Persistent chemicals and emerging pollutants are continuously detected in marine waters and biota. Out of these, polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs) are significant contaminants with decades of presence in the marine environment. The Mediterranean Sea is an ecosystem directly affected by a variety of anthropogenic activities including industry, municipal, touristic, commercial and agricultural. The Mediterranean mussel (Mytilus galloprovincialis) is a filter feeder, which presents wide distribution. In this regard, the specific organism was used as a biological indicator for the monitoring and evaluation of pollution in the studied areas with focus on the mentioned chemical groups. Pristine Turkish sites with minimum effect from anthropogenic activities, in contrast with Greek sites which were subjected to heavy industrial and shipping activity, were selected. A gas chromatographic tandem mass spectrometric method (GC-MS/MS) was developed and validated to monitor 34 compounds (16 EPA priority PAHs and 18 OCs). Analyses of mussel samples in 2011 from sites with the limited anthropogenic pollution shores have shown the occurrence of 11 pollutants (6 PAHs, 5 OCs), while in the samples from sites with intensive activity and expected pollution, 12 PAHs and 6 OCs were detected. Biochemical and biological responses studied only in mussels samples from the sites with the highest contamination showed a situation that was under strong seasonal influence. The intensity of the response was also influenced by deployment duration. Noteworthy correlations were detected among biochemical/biological effects and between mussel body burden and these effects. Continuous monitoring of priority pollutants of East Mediterranean Sea is vital both for ecological and human risk assessment purposes. (C) 2014 Elsevier Ltd. All rights reserved.