The Site is situated in Bexar County, in the City of Leon Valley, in the northwest section of the City of San Antonio, Texas. The current plume size is estimated to be approximately one mile long by one-half mile wide. The plume is centered in a business area, and extends 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 six private drinking water wells that draw water from the Edwards aquifer. The wells are approximately 350 to 400 feet deep. The maximum observed concentration in the wells is 111.6 ppb of PCE and 5.76 ppb of TCE. 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.
EPA On scene Coordinator Cindy Santiago and RPMs Chris Villarreal and Scott Harris visited the site to contact the property owners where contaminated wells have been determined to be a health threat. EPA provided information and answerd questions about the removal and remediation actions that will take palce on site.
Additional wells located by the USGS survey were sampled.
Additional investigations are continuing to attempt to identify the source(s) and to define the extent of the plume.
The removal action involves the installation of a water line and connection to public water systems. Currently, five properties will be connected to an existing water supply line from a Municipal Utility District (MUD) or other water supply authority. Other properties may be identified with contaminated wells as the investigation continues. The property owners will be responsible for paying for their water use. If the existing water wells are to remain in service, they will be isolated from the public system. Trenches and any disturbance of sidewalks, driveways, or other structures will be restored.
Activated Carbon filters were installed in the wells by TCEQ, which will give the residents access to safe water before and during the removal actions. Once the removal actions are finished, residents will have immediate access to the city water.
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