A congener-specific PCDD/F emissions inventory for the UK: do current estimates account for the measured atmospheric burden?

Considerable effort has been expended in the UK and elsewhere to quantify a nd rank PCDD/F primary sources and emissions to the environment, principall y the atmosphere, so that cost-effective source reduction measures can be t aken. Here, we predict a congener-specific emissions inventory for primary and secondary nondioxin-regulated sources to the UK atmosphere, estimated t o have ranged from 3 to 22 kg in 1996. The inventory profile is dominated b y OCDD (similar to 30-40%), 1,2,3,4,6,7,8-HpCDD (similar to 15-19%) and 1,2 ,3,4,6,7,8-HpCDF (similar to 14-19%). Congeners 2,3,4,7,8-PeCDF and 1,2,3,7 ,8-PeCDD dominate the Sigma TEQ composition. Mass balance modelling suggest s that the predicted congener pattern in UK air (based on the emission inve ntory) is similar to observed measurements, with absolute concentrations be ing estimated within a factor of 2 for most congeners. Calculations taking into account atmospheric weathering processes and long range (advective) tr ansport suggest that PCDD/F sources to ambient air are primarily ongoing an d that atmospheric mixing will mask individual emission source profiles/ide ntities. This supports measured evidence for the consistency of PCDD/F air profiles observed around the UK throughout the year. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.