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Tire wear microplastics (TWMs) are continuously generated during driving and are subsequently released into the environment, where they pose potential risks to aquatic organisms. In this study, the effects of untreated, hydrated, and aged (in stream water) TWMs on the growth, root development, photosynthesis, electron transport system (ETS) activity, and energy-rich molecules of duckweed Lemna minor were investigated. The results indicated that untreated and aged TWMs have the most pronounced negative effects on Lemna minor, as evidenced by reduced growth and impaired root development. In contrast, the effects of hydrated TWMs were less pronounced compared to untreated and aged TWMs. The negative effects associated with untreated and hydrated TWMs are primarily attributed to the abrasive nature of these particles, which physically damage the plant tissue. On the other hand, aged TWMs showed a different mode of action as they serve as transport vectors for algae. Once introduced into a new environment via aged TWMs, these algae competed with Lemna minor for available nutrients and space, further impairing the growth, root length, photosynthetic efficiency, and carbohydrate content of Lemna minor. This study revealed the dual threat posed by TWMs: direct physical damage from newly released particles and indirect ecological disruption from aged particles that facilitate the spread of algae., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The growing body of scientific evidence suggests that micro- and nanoplastics (MPs/NPs) pose a significant threat to aquatic ecosystems and human health. These particles can enter organisms through ingestion, inhalation, dermal contact, and trophic transfer. Exposure can directly affect multiple organs and systems (respiratory, digestive, neurological, reproductive, urinary, cardiovascular) and activate extensive intracellular signaling, inducing cytotoxicity involving mechanisms such as membrane disruption, extracellular polymer degradation, reactive oxygen species (ROS) production, DNA damage, cellular pore blockage, lysosomal instability, and mitochondrial depolarization. This review focuses on current research examining the in vivo and in vitro toxic effects of MPs/NPs on aquatic organisms, particularly fish, in relation to particulate toxicity aspects (such as particle transport mechanisms and structural modifications). Meanwhile, from the perspectives of the food chain and environmental factors, it emphasizes the comprehensive threats of MPs/NPs to human health in terms of both direct and indirect toxicity. Additionally, future research needs and strategies are discussed to aid in mitigating the potential risks of particulate plastics as carriers of toxic trace elements to human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The adverse effect of chemical additives leaching from microplastics (MPs) on Daphnia magna populations is not fully understood. In this study, D. magna populations were exposed to polyethylene (PE) MP fragments (5.0 mg/L), PE MP fragments containing the ultraviolet stabilizer benzophenone-3 (MP/BP-3 fragments, 5.0 mg/L), and BP-3 leachate (79 ± 10 µg/L) from PE MP/BP-3 fragments. The test duration was 42 days to observe the population dynamics of D. magna. BP-3 leachate delayed the development and somatic growth of D. magna, resulting in a significantly lower (p < 0.05) population size (number of organisms) compared with the control group. For instance, the population size was 7.7 ± 8.1 and 115 ± 3.5 (n = 3), respectively, at 18 d. However, both MP and MP/BP-3 fragments did not significantly decrease (p > 0.05) the population size of D. magna until day 18. These findings suggest that chemical additive leachates from MPs may have a distinct adverse effect on aquatic organisms, requiring further comprehensive investigation., Competing Interests: Declarations. Conflict of Interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The ultraviolet (UV) weathering of microplastics (MPs) can lead to higher adsorption of harmful contaminants, thus increasing the potential risks of their combined effects. Because biodegradable MPs are more susceptible to UV weathering than conventional MPs, concerns have arisen about their ecological toxicity and environmental impact. Therefore, this study investigated the mechanisms associated with the adsorption of the pesticide diflubenzuron (DFB) onto polylactic acid (PLA) MP particles after UV weathering