Pure Environmental Solutions

Pure conducted an Affected Property Assessment in accordance with TRRP
guidelines at a former retail gasoline facility which was in operation until
about 2004. The former facility is located approximately one-half mile east of
Loop 1604 West in a rapidly growing suburban residential area of northwest
San Antonio. The facility ceased retail gasoline operations in early 2004 and
the tanks and associated lines were removed in April 2004. The laboratory
analyses for the soil samples collected during tank removal activities revealed
MTBE concentrations above the MTBE action level of 0.62 mg/kg in two soil
samples. Those locations were overexcavated until the laboratory analysis
revealed MTBE concentrations below the action level. Two monitor wells were
installed adjacent to the areas which revealed MTBE concentrations above
the action level. Because the groundwater analyses revealed MTBE
concentrations in the groundwater samples collected from well MW-2 to be
above the MTBE Action Level of 0.24 mg/L, an Affected Property Assessment
was conducted for the former retail gasoline facility.

A total of five soil borings which were converted to monitor wells MW-1
through MW-5, were installed as part of the Affected Property Assessment.
The soil analyses revealed either no detectable BTEX or TPH concentrations
or concentrations below the applicable assessment levels.

Based on all the data collected and reviewed for this facility, it appeared that
the groundwater bearing unit encountered beneath the subject property was
an areally limited perched aquifer. Consequently, well yield tests were
conducted to determine the groundwater flow rate and to determine if the
encountered groundwater bearing unit could be classified as a Class 3 water
supply. Based on the results of the well yield tests, the groundwater bearing
unit was reclassified as a Category 3 water supply. MTBE concentrations in
the groundwater samples collected from the monitor wells ranged from 0.2781
mg/L to 2.866 mg/L, which were below the applicable assessment level for a
Class 3 water supply of 24 mg/L. Consequently, case closure was requested
and granted based on the results of the investigation.

Back to Experience & Case Histories