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In recent times, microplastics have become a disturbance to both aquatic and terrestrial ecosystems and the ingestion of these particles can have severe consequences for wildlife, aquatic organisms, and even humans. In this study, two types of biochars were manufactured through the carbonization of naturally found starfish (SF-1) and aloevera (AL-1). The produced biochars were utilized as sensing electrode materials for the electrochemical detection of ∼100 nm polystyrene microplastics (PS). SF-1 and AL-1 based biochars were thoroughly analyzed in terms of morphology, structure, and composition. The detection of microplastics over biochar based electrodes was carried out by electrochemical studies. From electrochemical results, SF-1 based electrode exhibited the detection efficiency of ∼0.2562 μA/μM∙cm2 with detection limit of ∼0.44 nM whereas, a high detection efficiency of ∼3.263 μA/μM∙cm2 was shown by AL-1 based electrode and detection limit of ∼0.52 nM for PS (100 nm) microplastics. Process contributed to enhancing the sensitivity of AL-1 based electrode might associate to the presence of metal-carbon framework over biochar's surfaces. The AL-1 biochar electrode demonstrated excellent repeatability and detection stability for PS microplastics, suggesting the promising potential of AL-1 biochar for electrochemical microplastics detection. [Display omitted] • Biochars are produced by the carbonization of naturally found starfish (SF-1) and aloevera (AL-1). • Manufactured biochars utilize as sensing electrode materials for the electrochemical detection of PS (100 nm) microplastics. • A high detection efficiency of ∼3.263 μA/μM∙cm2 is recorded by AL-1 based electrode for PS (100 nm) microplastics. • AL-1 biochar electrode demonstrates excellent repeatability and detection stability for PS microplastics. [ABSTRACT FROM AUTHOR]

Superworm (larve of Zophobas atratus) could consume foams of expanded polystyrene plastics. However, there is no sufficient understanding of the impact of microplastics on superworms and the degradation pathways of polystyrene. Herein, we explored the weight and survival change of superworms while fed with polystyrene microplastics, and found that survival rate and mean weight would reduce. In terms of gut microbial community structure of surperworms, significant shifts were detected with the relative abundance of Hafnia-Obesumbacterium sp. increasing. In addition, we domesticated two microbiota from the gut of superworms, and confirmed their ability to degrade PS in vitro. The last but most important, 1291 metabolites were identified by HPLC-TOF-MS/MS, and six metabolites related to polystyrene degradation were identified through comparative metabolomic analysis. According to the content and pathways of these metabolites, three metabolic pathways of polystyrene were (a) styrene-phenylacetyl-CoA-L-2-aminoadipic acid; (b) styrene-phenylacetyl-CoA-benzaldehyde; (c) styrene-2-hydroxyacetophenone. These results would help to further screen bacteria of PS degradation and investigate PS metabolic pathways in invertebrates. [Display omitted] • PS microplastics negatively affected the survival rate of surperworms. • Two microbiotas degrading PS were selected from gut microbiome. • Three metabolic pathways of PS degradation in superworms were proposed. [ABSTRACT FROM AUTHOR]

Weathering-induced polymer degradation is typically heterogeneous which plays an integral part in fragmentation. Despite that, the current selection of techniques to investigate such heterogeneities, especially beneath the sample surface, is sparse. We introduce Laser-induced Breakdown Spectroscopy (LIBS) as an analytical tool and evaluate its performance for depth profiling. Three types of polymers were selected (polyethylene, polypropylene, and polystyrene) that were aged under controlled conditions. We demonstrate that LIBS can detect heterogeneous oxidation on the surface and inside the samples. The results reveal that different oxidation behaviors are linked to the sample's lattice structure and the subsequent formation of microcracks. This implies that LIBS is beneficial to give additional insights into the weathering and degradation behavior of environmentally relevant plastics. [Display omitted] • Heterogeneous plastic degradation is related to the plastic's lattice structure. • Degradation processes should be studied over the entire sample volume. • LIBS can conduct three-dimensional chemical mapping without exposing the cross-section. • PE, PP and PS samples have been studied for different weathering times. [ABSTRACT FROM AUTHOR]

