Particle affinity and bioavailability of PAHs associated with coal tar pitch

Abstract

This project has investigated the particle affinity and bioavailability of coal tar pitch related PAHs from sediments outside several Nordic aluminium smelters using the Søderberg technology. Passive samplers (POM) have been used for assessing water-sediment partitioning for PAHs and actual bioaccumulation has been addressed in an experimental setup.The results showed that the PAHs associated with the sediments in the vicinity of the smelters were stronger (a median factor of at least a magnitude) adsorbed/absorbed to the particles than free energy relationship implies. This further implies that the bioavailable fraction is correspondingly lower, and one would expect lower bioaccumulated concentrations. The accumulated concentrations measured in Nereis diversicolor and Hinia reticulata were in fact very similar to biota concentrations expected based on the POM-deduced sediment-water partitioning coefficients. Thus, the measured biota to sediment accumulation factors (BSAFs) agreed also very well with those expected from the POM-deduced sediment-water partitioning coefficients. On the other hand, this good correspondence was not observed for the third species, the bivalve Nuculoma tenuis. There were however logistical intractabilities connected to this species biology and size that render it probable that particulate sedimentary matter contaminated the Nuculoma tissues analyses. The uncertainties associated with Nuculoma tenuis render the interpretations somewhat inconclusive for this species, and further investigations would be necessary to eliminate the uncertainties.