|Bandera Road Ground Water Plume||Leon Valley, Texas|
The Bandera Road Ground Water Plume site is situated in Bexar County, in the City of Leon Valley, which is in the northwestern section of the City of San Antonio, Texas. The site encompasses an area approximately one mile long by one-half mile wide. The plume is centered in a business area, with some residential homes nearby, between Poss Road and Grissom Road, approximately 590 feet southwest of Bandera Road.
This plume was identified through assessment activities conducted by the Texas Commission on Environmental Quality (TCEQ) Voluntary Cleanup Program. The investigation identified the presence of tetrachloroethene (PCE) and trichloroethene (TCE) in concentrations above the Safe Drinking Water Maximum Contamination Level (MCL) of 5.0 parts per billion (ppb) within the Edwards Aquifer. The site consists of a PCE and TCE contaminated ground water plume originating from unidentified source(s).
Five private water wells have been determined to contain concentrations of PCE above the MCL, and several of these also have TCE above the MCL. The concentration of PCE ranges from 23 to 82 ppb and the concentration of TCE ranges from 0.530 to 7.53 ppb in the five wells. Six other private water wells have been sampled and the results indicate detected concentrations below the MCL.
Potential Impacts on Surrounding Community/Environment:
Five residential wells with concentrations above the PCE MCL have been identified. There are currently 6 other residential wells below the MCL. Two City of Leon Valley public water supply wells are within one mile of the center of the contaminated ground water plume. The contaminated wells are screened in the Edwards Aquifer which is typically at a depth of 350 to 400 feet in the area. The Edwards aquifer is a karst aquifer and a sole source aquifer for central Texas. Continuous sampling of private drinking water wells in the aquifer suggests that the plume is spreading and potentially threatening other private and public drinking water wells.
Response Activities (to date):
TCEQ installed granulated activated charcoal water filtration systems on the five contaminated private wells (PCE concentrations greater than the MCL). TCEQ is currently sampling the wells on a semi-annual basis.
[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent FR notices.]
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.