Assessing the dietary accumulation of nanoplastics in animals following very-low exposure concentrations is restricted due to analytical limitations. This study adapted a method for synthesising semi-stable 14C-PS NPs (through styrene polymerisation) in small volumes for deployment in environmental studies. The method was developed with non-labelled material where the final polystyrene product had a primary particle size of 35 ± 8 nm (as measured by transmission electron microscopy). This method was then applied to 14C-labelled styrene to produce radiolabelled polystyrene nanoplastics (14C-PS NPs). The 14C-PS NPs were added (top-dressed) to a commercially available fish feed, with a measured concentration of 27.9 ± 2.1 kBq kg−1 (n = 5), equating to 5.9 μg polystyrene kg−1 feed. Fish (rainbow trout; Oncorhynchus mykiss) were fed this diet at a ration of 2% body weight per day for a period of two weeks. On day 3, 7 and 14, the fish were sampled for the mid intestine, hind intestine, kidney and liver, and measured for tissue radioactivity (determined by liquid scintillation counting). Some background activity was detected in the control samples (e.g., 1–16 and 4–11 Bq g−1 in the hind intestine and liver, respectively) which is due to natural background fluorescence. By the end of the experiment, the hind intestine and liver had significantly elevated radioactivity (25.3 and 15.0 Bq g−1, respectively) compared to the control, indicating the accumulation of nano polystyrene. In the liver, this equated to 1.8 μg polystyrene g−1 dry weight. This study confirms the accumulation of nano particles in vertebrates at low, environmentally relevant concentration, and highlights radiolabelling as a methodological approach suitable for exploring the bioaccumulation of nanoplastics and potential impacts. [Display omitted] • Exposures using very-low concentrations of nanoplastics are lacking. • Polystyrene nanoplastics were synthesised with a radiolabel and fed to fish. • There was no change in feeding activity of the fish. • Increased radioactivity was observed in the hind intestine and liver. [ABSTRACT FROM AUTHOR]

Abstract Biodegradable plastics, as alternatives to conventional plastics, are increasingly used, but their interactions with organic pollutants are still unknown. In this study, the sorption and desorption behaviors on a type of biodegradable plastic−poly(butylene adipate co-terephtalate) (PBAT) were investigated, and at the same time two types of conventional plastics−polyethylene (PE c and PE v) and polystyrene (PS) were used for comparison. Phenanthrene (PHEN) was chosen as one of representative organic pollutants. Results indicated that the sorption and desorption capacities of PBAT were not only higher than those of the other types of microplastics, but also higher than those of carbonaceous geosorbents. The surface area normalized results illustrated that sorption and desorption of the microplastics were positively correlated with their abundance of rubbery subfraction. The sorption kinetic results showed that the sorption rates of PBAT and PE c were higher than PE v and PS. The effects of water chemistry factors including salinity, dissolved organic matter and Cu2+ ion on the sorption process displayed the same trend, but the degrees of influence on the four microplastics differed. The degrees of influence were mainly dependent on the abundance of rubbery subfraction for microplastics. These findings indicate that the biodegradable poly(butylene adipate co-terephtalate) microplastics are actually stronger vectors than the conventional microplastics, and crystallization characteristics of the microplastics have great influences on the vector effect. Graphical abstract Image 1 Highlights • Biodegradable microplastics sorbed/desorbed more PHEN than conventional ones. • Sorption/desorption capacities depended on the content of rubbery subfraction. • Plastic additives didn't alter the microplastics adsorption process. • High salinity and low DOM strengthen the sorption of PHEN onto microplastics. [ABSTRACT FROM AUTHOR]

Aqueous environments are generally thought to be a source of pooling and re-distribution for both micro-plastics (MPs) and nano-plastics (NPs); however, significantly less data on NPs than MPs have been reported. The occurrence of salts, proteins, and other organic matter may promote or inhibit the aggregation of NPs to form agglomeration particles, making their detection more difficult. In this study, 80 and 500 nm polystyrene nano-plastics (P S-NPs) modified by four different functional groups (P S-Bare, P S-COOH, P S-NH 2 , and P S–CHO–500 nm) were selected to mimic the flocculation and/or sedimentation of NPs in salts (NaCl, CaCl 2 , and Na 2 SO 4) and protein solutions. The results showed that the 80 nm P S-NPs are only colloidal in pure water. All four strong electrolyte solutions that were tested significantly promoted the aggregation of P S-NPs, including those that were protein-coated. In addition, 500 nm P S-CHO did not flocculate but gradually settled into sedimentation. Therefore, Raman spectrometry can be used to analyze assembled P S-NPs, but is not suitable for analyzing normal P S-NPs. By combining fractal morphology, this study provides insight into the comprehensive analysis of P S-NPs in water solutions, including the digestion of biological samples. [Display omitted] • Colloidal NPs in aquatic environments other than Milli-Q water will aggregate. • Aggregated NPs either float or sink depending on their density in aquatic environments. • Extraction and detection of individual NPs in aquatic environments is challenging. • A salt solution promotes the aggregation of NPs by regulating their surface charge. [ABSTRACT FROM AUTHOR]

