Browsing by Author "Veber, Alexander"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- 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.
- Exploring the Potential of Microscopy Techniques to Study Microplastics and Biofilms in Environmental SamplesPublication . José, Silvia; Nogueira, Isabel; Veber, Alexander; Schade, Ulrich; Jordão, LuisaMicro and nanoplastic are found worldwide in aquatic ecosystems ranging from highly populated industrialized areas to the most remote regions of the planet being a hot research topic and a concern. Marine waters have been the major research focus. Despite less studied, freshwaters are of crucial importance since life in general and human beings in particular are highly dependent of freshwater for drinking and food production. This fact shows that freshwater could function as a vehicle for MPs toxicity through all levels of the ecosystem. Although it has been suggested that toxicity is driven not only by the plastic forming units (monomers) but also by adsorbed pollutants (such as PAH, pesticides, PCBs) and associated microorganisms little is known about the underlying mechanisms. The lack of validated protocols for isolation and a gold standard technique to identify micro/nanoplastics are important issues. Infrared microscopy (IRM) with diffraction-limited infrared synchrotron radiation sources adds resolution to the traditional fingerprint IR spectra being a potential candidate to a gold standard technique not only for micro/nanoplastic identification but also for adsorbed pollutants. In the present work, IRM allowed us to identify MPs isolated from freshwater samples. Polyethylene (PE) and polystyrene (PS) were among the most common plastic polymers identified. The colonization of environmental samples of MPs by biofilms was monitored by scanning electron microscopy (SEM). Our data suggests that the presence of biofilms on MPs does not interfere with polymer identification by IRM. Biofilm assembly on MPs by microorganisms isolated from water samples in conditions mimic those found in their natural’s habitats was followed over 3 months. Biofilm biomass was accessed by spectrophotometric methods whereas SEM was used to evaluate biofilm distribution on the MPs particles. The results obtained in vitro correlate with those observed in “real samples”. Biofilms assembled by the microbial consortium used were more abundant on the most common plastics detected in the environmental samples (PE and PS).
- 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 persistent organic pollutants at Alqueva's 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, IsabelFreshwater pollution is a huge concern. A study aiming to evaluate water quality and occurence 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. Samples were collected at three spots related to touristic activities (two beaches and one marina) once by season. In addition, we assessed and compared the presence of biofilms on plastic and natural materials. Water quality was acceptable with a low eutrophication level. PAHs concentration levels were lower than the standard limits established for surface waters. PAHs profiles showed significant differences when comparing the dry and rainy seasons, with a higher number of different compounds detected in Spring. Low molecular weight compounds, usually associated with the atmospheric deposition and petroleum contamination, were more prevalent. MPs were detected in all samples except one during Winter. Eight polymers were detected being polyethylene the most frequent. Plastics were more prone to biofilm colonization than natural materials. In addition, biofilms detected on plastics were more complex with higher microbial diversity and richer in EPS. 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.
- 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.