Source apportionment of polycyclic aromatic hydrocarbons in the New York/New Jersey Harbor and Newtown Creek
Creators: name: Al Hilo, Mohsin
Publisher: name: No Publisher Supplied
Year: 2023

description: This dissertation is a data mining exercise that analyzes existing data on the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and related compounds in the sediment of the New York/New Jersey Harbor, which includes the Newtown Creek Superfund site, to identify and quantify the sources of the PAHs and the processes that affect their environmental fate. Chapter 1, which has been published, examines PAHs sources to the New York/New Jersey Harbor using data from the Contamination Assessment and Reduction Project (CARP). This data was examined via Positive Matrix Factorization (PMF), which revealed six sources. Two represented the higher and lower molecular weight (MW) fractions of coal tar and/or creosote (pyrogenic) sources and explained 49% of PAH mass in the sediment samples. Two sources were related to uncombusted petroleum (petrogenic) sources, such as heavy fuel oil and crude oil, and explained 30% of PAH mass. The final two sources were related to combustion (pyrogenic) sources such as gasoline- and diesel-fueled vehicles and explained 21% of the PAH mass. Sediment cores revealed that Σ22PAH increased from the pre-industrial period until about 1980, and then decreased due to efforts to control water pollution via mechanisms such as the Clean Water Act.Chapter 3 addresses PAHs in the sediments of the Newtown Creek Superfund Site, which is located in New York City. Measurements of fifty PAHs in over 1,000 surficial sediment and sediment cores and 68 ground water samples from this site were obtained from the Remedial Investigation database and examined using PMF. The PMF analysis isolated six factors (NC1 through NC6) that represented different types of sources. To identify these factors, a weight-of-evidence approach was used that included comparing their fingerprints to stormwater and groundwater data from the creek and PAH profiles from the scientific literature, as well as examining their spatial and temporal variations. NC1 and NC5 were identified as coal-related sources, with NC1 representing the low molecular weight (MW) fraction and NC5 representing the high MW fraction. NC2, NC3, and NC4 represented petrogenic sources and explain about half of PAHs in the sediment, probably reflecting the history of petroleum refining and discharges into the creek. NC3 and NC4 are similar to fingerprints detected in groundwater, suggesting that they are related to subsurface contamination, probably the large NAPL pools present near the creek. Slight differences between groundwater and sediment fingerprints may be related to aerobic biodegradation of PAHs. NC2 was not similar to groundwater fingerprints, suggesting that it is related to direct historical discharges directly to the creek, possible crude oil spills and refinery emulsions. NC6 was a high MW pyrogenic profile that probably represents PAHs in urban background and runoff. Chapter 4 attempts to improve the source apportionment of PAHs in Newtown Creek sediment by examining data on petroleum biomarkers, which are naturally occurring, stable hydrocarbons that can be used to determine the sources of oil spills. A suite of 53 biomarkers was measured in a subset of sediment samples (295) from Newtown Creek, including surface sediments and cores. These data, combined with measurements of the 50 PAH compounds examined in Chapter 3, were analyzed via PMF in order to provide further information about PAH sources beyond what was identified in Chapter 3. This represents the first known use of PMF to analyze petroleum biomarker fingerprints. The results suggest that there are two main types of petrogenic biomarker sources in Newtown Creek, which are thought to represent the two types of crude oil that were refined there. A weight-of-evidence approach aided in the identification of the PMF-derived factors based on the characteristics of the fingerprints, comparison of these fingerprints to literature sources, spatial and temporal (i.e., depth in sediment cores) variations, and comparisons to relatively uncontaminated reference areas. The results generally corroborate the conclusions in Chapter 3 that there are three main sources of petrogenic PAHs in Newtown Creek. One derives from Pennsylvanian crude and is found in older sediment. The other two derive from Venezuelan crude and are dominant in more recent sediments. PMF was found to be a useful tool for analyzing biomarker data to understand PAH sources in Newtown Creek.This dissertation furthers the overarching question of what can be done with data that already exists to understand the sources of pollutants and the processes that drive their concentrations in the environment. The answer is a great deal as long as the data is of sufficient quality and quantity.