ENVIRONMENTAL MODIFICATION OF PAH COMPOSITION IN COAL-TAR CONTAINING SAMPLES

The PAH composition of coal tar containing samples collected at a numb er of coal gasworks sites has been studied. Samples were removed from areas where the coal tar components would have undergone varying degre es of environmental modification since deposition. The degree of envir onmental modification for individual PAHs exhibits a strong correlatio n with various molecular descriptors including octanol/water partition coefficient (K(OW)). Regression lines for environmental modification ratio-descriptor relationships show an increasing slope with increasin g environmental attenuation of the coal tar sample. Aqueous partitioni ng and volatilization are probably the main processes which control en vironmental modification of coal tar at gasworks sites. The applicatio n of molecular descriptors shows promise for modelling the environment al behaviour of PAHs in these situations.