M12 PM Remediation
Monday, 14 November 2005: 1:50 PM - 5:30 PM in 345-346

(DEM-1117-826234) Achieving a Cleanup Goal of 1 ppm PCBs in Sediment – Overcoming Logistical and Regulatory Hurdles.

Demers, G.¹, Brody, K.¹, McTigue, J.¹, Lynch, J.², Dow, K.², ¹ ERM, Boston, MA, USA² Yankee Atomic Electric Company, Rowe, MA, USA

ABSTRACT- A release of paint chips containing polychlorinated biphenyls (PCBs) resulted in the need to remediate sediments in a reservoir in western Massachusetts. A quantitative risk assessment was performed to evaluate the risks posed by PCBs and other constituents detected in the sediments, such as metals, semi-volatiles, and radiological compounds. Qualitative evaluations were also performed to evaluate which cleanup goals had been established at other sites in New England. The method selected for removal of sediment needed to take into account several factors including: proximity to an active hydroelectric dam, weight limitation of existing boat ramps, space constraints at the site, the presence of a fish species of special concern, as well as the requirements of a wide range of wetland and environmental regulatory and permitting requirements. Environmental dredging using a land-based crane was selected as the preferred remedial option in consideration of the above factors. During implementation of the dredging, several measures were employed to minimize adverse impacts to the environment during the dredging activities. A silt curtain was installed at the perimeter of the dredging area to isolate the work area from the rest of the reservoir. Electrofishing was used to remove the fish, including those species of special concern, from within the remedial work area prior to the start of dredging. Turbidity monitoring was performed three times per day during dredging to evaluate the integrity of the silt curtain. Lastly, a compliance monitor performed full-time oversight of the dredging activities to ensure compliance with the permit conditions. The dredging operation was successful in meeting the cleanup goal without re-dredging any locations. Confirmatory sampling documented a 90% reduction in the PCB concentrations in the remedial area and the cleanup goal of 1 ppm was achieved with minimal adverse impacts to the environment.

Key words: PCBs, Sediment, Permits, Dredge