Launch Complex 34, SWMU Cc054 2021 DNAPL Source Zone Operations, Maintenance, and Monitoring, and Hot Spot 6 Air Sparge System Annual Performance Monitoring Report Cape Canaveral Space Force Station, Florida

This Annual Performance Monitoring Report (PMR) for the Dense Non-Aqueous Phase Liquid
(DNAPL) Source Zone (DSZ) and Hot Spot 6 (HS 6) Air Sparge (AS) System presents the results of Year 12 operation of the hydraulic containment (HC) Interim Measure (IM), the results of performance monitoring direct-push technology (DPT) sampling and monitoring well sampling conducted in the DSZ, and the results of operations and performance sampling of the HS 6 AS IM at Launch Complex 34 (LC34), located at Cape Canaveral Space Force Station (CCSFS), Florida. Site-wide biennial LTM sampling was not conducted during this reporting period and is scheduled to be conducted in December 2022. The timeframe for activities documented in this PMR extends from April 1, 2021 to March 31, 2022. LC34 has been designated Solid Waste Management Unit CC054 under the Kennedy Space Center (KSC) Resource Conservation and Recovery Act Corrective Action Program.

The objective of the HC IM at LC34 is to contain the DSZ and deep dissolved-phase trichloroethene (TCE) high concentration plume via operation of a hydraulic containment system
(HCS). The pre-IM design 300 micrograms per liter (μg/L) TCE groundwater contour was used
to establish the deep zone capture area for deep recovery wells, and the shallow zone capture
area was defined by the DSZ. The system began operating in 2010, and in 2015, the system was
expanded to provide HC for areas within the 300 μg/L TCE groundwater isocontours of HS 3
and 4. In 2018 and 2019, an investigation was conducted to re-characterize the DSZ, which
included investigating TCE mass in Layer 7. This data was subsequently used to optimize the
pumping rates of the HCS to more adequately capture residual contaminant mass.

The operational period for Year 12 of the HCS was from April 1, 2021 to March 31, 2022.
Operational runtime for the system was 94 percent during Year 12, with downtime events
attributed to planned maintenance, system repairs, and power outages. As of March 31, 2022, a
total of 285,712,801 gallons of groundwater containing 84,933 pounds of VOCs have been
removed by the HCS. Influent concentrations of TCE have decreased since startup from
approximately 280,000 µg/L (January 2010) to 12,000 µg/L (March 2022). During the reporting
period, all effluent concentrations from the HCS (aqueous and vapor) were below regulatory
reporting limits, indicating the system continues to operate as intended.

Performance monitoring was conducted in December 2021 within the DSZ to evaluate TCE
contamination. Groundwater samples were collected via DPT at nine locations, consistent with
previous events in 2017, 2018, 2019, and 2020. Full vertical profile sampling was completed at
each DPT from 8 to 98 ft bls, at 5 foot intervals. The DPT performance monitoring results are
summarized in this PMR. The results revealed TCE remains at concentrations greater than
11,000 µg/L in the DSZ (1-percent solubility, indicative of DNAPL) at eight of the nine DPT
locations at depths ranging from 8 to 98 ft bls. An overall increasing trend of TCE concentrations
was observed in DPT samples during this reporting period, which may be due to several recovery
wells that were turned off during the AS Pilot Study in the DSZ that operated from July 2021 to
February 2022 (documented separately from this report). The maximum TCE concentration in
2021 was 15,400,000 µg/L in the 58 ft bls depth interval at DPT597 (previous maximum result
in 2020 was 1,690,000 at 48 ft bls at DPT596). During the 2021 DPT event, the overall majority
of TCE contamination was identified in the 58 ft bls interval (below Layer 4), where in the
previous year the majority of mass was observed in Layer 4. This trend appears to indicate
continued mass discharge from Layer 4 (fine-grained unit). In addition to DPT sampling,
monitoring well samples were collected from deep wells in the DSZ area (Layers 7 and 8) to
verify vertical delineation. All monitoring well results were non-detect or below cleanup levels,
with exception of one well (IW0162, screened 105 to 115 ft bls, which is below the existing
recovery well capture zone) where TCE was identified above cleanup target levels.

The HS 6 AS system remained operational during the reporting period covered under this report.
The HS 6 AS IM was initiated in 2018 with 160 AS wells, and expanded in 2019 with an
additional 140 AS wells. Quarterly performance monitoring was reduced to semi-annual prior to
this operational period. The results of the HS 6 system operation and semi-annual performance
monitoring are summarized in this report. Semi-annual monitoring results collected in April and
October 2021 show concentrations of contaminants of concern (cis-1,2-dichloroethene, trans-1,2-
dichloroethene, and vinyl chloride) are generally decreasing and not impacting the surface water
drainage canal, indicating the HS 6 IM is meeting objectives.

Overall, the tasks associated with Year 12 operation of the HC IM and operation of the HS 6 AS
IM were performed in accordance with the recommendations of the 2020 LC34 (Year 11) Operations, Maintenance, and Monitoring Report for DNAPL Source Zone, Site Wide LongTerm Monitoring, and Hot Spot 6 Air Sparging System PMR (NASA, 2021c). Evaluation of
results from the HC IM and HS 6 IM show that these systems are operating as designed and
meeting performance objectives.