The Centredale Manor Restoration Project (CMRP) is an active Superfund clean-up site in North Providence and Johnston, Rhode Island. The Source Area (SA) of the CMRP once contained a chemical plant and a drum reconditioning facility whose operations resulted in releases of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin and its congeners (dioxin) into the local environment, including two dammed ponds downstream of the SA. Allendale Pond (AP) – the pond immediately adjacent to the south of the SA – contains sediment contaminated with dioxin and was the subject of this project.
Our team was tasked with compiling environmental sampling data of dioxin concentrations taken from AP; utilizing professional statistical software to analyze that data to determine compliance with regulatory limits for planned remediation by excavation; considering and recommending sediment dewatering and disposal methods; and considering an alternative remedial option: armored capping with a chemical isolation layer.
Based on regulatory cleanup goals and available data, the team utilized statistical software to analyze sampling data and compute the UCL95 using USEPA-approved statistical methods. In addition, the required excavation, dewatering and disposal of AP sediment were estimated based on analytical and statistical results, and an alternative remedial design was made.