However, the 2019 monitoring event showed lower concentrations, but more widespread distribution of one type of PCB. It is worth noting that Lockheed Martin is using a new laboratory whose equipment is capable of detecting lower levels of PCBs, so it cannot be said with certainty that PCBs were not more consistently present at such low levels previously.
Lockheed Martin also sampled sediments in Dark Head Cove. Monitoring showed that the dredging and the layer of activated carbon previously placed atop untreated sediments is achieving reductions in PCBs more quickly than anticipated.