Our exploratory work examines the nature and origin of molecular and nanoscale interactions between polycyclic aromatic hydrocarbons (PAHs) and specific particle types (e.g., carbonaceous matter) and particle size fractions in the Lower Hudson River. Our approach is to examine the molecular and carbon isotopic compositions of PAHs in atmospheric particulates, road sweeps, water column particulates, sediments and water samples from the Lower Hudson. Additionally, we will characterize the size and compositional characteristics of all particulate and sediment samples and perform PAH-particle interaction experiments to complement our field observations. Our central hypothesis is that the PAH-particle association in the Lower Hudson is determined primarily during their co-generation (in the PAH source) and alterations that occur during their transport prior to riverine deposition, and less so by water-particle partitioning in the deposited sediments. The implication of these distinctions is not trivial, as each of these assumptions can lead to differing approaches to modeling sources, transport and fate or devising strategies for prevention, containment or remediation of the hydrophobic contaminants.
The elucidation of the nature and origin of particle-PAH association is immensely critical for the broader evaluation of the natural disposition, fate and remediation of PAHs and other organic contaminants in aquatic environments. Surface water and related aquatic resources face continuing threats of contamination from by-products of industrial, agricultural, commercial and urbanization activities. Many of these toxic compounds, such as PAHs, have properties that give them a high affinity for solid and organic phases, resulting in their enrichment in particle surfaces as well as their bioaccumulation in food chains. An improved understanding of these processes will assist in controlling contaminant impacts and allow better management of the remediation of contaminated aquatic environments. This is pertinent given the recently approved plans to initiate the largest remediation project in U.S. history - the dredging of PCB-contaminated sediments in a 40-mile stretch of the Hudson River. This SGER project also has broader Educational and Partnership and supports graduate student research, and will involve undergraduate research participants, government and private research collaborators and high school students in the Hudson valley region.
