Microplastics are very complex pollutants; they can be made of many polymer types and exist in various shapes and sizes. When they enter the environment they are affected by biotic and abiotic ...factors that cause their properties to change. In this context, the aim of our study was to evaluate the extent to which biofouling affects the properties and toxicity of microplastics. Cosmetic polyethylene microbeads were incubated in stream water for four weeks resulting in biofouling and aging. Subsequently, the changes in properties (sinking, particle size, adsorption, and leaching of model metal – silver) and the microplastics toxicity to daphnids Daphnia magna and duckweed Lemna minor were evaluated. Pristine microplastics did not affect daphnids but they significantly affected the root growth of duckweed. On the other hand, reference natural particles (beech sawdust) did not show any negative effects. We observed significant differences in the properties of aged versus pristine microplastics. When compared to pristine microplastics, aged microplastics adsorbed more silver and the subsequent leaching of silver was more intensive, especially in the medium with an acidic pH. Microplastics with adsorbed silver had a high ecotoxicological potential and at environmentally relevant concentrations affected both daphnids and duckweed. This study suggests that biofouling is an important parameter that affects microplastics properties, pollutant adsorption and release into the environment, and toxicity. Overall, there are significant alterations of the microplastics properties, behaviour, and fate in the environment.
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•Biofouling (aging) of microplastics (MPs) significantly alters their properties.•Adsorption of Ag and its leaching is enhanced on MPs with a biofilm.•Environmentally relevant concentrations of aged MPs with Ag affect organisms.•MPs with adsorbed silver had high ecotoxicological potential.
Current understanding of how environmental aging of microplastics contributes to their ecotoxicity is low. We investigated whether incubation of microplastics in waters with different organic load ...and toxic potential alters the toxicity of microplastics to crustacean Daphnia magna, fish embryos Danio rerio and plant Lemna minor. Polyethylene primary microplastics; specifically microbeads from facial scrub; were subjected to 3-weeks incubation in low affected spring water, river water, effluent from the municipal wastewater treatment plant (WWTP) and municipal landfill leachate. Primary microplastics had no acute effect on D. magna mobility and D. rerio embryos development. While high organic load wastewaters; WWTP effluent and landfill leachate; showed evident toxicity for D. magna and D. rerio embryos, microplastics aged in these wastewaters had no effect. This suggests that adsorption of pollutants from wastewaters to microplastic particles was not high enough to induce acute toxicity to D. magna and D. rerio. On the contrary, primary microplastics affected the root growth of L. minor. Interestingly, aging of microplastics in low organic-load waters mitigated the toxicity of microplastics for L. minor, while microplastics aged in high-organic load waters had the same adverse effect as primary microplastics. Partly, these effects can be explained by different extent of coating on microplastics in different water samples. This study suggests that aging of microplastics in wastewaters and natural waters did not significantly enhance the toxicity to selected test species, but further studies on plants may be of interest.
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•Coating of aged microplastics in natural waters and wastewaters differs from primary microplastics.•Aged microplastics have different sinking properties.•Aging of microplastics does not increase the toxicity to daphnids, duckweed and zebrafish.•Primary microplastics affect only duckweed root length.•Aging in some waters may mitigate toxic effects of microplastics for roots.
Microplastics aged in wastewaters and natural waters are not more toxic as primary microplastics.
Current data regarding the effects of microplastic (MP) on terrestrial organisms are very scarce. Isopods play an important role in plant litter decomposition processes and are commonly used test ...species in terrestrial ecotoxicity studies. Their altered feeding behaviour and energy reserves are established biomarkers of adverse effects upon stressor exposure. For this study we assessed the effects of MP derived from plastic bag film (mean size 183±93μm) and particles from a facial cleanser (mean size 137±51μm) on the terrestrial isopod, Porcellio scaber. Isopods were exposed to MP via feeding on food pellets (4mgg−1 dry weight; 0.4% w w−1) for 14days under laboratory conditions. A control group was exposed to food pellets with no MP added. In line with previously suggested modes of MP action on animal ingestion, we assessed the food ingestion rate, defecation rate, food assimilation rate and efficiency, body mass change, mortality and energy reserves (proteins, carbohydrates, and triglycerides) in the digestive glands (hepatopancreas) of individual isopods. Contrary to our expectations, no effects on either end-point were observed under the given exposure conditions. Further work should be carried out to investigate the potential longer-term effects of such exposure. We conclude that 14days exposure to plastic bag and facial cleanser MP is not severely hazardous to isopods.
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•Plastic bag and facial cleanser microplastic had no affect on the feeding rate of isopods.•No alterations in isopod body mass were found.•Microplastic had no effect on energy reserves in digestive glands of isopods.•14days exposure to tested microplastic is not severely hazardous to isopods.
