Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Monastir Bay (Tunisia, Central Mediterranean): distribution, origin and seasonal variations

To assess PAH contamination state of Monastir Bay, surface sediments were collected and analysed for 17 selected parent PAHs by GC/MS. Sediments were sampled from five sites in wet and dry seasons. Total PAH concentrations were in the range of 25.6 to 576.8ng/g d.wt in winter and 44.9-395.8ng/g d.wt in summer. Comparison of results with Sediment Quality Guidelines suggested no eco-toxicological risk for benthic organisms. The use of molecular indices has shown that PAHs in surface sediments originate mainly from pyrolytic sources. Total PAH concentrations in surface sediments showed no significant correlations with organic matter content and pelite fraction. The analysis of spatial and seasonal variations of PAHs in surface sediments has demonstrated that final distribution of PAHs in surface sediments is mainly governed by hydrological conditions.