TP24 Delaware River / Bay|
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall
TP253 (LIA-1117-852064) PCB water quality model for Delaware Estuary (DELPCB): What DELPCB can do?
Start time: 8:00 AM
Liao, S.L.1, 1 Delaware River Basin Commission, West Trenton, NJ, USA
DRBC has developed a general purpose sorbent dynamic PCB model for the Delaware River Estuary (DELPCB). The real time model simulates tidal flows, spatial and temporal distributions of two organic carbon (OC) and PCB (penta PCB homolog) for four layers (water column and three sediment layers). The fate and transport of PCB include (1) PCB partitioning into particulate- PCB, truly dissolved-PCB (actively interacted with the gaseous phase PCB), and dissolved organic carbon (DOC) bound-PCB phases (five phases) and (2) its transport with OC (including biotic carbon [BIC] and particulate detrital carbon [PDC]) for the water column and sediment layers. Spatial varying DOC concentrations were used. As for the value of partition of PCB to carbon, DOC was 10 percent of the value for BIC and PDC. Newly developed empirical formulas for temperature dependent Henry's law constant by Bamford et al. 2002 were included into the model. Seven sets of spatially specific and temperature dependent gaseous PCB empirical formulas derived by Totten et al. 2003 were incorporated into the model. DELPCB incorporates Thomann and Fitzpatrick (1982) equation which provided both tidal velocity and wind-driven effects for tidal systems in a continuous format. With appropriate conversion, both liquid and gas-film coefficient of PCB were obtained (Mills et al. (1982)). Model was calibrated and fine tuned. DELPCB has been recently upgraded in its PCB gaseous phase component (external spatial and temporal input instead of hardwired formulas). This paper will include the mass PCB of in and out of Delaware Estuary during the 19 month calibration period between fall 2001 and spring 2003 for all 5 PCB phases and three organic carbons (BIC, DOC, and PDC). The paper will include the comparison PCB air-water fluxes between DELPCB and other descriptive model described by Totten 2003. Sensitivity analysis results for gaseous phase PCB will be also included.
TP254 (YAG-1117-825563) Identification of Screening Level PCB Congeners for the Delaware Estuary.
Start time: 8:00 AM
Yagecic, J1, Cavallo, G1, 1 Delaware River Basin Commission, West Trenton, NJ, USA
As part of the development of Stage 1 TMDLs for Polychlorinated Biphenyls (PCBs) in the Delaware River, the Delaware River Basin Commission measured concentrations of 124 PCB congeners in fish tissue, sediments, and the water column using Method 1668A. The implementation plans for the Stage 1 TMDLs call for trackdown of currently unidentified sources. Sensitive analytical methods employing high resolution GC / high resolution MS and isotope dilution allow for detection of PCB congeners at low concentrations, but analytical costs for congener lists approximating total PCBs make wide scale application of these methods costly. Analytical costs in excess of $1000 per sample are typical, but are affected by the number of congeners required. Analysis of a short subset list of congeners by the same sensitive analytical method may be available at a substantially reduced cost, allowing for the possibility of wider scale applications such as screening of effluent and waste streams, trackdown of unidentified sources, and performance of more robust statistical analyses. In this paper we consider criteria for identification of a shorter subset list of congeners including high mass presence in multiple media, presence in major loading source categories, low occurrence in blanks, toxicity, and relative contribution to the composition of Aroclors. We will apply these criteria to the existing Delaware River fish tissue, sediment, and water column data sets, to identify a regional congener subset appropriate for wider scale application, such as screening and trackdown, and examine the analytical cost differential of the congener subset.
TP255 (EMS-1116-968239) Delaware River Refinery Effects Differentiated in Tissue, Sediment, and Dated Core Investigation.
Start time: 8:00 AM
Emsbo-Mattingly, S1, Uhler, A1, Hall, L2, Burton, D2, Alexander, C3, Liu, B1, 1 NewFields, Rockland, MA, USA2 University of Maryland, Queenstown, MD, 216583 Skidaway Institute of Oceanography, Savannah, GA, 31411
The assessment of refinery impacts on proximal and regional ecological systems poses many technical challenges. In this investigation, the integrated use of advanced chemistry, ecological risk assessment, and radiogenic dating helped distinguish discrete sources of PAHs from those associated with urban background. Here, a comprehensive evaluation of PAH sources was important because the refinery site was down river from a large metropolitan area and proximal to major shipping channels. The technical approach for this study employed many components including detailed hydrocarbon fingerprinting in horizontal, vertical, and temporal dimensions. In addition, the chemical signatures of sediments and selected biota were compared as part of the ecological risk assessment (sediment triad study). Principal components analysis (PCA) proved effective at comprehensively tracing refinery derived hydrocarbons in the river system. The results of this analysis helped identify the local distribution of refinery impacts to the zone where the PAHs were indistinguishable from urban background. Local variations in the background signatures were also observed and attributed to changes in local land use (urban, residential, rural, and wetland) that generally varied by watershed.