PARENT SESSION
Sediment Assessment & Management Poster Session.
Tuesday, November 14, 2000
8:00 AM to 12:00 PM
CC West/Center Exhibit Hall

(PTA061) Spatial characterization of dioxin/dioxin-like contamination in a navigation channel using the P450RGS cell-based assay.

McFarland, Victor A.¹, Inouye, Laura S.¹, Lutz, Charles H.¹, Yaw Ang, Choo², ^{1 2}

ABSTRACT- The P450RGS assay employs a transgenic HepG2 cell line in which luc has been stably transfected as a reporter. P450RGS conforms to APHA Standard Method 8070 and ASTM Standard E-1853. EPA has promulgated the assay as EPA Method 4425 in update IVA of the EPA SW846 Methods Manual. Modifications to the method made at ERDC WES include a combined extraction/cleanup procedure using accelerated solvent extraction (ASE) with a sulfuric acid/silica gel packing in the extraction cell, and a 96-well microtiter plate format for the assay. These modifications substantially increase the volume of sample throughput and reduce the cost of the assay. Assays in which TCDD EQs are reported are typically less than 1/10th the cost of dioxin analysis using GC/MS, and have comparable sensitivity. In this study 13 stations were designated at intervals extending from the mouth to the apex of a navigation channel requiring dredging. Cores from 3 to 12 feet sediment depth were sectioned and assayed for TCDD EQs using P450RGS. This paper describes the application of the assay in the context of a Tier II level evaluation of sediments prior to permitting dredging and disposal operations. More extensive sampling than would have been affordable using only conventional chemistry resulted in a fuller characterization of the extent of contamination, and substantial cost savings were obtained.

Key words: P450RGS, Dioxin, Analysis, Sediments