O'Keefe et al. (1984) reported the concentrations of 

 2,3,7,8-tetra-CDD and 2 , 3 , 7 , 8-tetra-CDF in sediments at three 

 locations in the Hudson River. The levels that they reported 

 ranged from <0.0056 to 0.010 ng/g for 2,3,7,8-tetra-CDD and from 

 0.005 to 0.046 ng/g for 2 , 3 , 7 , 8-tetra-CDF. The highest levels 

 were found in the lower portion of the river. The 2,3,7,8-tetra- 

 CDD concentration measured in the BRH Wetland sample is higher 

 than the levels measured in the Hudson River. Because of the 

 problems with coelution of the tetra-CDFs in the present study, 

 it is not possible to compare the results for 2 , 3 , 7 , 8-tetra-CDF. 



Kuehl et al . (1987) reported the concentrations of 

 2,3,7,8-tetra-CDD in freshwater sediments from the Wisconsin 

 River and Petenwell Reservoir (not used for potable water) in 

 Wisconsin. The Wisconsin River sediment had a 2,3,7,8-tetra-CDD 

 concentration of 0.039 ng/g and the Petenwell Reservoir sediment 

 had a level of 0.17 ng/g. The former is similar to the 

 concentration reported in the BRH Wetland sample and the later is 

 considerably higher. Kuehl et al . (1987) also quantified numerous 

 other congeners of PCDDs and PCDFs including several of the 

 2, 3 ,7,8-substituted congeners measured in the present study. The 

 levels that they reported for the Petenwell Reservoir sediment 

 were very similar to the results from the present study for both 

 series of compounds. 



Many of these same compounds were also quantified in 

 the sediments of several rivers from an industrialized area in 

 southwestern Germany and in Lake Constance (Hagenmaier et al., 

 1986). The 2,3,7,8-tetra-CDD and 2 , 3 , 7 , 8-tetra-CDF compounds 

 were not detected in any of the river samples, although 2,3,7,8- 

 tetra-CDF was detected at a level of 0.010-0.040 in Lake 

 Constance sediments. This level, as well as the levels of all of 

 the other congeners of both PCDDs and PCDFs measured in both 

 studies, were similar to those found in the 200 East and South 

 Reference sediments and lower than those of the BRH samples. 



Several studies have measured the concentrations of 

 PCDD and PCDF compounds as the sum of all compounds at each level 

 of chlorination. Petty et al. (1983) measured the concentrations 

 of PCDDs in the sediments of the Housatonic River in 

 Massachusetts. The concentrations that they reported were 

 generally similar to those measured at 200 East and South 

 Reference in the present study and lower than the BRH samples. 

 The total PCDF concentration that they measured was 1.3 5 ng/g. 



Czuczwa and coworkers have published several papers on 

 the levels of PCDFs and PCDDs in the Great Lakes. Hexa-, hepta- 

 and octa-CDDs were found in the highest concentrations. The 

 concentraticpns of total hexa-CDDs ranged from about 0.050 to 

 0.3 00 ng/g in Lake Huron, away from known areas of contamination, 

 and was about 4.0 ng/g in the relatively contaminated area of 

 Saginaw Bay (Czuczwa and Rites, 1984) . The concentration of 



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