Remedial Action Plan - Rochford Field - Newhall Remediation Project

levels of VOCs; cyanide was detected in one soil/fill sample tested. Impacts were widespread and
detected SVOCs, ETPH and metals at concentrations in excess of RSR RDEC and PMC. Chlorinated
pesticides were detected at concentrations below RSR criteria. The data did not detect significant
impacts to the natural overburden materials beneath the fill deposits.
The Phase II/III site investigations included six rounds of groundwater sampling at four monitoring
wells in Rochford Field. Groundwater samples were submitted to a Connecticut-Certified Laboratory
for testing for ETPH, VOCs, total and leachable metals, SVOCs, PCBs, pesticides, and cyanide.
Analytical results from Phase II/III and Supplemental Phase III groundwater testing are included in
Tables V and VI. The groundwater analyses detected SVOCs, ETPH, nickel and zinc at concentrations
above RSR GWPC; contaminants of concern were not detected above RSR Surface Water Protection
Criteria (SWPC) or Residential Volatilization Criteria (RVC).
On 29 April 2005, Haley & Aldrich issued a report titled “Report on Supplemental Phase III Data
Investigation and Preliminary Remedial Action Plan, Mill Rock Park, Sewer Pump Station, and
Rochford Field, Hamden, Connecticut.” In addition to summarizing the results of the October 2004 to
February 2005 supplemental investigations and chemical testing, the report included a recommended an
engineered cap and reclassifying site groundwater from GAA to GB. In October 2005, Haley &
Aldrich issued an addendum to the April 2005 report. The addendum, which was titled, “Supplemental
Phase III Data Investigation Report Addendum, Mill Rock Park, Sewer Pump Station, and Rochford
Field, Hamden, Connecticut,” included responses and additional information based on comments
provided by CTDEEP in a 12 September 2005 letter. Refer to the 2005 or previous reports for detailed
information on the previous testing, including boring and test pit logs and laboratory data reports.
1.4 Applicable Remediation Standards
The subject site is being regulated under CTDEEP Consent Order No. SRD-128 and as such, site
conditions are required to demonstrate compliance with CTDEEP Remediation Standard Regulation
(RSR) criteria.
The southern portion of Rochford Field is located in a groundwater area classified as "GB" by the
CTDEEP. The area was reclassified from the previous “GAA” classification in 2005. A “GB”
classification indicates that the water resource is not intended to be suitable for use as a drinking water
supply without prior treatment. The northern portion of Rochford Field parcel remains “GAA” water
resources which indicate that the area is regulated for potential future use as a public water supply. A
public water supply system is used to supply potable water to area residences and businesses.
Applicable RSR soil criteria are:
Residential Direct Exposure Criteria (RDEC)
GB Pollutant Mobility Criteria (GBPMC); and,
GAA Pollutant Mobility Criteria (GAPMC).
Applicable RSR criteria for groundwater quality are:
Groundwater Protection Criteria (GWPC);
Surface Water Protection Criteria (SWPC); and,
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