Occurrence and risk assessment of endocrine-disrupting compounds in fish muscle: The case study of the Douro River estuary (North East Atlantic Ocean).

This work was focused on evaluating the occurrence of endocrine-disrupting compounds (EDCs) in fish muscles, such as bisphenol analogues, personal care products, including some UV-filters and musk fragrances, and selected pesticides. A total of 238 muscle samples of three fish species (Platichthys flesus, Mugil cephalus, and Dicentrarchus labrax) of an important estuary ending in the North East Atlantic Ocean (Douro River estuary, Portugal), in different seasons of the year, was analysed. M. cephalus was the species with a greater occurrence of contaminants, mainly in fishes collected during the spring. Bisphenol A was the main bisphenol analogue detected with an average content of 23.1 µg/kg wet weight (w.w.). Among chemicals used in personal care products, galaxolide, tonalide, and 2-ethylhexyl salicylate, were the most often found, being present in 15.9% (2.2-538.4 µg/kg w. w.), 4.6% (1.1-57.8 µg/kg w. w.) and 3.4% (3.9-56.1 µg/kg w. w.) of the samples, respectively. About 14% of the samples contained residues of at least one pesticide, being alachlor, aldrin, p,p'-DDT, permethrin, and prochloraz the main chemicals observed, varying from 0.1 µg/kg w. w. (p,p'-DDT) to 37.8 µg/kg w. w. (prochloraz). The daily intake estimates of the most frequent EDCs found in the fish muscles suggested that there are no health concerns, based on the recommended weekly consumption of fish for adults.

Polybrominated diphenyl ethers and their methoxylated congeners in Douro river estuary biota: Seasonal occurrence and risk assessment.

Especially added on many industrial and domestic products as flame retardants (FRs), polybrominated diphenyl ethers (PBDEs) are among the chemicals of high environmental concern because of their potential harmfulness for environmental and human health. Seafood consumption is considered the main source of PBDEs and their methoxylated congeners (MeO-BDEs) for humans. The present study aims to investigate the seasonal occurrence of six PBDEs and eight MeO-BDEs congeners using Douro river biota (different trophic levels) as sentinels, as well as to evaluate the human exposure risk to PBDEs through seafood consumption. Biota samples (n = 273) were collected from one of the most important Portuguese estuaries in the north-western coast of Portugal at four different seasons (2019-2020). The analyses were performed by an environmental-friendly extraction procedure followed by Gas Chromatography coupled to a triple quadrupole detector (GC-MS/MS). PBDEs were detected in all seafood samples analysed, with means ranging from 0.02 ng g-1 ww (flounder in autumn) to 3.75 ng g-1 ww (mussel in winter). Levels of lower-brominated PBDE congeners were significantly higher than higher-brominated ones in all seasons (p < 0.01). MeO-BDEs ranged from 0.001 ng g-1 ww (grey mullet in summer) to 5.66 ng g-1 ww (green crab in spring). Crabs and mussels presented the highest means of PBDEs and MeO-BDEs. Regarding the health risk assessment of the studied PBDE congeners (47, 99, and 153), consumption of Douro river fish is not a case of concern for consumers.

Neurotoxicity, Behavior, and Lethal Effects of Cadmium, Microplastics, and Their Mixtures on Pomatoschistus microps Juveniles from Two Wild Populations Exposed under Laboratory Conditions-Implications to Environmental and Human Risk Assessment.

Microplastics (MPs) were found to modulate the toxicity of other pollutants but the knowledge on the topic is still limited. The goals of this study were to investigate the short-term toxicity of cadmium (Cd) to wild Pomatochistus microps juveniles, the potential modulation of acute Cd toxicity by 1-5 µm polyethylene MPs in this species, and possible differences of sensitivity to Cd and MPs-Cd mixtures between juveniles from two distinct wild populations. Juveniles were collected in the estuaries of Minho (M-est) and Lima (L-est) Rivers (NW Portugal). One 96 h bioassay with M-est juveniles and another one with L-est juveniles were carried out in laboratory conditions. Each bioassay had 12 treatments: control, 5 Cd concentrations, 1 MPs concentration, and 5 MPs-Cd mixtures. No significant differences in Cd-induced mortality between juveniles from distinct estuaries or between juveniles exposed to Cd alone and those exposed to MPs-Cd mixtures were found. The total 96h LC10 and LC50 of Cd alone were 2 mg/L (95% CI: 0-4 mg/L) and 8 mg/L (95% CI: 2-17 mg/L), respectively. Cd alone significantly decreased the post-exposure predatory performance (PEPP) of M-est (≥6 mg/L) and L-est juveniles (≥3 mg/L), and acetylcholinesterase (AChE) activity of M-est juveniles (13 mg/L). MPs alone (0.14 mg/L) significantly reduced the PEPP and AChE activity of L-est juveniles but not of M-est juveniles. MPs-Cd mixtures (3-13 mg/L of Cd + 0.14 mg/L of MPs) significantly inhibited the PEPP of juveniles from both estuaries and AChE of L-est estuary juveniles but not of M-est juveniles. Evidences of toxicological interactions, namely antagonism, between MPs and Cd were found. Overall, the results indicate that MPs modulated the sub-lethal toxic effects of Cd in wild P. microps juveniles, especially neurotoxicity. Moreover, the environmental conditions of the natural habitats to which juveniles were exposed during pre-developmental phases influence the sub-lethal toxicity of Cd, MPs, and their mixtures. The implications to environmental and human risk assessment are discussed and further research is needed.