Table 8. Polychlorinated Dibenzo-P-Dioxins and Dibenzofurans in 

 composited sediment from Black Rock Harbor. The first 

 column contains data from the present study. The 

 second two columns contain results of duplicate 

 analyses conducted at the U.S. Environmental Protection 

 Agency's Environmental Research Laboratory at Duluth, 

 MN (ERL-D)^. Concentrations as ng/g dry weight. 



Dibenzo-p-dioxins 

 2,3,7, 8-tetra-CDD 

 1,2,3,7, 8-penta-CDD 

 1,2,3,6,7, 8-hexa-CDD 

 1,2,3,4,6,7, 8-hepta-CDD 

 Octa-CDD 



This Study 



<0.078 

 0.073 

 0.088 

 1.29 

 13.0 



ERL-D 



0.057 



0.057 



0.094 



0.081 



0.128 



n.d. 



1.78 



1.74 



16.1 



18.0 



Dibenzof^^ans 

 2,3,7, 8-tetra-CDF 

 1,2,3,7, 8-penta-CDF 

 1,2,3,4,7, 8-hexa-CDF 

 1,2,3,4,6,7, 8-hepta-CDF 

 Octa-CDF 



0.2 5'=' 



0.039 



0.15^ 



0.54 



1.38 



0. 



.057 



0, 



,060 



0. 



.091 



0. 



,070 



0, 



.134 



0. 



,134 



1, 



.07 



1, 



.05 



2, 



.79 



3. 



.09 



^ - Data from Norwood et al.. In preparation. 



^ - Incomplete resolution of the specific isomer from coeluting 

 isomers. 



n.d. - not detected. 



