Date of Award

5-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Gregory Pope

Committee Member

Michael Kruge

Committee Member

Yang Deng

Subject(s)

Soot--Environmental aspects, River sediments--Hackensack River (N.Y. and N.J.)

Abstract

Black Carbon (‘BC’) is routinely defined as the residual carbon fraction resulting from the incomplete combustion of biomass and/or biofuels (Agarwal et al. 2011). BC is best described as spectrum of carbonaceous combustion by-products, encompassing partially combusted, charred plant tissues, to highly graphitized soot (Shrestha et al. 2010). The highly condensed aromatic structures which exist in the BC matrix are largely responsible for its resistance to further biological or chemical degradation, as well as, its efficient sorption properties in soils and sediments (Forbes et al., 2006; Shrestha et al., 2010). Using a multi-tiered geochemical approach, quantification of BC was coupled with environmental forensics of other contaminants of concern in a highly urbanized/industrialized, tidally influenced river (Lower Hackensack River, New Jersey, USA). This approach allowed for further understanding involving the accumulation and mobility of BC particles in relation to other contaminants of concern and the sedimentation fluxes and hydrodynamic processes which influence them. Review of BC as a potential index parameter for other hydrophobic organic compounds, such as the ever-persistent polycyclic aromatic hydrocarbons (PAHs), was included as part of this research due to their synchronous co-emission inputs and complimentary high sorption capabilities. Analytical quantitative efforts included an array of chemical, thermal and oxidative isolation/extraction techniques including: the Lloyd Kahn method for total organic carbon (TOC) analysis, modified TOC analysis for BC determination, EPA Method 8270 for priority PAHs, loss on ignition (LOI), pyrolysis-gas chromatography mass spectrometry (Py-GC/MS) for evaluation of parent and alkylated PAH assemblages, chemothermal oxidation at 375oC (CTO-375), and major and minor elemental analysis involving scanning electron microscopy (SEM). PAH ratios of various principal masses (m/z 178, 202, 228, etc.,) were also utilized in conjunction with alkyl PAH series ratios to infer potential BC source inputs and to allow for a comprehensive analysis of the chemical characteristics of the historically impacted Lower Hackensack River sediment. Lastly, routine ecological and risk assessment analytical techniques, such as grain size distribution and percent moisture (of sediments) were included as part of this comprehensive sediment study. Historical river-sediment data provided by several federal and state agencies were also evaluated to allow for elucidation of spatial trends relative to heavy metal concentrations, PAHs and other contaminants of concern. Ultimately, the results indicate relatively low concentrations of BC (in comparison to TOC) throughout the lower river sediments, with a general increasing trend observed further downstream adjacent to various petroleum related industries. Qualitative and quantitative analysis of BC particles via SEM further revealed the likely presence of coal fly ash, and various amorphous pyrolytic BC particles. The results of this study also demonstrate the importance of considering different analytical approaches when attempting to quantify BC stocks in an urbanized waterway such as the Lower Hackensack River.

File Format

PDF

Available for download on Wednesday, June 09, 2021

Share

COinS