The presence of microplastics (MPs) in the environment has raised many concerns, and therefore approaches and technologies to remove them in situ are of high interest. In this context, we ...investigated the interactions between polyethylene MPs (fragments with a mean size of 149 ± 75 μm) and an aquatic floating macrophyte Lemna minor in order to assess its potential use for in situ phytoremediation. We first investigated the long-term effects of a high (100 mg/L = 9600 MPs/L), but still environmentally relevant concentration of MPs on L. minor. Subsequently bioadhesion of MPs was studied and the number and strength of MPs adhering to plant biomass were assessed. MPs did not adversely affect various parameters of plants (e.g., specific growth rate, chlorophyll contents, total antioxidant capacity, electron transport system activity, and contents of energy-rich molecules) throughout the duration of the experiment (12 weeks), except for the first week of the experiment, when protein content and total antioxidant capacity were affected. On the other hand, MPs affected the root length of L. minor during the first eight weeks of the experiment, while further exposure resulted in a decrease in the effects, indicating the ability of L. minor to tolerate the presence of MPs for a long period of time. MPs adhered rapidly to the plant biomass and the average percentages of strongly and weakly adhered particles were 6.5% and 20.0%, respectively, of the total MPs applied. In summary, results of this study suggest that L. minor can tolerate hotspot concentrations of MPs and can collect MPs from the water surface. Therefore, phytoremediation using floating plants could be considered as a potential method for in situ removal of MPs from the aquatic environment.
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•Microplastics (MPs) adhere to the biomass of Lemna minor.•MPs have no significant effect on Lemna minor growth over a 12-week period.•6.5% and 20.0% of all MPs are strongly and weekly adhered, respectively.•Phytoremediation could be used to remove MPs from the aquatic environment.
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•The effects of polyester fibers on soil animals were studied for the first time.•Enchytraeid reproduction decreased up to 30% but only by long fibers in soil.•Isopod energy reserves ...and feeding activity were affected by fibers in soil.•Polyester fibers were not very harmful to soil invertebrates in 21–28-days exposure.•Polyester fibers can enter terrestrial food webs by ingestion by soil invertebrates.
Polyester fiber is one of the most abundant types of microplastics in the environment. A major proportion of the fibers entering wastewater treatment plants end up in sewage sludge, which is used as a soil fertilizer in many countries. As their impacts in the terrestrial environment are still poorly understood, we studied the effects of polyester fibers on enchytraeids (Enchytraeus crypticus), springtails (Folsomia candida), isopods (Porcellio scaber) and oribatid mites (Oppia nitens), all playing an important role in soil decomposer food webs. We exposed these invertebrates in the laboratory to short (12 µm–2.87 mm) and long (4–24 mm) polyester fibers, spiked in soil or in food at five concentrations ranging from 0.02% to 1.5% (w/w) and using five replicates. Overall the effects of polyester fibers on the soil invertebrates were slight. Energy reserves of the isopods were slightly affected by both fiber types, and enchytraeid reproduction decreased up to 30% with increasing fiber concentration, but only for long fibers in soil. The low ingestion of long fibers by the enchytraeids suggests that this negative impact arose from a physical harm outside the organism, or from indirect effects resulting from changes in environmental conditions. The short fibers were clearly ingested by enchytraeids and isopods, with the rate of ingestion positively related to fiber concentration in the soil. This study shows that polyester fibers are not very harmful to soil invertebrates upon short-term exposure. However, longer lasting, multigeneration studies with functional endpoints are needed to reveal the possible long-term effects on soil invertebrates and their role in the decomposition process. This study also shows that polyester fibers can enter terrestrial food web via ingestion of fibers by soil invertebrates.
This study investigated four different environmentally relevant microplastic (MP) pollutants which were derived from two facial cleansers, a plastic bag and polyethylene textile fleece. The mean size ...range of the particles (according to number distribution) was 20–250 μm when measured as a powder and 0.02–200 μm in suspension. In all MP exposures, plastic particles were found inside the guts of D. magna and A. franciscana, but only in the case of daphnids a clear exponential correlation between MP uptake in the gut and the size of the MP was identified. Exposure tests in which the majority of the MP particles were below 100 μm in size also had higher numbers of daphnids displaying evidence of MP ingestion. As the average MP particle size increased, the percentage of daphnids which had MP in their gut decreased. Using a number distribution value to measure particle size when in a suspension is more experimentally relevant as it provides a more realistic particle size than when samples are measured as a powder. Generally, artemias had fewer MP particles in the gut, than the daphnids, which could be explained by their different food size preferences. No acute effects on D. magna were found, but the growth of A. franciscana was affected. We conclude that zooplankton crustacean can ingest various MPs but none of the exposures tested were highly acutely hazardous to the test species. In addition, no delayed lethal effects in a 24 h post-exposure period were found.
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•All tested microplastics were found inside the guts of D. magna and A. franciscana.•The uptake of microplastics in daphnids is exponentially related to the size of particles.•A small mass of particles is sufficient to fill the gut of daphnids.•No acute mortality of daphnids and artemias was observed.•No delayed acute effects were found and microplastic was depurated from organisms.
