Background
Polychlorinated biphenyls are human made organic chloride compounds. Due to their oily and viscous properties, these polychlorinated biphenyls (PCBs) were used in electric apparatus as dielectric and coolant fluids. They were also used in carbonless copy paper and the heat transfer system. PCBs were widely used due to their longevity until a number of problems started to be associated with them. They were proven to be environmental toxic and by 1978 their production had been banned by the US government. In 1979 fishing was closed in New Bedford Harbor due to the BCPs pollution and clean up processes were deployed by the environmental scientists.
The Clean-up Process
The most adverse PCB contamination was experienced in the New Bedford Harbor Superfund site. Community representation played a big role in forcing remediation process since it was concerned by the health of the residents. In early 1990s the community formed a member-based advocacy group known as HARC. HARC’s main concern was the contamination of the Acushnet River and New Bedford Harbor. In 1995 HARC steered a fight that forced EPA to abandon its plan to construct an onsite PCB incinerator. In 2004, the advocacy groups started the hydraulic dredging of the PCB hotspot. The plan was to keep the dredge soil in a CAD; confined aquatic disposal. The other way of Superfund remediation program entailed a mechanical process which included the dredging of contaminated sediments. The dredged material was lifted by crane onto a barge that moved it down the harbor, final destination being the CAD cell.
Cost Regulation
EPA and a group of engineers performed multiple targeted clean up processes before commencing the full-scale dredging in 2004. The two parties focused on cleaning the hot spot areas first as funds were not enough. Nine years later, New Bedford reached a $366,250,000 settlement with a responsible party. This settlement increased speed for clean up that resumed in 2014. As of September 2018, EPA managed to clean up to 485 thousand cubic yards of PCB-contaminated Harbor sediment on the upper side through dredging and off-site disposal. The clean-up process was carried step by step as the city looked for settlements from external parties.
Follow up clean up was carried out in the lower Harbor and remaining portion of Upper Harbor during 2016-2018. Finally, EPA facilitated clean up of about 34 thousand cubic yards off the shoreline and disposed the sediments off-site as of September 2018.
References
Helaleh, Murad IH, Amal Al-Rashdan, and A. Ibtisam. 2012. “Talanta.” Simultaneous analysis of organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) from marine samples using automated pressurized liquid extraction (PLE) and Power Prep™ clean-up. (94): 44-49.
Martinez, Andres, Bailey N. Hadnott, Andrew M. Awad, Nicholas J. Herkert, Kathryn Tomsho, Komal Basra, Madeleine K. Scammell, Wendy Heiger-Bernays,Keri C. Hornbuckle. 2017. “Release of airborne polychlorinated biphenyls from New Bedford Harbor results in elevated concentrations in the surrounding air.” Environmental science & technology letters 127-131.
Nelson, W.G., and B.J. Bergen. 2012. “The New Bedford Harbor Superfund site long-term monitoring program (1993–2009).” Environmental monitoring and assessment 184 (12): 7531-7550.
