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Geosyntec
<br /> consultants
<br /> • In 1988, the Navy conducted a Verification Study, which included installing
<br /> piezometers, wells, and staff gauges. During this study, VOCs were detected in
<br /> groundwater at Site 3, Site 4, and the Landfill Area(Kleinfelder, 1988).
<br /> • In 1989, the Navy conducted site investigations at Sites 5A though 5J.
<br /> • In 1992, the Navy conducted site investigations at a total of 31 sites at RRI.
<br /> • Between 1992 and 1995, the Navy conducted removal actions at Sites 3, 4, 5A, 5C,
<br /> 5E, 5G, 5J, 5H, 5I, IAS-03/04, IAS-05, and IAS-09.
<br /> • In 1995, the Navy initiated surface water and sediment investigations at RRI, installed
<br /> stream gauges, and collected samples from the drainage channels (PRC, 1997c).
<br /> • Between 1995 and 1997, the Navy installed monitoring wells, collected grab-
<br /> groundwater samples, and conducted groundwater pumping tests at Sites 3, 4, and
<br /> IAS-11 (PRC, 1997b).
<br /> • In 2002, the Navy prepared a Remedial Investigation (RI)Report for groundwater at
<br /> RRI in OU-4 (Tetra Tech EM, Inc. [Tetra Tech], 2002).
<br /> Following the property transfer, the Port conducted additional groundwater investigations,
<br /> including sampling groundwater monitoring wells, installing new groundwater monitoring wells,
<br /> collecting grab-groundwater samples, sampling surface water drainage channels for comparison
<br /> to groundwater, and demonstrating that arsenic is naturally occurring in groundwater at RRI.
<br /> Groundwater monitoring activities conducted by the Port from 2018 to 2021 since DTSC and
<br /> CVRWQCB approval of the 2018 GMWP have included the following:
<br /> • Annual groundwater monitoring events were conducted in the third quarters of 2018,
<br /> 2019, 2020, and 2021, which included assessing the well conditions, measuring the
<br /> depth to water and total depth in the wells, and sampling the wells for potential COCs
<br /> per the 2018 GMWP and addendums.
<br /> • In January 2018, at the request of DTSC, the Port sampled select wells at Site 3 for
<br /> PFAS, and PFAS were detected in groundwater. Responsibility for PFAS is retained
<br /> by the Navy per the Environmental Services Cooperative Agreement (ESCA). Once
<br /> PFAS were detected in groundwater, the Navy was notified, and the Navy has been
<br /> working with DTSC and CVRWQCB on further investigation and monitoring of
<br /> PFAS at RRI.
<br /> • In August 2018, the Port re-surveyed the wells at RRI that were able to be located to
<br /> obtain updated top of casing elevations and well coordinates.
<br /> • In April and May 2019, the Port sampled wells for dioxins and furans in areas where
<br /> dioxins and furans were identified as potential COCs based on historical site use.
<br /> • In April and May 2019, the Port collected grab-groundwater samples at three
<br /> locations at Site 3, seven locations at Site 4, four locations in the Central Area, and 10
<br /> locations in the Landfill Area for analysis of VOCs to evaluate the extent of the
<br /> VOCs plumes.
<br /> RRI Groundwater Monitoring Work Plan 4 June 2022
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