PERSISTENCE OF POLYCYCLIC AROMATIC-COMPOUNDS OF DIFFERENT MOLECULAR-SIZE AND WATER SOLUBILITY IN SURFICIAL SEDIMENT OF AN INTERTIDAL SANDFLAT

The persistence of 13 polycyclic aromatic hydrocarbons (PAHs), ranging from two- to six-ring compounds, in an intertidal sandflat was studie d by applying uniform amounts (0.10 g) of each to the surface of the s andflat and then monitoring concentrations over time. The mass of tota l PAH, after initial losses, declined slowly, so that after 256 d 12% of the applied material remained. Vertical concentration profiles indi cated that little downward movement occurred and that most of the mass was concentrated in the top 2 cm, where most losses also occurred. Th e study has shown that anthropogenic PAHs have persistences comparable with organochlorine pesticides in aerobic sediments of intertidal san dflats. Rank correlations showed that the order of persistence may be predicted on the basis of molecular size parameters, such as molecular weight, molecular volume, and area. Persistence of PAHs in intertidal sandflats appears to be regulated by simple, physical processes.