Polycyclic Aromatic Hydrocarbons (PAHs) in Cetacean from Western Mediterranean Coast

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants derived from the combustion of organic matter, highly lipophilic and present in all the world's seas and oceans, as well as in the atmosphere and soils. However, the analysis and impact of these compounds on cetaceans are scarce. Cetaceans, which are considered as oceanic sentinels of human and wildlife health, have been suggested to be especially susceptible to the toxic effects of PAHs. The aim of this work was to detect and quantify 16 PAHs in blubber samples from 58 individuals of various endemic cetacean species stranded on the Murcia coastline (Western Mediterranean) between 2011 and 2018. Only six of the 16 studied compounds were detected with detection frequencies ranging from 17.24% (anthracene) to 98.28% (phenanthrene). The concentrations detected are in line with those obtained by other authors in marine mammals from areas with high anthropogenic pressure. Phenanthrene was the PAH showing the highest concentrations (maximum 205.14 μg/kg lw.), followed by naphthalene, acenaphthene, fluoranthene, fluorine and anthracene. Our results in striped dolphin (the species with the largest number of samples, n=40) followed the same distribution pattern than others striped dolphins elsewhere, dominated by naphthalene (46.86 ± 27.48 μg/kg). This compound is used as a precursor in many industrial processes, as well as a component of pesticides and fuels, so high levels in the study area, characterized by its intensive agriculture (up to 10.9% of the total pesticides used in all of Spain), were expected. On the other hand, the profile of PAHs detected in the study area is mainly composed of low molecular weight compounds, which have the lowest carcinogenic and mutagenic potential. However, some studies have demonstrated the greater genetic susceptibility of Mediterranean cetaceans to the adverse effects of PAHs. Therefore, toxic effects affecting the status of studied populations should be addressed. This is the first work assessing PAHs concentrations in cetaceans from the Region of Murcia, so the data presented in this work could serve as a reference for future research.