Survey of polycyclic aromatic hydrocarbons in canned bivalves and investigation of their potential sources

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment derived from uncontrolled petroleum spills, marine transports, discharges from ships, and urban runoff. The NW coast of Spain (Galicia) has a characteristic hydrography, defined by a continuous suite of estuarine systems called “Rías Gallegas”. Some of these estuaries support important industrial and urban centres while others are preserved from human influence. The PAH contents in invertebrate organisms, such as bivalves, have been widely investigated because they are good bioindicators of pollution due to their ability to filter the water. 12 PAHs were determined in canned mussels (Mytilus galloprovincialis), clams (Venerupis pullastra), cockles (Cerastoderma edule) and knives (Ensis ensis) from the Galician “Rías Gallegas” to perform a possible risk assessment on these contaminants. Pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene were detected in all the selected samples by liquid chromatography coupled with fluorescence spectroscopy. With regard to benzo[a]pyrene, which represents the most potentially carcinogenic PAHs, European Regulation 1881/2006/EC fixed at 10 μg/kg of wet weight the MRL (maximum residual level) in bivalve molluscs. None of these marine invertebrates showed values higher than the MRL and therefore, they do not suppose risk for human health. Mussels hydrocarbon body burden levels were highest than exhibited by others bivalves. Some factors may determine this feature, as lipid content or habitat. Lower PAH levels of five and six benzene rings were detected in canned mussels in pickle sauce (vegetable oil, vinegar, paprika, salt and other spices) than in mussels in natural sauce (water, salt and other spices). PAHs migration from mussels to the vegetable oil in pickle sauce was verified to be the reason.