and the acute effects (48 h) of their combination on the water flea Daphnia magna. These effects were also compared with those of the conventional MP polyethylene terephthalate (PET). UV weathering led to a greater number of cracks and pores in the PLA particles compared to PET, as well as a higher number of oxygen-based functional groups and a larger surface area. These surface changes in UV-weathered PLA particles promoted higher DFB adsorption, which in turn led to stronger acute toxicity for D. magna compared to UV-weathered PET particles. Combined exposure to 25 ng L -1 DFB and both UV-weathered and non-UV-weathered MPs significantly reduced the chitin content in D. magna, while combined exposure to 12.5 ng L -1 DFB and the MPs increased the chitin content. This effect was more pronounced for UV-weathered PLA exposure than UV-weathered PET exposure. The expression of the genes for chitinase and endocrine glycoprotein, both of which are closely associated with the toxic mechanisms of DFB, showed no significant changes with the combination of 25 ng L -1 DFB and non-UV-weathered MPs but were significantly downregulated after UV weathering. Overall, the UV weathering of PLA promoted the adsorption of DFB, thus increasing its toxic effects. Our findings demonstrate the importance of considering the effects of UV weathering and interactions with environmental pollutants when assessing the ecological risks associated with biodegradable MPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biodegradable microplastics (MPs) can form biofilms through interactions with various microorganisms in aquatic system and can be exposed to organisms. This study first investigated biodegradability of polylactic acid (PLA) MPs and the characterization of PLA MPs before/after biofouling (4 weeks) and their toxic effects on the freshwater invertebrate Daphnia magna. The biodegradability rate of PLA MPs was up to 50% over 28 days, suggesting that even biodegradable MPs do not easily decompose under environmental conditions. Furthermore, biofouling of MPs led to an increase in size and, in the process, induced an additional functional peak in the PLA MPs. The exposure of biofouled MPs did not lead to a reduction in survival, reproduction, or growth during chronic exposure, nor did it cause feeding inhibition in juvenile (<4 days old) D. magna. However, pristine MPs significantly reduced survival, reproduction, and growth at concentrations of 5.0 mg L -1 . Overall, pristine MPs caused inhibition of reproduction and growth and high mortality in D. magna, while the biofouling process did not induce these effects. Our findings highlight the complex interactions between MPs and biological components in aquatic environments, emphasizing the importance of considering biofouling dynamics when assessing the ecological impacts of biodegradable MPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Plastic pollution is a consequential problem worldwide, prompting the widespread use of biodegradable plastics (BPs). However, not all BPs are completely degradable under natural conditions, but instead produce biodegradable microplastics (BMPs), release chemical additives, and absorb micropollutants, thus causing toxicity to living organisms in similar manners to conventional plastics (CPs). The new problems caused by biodegradable plastics cannot be ignored and requires a thorough comparison of the differences between conventional and biodegradable plastics and microplastics. This review comprehensively compares their environmental fates, such as biodegradation and micropollutant sorption, and ecotoxicity in soil and water environments. The results showed that it is difficult to determine the natural conditions required for the complete biodegradation of BPs. Some chemical additives in BPs differ from those in CPs and may pose new threats to ecosystems. Because of functional group differences, most BMPs had higher micropollutant sorption capacities than conventional microplastics (CMPs). The ecotoxicity comparison showed that BMPs had similar or even greater adverse effects than CMPs. This review highlights several knowledge gaps in this new field and suggests directions for future studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The adverse effects of microplastics (MPs) on Daphnia magna have been extensively studied; however, their population-level effects are relatively unknown. This study investigated the effect of polyethylene MP fragments (33.90 ± 17.44 μm) and