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Polychlorinated‐dibenzo‐p‐dioxins and dibenzofurans (PCDD/Fs) in dated environmental samples, and their connection to known sources

This article investigates the available environmental data from measurements of the everywhere present contaminant polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/Fs) in dated trends in sediment, soil and herbage from locales in Europe and North America. The PCDD/F data are examined in relation to potential major PCDD/F sources based on volume: wood and coal, example of natural combustion; pentachlorophenol (PnCP), example of chlorinated aro‐matics; and polyvinyl chloride (PVC)‐pyrolysis, example of chlorinated aliphatic. Collected PCDD/F data of congener sums and 2,3,7,8‐substituted congener (PCDD/F profiles) have been investigated with multivariate methods: principal component analysis (PCA) and partial‐least‐squares projection to latent structures (PLS) model. The results show that PCDD/F data from twelve locales can be separated in one to three independent profiles. Normally one profile is related to the PCDD/F found in PnCP and another to combustion. A subtype of the ‘PnCP’ and ‘combustion’ profiles indicates PCDD/F contributions from PVC‐related combustions. The environmental profiles exhibit some differences from the suggested sources. The relatively unprotected PCDD/F related to PnCP is suggested to have passed photolytic and/or thermal dechlorinations. Lower‐chlorinated congeners in environmental profiles related to combustion appear to have been influenced by environmental distribution processes. PCDD/F data before industrial production of chlorinated organics have only limited similarity to PCDD/F in technical PnCP profiles; an average 4.6% of the PCDD/F is related to PnCP. This suggests that PnCP similarity in recent deposition profiles cannot be a result of environmental transformation. The average proportion of PnCP‐related PCDD/F profile in recent depositions is 35% with North America high (average 57%) and Europe low (average 24%).