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1.
Chemosphere ; 253: 126705, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302904

RESUMO

Polystyrene microplastics (PSMPs) with different sizes, surface charges and aging statuses simulated field PSMPs and were applied to understand their cytotoxicity to Escherichia coli. The PSMPs hardly affected the viability, membrane integrity, ROS generation and ATPase activity of E. coli, and the cytotoxicity of field PSMPs is marginal and assumed to be overestimated. Low concentrations (1.0 mg L-1) of PSMPs dynamically affect the cytotoxicity of Ag+ to E. coli through various toxic mechanisms. PSMPs likely mitigated the cytotoxicity of Ag+ during the initial 24 h of co-exposure by protecting the cell membrane, inhibiting ROS generation and/or recovering ATPase activity (p < 0.05 or p < 0.01). During prolonged co-exposure for 48 h, nonfunctionalized polystyrene (PS-NF) still mitigated the cytotoxicity of Ag+ by protecting the integrity of the cell membrane, and aged PS-NF slightly affected cytotoxicity. PS-NH2 and PS-COOH intensified the cytotoxicity of Ag+ because PS markedly promoted ROS generation and inhibited ATPase activity. Thus, field PSMPs were assumed to exhibit marginal cytotoxicity to E. coli and can combine with surrounding Ag+ to modify the E. coli population levels and even the structure of aquatic ecosystems. Accordingly, the environmental and health risks of field PSMPs require further intensive investigation, and the combined toxicity effects of field PSMPs with Ag+ should be considered carefully due to their dynamic toxic effects and mechanisms.


Assuntos
Microplásticos/toxicidade , Poliestirenos/toxicidade , Prata/toxicidade , Ecossistema , Escherichia coli/efeitos dos fármacos , Íons , Microplásticos/química , Poliestirenos/química , Prata/química
2.
Ecotoxicol Environ Saf ; 194: 110362, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32171964

RESUMO

The effects of microplastic on mortality and sublethal responses on larval development of meroplankton are still largely unknown. Present study investigated the effects of four sizes of virgin spherical polystyrene microplastics (diameter 1.7, 6.8, 10.4, 19.0 µm) on naupliar (stage II-VI) and cypris larvae of barnacle Amphibalanus amphitrite at environmentally relevant concentrations (1, 10, 100, 1000 beads mL-1). Essential life-history traits, including mortality, development time and rates of growth, settling, and metamorphosis were measured throughout the entire larval development. Feeding experiments were conducted to evaluate if microplastics decreased naupliar feeding due to physical impacts or selective feeding of nauplii. The results showed that A. amphitrite stage II nauplii were able to ingest and efficiently egest all sizes of microplastics. All the life-history endpoints measured were not significantly affected by all sizes of microplastics at any concentration tested. Presence of all sizes of microplastics did not cause physical interference on naupliar feeding and all stages of nauplius larvae (stage III-VI) did not selectively feed on microplastics. However, the feeding ability of stage III nauplius appeared to be affected by 1.7 µm at 1000 beads mL-1 which was possibly due to individual variations rather than microplastics' impacts. Overall, the full larval development of barnacle A. amphitrite was not affected by microplastics at environmentally relevant concentrations under laboratory condition.


Assuntos
Microplásticos/toxicidade , Poliestirenos/toxicidade , Thoracica/fisiologia , Animais , Larva/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Plásticos , Thoracica/efeitos dos fármacos , Testes de Toxicidade
3.
PLoS One ; 15(3): e0229777, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32187189