benzophenone-3 (BP-3), which is a widely used plastic additive (2.91 ± 0.02% w/w), on D. magna population dynamics in a 34-day microcosm experiment. In the growth phase, neither MP nor MP/BP-3 fragments changed the population size of D. magna compared with the control. However, MP/BP-3 fragments significantly reduced (p < 0.05) the population biomass compared to that of the control, whereas MP fragments did not induce a significant reduction. The MP/BP-3 group had a significantly higher (p < 0.05) neonate proportion than that in the control and MP groups. MP/BP-3 fragments upregulated usp and downregulated ecrb, ftz-f1, and hr3, altering gene expression in the ecdysone signaling pathway linked to D. magna growth and development. These findings suggested that BP-3 in MP/BP-3 fragments may disrupt neonatal growth, thereby decreasing population biomass. In the decline phase, MP fragments significantly decreased (p < 0.05) the population size and biomass of D. magna compared with the control and MP/BP-3 fragments. This study highlights the importance of plastic additives in the population-level ecotoxicity of MPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The increase in the usage of biodegradable microplastics (MPs) as an alternative to conventional plastics has necessitated comprehensive ecotoxicity assessments of biodegradable MPs alongside conventional MPs. This study aimed to assess ecotoxicity of biodegradable polylactic acid (PLA) MPs at concentration of 1 and 5 mgL -1 including a genetic analysis of Daphnia magna, and compared to effects of conventional polyethylene terephthalate (PET) MPs. The survival rate for D. magna exposed to 5 mg L -1 of PLA-MPs declined to 52.4 %, signifying a higher rate of mortality when contrasted with PET-MPs, which exhibited 85.7 % survival rate. Chronic exposure to 1 and 5 mgL -1 PLA-MPs resulted in a decrease of offspring, while increasing the sex ratio and deformed embryo. Interestingly, down-regulation of the SOD and AK genes was observed in D. magna after exposure to 5 mgL -1 of PLA-MPs, while 1 mgL -1 of PLA-MPs up-regulated. These results means that 5 mgL -1 PLA-MP could not produce energy and cope with oxidative stress, resulting in high mortality, and 1 mgL -1 of MP was maintained survival due to energy production and antioxidant action. This study contributes to our understanding of biodegradable microplastics (BMPs) toxic effects on D. magna which could be similar to conventional MPs and provide the importance of ecotoxicological data for risk assessment of BMPs in aquatic organisms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Plastic additives may accelerate adverse effects of microplastics (MPs). This study aimed to identify the role of benzophenone-3 (BP-3) additive (10.82 ± 1.20% w/w) in chronic toxicity of polyethylene MP fragments to Daphnia magna (D. magna). MP fragments with and without BP-3 (48.37 ± 6.26 and 44.39 ± 11.16 μm, respectively) were synthesized and 4 d-old D. magna were exposed for 17 d. Daphnids exposed to MP/BP-3 fragments (98%) showed higher survival than those exposed to MP fragments (62%), which can be explained by a significantly low (p < 0.0001) bioconcentration of MP/BP-3 fragments. BP-3 leachate induced significantly low (p < 0.05) phototactic behavior of D. magna, likely leading to the low bioconcentration of MP/BP-3 fragments. Unlike MP fragments, both MP/BP-3 fragments and BP-3 additive inhibited embryonic development and offspring growth in a similar manner. Additionally, only BP-3 additive significantly induced (p < 0.05) higher lipid peroxidation in D. magna. This study suggests the critical role of plastic additives in MPs chronic toxicity to aquatic organisms, which should be further identified for other environmentally relevant plastic additives., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Plastic products are extensively used worldwide, but inadequate management of plastic waste results in significant plastic pollution. Biodegradable plastic (BPs) offers an alternative to traditional plastics, however, not all BPs can fully degrade under natural conditions. Instead, they may deteriorate into biodegradable microplastic (BMPs) at a faster rate than conventional plastic, thereby posing an additional hazard to aquatic environments. This study provides a comprehensive overview of the fate of BPs in aquatic systems and their eco-toxicological effects on aquatic organisms such as algae, invertebrates, and fish. The findings highlight that BMPs have