Source characterisation and mid-term spatial and temporal distribution of polycyclic aromatic hydrocarbons in molluscs along the Basque coast (northern Spain)

Abstract

The variability of polycyclic aromatic hydrocarbons (PAH) measured in the soft tissues of Mediterranean mussels (Mytilus galloprovincialis) and Pacific oysters (Crassostrea gigas) are investigated. Samples were collected from estuarine waters within the Basque Country (Bay of Biscay), between 2003 and 2011. PAH bioaccumulation showed some seasonality and significant differences were observed between cold (autumn–winter) and warm (spring–summer) seasons. Sites located within the ports of Bilbao and Pasaia showed the highest PAH concentrations in molluscs, and the highest percentages of samples above the established Environmental Quality Standards and Environmental Assessment Criteria. Probably due to human activities carried out in the area, no clear trends were observed, between 2003 and 2011, for the autumn data. Since the Basque coast is an area with high population density and industrial activity, the congener profiles (which reveal the predominance of tetra-aromatics) and the diagnostic ratios identified urban/industrial combustion processes as the main PAH sources. However, natural and petrogenic sources cannot be disregarded.

Keywords:

• mussel
• oyster
• polycyclic aromatic hydrocarbons (PAH)
• pollution sources
• Basque Country

Acknowledgements

Data used in this contribution were obtained from the projects ‘Monitoring Network for the Ecological Status Assessment of Transitional and Coastal Waters within the Basque Coast’ and ‘IMPRES’ undertaken by AZTI-Tecnalia for the Basque Water Agency and the Basque Government, respectively. We wish to thank AZTI-Tecnalia staff for assistance in the collection of data and Professor Michael Collins (School of Ocean and Earth Science, University of Southampton (UK) and AZTI-Tecnalia, Marine Research Division), for advising us on some details of this paper. The suggestions from two anonymous reviewers and the editor of the Journal have considerably improved the first version of this manuscript. This is contribution number 708 from AZTI-Tecnalia Marine Research Division.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplemental data

Supplemental data for this article can be accessed at 10.1080/02757540.2015.1051041.