The Site is situated in Bexar County, in the City of Leon Valley, in the northwest section of the City of San Antonio, Texas. It consists of a plume with an estimated size of one mile long by one-half mile wide, extending from a business area to a residential area. The Site is bounded by Poss Road and Grissom Road, southwest of Bandera Road. Ongoing sampling and investigation may alter the estimated plume extent.
The Site currently includes eight private wells. Six are drinking water wells and two are not. The wells draw water from the Edwards aquifer and are approximately 350 to 400 feet deep. The maximum observed concentration in the wells is 111.6 ppb of PCE (perchloroethylene) and 5.76 ppb of TCE (trichloroethene). The MCL for both is 5 ppb. PCE and TCE cannot be detected by taste or smell in water until it reaches concentrations well above the MCL. There are two City of Leon Valley public water supply wells within one mile of the center of the plume.
Releases or threatened release into the environment of a hazardous substance, pollutant or contaminant PCE has been detected above the MCL in six wells within the Site boundaries. PCE is a hazardous substance listed in Section 101(14) of CERCLA, 42 U.S.C. '9601(14) and 40 CFR '302.4. The Texas Department of Health and Human Services (DHHS) has determined that PCE may reasonably be anticipated to be a carcinogen.
The Site was added to the National Priorities List (NPL) on March 7, 2007. On March 28, 2007 the Superfund Division Director approved a Time Critical response action to address the potential exposure to PCE and TCE from private drinking water wells.
On May 8, 2007, EPA contractor mobilized to the site and started trenching and installing water lines. Pressure regulators were installed to prevent leaks due to a possible increase in the water pressure. A total of six properties were connected to a public water system. Five properties were connected to the City of Leon Valley Public Water System. Due to its proximity to the San Antonio Water System (SAWS) the remaining property was connected to the SAWS water main. In this same property, the well pump was removed with the purpose of converting the well into a sampling station for the remedial investigation. The same type of well conversion was made at two other properties where municipally supplied water was already in place. The well conversions had the purpose of facilitating the remedial action investigation.
Community meetings have been held to keep the public informed about the site status and expectations at the Bandera Road Groundwater Site.
On February 27, 2008 the last field work activities were completed. All the properties where EPA performed removal activities were restored to their original conditions.
The Remedial Branch of the EPA Superfund Division will continue the investigation to identify the source(s), define the extent of the plume and plan subsequent remedial investigation activities. Additional properties may be identified with contaminated drinking water wells as the investigation continues. EPA's Removal Branch will continue to communicate with the Remedial Branch in case there is a need for additional action.
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