Trophic transfer of DDE, BP-3 and chlorpyrifos from microplastics to tissues in Dicentrarchus labrax.

Microplastic pollution and associated chemical contaminants is a topic of growing interest. In recent years, the number of publications reporting the presence of microplastics (MPs) in marine organisms has increased exponentially. However, there is a gap in knowledge about the trophic transfer of contaminants from microplastics to animal tissues, as well as possible health effects. In this study we analyzed the trophic transfer and biomagnification of three chemical pollutants present in microplastics: dichlorodiphenyldichloroethylene (DDE-p,p'), benzophenone 3 (BP-3) and chlorpyrifos (CPS). The reference values used were concentrations found in environmental microplastics in the Canary Islands (minimum and maximum). European seabass (Dicentrarchus labrax) were fed for 60 days with 5 different treatments: A) feed; B) feed with chemical pollutants at maximum concentration; C) feed + 10 % virgin MPs; D) feed + 10 % MPs with chemical pollutants at minimum concentration; E) feed + 10 % MPs with chemical pollutants at maximum concentration. We detected trophic transfer of DDE-p,p', CPS and BP-3 from the feed (treatment B) to the muscle and liver of fish. In the case of DDE-p,p', transfer to liver and muscle was also observed in the treatments consisting of feed plus plastics with different levels of contamination (C, D and E). No effect of the experimental treatments on fish condition indices was observed.

Bioaccumulation of additives and chemical contaminants from environmental microplastics in European seabass (Dicentrarchus labrax).

Marine microplastic pollution is one of the biggest environmental problems we face. The growth of plastic production has not ceased since the 1950s and it is currently estimated that 368 tons of plastic were produced in 2019 (PlascticsEurope, 2020). Geyer et al. (2017) estimate that 79% of the plastic produced in the world still remains in the environment; this plastic due to the effect of degradation and subsequent fragmentation, is present in the form of microplastics in all oceans and, due to its small size can be ingested by fish and filter-feeding organisms. In addition, microplastics have additives and chemical contaminants associated with them, and the potential effect of microplastic ingestion on marine organisms, and through them, the potential risk to humans, is unknown. In the present study, European seabass (Dicentrarchus labrax) were fed for 60 days with three treatments: Control (feed), MP (feed with 10% virgin microplastics) and EMP (feed with 10% environmental microplastics), being the first study to evaluate long-term accumulation of contaminants due to ingestion of environmental microplastics (EMP) in fish. Both plastic additives such as PBDEs, and chemical contaminants adsorbed from the environment such as PCBs and DDE, were analyzed in the EMP, feed and liver. The concentration of microplastics in the feed was calculated based on the MPs/zooplankton wet weight (WW) ratio of 0.1 found in an area of maximum accumulation in the Canary Islands. Therefore, it is an experiment that simulates real conditions, but in the worst-case scenario, using both, concentrations based on data obtained in oceanographic campaigns and microplastics collected from the environment. Our results show that in this scenario, additives and chemical contaminants adsorbed on EMPs bioaccumulate in fish liver due to long-term ingestion of microplastics.

Impact of polypropylene microplastics and chemical pollutants on European sea bass (Dicentrarchus labrax) gut microbiota and health.

Plastic pollution has become a global problem for marine ecosystems. Microplastics (MPs) are consumed by several marine organisms, including benthic and pelagic fish species that confuse them with food sources, thus contributing to bioaccumulation along the food chain. In addition to structural intestinal damage, ingestion of MPs represents a pathway for fish exposure to potentially hazardous chemicals, too. Most of them are endocrine disrupters, genotoxic or induce immune depression in fish. Accordingly, we assessed the combined toxicological effects of microplastics (MPs) and adsorbed pollutants by adding them to marine fish diet. European sea bass (Dicentrarchus labrax) juveniles were fed for 60 days with feeds containing polypropylene MPs, either virgin or contaminated with chemical pollutants (a blend of dichlorodiphenyldichloroethylene, chlorpyrifos, and benzophenone-3). The data demonstrated a synergic action of MPs and chemical pollutants to induce an inflammatory-like response in distal intestine of sea bass as shown by the up regulation of cytokine il-6 and tnf-α expression. Morphological analysis detected the presence of a focus of lymphocytes in anterior and posterior intestinal segments of fish fed with contaminants in the diet. With regard to microbiota, significant changes in bacterial species richness, beta diversity, and composition of gut microbiota were observed as a consequence of both pollutants and polluted MPs ingestion. These perturbations in gut microbial communities, including the reduction of beneficial lactic acid bacteria and the increase in potential pathogenic microorganism (Proteobacteria and Vibrionales), were undeniable signs of intestinal dysbiosis, which in turn confirmed the signs of inflammation caused by pollutants, especially when combined with MPs. The results obtained in this study provide, therefore, new insights into the potential risks of ingesting MPs as pollutant carriers in marine fish.

Microplastic ingestion in jellyfish Pelagia noctiluca (Forsskal, 1775) in the North Atlantic Ocean.

The present study is the first evidence-based study about the ingestion of plastic and microplastics in jellyfish Pelagia noctiluca in the North Atlantic Ocean. A bloom of this organism was collected from Gran Canaria Island coast. It was digested using KOH to quantify the plastic particles and by separating the umbrella from tentacles. About 97% of the organisms analysed showed the presence of microdebris. The majority of the microfibers were with blue or uncorrected fibre concentrations and mainly composed of cotton. Their presence in the gastrovascular cavity of the jellyfish was confirmed. These results warn about the impact of various factors such as jellyfish health, the transfer to jellyfish predators, human consumption of jelly fish, and the transport of carbon and microplastics in the water column.

Study of plastic pollution and its potential sources on Gran Canaria Island beaches (Canary Islands, Spain).

In order to understand the origin of plastic debris pollutants that accumulate in the Canary Islands coastline, six beaches of Gran Canaria Island were studied during different seasons to estimate the abundance and the types of two microplastics fraction sizes (0.01-1 mm and 1-5 mm) and mesoplastics fraction (5-25 mm). For the larger fraction of microplastics and mesoplastics, a high percentage of fragments and foams were found; moreover, both fractions show the same accumulation pattern in relation with the wave, wind, and current. The debris was checked for exogenous and local origins. Moreover, for the smaller fraction of microplastics, only natural, semi-synthetic, and synthetic fibres were found, showing a totally different spatial distribution from the others fractions. This result suggests a possible endogenous origin of the contamination, in relation to the type and amount of wastewater discharges and beach users.