1600 MADISON ST 2016-01-01 MF Import

. MTCA Soil Cleanup Levels (for the analyted compounds) were not exceeded in any of the eight submitted samples, including those samples with noted odors. Groundwater was not discovered in the two newly installed monitoring wells, as measured on several occasions. However, water was discovered at a depth of 16 feet in the previously installed vapor-monitoring well, VW-2. 7'he analyzed water sample from VW-2 was found to containing peroleum hydrocarbons, quantified as gasoline, at a concentration of 6,600 ug/1. This concentration is above the MTCA Groundwater Cleanup Level of 1,000 ug/l. Benzene was not detected in the sample, but ethylbenzene, toluene, and xylenes were detected at concentrations above their coaesponding MTCA Method A Cleanup Levels. MTBE was not detected in the analyzed sample. 6.0 DISCUSSION The following section presents our opinions.conceming the discovered findings of this exploration. • Our exploration findings indicate that relatively minor concenuations of soil contaminanu remain beneath the fire station property and the adjacent residential property (Figure 3). This finding is documented by the sampling of two soil borings to depths 30 feet greater than borings previously completed at this location. • Appreciable quantities of groundwater were not discovered within the explored depths (to 60 feet), but moisture was discovered rvithin scattered and discontinuous soil laycrs. However, these layers did not yield measurable quantities of groundwater, as indicated by pericdic measurements in the two monitoring wells installed in these zones. . When VW-2 was sampled, the water level dropped considerably indicating a limited rechazge azea. This finding is supported by the fact that the newly installed well MW-2, located approximately 20 feet to the west and screened to a similaz depth, consistently has not contained water when measured. . The primary (tank) and secondary (contaminated soil) sources of pctroleum- hydrocazbon contaminants have been removed from this site for almost ten years. Residual concentrations of hydrocazbons identified during this exploration do not appear to be migrating at concentrations of concem. Additionally, the identified concentrations aze expected to decrease over time now that the sources aze no longer present. . MTCA Cleanup Levels were exceeded in the water sample from VW-2 for gasoline hydrocazbons, ethylbenzene, toluene, and xyiene.s. However, when the re: ults were compazed to the proposed Cteanup Levels presented in OIAI05•C-RT.da . � S��'�� CoPyriBht 2001 G-Logics, Ine. Psge I 1 of 14