POTENTIAL BIOMAGNIFICATION OF PCDD FS - NEW POSSIBILITIES FOR QUANTITATIVE ASSESSMENT USING STABLE-ISOTOPE TROPHIC POSITION/

The transport of PCDD/Fs in two Baltic food chains is studied with a n ew method which quantitatively estimates biomagnification. Metabolic f ractionation of stable isotopes of nitrogen is used to numerically est imate the trophic position of organisms. An application of the method to PCDD/F data from two Baltic food chains indicates that summed whole body concentrations of 2378-substituted PCDD/Fs decrease with increas ing trophic position. The sum of TEQs however increases with trophic p osition. The main reason for this is the decrease in OCDD concentratio ns and a selective biomagnification of the three most toxic isomers 23 78-TCDD, 23478-PnCDF and 12378-PnCDD.