Seasonal occurrence and risk assessment of endocrine-disrupting compounds in Tagus estuary biota (NE Atlantic Ocean coast)

Estuaries are continually threatened by anthropogenic pressures, consequently, a large group of contaminants harmful to human health affects the aquatic biota; therefore, it is necessary to monitor their quality. This study deals with the determination of a large group of compounds representing different endocrine-disrupting compounds (EDCs) classes [21 pesticides, 4 polycyclic musk fragrances, 4 UV-filters, 7 bisphenols, 6 polybrominated diphenyl ethers (PBDEs) and 8 of their methoxylated (MeO-BDEs)] in several estuarine species (fish, bivalves, crustaceans, earthworm, and macroalgae) collected seasonally along one year in two distinct areas of Tagus River estuary ("contaminated" vs. "clean" areas). The most abundant compounds found were galaxolide (HHCB) (81% positive samples; 0.04-74 ng/g ww), isoamyl 4-methoxycinnamate (IMC) (64%; 1.13-251 ng/g ww), alachlor (44%; 0.08-16 ng/g ww), and BDE-47 (36%; 0.06-2.26 ng/g ww). Polycyclic musks were the most frequent contaminants in fish (seabass, barbus, mullet, and sole) and macroalgae samples, while UV-filters were predominant in bivalves and crustaceans, and bisphenols in earthworms. Seasonal variation was verified for Σpesticides and Σmusks, with significantly higher levels in summer and autumn, whereas ΣUV-filters highest levels were found in spring and summer, and for ΣPBDEs statistically higher levels were registered in cold seasons (autumn and winter). Σbisphenols were significantly lower in spring than in the other seasons. In general, considering all species analysed in both areas, no statistically significant differences (p > 0.05) were verified between the two collection areas. Based on the estimated daily intake data, consumption of fish from this estuary is unlikely to be a human health concern, since the levels of contamination were below the toxicological threshold values. Overall, the data obtained in this study will allow regulatory authorities to identify and prioritize contaminants monitoring programs in estuaries, such as the case of bisphenol A, which was found, for the first time, in earthworm and clam species.