HIGHWAY 18 GROUND WATER
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The Highway 18 Groundwater site is a contaminated groundwater plume located in Kermit, Winkler County,Texas; at Latitude: 31.8556790, Longitude: -103.0973350; in the Texas 23rd Congressional District. The city of Kermit supplies water to 5,714 individuals on 2,465 connections.
The site consists of a groundwater plume of chlorinated solvents from an unknown source (or sources) that released volatile organic compounds (VOCs) into the Santa Rosa Aquifer. The Kermit Public Water Supply (PWS) first detected trichloroethene (TCE) in its system in 1994; tetrachloroethene (PCE) was first detected in 2000. The TCEQ confirmed contamination through a Superfund Site Discovery and Assessment Program (SSDAP) sampling event in June 2013, a Site Inspection (SI) sampling event in July 2014, and an Expanded Site Inspection (ESI) sampling event in October 2015. Despite efforts to identity the surface sources of the groundwater contamination through soil sampling of dry cleaner and automotive repair facilities during the SI and ESI, contamination was determined to originate from an unknown source (or sources) that released into soils and migrated down into the Santa Rosa Aquifer.
Groundwater is contaminated with PCE and TCE. These contaminants were found at concentrations greater than the Safe Drinking Water Act’s Maximum Contaminant Levels (MCLs) within the Santa Rosa Aquifer. The Kermit Public Water Supply (PWS) draws its municipal supply from the Santa Rosa Aquifer. The KermitPWS system presently operates nine PWS wells, all located within the Kermit city limits, which supply water to the community. Currently, seven of the City of Kermit’s nine PWS wells contain either TCE or PCE. Two of the seven PWS wells were found to contain PCE concentrations above the health-based limit (the Maximum Contaminant Level [MCL]). Because two wells contain PCE above the health-based limits, the Kermit Public Water Supply system treats (water is chlorinated) and blends water prior to distribution to ensure it meets drinking water standards. Although PCE was also detected in the remaining five PWS wells during sampling between 2013 and 2015, concentration levels are below the health-based limits. Three Kermit PWS wells also detected TCE, which are all below the health-based limits.
The Texas Commission on Environmental Quality referred the site to the EPA due to chlorinated solvents in groundwater used for drinking. Without identification and investigation of the source of groundwater contamination and remediation of the contaminated groundwater plume, additional public and private wells may be threatened. Other federal and state cleanup programs were evaluated but are not viable at this time. The EPA received a letter in support of proposing to add this site to the NPL from the state of Texas. The EPA proposed the site to the National Priorities List (NPL) on September 9, 2016. The Site was listed to the NPL on August 3, 2017.
What Has Been Done to Clean Up the Site?
The EPA is preparing to conduct the Remedial Investigation (RI). The investigation is conducted to determine the source and extent of contamination in soils and groundwater, and if that contamination poses a human health risk. The investigation may involve placing several new monitoring wells within the City and also placing drive-points in the shallow subsurface soil to determine the source point for the groundwater contamination. EPA has met with City officials in the past to discuss EPA’s path forward and will meet with the community in the near future to present the investigative approach and how the community and the City can assist in that investigation. Following completion of the RI field work, the EPA will conduct a baseline human health and ecological risk assessment. The objective of these assessments is to characterize and quantify, where appropriate, the current and potential human health and environmental risks that would prevail if no further remedial action is taken.
EPA adds sites to the NPL when contamination threatens public health and the environment. EPA typically initiates Superfund involvement at a site because states, tribes or citizens ask for EPA involvement. EPA conducts a remedial investigation (RI) to define the extent of soil and groundwater contamination. If EPA determines that a risk to human health or the environment exists, EPA then proposes the cleanup method; EPA holds a Public Meeting to present the proposed cleanup method to the community, and to receive comments. Following proposal and the comment period, EPA develops the Record of Decision, which documents the cleanup process/method. A Remedial Design is then developed and EPA and the EPA contractor conduct the cleanup through the Remedial Action.
What Is the Current Site Status?
Two of the seven Kermit PWS wells have PCE contamination above the maximum contaminant level (the health based limit). The Kermit water system treats and blends water prior to distribution to ensure that drinking water standards are met. No other response actions have been taken.The EPA is preparing to conduct the Remedial Investigation (RI). The RI shall provide information to assess risks to human health and the environment and to support the development, evaluation, and selection of appropriate response alternatives. EPA will take soil and groundwater samples from many locations within the City. The soils investigation will be conducted to determine if soils are a health risk and to determine the source point for groundwater contamination and if those soils are a continuing source of groundwater contamination. Monitoring wells will define the subsurface geology to determine the water bearing aquifers and the mechanisms that receive and transport contaminants. The groundwater investigation will define the vertical and lateral extent of groundwater contamination; which will allow EPA to determine if a cleanup is required or if other avenues can be used to better protect drinking water resources. The remedial investigation will expand the past investigations to further define the source point, if the groundwater plume is migrating or is degrading, and a remedy to protect human health and the environment.