TP24 Delaware River / Bay
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(YAG-1117-825563) Identification of Screening Level PCB Congeners for the Delaware Estuary.

Yagecic, J¹, Cavallo, G¹, ¹ Delaware River Basin Commission, West Trenton, NJ, USA

ABSTRACT- 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.

Key words: PCBs, Congeners, Screening, Trackdown