Temporal-spatial survey of PAHs and PCBs in the Atlantic Iberian northwest coastline, and evaluation of their sources and risks for both humans and aquatic organisms.

Herein, sixteen priority sixteen priority polycyclic aromatic hydrocarbons (PAHs) and seven polychlorinated biphenyls (PCBs), considered seawater quality indicators, were quantified in four beaches of the Iberian (Portuguese) northwest coastline, including one ornithological reserve. These seashores are close to an important industrial region and a harbour. Water samples were extracted for PAHs and PCBs in their aqueous phase (DAP) and suspended particulate matter (SPM) and analysed by GC-MS/MS. Annual average concentrations reached ∼8 ng/L (DAP) and ∼100 ng/g dw (SPM) for PAHs and ∼3 ng/L (DAP) and ∼19 ng/g dw (SPM) for PCBs. PAHs and PCBs had fluctuations suggestive of seasonality. The possible origins of PAHs point to pyrogenic (forest fires) and petrogenic activities linked to maritime transports. The source(s) of PCBs appear to be related with leaks from waste sorting centres located in the vicinity of the sampling sites, together with the burning of contaminated materials. Toxic equivalents (TEQs) suggested a low carcinogenic potential for PAHs in seawater samples (∼0.3 ng/L and ∼4 ng/g dw, for DAP and SPM). Evaluation of risk coefficients for Σ16 PAHs revealed "Low-risk" of both matrices in all sampling areas. PCBs thyroid toxicity equivalents (TEQs-TH), suggested a low impact on biota (∼7.0E-05 ng/L and ∼5.2E-04 ng/g dw, for DAP and SPM). However, in vivo acute assays with Artemia salina exposed to environmental concentrations of PAHs, PCBs, and mixtures, confirmed the theoretical approach, showing that this coastline is not "Risk-free". This fact calls for further toxicological approaches to fully understand the risks posed by these compounds locally.