Polycyclic aromatic hydrocarbon levels in European catfish from the upper Po River Basin

Polycyclic aromatic hydrocarbons (PAHs) are a major concern in environmental studies as many of them have been labeled as probable carcinogens by the International Agency for Research on Cancer (IARC 1983). Due to their lipophilic properties and resistance to degradation, PAHs can accumulate in organic tissue. As a consequence, alarming concentrations of these compounds have been found in many aquatic species. The European catfish (Silurus glanis) is a top food-chain predator that is considered to be a reliable bio-indicator of environmental pollution. From 2009 to 2011, 54 specimens of S. glanis were captured from four different sites covering the area of the Po River basin (Northern Italy). Fish muscles were analyzed in the laboratory to determine the levels of nine PAHs, namely: naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, benz[a]anthracene, chrysene, and benz[a]pyrene (BaP), which were detected by High-Performance Liquid Chromatography (HPLC). The total average concentration of PAHs was 26.90 ± 49.50 ng g-1 (min 0.60, max 275.75 ng g-1). Analysis showed that 9.20% of the fish muscles exceeded the maximum levels of 2 ng g-1 set for BaP by European regulations (1881/2006 EC). Values measured for benz[a]pyrene ranged from 0.05 to 8.20 ng g-1 (mean 1.07 ± 1.58 ng g-1). Chrysene and benz[a]anthracene, both considered potential human carcinogens (PAH2), were found at levels of 4.40 ng g-1 and 0.05 ng g-1 (mean values), respectively. The highest mean concentration was recorded for anthracene (12.92 ng g-1), which has been recently included in the list of Substances of Very High Concern (SVHC) by the European Chemicals Agency (2009).