Field Survey of Polychlorinated Dibenzo-p-dioxins and Polychlorinated Dibenzofurans (PCDD/Fs) in Sewage Biosolids Treated Agricultural Soils

3.0 Analytical Results

There are over 200 congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Analytical results are reported both as totals for the 10 different homologues (members of a homologue have the same number of chlorines), and as individual results for the 17 congeners that have substituted chlorines in the 2,3,7,8- positions on the molecule. The latter are the congeners of greatest concern with respect to toxicity.

The international toxicity values (I-TEQs) for the soils and sewage biosolids included in this study are presented in Table 3. Similarly, the homologue toxicity values (H-TEQs) for these materials are presented in Table 4. Data for congeners and homologue groupings in the soils are presented in Table 5, and in the sewage biosolids are presented in Tables 6 and Table 7.

The proportion of the different congeners and homologues present in a sample is a signature which can sometimes give clues to the origins of the dioxins and furans. For this reason, the percent occurrence of the different congeners and homologue groups is presented in Table 8.