Polyethylene Devices and the Effects of Sediment Resuspension on the Cycling of PAHs and PCBs in the Lower Hudson Estuary

Polyethylene Devices and the Effects of Sediment Resuspension on the Cycling of PAHs and PCBs in the Lower Hudson Estuary

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(Cont.) KPEWs for eleven PAHs and PCBs were found to correlate closely with octanol-water equilibrium partitioning constants (Kows; log KPEW = 1.1 log Kow-0.45, R2 = 0.85). Temperature and salinity dependence of KPEW for the chemical of interest can be predicted with that chemical's excess enthalpy of solution and Setschenow constant, respectively. DpEs for several HOCs were measured in the laboratory so that the time for equilibrium uptake in the field could be predicted. PEDs allowed for quick, in situ, time-averaged measurements of phenanthrene and pyrene at pM concentrations and PCB #52 at fM concentrations in Boston Harbor seawater. Observations of disequilibrium between sorbed HOCs (e.g., PAHs a PCBs) and the surrounding environmental waters indicate that the times for desorption are important for understanding the fate of HOCs. Settling and resuspended particles can play a significant role in the cycling of HOCs. For PAHs, like pyrene, these chemicals' strong affinity for black carbon in the environment makes the rate of desorption less certain. The desorption rate for pyrene from native Hudson River sediment was measured in the laboratory and a diffusion rate constant (effective diffusivity/particle radius2) ranging from 1. OE-7 to 5.6E-7 s-1 was measured. The results were in good agreement with a physically- and chemically-based model for estimating effective diffusivity and the rate of desorption.A concentric ring of 9 x 200 nm diameter fibers delivers the emission radiation to a Va-vr. imaging spectrograph (SPEX, Model ... A time delay unit (Princeton Instruments Model PG-200) controls the time gating via a 100 nm fiber connecting the laser and the optical trigger on the delay unit (65). ... The data was then filtered (smoothed with a low-pass filter) and plotted using a Matlab code written by Stevenanbsp;...


Title:Polyethylene Devices and the Effects of Sediment Resuspension on the Cycling of PAHs and PCBs in the Lower Hudson Estuary
Author: Rachel Gwen Adams
Publisher: - 2003
ISBN-13:

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