OSWER/OSRTI Washington, DC 20460



### ATIONAL RIORITIES IST 

## N P L (NPL) ***Proposed Site *** October 2010 

### WEST COUNTY R OAD 112 G ROUND WATER Midland , Texas

Midland County

 **Site Location :**  The West County Road 112 Ground W ater site is a ground water plume of chromium /hexavalent chromium located in a rural area of Midland C ounty, Texas immediately to the southwest of the city limits of Midland. The center of the site is designated as 2601 West County Road 112

, Midland, Texas. The site plume currently extends 1 1⁄4 miles from the center of the site and is situated under appro ximately 260 acres

.

 **Site History:** The site was identified in April 2009 by a local resident who asked the Texas Commission on Environmental Quality (TCEQ) to test his private well due to yellow discoloration. Sampling of this well revealed the presence of 5,280 ppb of hexavalent chromium. To date, approximately 234 water wells have been sampled by the TCEQ and 46 water wells have concentrations of total chromium above the Maximum Contaminant Level s (MCL s) of 100 ppb

. TCEQ has installed water filtrati on systems at homes where total chromium has been detected above the MCLs.

 **Site Contamination/Contaminants:** An Expanded Site Investigation was conducted in February 2010

, and no sources were identified. The site is being evaluated as a ground water plum e of chromium/hexavalent chromium with no identified source. Concentrations of chromium in the wells are as high as 5,280 ppb.

 **Potential Impacts on Surrounding Community/Environment :**  Forty

- six residential wells have c hromium contamination above MCL s, in some cases more than ten times the MCL . U ntil the source has been identified and controlled

, th e plume will continue to contaminate remaining private and public wells. The drinking water wells in the contaminated aquifer are the only source of water for these residents, who have been drinking the water as well as using it fo r other consumptive purposes.

 **Response Activities (to date):** The TCEQ is currently monitoring the ground water plume and to date have sampled 234 wells and i nstalled treatment
sy stems on wells that have been identified with hexavalent chromium concentrations exceeding MCL. TCEQ is providing the systems and quarterly monitoring at no costs to the residents. EPA Region 6 is currently evaluating the site for a possible Superfund re moval action.

 **Need for NPL Listing:** The S tate of Texas referred th e site to EPA for NPL listing and potential remedial activities. The potable water is in a relatively shallow aquifer (70

- 100 feet deep). Without identification and investigation of th e source of ground water contamination and remediation of the contaminated ground water plume, the remaining public supply an d private wells will be contaminated

. Other federal and state cleanup programs were evaluated but are not viable at this time.

[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.]

For more information about the hazardous substances identified in this narrative summary, including general information regar ding the effects of exposure to these substances on human health, please se e the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet
at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1

- 888

- 42

- ATSDR or 1

- 888

- 422

- 8737.