37 research outputs found
Impact of Emergency Online Teaching on Teachers’ Professional Digital Competence: Experiences from the Nordic Higher Education Institutions
During the COVID-19 pandemic, Nordic higher education institutions (HEIs) as any other learning providers had to abruptly switch from onsite in-person delivery strategies to a more ‘pandemic-friendly’ online mode. To manage these emergent transformations of learning environments successfully, development of teachers’ digital competence became pivotal. This study investigates the experiences of teachers and students from HEIs in the Nordic countries of the impact of the transition to online teaching during the pandemic crisis on teachers’ professional digital competence (TPDC). The findings indicate that the pandemic promoted teachers’ creativity and innovation, enabling individual initiatives, openness, and decentralization that demonstrates the Nordic HEIs readiness to mobilize relevant digital infrastructure and exert academic freedom in times of crises. The study further broadens the concept of TPDC involving aspects of well-being and physical environment as additional indicators, to ensure equality, inclusion, and sustainability in the future of online education in higher education
Effect of Composting on the Behavior of Polyolefin Films - A True-to-Life Experiment
Commercial polypropylene (PP), high-, medium- and low density polyethylene (HDPE, MDPE, LDPE) films, as well as MDPE films containing pro-oxidative additives and thermoplastic starch (TPS) were composted for six weeks together with biologically degradable films, such as poly (lactic acid) (PLA), Ecovio (BASF), Mater Bi(Novamont) and cellophane. Visual appearance of the polyolefin-based films did not change significantly, while the biologically degradable films fell apart. Thickness and mechanical properties of the polyolefin-based films also did not vary significantly after composting. The thickness of the degradable films however increased due to biofilm formation and finally decreased due to biodegradation, and their mechanical properties drastically dropped. FTIR proved the formation of carbonyl absorption of commercial and of the additive-containing films respectively) after composting due to oxidation. The FTIR-spectrum of the biodegradable films showed drastic change after composting. Formation of free radicals was detectable by ESR-spectroscopy, if pro-oxidative additive containing MDPE film was exposed for one week to sunlight, and the intensity of free radical formation increased after composting. The number-average molecular mass of MDPE films containing pro-oxidative additives decreased, low molecular mass fractions appeared and polydispersity increased after composting. Commercial polyolefin films were covered by microorganisms much more densly than films containing pro-oxidative additives detected by SEM. Even TPS did not increase the quantity of microorganisms. Biodegradable films were densly covered by microorganisms of different types and they became porous and holes were observable on their surface. It can be concluded that composting had no significant effect on the behaviour of the commercial PP and PE films. Signs of initial degradation were observable on MDPE films with pro-oxidative additives and TPS after 6 weeks composting, although it cannot be considered as biological degradation. Non of the tested polyolefin films suffered such degree of degradation in compost, as the biologically degradable films. It may be concluded that polyolefin films neither degrade in compost nor they undergo biodegradation
Spatiotemporal analysis of multi-pesticide residues in the largest Central European shallow lake, Lake Balaton, and its sub-catchment area
Background
The present study aimed to gain a comprehensive knowledge of the presence and environmental risks of pesticide and repellent residues in Lake Balaton and its sub-catchment area (Hungary). A unique analysis of 439 active substances and 17 metabolites was carried out on surface waters and one effluent wastewater as the only direct discharge into Lake Balaton from June 2017 until August 2020. Altogether 203 water- and 85 sediment samples were collected and analysed during the 3-year monitoring period. To determine the environmental risks of the detected pesticides to aquatic ecosystems, environmental risk assessment (ERA) was carried out using two approaches (worst- and general-case scenarios).
