Microplastic ingestion in key fish species of food webs in the Southwest Atlantic (Marine Protected Area Namuncurá / Burdwood Bank).

Microplastics (MPs) are currently one of the main problems of marine pollution, being found in all environmental matrices. Due to their size, they can be ingested by organisms directly (from the environment) or indirectly (with their prey). The objective of this study was to analyze the occurrence, abundance, concentration, and chemical nature of MPs present in the gastrointestinal tract of two fish species, Patagonotothen guntheri and Patagonotothen ramsayi, both of which are key in the food web of the Marine Protected Area Namuncurá/ Banco Burdwood (MPA N/BB). The analyzed species presented high values of MPs per individual (MPs/ind.) and occurrence compared to other studies. P. guntheri tended to have a lower number of MPs/ind. and occurrence than P. ramsayi (P. guntheri: 2.50 ± 1.93 MPs/ind., 82.50  %; P. ramsayi: 3.93 ± 2.91 MPs/ind., 90.60  %). While fibers were the predominant MPs in both species, P. ramsayi had a greater number of fragments and a greater variety of MPs chemical composition than P. guntheri. The prevailing chemical composition was cellulosic material (cellulose and cellulose mixed with polyamide and polyester). Synthetic fibers and fragments such as polyester (PET), alkyd resin, polyurethane, polyethylene, polyacrylic fiber and poly(ethylene-co-vinyl acetate-co-vinyl chloride) were also found. Although both species have a generalist diet, the differences found may be due to the fact that P. guntheri has benthopelagic feeding habits while P. ramsayi has demersal-benthic. Our study is the first report on the presence and characterization of MPs in organisms relevant to food webs in the Southwest Atlantic.

Microplastics pollution in the intertidal limpet, Nacella magellanica, from Beagle Channel (Argentina).

Microplastics (MPs) have been identified in diverse marine invertebrates; however, there are few studies on limpets. This study aimed to evaluate and compare the presence of MPs in Nacella magellanica among sites of the Beagle Channel with different degree of anthropogenic influence. Intertidal limpets were sampled in three sites: Ushuaia Bay (UB) (inside Ushuaia city), a site with high anthropogenic influence owing to population growth, and fisheries, industrial and port activities; Ensenada Zaratiegui (EZ) and Playa Larga (PL) (west and east of Ushuaia city, respectively), both sites with a certain degree of environmental protection and low anthropogenic influence. MPs were isolated from the whole soft tissue of individuals by oxidative digestions with H2O2 (30%; 1:10 w/v). MPs occurrence was 100% in organisms from UB and EZ, whereas 90% in PL. Limpets from UB showed 10 ± 6.69 MPs/ind and 2.22 ± 0.78 MPs/g ww, while in PL and EZ there were 2.90 ± 2.02 MPs/ind and 0.96 ± 0.94 MPs/g ww; and 5.60 ± 2.59 MPs/ind and 2.41 ± 1.47 MPs/g ww, respectively. Fibres were the most abundant MPs type, followed by fragments and films. Fibres and films were identified as semi-synthetic cellulose and, although the polymer matrix of fragments was masked by copper phthalocyanine, one of them could be identified as polystyrene. As expected, the highest abundance of MPs was found in UB. However, a lower abundance of particles was detected in PL (downstream of UB) than in EZ (upstream of UB). This could be due to the influence of both the main current of the Beagle Channel and fluvial discharges, reducing the buoyancy of MPs. More studies are needed to understand the contribution of regional and local features to the accumulation of MPs in these environments and their interaction with the biota.

Azinphos-methyl causes in Planorbarius corneus toxic effects on reproduction, offspring survival and B-esterases depending on the exposure time.

This work aimed to study in the freshwater gastropod Planorbarius corneus the effects of acute (2 days) and subchronic (14 days) exposures to an environmental concentration of the organophosphate azinphos-methyl on different reproductive parameters, offspring survival and B-esterase activities in gonads and in the whole organism soft tissue. The acute exposure inhibited only carboxylesterase activity in both tissues while the subchronic exposure also inhibited cholinesterase activity, decreased the number of hatched-eggs and increased offspring lethality (92%). On the other hand, B-esterases in gonads were more effective biomarkers than B-esterases in the whole organism due their inhibition appeared earlier in time (cholinesterase activity) and their activity remained inhibited for a longer time (carboxylesterase activity) when recovery studies were performed. We concluded that B-esterases and reproductive parameters can be used as effect biomarkers of aquatic contamination with azinphos-methyl. Our studies showed that a 14 days exposure to an environmental concentration of azinphos-methyl produced severe signs of toxicity in adult organisms, egg masses and juveniles that could cause negative effects at the population level in contaminated environments.