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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 H 2 O 2 (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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Neonicotinoids emerged as an environmentally safe alternative to previous generations of insecticides becoming one of the most widely applied in modern agriculture. Nevertheless, they have been reported to affect several non-target organisms. Most toxicity studies focus on the effects on pollinators or terrestrial invertebrates and evaluate either the active ingredient or the commercial formulation. In the present study, we aimed to assess the long-term effects of the active ingredient acetamiprid and a broadly used commercial formulation (Assail® 70) on the non-target freshwater gastropod Biomphalaria straminea using a battery of biomarkers. A 14 day-exposure of adult organisms to both active ingredient and commercial formulation increased carboxylesterase activity and glutathione content, inhibited superoxide dismutase activity and decreased reactive oxygen species levels. The commercial formulation additionally increased glutathione S-transferase activity and inhibited catalase activity. The results indicate a greater toxicity of the commercial formulation than that of the active ingredient alone. Cholinesterase activity, development and offspring survival of B. straminea were not impaired. We conclude that the toxicity of acetamiprid on this gastropod species is mainly related to effects on detoxification and oxidative metabolism responses. This study provides novel information about the adverse effects of the active ingredient and a commercial formulation of a widely used neonicotinoid on a non-target aquatic species., (Copyright © 2020. Published by Elsevier Inc.)

Organophosphate insecticides (OPs) are commonly used in Argentina and around the world for pest control in food crops. They exert their toxicity through the inhibition of the enzyme acetylcholinesterase. In the present study, we aimed to evaluate biochemical and reproductive effects in Biomphalaria straminea, a freshwater gastropod naturally distributed in Argentina, of subchronic exposures to environmental azinphos-methyl concentrations (20 and 200 µg L -1 ). For biochemical parameters, adult organisms were exposed for 14 days and the activity of cholinesterases (ChEs), carboxylesterases (CEs), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), the production of reactive oxygen species (ROS), the total antioxidant capacity (TAC), glycogen and proteins were determined. For reproductive parameters, the egg masses of B. straminea were exposed to azinphos-methyl for one month, and the hatching time and success as well as the offspring survival were registered. We found different toxic effects elicited by the insecticide on the studied biomarkers. CEs activity was significantly inhibited while CAT and GST activities, ROS production and TAC were significantly increased, with respect to the solvent control group. ChE and SOD activities and protein and glycogen contents were not altered by azinphos-methyl. The hatching time and success were not statistically different from control. Nevertheless, the offspring survival was severely affected by the insecticide. Our results show that the primary target of the insecticide (ChE) was not inhibited but CEs, GST, CAT, ROS, TAC and offspring survival were sensitive biomarkers and valuable endpoints for subchronic toxicity assessments in this species., (Copyright © 2018 Elsevier Inc. All rights reserved.)