Micro-nanoplastics have become a new type of pollutant worldwide and have attracted widespread attention for their potential toxicity. However, the toxicity of polystyrene nanoplastics (PS-NPs) under continuous exposure of multi-generations is still unclear. In the present study, Drosophila melanogaster was selected as an in vivo biological model to investigate the reproductive toxicity and underlying mechanism induced by PS-NPs (100 nm; 1, 10, 50, and 100 mg L−1) after continuous exposure of five generations. The results showed that PS-NPs accumulated in the crop, gut and ovaries after 5 d of exposure. It was also observed that the number of egg production and eclosion rate decreased significantly (P < 0.05) accompanied by delayed development during continuous exposure PS-NPs of multi-generations. Further analysis revealed that the degree of apoptosis and necrosis of oocytes in the F5 generation increased with the increasing exposure dose. To elucidate the underlying toxicity mechanism mediated by PS-NPs, transcriptomic analysis was performed on the ovaries of the F5 generation. The results showed that there were 102 and 208 differentially expressed genes (DEGs) in the 1 mg L−1 and 100 mg L−1 PS-NPs treatment groups, respectively, compared with the control group. The transcriptome analysis further detected the KEGG pathway with significant enrichment of DEGs, revealing obvious reproductive toxicity at the molecular level. In conclusion, this research not only highlighted the negative physiological effects of multi-generational exposure to PS-NPs on Drosophila melanogaster , but also explored potential mechanisms by transcriptomic analysis to better understand reproductive toxicity induced by multi-generational exposure. [Display omitted] • The effects of polystyrene nanoplastics were evaluated over five generations of Drosophila melanogaster. • The multi-generational effects of polystyrene nanoplastics were produced in a generation-dependent manner. • Polystyrene nanoplastics were ingested and accumulated in the crop, gut, and ovary of Drosophila melanogaster. • The transcription of genes related to reproduction, metabolism, longevity, and apoptosis was altered. [ABSTRACT FROM AUTHOR]

Plastic pollution is a serious issue in the aquatic environments. This concerning issue of negative impacts of synthetic plastic debris particles in the aquatic ecosystem give rise to the bioplastic materials. These bioplastics are synthesized from biological organisms, retaining same structural and functional ability as synthetic plastics. However, their degradability and toxicity in natural environment is still unknown. So, in this study we have focused on to elucidate the toxicity caused by Bacillus subtilis synthesized biopolymer - polyhydroxybutyrate (PHB) microspheres and compare their effects with synthetic plastic. The effect of Synthetic plastic (Polystyrene microspheres) and bioplastic (PHB microspheres) were studied on acute exposure to in-vitro and in-vivo model of Lates calcarifer. PHB microspheres were characterized and confirmed using Flurospectrophotometer, Fourier-Transform infrared spectroscopy (FTIR), Particle size analyzer (PSA), Zeta potential and Scanning electron Microscope (SEM). Histopathology assessment for in-vivo model and MTT assay for in-vitro model were performed. The results of fish exposed to 0.5 μg/ml and 1 μg/ml of both microspheres have shown significant necrosis and alteration in muscle, gill and heart tissues. The increased cytotoxicity observed in spleen cell line of Lates calcarifer on exposure to 0.5 μg and 1 μg of both microspheres. Bioplastics are needs specific times for degradation into the aquatic environment. In these results suggest, that even bioplastic have the risk of inducing toxicity similar to the synthetic plastic. [Display omitted] • PHB synthesized from Bacillus subtilis induced toxicity in Lates calcarifer. • Negative effects of bioplastic in fish tissues were similar to polystyrene impact. • Significant cytotoxicity was observed in 0.5 μg/ml of PHB and polystyrene microspheres. • Significant disruption of primary and secondary lamellae in gill tissue. • Significant necrosis of myocardial tissue and alteration of muscle bundles. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and endocrine disrupting chemicals are ubiquitous pollutants in marine environments, but their combined ecological risk is unclear. This study exposed male marine medaka (Oryzias melastigma) to 10 ng/L 17α-ethynylestradiol (EE 2) alone or EE 2 plus 2, 20, and 200 μg/L polystyrene MPs for 28 days to investigate the impacts of MPs on the reproductive disruption of EE 2. The results showed that 10 ng/L EE 2 alone did not affect biometric parameters, while co-exposure to EE 2 and 20, 200 μg/L MPs suppressed the growth and decreased gonadosomatic and hepatosomatic indices. Compared to EE 2 alone, EE 2 plus MPs exposure significantly increased plasma 17 β- estradiol (E 2) levels in a dose-dependent manner, and co-exposure to EE 2 and 20, 200 μg/L MPs significantly increased the ratios of E 2 /testosterone (T). Moreover, EE 2 plus MPs exposure elevated the transcription levels of estrogen biomarker genes vitellogenin and choriogenin , and estrogen receptor (ERα and ERβ). Morphological analysis also showed that co-exposure to EE 2 and MPs induced more severe damage to the testes and livers, indicating that MPs increased the toxicity of EE 2. The actual EE 2 concentrations in the solution increased with the exposure concentrations of MPs, suggesting that MPs changed the fate and behavior of EE 2 in the seawater. These findings demonstrate that MPs could increase the estrogenic effects of EE 2 on marine fish, suggesting that the combined health risk of MPs and endocrine disrupting chemicals on marine organisms should be paid great attention. [Display omitted] • MPs, not EE 2 , suppressed the growth, HSI and GSI indices of male marine medaka. • MPs increased EE 2 -induced E 2 levels in a dose-dependent manner. • EE 2 plus MPs induced higher expression of estrogen biomarker genes than EE 2 alone did. • 2, 20, and 200 μg/L MPs increased the actual EE 2 concentrations in the seawater. • Histopathological damages in livers and testes were observed in EE 2 plus MPs group. [ABSTRACT FROM AUTHOR]