comparable or heightened effects compared to conventional microplastics (MPs) which physiochemical characteristic of the polymer itself or by the chemical leached from the polymeric matrix can affect aquatic organisms. While BPs is not a flawless solution to address plastic pollution, future research should prioritize investigating their production, environmental behavior, ecological impact, and whether BMPs inflict greater harm than conventional MPs. [Display omitted] • The toxicity effect of biodegradable plastics (BMP) to aquatic organisms are summarized. • Not all BMP easily biodegrade in aquatic environments. • UV weathering and biofilm can alter the physicochemical properties of BMP. • BMP can have comparable or higher toxicity to aquatic organisms than conventional plastics. [ABSTRACT FROM AUTHOR]

Biodegradable plastics (BPs) are widely used as alternatives to non-BPs due to their inherent ability to undergo facile degradation. However, the ecotoxicological impact of biodegradable microplastics (MPs) rarely remains scientific documented especially to aquatic ecosystem and organisms compared to conventional microplastics. Therefore, this study aimed to investigate the ecotoxicity of biodegradable polylactic acid (PLA) MPs to Daphnia magna with that of conventional polyethylene (PE) MPs with and without ultraviolet (UV) treatment (4 weeks). The acute toxicity (48 h) of PLA MPs was significantly higher than that of PE MPs, potentially attributable to their elevated bioconcentration resulting from their higher density. UV treatment notably reduced the particle size of PLA MPs and induced new hydrophilic functional groups containing oxygen. Thus, the acute lethal toxicity of PLA MPs exhibited noteworthy increase, compared to before UV treatment after UV treatment, which was greater than that of UV-PE MPs. In addition, UV-PLA MPs showed markedly elevated reactive oxygen species concentration in D. magna compared to positive control. However, there was no significant increase in the level of lipid peroxidation, possibly due to successful defense by antioxidant enzymes (superoxide dismutase and catalase). These findings highlight the ecotoxicological risks of biodegradable MPs to aquatic organisms, which require comprehensive long-term studies. [Display omitted] • PLA MPs showed higher bioconcentration and acute toxicity in D. magna than PE MPs. • UV treatments degraded PLA MPs and produced hydrophilic functional groups on their surface. • UV-PLA MPs showed higher acute lethal and sublethal toxicity than that of PLA before UV treatments. [ABSTRACT FROM AUTHOR]

Microplastics and antibiotics are emerging as ubiquitous contaminants in farmland soil, harming crop quality and yield, and thus threatening global food security and human health. However, few studies have examined the individual and joint effects of degradable and/or non-degradable microplastics and antibiotics on crop plants. This study examined the individual and joint effects of polyethylene (PE) and polylactic acid (PLA) microplastics and the antibiotic oxytetracycline (OTC) on pak choi by measuring its growth, photosynthesis, antioxidant enzyme activity, and metabolite levels. Microplastics and/or oxytetracycline adversely affected root weight, photosynthesis, and antioxidant enzyme (superoxide dismutase, catalase, and ascorbate peroxidase) activities. The levels of leaf metabolites were significantly altered, causing physiological changes. Biosynthesis of plant secondary metabolites and amino acids was altered, and plant hormones pathways were disrupted. Separately and together, OTC, PE, and PLA exerted phytotoxic and antagonistic effects on pak choi. Separately and together with OTC, degradable microplastics altered the soil properties, thus causing more severe impacts on plant performance than non-degradable microplastics. This study elucidates the effects on crop plants of toxicity caused by co-exposure to degradable or non-degradable microplastic and antibiotics contamination and suggests mechanisms. [Display omitted] • Both separate and joint treatments of MPs and antibiotics affected pak choi growth. • The degradable MPs had worse impacts on pak choi than the non-degradable MPs. • Antibiotics combined with degradable MPs induced greater toxic effects on pak choi. • The joint risk of the soil degradable MPs and antibiotics need extensive attention. [ABSTRACT FROM AUTHOR]

