Browsing by Subject "microplastic"
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(2023)Both microplastics (MPs, size 0.1 to 5 mm) and pharmaceuticals and personal care products (PPCPs) are ubiquitous in aquatic environments globally. Polystyrene microplastic (PS-MP) and diclofenac (DCF) are among the most widespread and commonly occurring MPs and PPCPs in the environment. Exposure to these chemicals in single has been reported to cause oxidative stress, immobilization, changes in growth and reproduction and even mortality in Daphnia magna. Moreover, MPs have the ability to act as a vector for PPCPs, and several laboratory studies have reported that PS-MP is able to absorb DCF. However, the combined toxicity of MPs and PPCPs remains largely unknown, especially as is the case for the combined toxicity of PS-MP and DCF in D. magna. In this study, D. magna was exposed to PS-MP and DCF, both in single and combined, at a concentration of 0.5 mg/L each. The aim was to assess the combined toxicity of the two, and determine whether they had a synergistic, additive, or antagonistic effect in D. magna. Whole organism endpoints monitored included mortality, immobilization, and moulting. Physiological endpoints monitored focused on oxidative stress and antioxidant defence, including reactive oxygen species (ROS), superoxidase dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST). The results indicated that both PS-MP and DCF in single were able to significantly alter D. magna antioxidant and biotransformation enzyme activities by inhibition of SOD and GST, while there were no observed impacts on the monitored whole organism endpoints or ROS and CAT. However, similar significant inhibition of SOD and GST was not observed in the combined exposure, which indicates that the combined toxicity of PS-MP and DCF in D. magna was most likely antagonistic. These results highlight that the combined toxicity of MPs and PPCPs is a complex topic that still needs further investigation to fully understand the complex interactions between MPs and PPCPs.
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(2024)Microplastic (MP, <5 mm) contamination of soils has become a critical environmental concern. Plastic mulching films applied in agricultural soils can degrade into MPs, potentially negatively affecting terrestrial ecosystems. Conventional plastics are mainly used in agricultural practices, but the use of biodegradable materials has increased. However, the effects of these polymers on the environment still need to be better understood. The objective of this study was to assess and compare the ecotoxicological effects of mulching film-based microplastics, conventional low-density polyethylene microplastics (PE-MPs) and biodegradable polybutylene adipate terephthalate microplastics (PBAT-BD-MPs), on the earthworm Eisenia andrei. The measured parameters were survival, reproduction, growth, and oxidative stress. In this study, an eight-week reproduction test was conducted using adult earthworms of synchronised age. They were exposed to seven microplastic concentrations: 0%, 0.005%, 0.05%, 0.1%, 0.5%, 1%, 5% (w/w). Oxidative stress was evaluated by analysing six different biomarkers, catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), and lipid peroxidation (LPO). The Integrated Biomarker Response Index (IBR) was provided from biomarker assays, and the soil water-holding capacity and pH were also measured. The results indicated adverse effects on earthworms from both conventional and biodegradable MPs, although impacting different parameters. Responses were observed even at low concentrations; however, no clear dose-response relationship was observed. While exposure to PE-MPs resulted in a decline in earthworm biomass with increasing concentrations, PBAT-BD-MP exposure led to enhanced earthworm growth at lower concentrations. MP exposures did not alter the production of juveniles significantly. However, a minor descending trend in juvenile production was noted with increasing PE-MP concentration, and the juveniles exposed to a 5% concentration of PBAT-BD-MP exhibited lower biomass than the control group. Both MPs caused oxidative stress already at environmentally relevant concentrations. Biomarkers CAT and GR showed significant activation at PE-MP exposure, whereas SOD and LPO levels were impacted at PBAT-MP exposure. This indicates the oxidative damage caused by PBAT-BD-MP exposure. Moreover, both MP types increased soil pH and water-holding capacity at the highest concentration (5%), potentially influencing the observed responses in earthworms subjected to these concentrations. This study provides novel insights into the effects of conventional and biodegradable microplastics on earthworms over various concentrations. Furthermore, it highlights the complexity of microplastics and soil systems, influenced by plastic type, concentration, and environmental conditions.
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(2020)Microplastics are widely studied subject and have raised concern towards water security worldwide but the vector effect of microplastic has not yet fully understood. In this study the ability of microplastic to attach hydrophobic organic compounds is tested with a nonsteroidal anti-inflammatory drug diclofenac. The ability to attach hydrophobic organic compounds has been proved by microplastics but not with diclofenac. Diclofenac is also causing water security threats nearby wastewater treatment plants because it is biologically active and can cause stress to the aquatic organisms even in small quantities. The aim of this study is to see if microplastic has vector effect for the diclofenac. If microplastic retains diclofenac on its surface area it would decrease the stress factor effect of diclofenac towards the investigated macroalgae Aegagropila linnaei. The possible change of oxidative stress levels in A. linnaei is measured by peroxidase enzyme activity. The aim is to see if the enzyme activity raises or decreases when A. linnaei is exposed to microplastic with and without diclofenac. If the peroxidase enzyme activity decreases in macroalgae while exposing A. linnaei to both microplastic and diclofenac it would strengthen the vector effect hypothesis. As a result, the peroxidase enzyme activity seems to have a decreasing trend when the diclofenac concentrations increase. Diclofenac affected to peroxidase enzyme activity but microplastic does not show any signs of binding of diclofenac in this study, and therefore microplastic cannot act as a vector for diclofenac.
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(2022)Aims and methods: Global plastic production is increasing annually and microplastics (MPs, particles of <5 mm in size) have been reported in the environment worldwide. In aquatic systems plastic pollution is present especially in coastal habitats, and MPs can concentrate within littoral zone vegetation. Numerous marine animals are known to be able to ingest MPs, and plastics can also have adverse effects on the health and behaviour of the exposed animals. This Master’s thesis examined trophic transfer of MPs in a Baltic Sea littoral food chain. Laboratory experiments with 10 µm fluorescence microspheres were conducted to study trophic transfer between food chains of different lengths. The longest food chain had three trophic levels: zooplankton, chameleon shrimp (Praunus flexuosus) and rockpool prawn (Palaemon elegans). Also, the gut passage time of rockpool prawn was experimentally studied. The digestive tracts of the studied animals were analysed for MPs under an epifluorescence microscope. Results: The results show that trophic transfer may be an important pathway of microplastic exposure for animals at higher trophic levels. The number of ingested microspheres in both chameleon shrimp and rockpool prawn was higher when the animals were exposed through pre-exposed prey in comparison to direct exposure from the water. In addition, the prawns ingested more MPs in the experiment with three trophic levels than in the two-level experiment. The results support earlier findings, that the feeding mode affects the microplastic exposure of animals. There were no clear results from the gut passage time experiment.
Now showing items 1-4 of 4