Results
Fifty-two pesticides and one insect repellent were detected, of which 26 belonged to herbicides (24 active substances and two metabolites), 15 to fungicides (15 active substances), and 11 to insecticides (eight active substances and three metabolites), of which only nine of the total analysed compounds are listed to be monitored in surface waters with threshold limit values (TLVs). The most frequently detected compounds were terbuthylazine, diethyltoluamide (DEET), desethyl-atrazine, and metolachlor. Glyphosate, aminomethylphosphonic acid (AMPA), and DEET were found with the highest concentrations of 3.0, 2.0, and 1.57 µg/L, respectively. The pesticide exposures were higher during the summer periods indicating a stable seasonal pattern. According to the performed ERA, the calculated Risk Quotients (RQs) indicated 18 compounds with a high level of risk including nine that had been banned for at least a decade.
Discussion
This study expands knowledge on the spatiotemporal occurrence of pesticides in inland surface waters and highlights the need to consider widening the number of analysed pesticides beyond the European Water Framework Directive (EWFD). According to our results, additional authority and legislation procedures should come into force for pesticides not indexed in the priority European Union Watch List
Glyphosate and glyphosate-based herbicides (GBHs) induce phenotypic imipenem resistance in Pseudomonas aeruginosa
GBHs are the most widely used herbicides for weed control worldwide that potentially affect microorganisms, but the role of their sublethal exposure in the development of antibiotic resistance of Pseudomonas aeruginosa is still not fully investigated. Here, the effects of glyphosate acid (GLY), five glyphosate-based herbicides (GBHs), and POE(15), a formerly used co-formulant, on susceptibility to imipenem, a potent carbapenem-type antibiotic, in one clinical and four non-clinical environmental P. aeruginosa isolates were studied. Both pre-exposure in broth culture and co-exposure in solid media of the examined P. aeruginosa strains with 0.5% GBHs resulted in a decreased susceptibility to imipenem, while other carbapenems (doripenem and meropenem) retained their effectiveness. Additionally, the microdilution chequerboard method was used to examine additive/antagonistic/synergistic effects between GLY/POE(15)/GBHs and imipenem by determining the fractional inhibitory concentration (FIC) indexes. Based on the FIC index values, glyphosate acid and Total demonstrated a potent antagonistic effect in all P. aeruginosa strains. Dominator Extra 608 SL and Fozat 480 reduced the activity of imipenem in only one strain (ATCC10145), while POE(15) and three other GBHs did not have any effect on susceptibility to imipenem. Considering the simultaneous presence of GBHs and imipenem in various environmental niches, the detected interactions between these chemicals may affect microbial communities. The mechanisms of the glyphosate and GBH-induced imipenem resistance in P. aeruginosa are yet to be investigated
Presence, variation, and potential ecological impact of microplastics in the largest shallow lake of Central Europe
The presence of microplastics (MPs) in the global ecosystem has generated a rapidly growing concern worldwide. Although their presence in the marine environment has been well-studied, much less data are available on their abundance in freshwaters. MPs alone and in combination with different chemicals has been shown to cause acute and chronic effects on algae and aquatic invertebrate and vertebrate species at different biological levels. However, the combined ecotoxicological effects of MPs with different chemicals on aquatic organisms are still understudied in many species and the reported data are often controversial. In the present study, we investigated, for the first time, the presence of MPs in Lake Balaton, which is the largest shallow lake of Central Europe and an important summer holiday destination. Moreover, we exposed neonates of the well-established ecotoxicological model organism Daphnia magna to different MPs (polystyrene [3 μm] or polyethylene [≤ 100 μm]) alone and in combination with three progestogen compounds (progesterone, drospirenone, levonorgestrel) at an environmentally relevant concentration (10 ng L−1) for 21 days. The presence of 7 polymer types of MPs in the size range of 50–100 μm was detected in Lake Balaton. Similarly to the global trends, polypropylene and polyethylene MPs were the most common types of polymer. The calculated polymer-independent average particle number was 5.5 particles m−3 (size range: 50 μm – 100 μm) which represents the values detected in other European lakes. Our ecotoxicological experiments confirmed that MPs and progestogens can affect D. magna at the behavioral (body size and reproduction) and biochemical (detoxification-related enzyme activity) levels. The joint effects were negligible. The presence of MPs may lead to reduced fitness in the aquatic biota in freshwaters such as Lake Balaton, however, the potential threat of MPs as vectors for progestogens may be limited