Figure 3. Correlation of calculated TCDD TEQs for GC/MS data with measured TCDD TEQs using the P450RGS assay

Technical Note DOER-C8

July 1999

Figure 3. Correlation of calculated TCDD TEQs for GC/MS data with measured TCDD TEQs using the

P450RGS assay (A) or the EROD assay (B) on 10 crude NYDMMP sediment extracts (Means

of six replicates SD)

Miscellaneous Sediments. To further compare the sensitivity of the P450RGS and EROD

assays, a set of 15 sediment samples obtained from various other sites were analyzed. Results were

expressed and presented as for the NYDMMP sediments. The miscellaneous sediments were not

as well characterized by chemical analysis as were the NYDMMP sediments. Only PCDD/PCDF

GC/MS chemical analysis was performed on these sediments. One sample, however, was analyzed

for both PCDD/PCDF and PCB. In this sample, PCDD/PCDF contributed 99.7 percent of the total

TEQs, while PCBs contributed only 0.3 percent (Table 1).

Dioxin activity was detected in all 15 sediment extracts with the P450RGS assay. The correlation

between P450RGS and GC/MS data was good (r2 = 0.714) (Figure 5A). Of the 15 samples, only

six had detectable dioxin activity in the EROD assay, and the correlation of these six points with