Tire particles pose a potential threat to terrestrial organisms because they are deposited in large quantities in the soil by tire wear abrasion, and moreover their chemical complexity poses an ...additional risk. Microplastics can affect several physiological processes in organisms, including those related to immunity. Therefore, we investigated the expression profile of selected immune-related genes (MnSod, Manganese Superoxide dismutase; Cat, Catalase; CypG, Cyclophilin G; Nos, Nitric oxide synthase; Ppae2a, Prophenoloxidase-activating enzyme 2a; Dscam, Down syndrome cell adhesion molecule; Myd88, Myeloid-differentiation factor 88; Toll4, Toll-like receptor 4; Mas-like, Masquerade-like protein) in haemocytes and the digestive gland hepatopancreas of terrestrial crustacean Porcellio scaber after two different time exposures (4 and 14 days) to tire particles in soil. Our results reveal for the first time the response of P. scaber after microplastic exposure at the transcriptome level. We observed time- and tissue-dependent changes in the expression of the analysed genes, with more pronounced alterations in haemocytes after 14 days of exposure. Some minor changes were also observed in hepatopancreas after 4 days. Changes in the expression profile of the analysed genes are a direct indication of a modulated immune status of the test organism, which, however, does not represent an adverse effect on the test organism under the given conditions. Nevertheless, the question remains whether the observed change in immune status affects the immunocompetence of the test organism.
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•Exposure to tire particles in soil impacts the expression of tested genes in woodlice.•Modulations in immune-related gene expression were time- and tissue-dependent.•The most striking changes were observed in haemocytes after 14 days.•Some genes were also changed in hepatopancreas but only after 4 days.
Microplastics are very common contaminants in the environment. Despite increasing efforts to assess the effects of microplastics on soil organisms, there remains a lack of knowledge on how organisms ...respond to diverse types of microplastics after different exposure durations. In the present study, we investigated the immune response of the terrestrial crustacean Porcellio scaber exposed to the two most common microplastic particles in the environment: polyester fibres and tyre particles. We also tested two natural particles: wood dust and silica powder, with all treatments performed at 1.5% w/w. The response of P. scaber was evaluated at the level of the immune system, and also the biochemical, organism and population level, after different exposure durations (1, 2, 4, 7, 14, 21 days). These data reveal dynamic changes in the levels of some immune parameters shortly after exposure, with a gradual return to control values. The total number of haemocytes was significantly decreased after 4 days of exposure to tyre particles, while the proportion of different haemocyte types in the haemolymph was altered shortly after exposure to both polyester fibres and tyre particles. Moreover, 7 days of exposure to tyre particles resulted in increased superoxide dismutase activity in the haemolymph, while metabolic activity in whole woodlice (measured as electron transport system activity) was increased after exposure for 7, 14 and 21 days. In contrast, the natural particles did not elicit any significant changes in the measured parameters. Survival and feeding of P. scaber were not altered by exposure to the microplastics and natural particles in soil. Overall, this study defines a time-dependent transient immune response of P. scaber, which indicates that immune parameters represent sensitive biomarkers of exposure to microplastics. We discuss the importance of using natural particles in studies of microplastics exposure and their effects.
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•We studied natural particles and microplastics for immune effects in Porcellio scaber•Haemocyte proportions in haemolymph rapidly and transiently changed for microplastics•Exposure to tyre particles significantly increased whole woodlouse metabolic activity•There were no changes in measured parameters for exposure to natural particles
Microplastics and agrochemicals are common pollutants in terrestrial ecosystems. Their interaction during coexistence in soils may influence their fate and adverse effects on terrestrial organisms. ...The aim of this study was to investigate how the exposure to two types of microplastics; polyester fibres, and crumb rubber; induce changes in immune parameters of Porcellio scaber and if the co-exposure of microplastics affects the response induced by the organophosphate pesticide chlorpyrifos. A number of immune parameters, such as total haemocyte count, differential haemocyte count, and phenoloxidase-like activity were assessed. In addition, the acetylcholinesterase (AChE) activity in the haemolymph was evaluated as a measure of the bioavailability of chlorpyrifos. After three weeks of exposure, the most noticeable changes in the measured immune parameters and also a significantly reduced AChE activity were seen in chlorpyrifos-exposed animals. Both types of microplastic at environmentally relevant concentrations caused only slight changes in immune parameters which were not dependent on the type of microplastic, although the two types differed significantly in terms of the chemical complexity of the additives. Mixtures of chlorpyrifos and microplastics induced changes that differed from individual exposures. For example, alterations in some measured parameters suggested a reduced bioavailability of chlorpyrifos (AChE activity, haemocyte viability) caused by both types of microplastics exposure, but the increase of haemocyte count was promoted by the presence of fibres implying their joint action. In conclusion, this study suggests that immune processes in P. scaber are slightly changed upon exposure to both types of microplastics and microplastics can significantly modulate the effects of other co-exposed chemicals. Further research is needed on the short-term and long-term joint effects of microplastics and agrochemicals on the immunity of soil invertebrates.
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•Immune parameters are slightly changed upon exposure to plastic fibres or crumb rubber.•Chlorpyrifos caused significant changes in Porcellio scaber immune parameters.•Microplastics decreased the bioavailability of chlorpyrifos for P. scaber.•Mixtures of plastic fibres and chlorpyrifos resulted in greater response in haemocyte count.
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