Microplastic (MP) pollution poses a growing concern in freshwater ecosystems, which are further threatened by global warming. Thus, this study investigated the effect of elevated temperature (25 °C) on acute toxicity of polyethylene MP fragments to Daphnia magna over a 48 h period. At the reference temperature (20 °C), MP fragments (41.88 ± 5.71 µm) induced over 70 times higher lethal toxicity than that induced by MP beads (44.50 ± 2.50 µm), with median effective concentrations (EC 50) of 3.89 and 275.89 mg L−1, respectively. Elevated temperature significantly increased (p < 0.05) the lethal (EC 50 = 1.88 mg L−1) and sublethal (lipid peroxidation and total antioxidant capacity) toxicity in D. magna exposed to MP fragments compared to those at the reference temperature. Additionally, the elevated temperature led to a significant increase (p < 0.05) in the bioconcentration of MP fragments in D. magna. Overall, the present study increases understanding for the ecological risk assessment of microplastics under global warming, highlights that elevated temperature can be seriously increased bioconcentration of MP fragments, leading to increased acute toxicity in D. magna. [Display omitted] • Elevated temperature increased bioconcentration of microplastics in Daphnia magna. • Elevated temperature enhanced acute immobilization of microplastics to Daphnia magna. • Elevated temperature enhanced acute oxidative stress of microplastics to Daphnia magna. • Increased bioconcentration of microplastics induced enhanced acute toxicity. [ABSTRACT FROM AUTHOR]

Fragmented microplastics (MPs) are emerging contaminants in freshwater environments; however, long-term assessment of their toxicity remains limited. This study aimed to evaluate and compare the chronic toxicity (21 d) of synthesized polyethylene MP fragments and commercial polyethylene MP beads to Daphnia magna. Ingestion of small- and large-sized MP fragments (17.23 ± 3.43 and 34.43 ± 13.09 μm, respectively) by D. magna was significantly (p < 0.05) higher, by 8.3 and 5.2 times, respectively, than that of MP beads (39.54 ± 9.74 μm). The survival of D. magna exposed to small- and large-sized MP fragments (20 and 60%, respectively) was significantly (p < 0.05) lower than that of individuals exposed to MP beads (90%). In particular, small-sized MP fragments significantly (p < 0.05) reduced algal feeding (from 95% to 76%), body length (from 4.20 mm to 3.98 mm), and the number of offspring (from 109 to 74) in D. magna , when compared with MP beads, likely due to their longer retention time and greater interference in the digestive tract. These findings suggest that fragmentation of MPs into μm-scale particles can pose a significant ecological risk to aquatic organisms; moreover, further studies are required to identify the underlying toxicity mechanism. [Display omitted] • Accumulation of microplastic (MP) fragments was higher than that of MP beads. • This likely resulted in higher mortality in Daphnia magna for MP fragments. • MP fragments decreased the carbohydrate and protein reserves of D. magna. • Inhibition of feeding in D. magna depended on the size of MP fragments. • This may lead to size-dependent reduction in growth and reproduction of D. magna. [ABSTRACT FROM AUTHOR]

• Synthesized microplastic fragments with known amounts of benzophenone‐3 (BP-3). • Synergistic toxicity of microplastic fragments and BP-3 in D. magna was assessed. • Effect of microplastic fragments on bioconcentrations of BP-3 was evaluated. The interactive effect of polyethylene microplastic (MP) fragments and benzophenone‐3 (BP-3) additives on Daphnia magna was assessed in the present study. The 48 h median effective concentration (EC 50) revealed that MP fragments (37.24 ± 11.76 μm; 3.90 mg L−1) were over 80 times more acutely toxic than polyethylene microbeads (37.05 ± 3.96 μm; 323 mg L−1), possibly because of their irregular shape and high specific surface area. Moreover, the addition of BP-3 (10.27 ± 0.40 % w/w) to MP fragments (MP + BP-3) resulted in greater acute toxicity to D. magna (EC 50 = 0.99 mg L−1) compared to MP fragments (EC 50 = 3.90 mg L−1) or BP-3 (EC 50 = 2.29 mg L−1) alone. Additionally, MP + BP-3 exposure induced a synergistic increase in reactive oxygen species, total antioxidant capacity, and lipid peroxidation in D. magna. These synergistic effects can be attributed to enhanced bioconcentrations of BP-3 in D. magna caused by MP fragments. These findings suggest that MP fragments containing chemical additives represent a synergistic ecological risk and have the potential to harm aquatic organisms. [ABSTRACT FROM AUTHOR]