PAHs in water and surface sediments from Douro River estuary and Porto Atlantic coast (Portugal)-impacts on human health.

This study investigated the presence of 16 priority polycyclic aromatic compounds (PAHs) in waters from the Douro River estuary and nearby Atlantic seacoast, which both bath the Porto metropolis. In the area, there is an oil refinery, an important harbour, an intense maritime traffic, small marinas and highly inhabited cities. For the analysis of PAHs, water samples were taken from four sampling sites, at six different times of the year (2011), and extracted by solid-phase extraction (dissolved fraction) and by ultrasound technique (suspended fraction), before their quantification by gas chromatography-mass spectrometry. Results not only proved the ubiquitous distribution of all analysed PAHs in the present habitat, but also that their global amounts (∑16PAHs) were extremely high at all sampling sites. Their average concentrations attained ≈ 55 ng/L and ≈ 52 μg/g dry weight (dw), respectively, in water and surface sediments. Accordingly, the surveyed area was classified as highly polluted by these organics and so, in view of the concentrations, mutagenic/carcinogenic responses in both humans and aquatic animals are possible to occur. The percentages of carcinogenic PAHs for humans (group 1) dissolved in water and in surface sediments were ca. 5 and 6%, respectively. These results are the first reported in the area and can be used as a baseline for future control of the PAHs levels locally while serving the building of global scenarios of PAHs pollution in Europe. Graphical abstract Percentage of PAHs, from different categories acordingly to WHO (2016), in both surface sediments and surface waters from Douro River estuary and Porto Atlantic seacoast; group 1 - carcinogenic, group 2A - probably carcinogenic, group 2B - possibly carcinogenic, and group 3 - not classifiable as carcinogenic to humans.