Polycyclic aromatic hydrocarbon contamination and LUMIStox solvent extract toxicity of marine sediments in the North Aegean Sea, Greece.

Organic extracts of surface marine sediment collected from six sites within the bay of Kavala (north Aegean Sea, Greece) were used for determining priority pollutant polycyclic aromatic hydrocarbons (PAHs) and doing toxicity testing. PAH analyses and LUMIStox acute toxicity measurements were conducted in two sediment grain-size fractions: silt/clay (< 63 microm) and sand (63-2000 microm). Sixteen PAH concentrations were found at low- to moderate levels, ranging from 44 to 166 ng/g dry weight in the fine fraction and from 45 to 148 ng/g dry weight in the coarse fraction. Molecular indices revealed that PAHs in the bay sediment originate mainly from pyrolytic sources, but some petroleum influence was also evident. A comparison of sedimentary PAH levels with sediment quality guidelines (SQGs) indicated an absence of acutely toxic concentrations. However, all sediment extracts were found to be toxic with the LUMIStox acute toxicity test, with 15-min EC(50)s in the ranges of 1.0-4.0 and 1.1-4.5 mg of dry sediment/mL for the fine and the coarse fractions, respectively. No significant correlations between EC(50)s and concentrations of individual or total PAHs was found, suggesting that chemical analysis of PAHs alone cannot be considered a reliable indicator of sediment toxicity.