Polycyclic Aromatic Hydrocarbon Accumulation and Biomarker Responses in Cockles from Moroccan Mediterranean Coasts

Abstract

This study aims to evaluate levels and effects of Polycyclic Aromatic Hydrocarbons (PAHs) in cockles (Acanthocardia tuberculatae) collected from two differently influenced areas in the Mediterranean Western Moroccan coasts. PAHs accumulation was studied in soft tissues using Soxhlet extraction and separation on silica column methods. The measure of those organic compounds was realized by Gas chromatography coupled to Mass spectrometer technics (GC/MS). The impact evaluation was carried out by the study of biochemical responses in gills and digestive gland using two enzymes activities: Glutathione S-Transferase (GST) and Acetylcholinesterase (AchE). The PAHs displayed significant rates of accumulation ranging from 10.12µg/g Dried Weight (DW) to 11.65µg/g (DW) respectively in Oued Laou and Martil sites. Pyrolytic and petrogenic origins were observed in both sites. Pyrolytic origin of PAHs was strongly detected in Oued Laou site while petrogenic origin was mostly detected in Martil site. Biochemical study revealed significant enzymatic response of GST and AchE in gills and digestive gland. The study showed significant biochemical response more important in Martil site than Oued Laou site traduced by GST induction and AchE inhibition. Those results seemed to be related to accumulation rates of PAHs, which was also suggested by the statistical analysis PCA.