Trends of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in baltic herring

This paper summarizes the results of six monitoring programs of herring year classes from 1979 until 2005. The data show that the concentration of PCDDs and PCDFs, expressed on a whole fish basis, remained practically constant during this period. The data also indicate that, because of the power dependence of concentration of these compounds on the age of fish (concentration = a* age(b), a,b = constants, b>l), predators feeding on larger fish ingest disproportionately larger amounts of PCDDs, PCDFs, and dl-PCBs. Principal Component Analysis (PCA) shows a difference in the levels of octachloro PCDDs and PCDFs between 1993/94 and 1999 samples and a very large difference in the profiles of dl-PCBs in the programs. An insufficient cleanup may have caused the anomalous profile of the latter.