• Comingled contamination
• VOCs, metals, chlorobenzenes, and PFAS
• Large network of monitoring overburden and bedrock wells located across five properties
• Delineation of groundwater impacts and development and implementation of remedial strategy for groundwater
• Utilized 3D geological model and other tools to visualize data and evaluate complex Site conditions
• CSM
• ISCO and MNA
• Remediation oversight
This 21-acre site was used for rail car maintenance and cleaning from the 1920s until it was decommissioned and sold in 1972. From the mid-1970s to 2019, site activities included contractor storage and laydown and scrap metal and vehicle salvaging. The site was recently redeveloped into a commercial warehouse. GZA was retained to continue the groundwater investigation and remediation.
Challenge
Comingled groundwater contamination from multiple historical site operations and an adjacent property, as well as prior soil and groundwater remedial activities, created complex environmental conditions. Groundwater impacts were not delineated, including in deep bedrock.
Solution
GZA designed and managed quarterly post-remedial groundwater monitoring and installation of additional wells, including bedrock monitoring wells, for delineation and long-term monitoring. Well installation required seamless coordination with multiple off-site property owners, their tenants, and their legal team, as well as several subcontractors. The remedial investigation (RI) included an evaluation of the efficacy of the in-situ chemical oxidation (ISCO) and bioaugmentation treatments and applicability of monitored natural attenuation (MNA) through trend analysis, a forensics study to identify the multiple sources of PFAS, and the development of a three-dimensional geological model using Leapfrog Works® to visualize the complex hydrogeological and contaminant conditions at the site to assist with GZA’s analyses and refinement of the conceptual site model (CSM).
Benefit
The 3D geologic model improved efficiency of data evaluation and facilitated communication of data and site information to stakeholders, including project team and regulatory agencies, through development of cross-sections, image renderings, and shareable interactive scenes. It allowed GZA to better identify and elucidate complex spatial and temporal relationships within the Site’s subsurface.