Source apportionment of polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and - furans at two Superfund sites in New York
Creators: name: Chitsaz, Mahdi
Publisher: name: No Publisher Supplied
Year: 2023

description: This dissertation employs data mining and analysis techniques to determine the sources of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), persistent organic pollutants known for their enduring environmental half-lives and bioaccumulative properties, in two Superfund sites: the Upper Hudson River and Newtown Creek, New York, USA. The extensive datasets acquired from remedial investigations at these locations were analyzed by a factor analysis/source apportionment method, Positive Matrix Factorization (PMF), to identify fingerprints of co-varying analytes that presumably represent sources.Chapter 2 addresses the Upper Hudson River (UHR), which has been contaminated by releases of specific Aroclors by General Electric during capacitor production at two sites starting in the 1940s. The analysis of the 2017 post-dredging sediment data that was produced by the New York State Department of Environmental Conservation revealed six fingerprints/factors that represent sources of PCB contamination. Even after the remedial dredging, 98% of the PCBs in UHR sediment originated from the Aroclors used by General Electric, while the remaining 2% stemmed from urban areas and tributaries.Chapter 3 examines the sources of PCBs to the sediment of the Newtown Creek Superfund site. The presence of PCBs in deep sediment layers may be a major driver of the cost of the remedy for the contamination there, and therefore allocation of the responsibility for the PCB contamination will be an important determinant of the financial responsibility for the cleanup. A data set containing hundreds of sediment samples was analyzed using PMF, which generated eight probable factors (fingerprints or sources). These sources included primary sources, such as Aroclors, as well as secondary sources, including the East River and Combined Sewer Outfalls (CSOs). The presence of rare Aroclors like 1232 and 1268 was notable. Aroclor 1268 was more abundant in deeper versus shallower sediments, while PCBs from CSOs were relatively more abundant in surface sediment.Chapter 4 attempts to apportion the sources of PCDD/Fs in Newtown Creek sediment. These contaminants, unintentionally produced, are prevalent in the New York/New Jersey Harbor, including Newtown Creek. Analyzing the dataset of PCDD/Fs independently and in combination with PCBs through PMF revealed eleven possible sources, many of which represented Aroclors. Based on the spatial distribution of the fingerprint, a metal (primarily copper) smelting and refining facility may be related to the dominant source of PCDD/F-related Toxic Equivalency Quotient (TEQ) in Newtown Creek sediments (51% of TEQ), while Aroclors are probably responsible for about 25% of the total TEQ. This analysis revealed two additional sources of PCDD/Fs to Newtown Creek sediment: the East River and Combined Sewer Outfalls (CSOs). The East River was responsible for most of the mass of 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD) in the sediment, presumably because it transports TCDD-laden sediment from the Passaic River into the Creek, but the contribution of this source to total TEQ was just 6%. CSOs contributed only about 0.5% of total TEQ in Newtown Creek sediment.This research elucidates the primary sources of PCBs and PCDD/Fs in the studied Superfund sites, paving the way for informed and targeted remediation strategies.