Site Narrative:
The former Coastal Refinery El Dorado Site (Site) is located at 1835 N Topeka St; northern outskirts of City of El Dorado in portions of Sections 26, 27, and 34, Township 25 South, Range 5 East, Butler County, Kansas. The Site encompasses approx. 420 acres & includes several subareas: former Main Process Area (MPA), former Asphalt Handling Area (or AHA), Wastewater/Stormwater ponds to the east, former South Tank Farm (STF). The West Branch Walnut River (WBWR) defines the northeastern boundary of the Site. The Site does not include the adjacent Pester Burn Pond Superfund Site (C2-008-00058), which is located north of the wastewater/stormwater ponds. The original discovery of groundwater (GW) and soil contamination was in 1987 during a site investigation conducted by Mid West Environmental Consultants.
In February 2003, El Paso Merchant Energy-Petroleum Company (El Paso) entered into a Consent Order with KDHE to perform a Comprehensive Investigation (CI)/Corrective Action Study (CAS) at the Site. The CI was conducted in three phases; Phase I, II & III (2003-2009). Third Phase CI Report was submitted 9/09. The investigations identified elevated concentrations of refinery-related contaminants in soil and groundwater at the Site; primary contaminants of concern include petroleum-related compounds (benzene, naphthalene, total petroleum hydrocarbons), select volatile organic compounds, and isolated impacts from metals contamination related to former activities at the Site.
Risk assessment activities were performed as part of the CI from 2008-2012, and include a Final Human Health Risk Assessment (HHRA) approved by KDHE in March 2012, a Baseline Ecological Risk Assessment (BERA) for the MPA and AHA areas and a separate BERA for the WBWR and STF area approved by KDHE in July 2011 and March 2012, respectively.
Several interim remedial measures (IRMs): completed at the Site between 2006 through 2014, and include construction of GW, seep, and spring interceptor trenches(IT), storm water collection structures, tar removal treatment system, and a wetland-based groundwater treatment system. Other IRMs completed include soil and waste excavation, stabilization, consolidation, and capping. Semi-annual GW monitoring, operation, maintenance, and monitoring of IT and associated GW and product treatment systems are currently on-going to monitor Site conditions and the effectiveness of the systems in place.
In November 2014 KDHE approved the Corrective Action Study (CAS) Report that evaluated potential remedial alternatives for the Site.
In July 2016 KDHE prepared a Draft Corrective Action Decision (CAD) document, which was finalized on Nov. 21, 2016. This outlined the preferred remedial alternatives for the Site which include a remedy consisting of hydraulic containment via operation of existing and proposed IT, wetland-based GW treatment system, phytoremediation technologies, additional soil excavation/ disposal, surface water sampling, cap maintenance, and the following critical components: environmental use controls (EUC), long-term monitoring, receptor management surveys, product recovery, MNA and natural source zone depletion (if confirmed through assessment), and continued operation of the existing GW and product treatment systems. Completion of the first year NSZD monitoring was in the spring of 2017.
The MPA Phytoremediation Design & O&M Plan, STF Creek Surface Water Sampling Work Plan, STF Suspected Waste Area Characterization Work Plan, LNAPL Recovery, Transmissivity, and NSZD Work Plan; Monitored Natural Attenuation (MNA) Work Plan, & the STF NE Plume GW IT Design: approved late 2018.
7/18: 2003 Consent Order Amended (conduct CAP/Corrective Action tasks).
1/19: STF excavation; LNAPL recovery 22 wells; wetlands controlled burns.
5/19: Proposal abandon 78 wells.
6/19: MNA Qtrly monitoring 53 wells/3 STF creek Surface Water samples.
12/19: STF NE Plume GW IT began; QAPP approved. |