Final Second Five-Year Review Report Fort Ord Superfund Site ...

identified in the Basewide RI Sites ROD were based on State or federal MCLs with the exceptions of
chloroform, PCE, and vinyl chloride, for which the aquifer cleanup levels are lower than State or federal
MCLs. The lower aquifer cleanup levels were based on risk calculations for each COC that estimated a
combined excess cancer risk of 6 x10 -5 . Since the original risk assessment, the State or federal MCLs that
were selected as aquifer cleanup levels have not changed, and toxicity values for the additional calculated
aquifer cleanup levels have not changed, with the exception of vinyl chloride. The toxicity values for
vinyl chloride are still within the parameters used for the original risk calculations, and the aquifer
cleanup levels remain protective of human health and the environment.
7.1.3.3 Question C
Has any information come to light that could call into question the protectiveness of the remedy?
The Sites 2/12 groundwater remedy is achieving the performance goals of the original design, reducing
concentrations and the aerial extent of COCs. Current system operation is compliant with the objectives
of the Basewide ROD.
7.1.4 Issues
This technical assessment did not identify any issues that could affect current or future protectiveness of
the Sites 2/12 groundwater remedy. Additionally, this assessment did not identify any unresolved issues
previously raised by regulatory agencies, the community, or other interested parties.
7.1.5 Recommendations and Follow-Up Actions
The Sites 2/12 groundwater remedy should continue to operate as designed until either aquifer cleanup
levels are reached or subsequent evaluation indicates that a modification is in order. Opportunities for
future system optimization include discontinuing groundwater pumping from individual wells where
cleanup goals (aquifer cleanup levels) have been attained, and increasing pumping from additional wells
that have higher COC concentrations. Ending extraction at an individual well will reduce the electricity
and O&M costs associated with that well and allow for increased extraction from other existing wells.
7.1.6 Protectiveness Statement
Soil – Because the remedial actions are protective, Sites 2/12 are protective of human health and the
environment.
Groundwater – The remedy will be protective of human health and the environment upon completion, and
in the interim, exposure pathways that could result in unacceptable risks are being controlled because of
the presence of Monterey County Ordinance 4011 and the CRUP.
7.2 Sites 16 and 17
Site 16 consists of the DOL Maintenance Yard, Pete's Pond (a surface water drainage area), and Pete's
Pond Extension. Site 17 consists of a Disposal Area and other areas (Plate 2). Sites 16 and 17 were
combined into one site after the first phase of the RI activities because of the similar contamination
identified at both sites.
Final
7-6
FORMER FT ORD 5YR REVIEW 2007_FINAL United States Department of the Army