Vorschlag zur Auswertung von PAK-Kontaminationen

The behaviour of this group of substances may be considered as an example for the ubiquitous occurence of xenobiotics in the environment. Regrettably, the measurements presented in numerous publications often cannot be directly compared with each other. A first step towards harmonization can be achieved by referring the measuring programmes or the presentation of results to the six aromatics of the German Drinking Water Ordinance (TWV) (Σ6) or the sixteen compounds of the EPA list. The tendency of the PAH group to fractionation in air, water, and soil as well as in some cases during analysis must be taken into acount. In this respect, the first six aromatics of the EPA list are only partially suitable for comparisons of results. The six TWV aromatics in soils, sediments, aquatic suspended solids, and sewage sludges, and to a certain extent also in airborne dust, make up a mass portion of C_Σ6=40–50% of the Σ16 according to EPA. For Fluoranthene (Fluo) and Benzo(a)pyrene (Bap) as quide parameters, concentration quotients single aromatic versus (Σ6)] may be given as estimates, which are on average C_Fluo=33%, and C_Bap=13%. By means of these quotients it is possible to calculate the values for the whole list by means of the data of the single aromatic C_Fluo×3=C_Σ6, or C_Bap×7,7=C_Σ6, and as a check C_Fluo/C_Bap=2,5. For estimating purposes, the relation between the two lists may be assumed als C_Σ6×2=C_Σ16. These estimating values apply to mixes of PAH, which originate from many single sources (emitters), are transported through the atmosphere with dust and settle, and/or enter water bodies after being washed from road surfaces. The estimates serve as plausibility check and for extrapolation, but they cannot replace the analysis for individual substances in the identification of the pollution source or in the study of their environmental behaviour.