Percorrer por autor "Puskar, Ljiljana"
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- Deciphering a potential toxic synergy between persistent organic pollutantsPublication . Puskar, Ljiljana; Jordão, LuísaPlastic, massively used in everyday life, inevitably accumulates in the environment, becoming a persistent pollutant due to its reduced and/ or extremely slow recyclability1. Plastic particles in the micro and nano range, known as micro (MP) and nanoplastics (NP), respectively represent a huge ecotoxicological challenge. Due to their high surface areas, they might ad/absorb other persistent pollutants with similar chemical properties, such as polycyclic aromatic hydrocarbons (PAHs), with unpredictable effects on persistence and distribution in the environment2. MPs/NPs, with or without pollutants ad/absorbed, could enter the trophic chain at the level of invertebrates, inflicting toxicological effects through all levels of the ecosystem3. Polystyrene MPs and PAHs previously found in water samples (e.g. fluoranthene, phenanthrene)4 and known to be adsorbed by MPs (Pyrene, benzo(a) pyrene)5 will be used in the study. PAH’s mixtures will be used to mimic environmental samples and single compounds will be used in order to understand the individual contribution of each compound for the observed toxic effect. This experimental approach will also allow to evaluate a potential synergy between compounds with effect on toxicity. Since PAHs and MPs have similar chemical properties, they are known to adsorb to each other. We will use PAHs adsorbed to MPs to test higher concentrations of PAHs (not soluble in aqueous solutions such as cell culture medium) and to document the intracellular distribution of adsorbed versus free PAHs. Concerning MPs only one material will be used at this stage. Polystyrene was selected because it is commercially available in spheres suitable for internalization by HepG2 cells and was previously isolated from environmental samples 4. This study could contribute to identify differences in toxicity and contribute to the elucidation of the underlying toxicity mechanisms using molecular biology protocols, light/electron microscopy and FTIR micro/spectrometry.
- Exploring the interplay between microplastics and biofilms in freshwaterPublication . Jordão, Luisa; Nogueira, Isabel; Veber, Alexander; Schade, Ulrich; Puskar, LjiljanaPlastic inevitably accumulates in the environment becoming a persistent. In the present work, we aim at documenting MPs occurrence in three collection spots of the biggest European artificial lake over one year period using infrared microscopy. Scanning electron microscopy was used to evaluate MPs colonization by biofilms. PE was the most abundant polymer and biofilms were identified in all plastics.
- Occurence of persistent environmental pollutants in freshwaterPublication . Jordão, Luisa; Mansilha, Catarina; Melo, Armindo; Nogueira, Isabel; Veber, Alexander; Puskar, Ljiljana; Schade, UlrichFreshwater pollution is a huge concern. Occurence of 2 groups of persistent pollutants with similar chemical properties (polycyclic aromatic hydrocarbons and microplastics) in Alqueva’s surface water were evaluated during 2021. Samples were collected, once per season, at 3 spots related to touristic activities. Biofilm presence on plastic and natural materials was monitored and compared.
- Occurrence of polycyclic aromatic hydrocarbons, microplastics and biofilms in Alqueva surface water at touristic spotsPublication . Raposo, Ana; Mansilha, Catarina; Veber, Alexander; Melo, Armindo; Rodrigues, Joao; Matias, Rui; Rebelo, Helena; Grossinho, José; Cano, Manuela; Almeida, Cristina; Nogueira, Isabel D.; Puskar, Ljiljana; Schade, Ulrich; Jordão, LuisaFreshwater pollution is a huge concern. A study aiming to evaluate physico-chemical characteristics, microbiota, occurrence of two groups of persistent environmental pollutants with similar chemical properties (polycyclic aromatic hydrocarbons- PAHs and microplastics - MPs) in Alqueva's surface water was performed during 2021. Water samples were collected at three spots related to touristic activities (two beaches and one marina) during the Winter, Spring, Summer and Autumn seasons. In addition, the presence of biofilms on plastic and natural materials (stone, wood/ vegetal materials) were assessed and compared. Water quality based on physicochemical parameters was acceptable with a low eutrophication level. PAHs concentration levels were lower than the standard limits established for surface waters by international organizations. However, carcinogenic compounds were detected in two sampling locations, which can pose a problem for aquatic ecosystems. PAHs profiles showed significant differences when comparing the dry seasons with the rainy seasons, with a higher number of different compounds detected in Spring. Low molecular weigh compounds, usually associated with the atmospheric deposition and petroleum contamination, were more prevalent. MPs were detected in all samples except one during the Winter season. The polymers detected were poly(methyl-2-methylpropenoate), polystyrene, polyethylene terephthalate, polyamide, polypropylene, styrene butadiene, polyvinyl chloride and low /high density polyethylene with the last being the most frequent. Biofilms were more often detected on plastics than on natural materials. In addition, biofilms detected on plastics were more complex with higher microbial diversity (e.g., bacteria, fungi/yeast and phytoplancton organisms) and richer in extrapolymeric material. Based on morphological analysis a good agreement between microbiota and microorganism present in the biofilms was found. Among microbiota were identified microorganisms previously linked to plastic and PAHs detoxification suggesting the need for further studies to evaluate the viability of using biofilms as part of a green bioremediation strategy to mitigate water pollution.