Tank 2206 Release

Project Detail:

Ensolum personnel provided environmental consulting services related to the release of petroleum hydrocarbons from an above-ground storage tank (AST) at a bulk storage and transmission facility. A release of Rerun Bottoms was identified during tank filling operations in March 2020. Ensolum was retained to investigate the potential magnitude and extent of petroleum hydrocarbons in on-site soil and groundwater in accordance with Title 30 Texas Administrative Code (TAC) Chapter 350. Ensolum’s services included an extensive risk-based subsurface investigation/evaluation. Ensolum conducted environmental investigation activities to evaluate the horizontal and vertical impact on surface soil and to determine if groundwater was impacted by the release.  Investigation activities included the installation of five permanent monitor wells, the collection of soil and groundwater samples from each soil boring/monitor well for laboratory analyses, top-of-casing survey, and aquifer characterization utilizing the Texas Commission on Environmental Quality (TCEQ) regulatory guidance document RG-366/TRRP-8 Groundwater Classification to classify the uppermost groundwater-bearing unit (GWBU). Ensolum utilized a risk-based evaluation to demonstrate that concentrations of chemicals of concern (COCs) in soil and groundwater at the Site were protective of  the GWSoil pathway based on 30 TAC 350 and evaluated total petroleum hydrocarbons (TPH) concentrations utilizing the TCEQ Texas Risk Reduction Program (TRRP) TPH Mixture Protective Concentration Levels (PCL) Spreadsheet to establish a TRRP Tier 1 Residential Critical PCL for the  complete TPH mixture (i.e., the whole product), for each source area and exposure pathway. Based on Ensolum’s evaluation, TPH was protective of the underlying groundwater and a GWSoil PCL did not need to be calculated for the TPH mixture. Ensolum’s site assessment demonstrated that soils were adequately protective of groundwater and that existing soil COC concentrations would attain the soil response objectives for groundwater protection. Ensolum recommended that no additional investigation or remediation was warranted, and submitted an Affected Property Assessment Report (APAR) to the TCEQ for review. The TCEQ concurred with Ensolum’s findings and approved a “No Further Action” determination for the site.