Forest

TRRP Affected Property Assessment

Former Retail Gasoline Facility

Pure Environmental Solutions conducted an Affected Property Assessment in accordance with TRRP guidelines at a former retail gasoline facility which was in operation until 2004. The former facility is one-half mile east of Loop 1604 West in a rapidly growing suburban residential area of northwest San Antonio. It 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 in two soil samples. Those locations were over-excavated 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 to be above the MTBE Action Level, 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 a 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 were below the applicable assessment level for a Class 3 water supply. Consequently, case closure was requested and granted based on the results of the investigation.