Determination of polychlorinated dibenzo-p-dioxin and dibenzofuran congeners in air particulate and marine sediment standard reference materials (SRMs)

Due to the limited number of environmental matrix certified reference mater ials (CRMs) with assigned values for natural levels of polychlorinated dibe nzo-p-dioxins and dibenzofurans (PCDD/Fs), an interlaboratory study was und ertaken by the National Institute of Standards and Technology (NIST) and En vironment Canada to establish reference concentration Values for selected P CDD/Fs in two well-characterized NIST Standard Reference Materials (SRMs): SRM 1649a (Urban Dust) and SRM 1944 (New York/New Jersey Waterway Sediment) . Results from 14 laboratories were used to provide reference values for th e seventeen 2, 3, 7, 8-substituted PCDD/F congeners, the totals for individ ual tetra- through hepta-substituted PCDD/F homologues, and the total amoun t of tetra- through hepta-substituted PCDD/Fs. The mass fractions for the i ndividual 2, 3, 7, 8-substituted congeners range from approximately 0.01 mu g/kg to 7 mug/kg dry mass.