Polycyclic Aromatic Hydrocarbon Degradation and Sorption Parameters in Coastal and Open-Sea Sediment

Abstract

This work describes the experimental deter- mination of the major degradation and sorption param- eters of polycyclic aromatic hydrocarbons (PAHs) in a sensitivemarineenvironment,theNorthernAdriaticSea (Mediterranean Sea). The persistence and sorption of complex PAH mixtures were analysed in the laboratory in conditions mimicking open-sea and coastal sedi- ments, which differ in grain size and organic carbon content and are characterized by different oceanograph- ic conditions including abiotic influences. The study investigated how sediment type and texture and salinity, temperature and solar irradiation conditions affect the partitioning of low molecular weight (LMW) and high molecular weight (HMW) PAHs into aqueous and solid phase, which critically influence their behaviour. With regard tothe changefromoffshoreto coastal conditions, HMW PAHs were found to be more sensitive to the increased salinity (from 21 to <37 parts per thousand), whereas LMW PHAs were more sensitive to the tem- perature increase (from 11 to 22 °C). HMW PAHs were more affected by sediment type changes in terms of distribution coefficient (Kd). Since the physicochemical properties of organic pollutants affect their distribution, transport, bioavailability and toxicity, analysing the ac- cumulation and persistence of dissolved pollutants can provide useful information for environmental risk as- sessment and management.