comprehensive site investigation and remediation objectives report

2010 and PNAs did not exceed Tier 1 groundwater ROs. Refer to discussions and data found
in Sections 2.7.4, Tables 2.1 to 2.4 (soils) and Tables 3.1 to 3.2 (groundwater).
5.2 DISTRIBUTION / NATURE OF CONTAMINATION
Nature and Extent of Soil Contamination
As previously discussed, soils at the Site are impacted with VOCs constituents, most notably
trichloroethene and tetrachloroethene, associated with former dry cleaning operations. The
extent of soil impacts are illustrated in Figure 3.3 and are described as follows:
• The extent of VOC contamination in excess of Tier 1 ROs is approximately 85 feet by
120 feet. Depths of impacts range from immediately below the concrete pavement to 11
feet bgs, and the majority of impacts were identified between 7.5-11 feet bgs. A third to
one half of the VOC impacted soils are located below the current Spartans’ Square
Shopping Center building.
• Tetrachloroethene exceeds soil saturation limits at SM-GP-108 from 10-11 feet bgs.
The exceedance is confined to a maximum 15 foot radius, based upon laboratory
analysis of adjoining samples that do not exceed soil saturation limits.
Nature and Extent of Groundwater Contamination
Groundwater at the Site is impacted with VOC constituents, mainly tetrachloroethene,
concentrations and its daughter products are associated with former dry cleaning operations. In
addition, concentrations of four metals (aluminum, iron, lead and manganese) exceeded Class I
groundwater remediation objectives in two locations near the southeastern boundary. The
lateral extent of groundwater impacts are illustrated in Figure 3.4 and are described as follows:
• Concentrations of VOCs (mainly tetrachloroethene) were detected above Class I
groundwater ROs in four temporary monitoring wells and three permanent monitoring
wells installed at the southeastern end of the Site and centered around the former dry
cleaning operations. Bromodichloromethane, chloroform, and bromoform were detected
above Class I ROs in two wells along the southeastern boundary. Based on the
proximity of the wells to the Site boundary and the direction of groundwater flow, it is
possible that VOCs impacts in groundwater extend off-site. Following future remedial
actions to remove saturated soils, Tier 2 modeling will be used to address the potential
extent of the remaining groundwater impacts. However, based on the concentrations
and Site conditions, it is anticipated that any off-site impacts will not exceed the existing
groundwater ordinance area.
• Concentrations of four metals (manganese and/or aluminum, iron, lead) were detected
above Class I groundwater ROs in the monitoring wells (SM-MW-01 and SM-MW-04)
installed at the southeastern end of the Site. As previously stated, it is not apparent that
the encountered concentrations represent a notable groundwater concern, and may be
the result of relatively high suspended solids within collected samples.
Refer to Section 6.3 for the full Tier 1 analysis of laboratory results.
Comprehensive Site Investigation Report V3 Companies, 23
Spartans’ Square Shopping Center May 2010