RESUMO

The extent to which small plastics and potentially associated compounds are entering coastal food webs, especially in estuarine systems, is only beginning to be realized. This study examined an estuarine reach at the mouth of urbanized Chollas Creek in San Diego, California to determine: 1) the extent and magnitude of microplastics pollution in estuarine sediments and fish, 2) the extent and magnitude of SVOC contamination in estuarine fish, and 3) whether fish preferentially ingested certain types of microplastics, when compared with the microplastic composition of creekbed sediments. Surface sediments (0-5 cm depth) contained about 10,000 small plastic pieces per m2, consisting mostly (90%) of fibers, and hard and soft pieces. Nearly 25% of fish contained small plastics, but prevalence varied with size and between species. Of the 25 types of small plastics found in sediment, fish preferred about 10 types (distinct colors and forms). Several SVOCs, both water soluble and sediment-associated compounds, were found in the two species of fish tested. This study revealed that a species' natural history may influence contamination levels, and warrants further study to better understand the pathways of plastics and associated contaminants into and throughout coastal food webs, and the potential health risks for small and/or low-trophic level organisms.


Assuntos
Estuários , Peixes/fisiologia , Cadeia Alimentar , Sedimentos Geológicos/química , Microplásticos/metabolismo , Poluentes da Água/metabolismo , Animais , California , Cidades , Peixes/metabolismo , Microplásticos/análise , Microplásticos/toxicidade , Poluentes da Água/análise , Poluentes da Água/toxicidade
4.
Ecotoxicol Environ Saf ; 195: 110484, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32200150

RESUMO

Microplastics and nonylphenol (NP) are considered as emerging pollutant and have attracted wide attention, while their combined toxicity on aquatic organisms is barely researched. Therefore, the combined toxicity influence of NP with three types of microplastics containing polyethylene (PE1000, 13 µm and PE, 150 µm), polyamide (PA1000, 13 µm and PA, 150 µm) polystyrene (PS, 150 µm) on microalgae Chlorella pyrenoidosa was analyzed. Both growth inhibition, chlorophyll fluorescence, superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) were determined. We found that single microplastics and NP both inhibited algal growth, thereby causing oxidative stress. The order of inhibition effect in single microplastics experiment was PE1000 > PA1000 > PE ≈ PS > PA. The combined toxicity experiment results indicated that the presence of microplastics had positive effect in terms of alleviating NP toxicity to C. pyrenoidosa, and the microplastics adsorption capacity to NP was the dominant contributing factor for this effect. According to the independent action model, the combined toxicity was antagonistic. Because the negative effect of smaller size microplastics on algal growth was aggravated with prolonged exposure time, the optimum effect of microplastics alleviated NP toxicity was PA1000 at 48 h, while this effect was substituted by PA at 96 h during combined toxicity. Thus, the toxicity of smaller size microplastics has a nonnegligible influence on combined toxicity. This study confirms that microplastics significantly affected the toxicity of organic pollutants on microalgae. Further research on the combined toxicity of smaller size microplastics with pollutants in chronic toxicity is needed.


Assuntos
Chlorella/efeitos dos fármacos , Microplásticos/toxicidade , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Adsorção , Catalase/metabolismo , Chlorella/enzimologia , Chlorella/metabolismo , Interações Medicamentosas , Malondialdeído/metabolismo , Microalgas/efeitos dos fármacos , Microalgas/enzimologia , Microalgas/metabolismo , Microplásticos/química , Estresse Oxidativo , Poliestirenos/toxicidade , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/química
5.
Chemosphere ; 248: 126067, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32041069

RESUMO

Microplastics (MPs) pollution and its potential environmental risks have drawn increasing concerns in recent years. Among which, microbeads in personal care and cosmetic products has becoming an emerging issue for their abundance as well as the knowledge gaps in their precise environmental behaviors in freshwater. The present study investigated the sorption process of tetrabromobisphenol A (TBBPA), the most widely applied and frequently encountered flame retardant in aquatic environments, on two sources of polyethylene (PE) particles (pristine PE particles and microbeads isolated from personal care and cosmetic products). Significantly enhanced adsorption capacity of microbeads was observed with up to 5-folds higher than the pristine PE particles. The sorption efficiency was also governed by solution pH, especially for the cosmetic-derived microbeads, indicating the strong adsorption of TBBPA on PE was dominated by both hydrophobic and electrostatic interactions. Additionally, combined effects on redox status of zebrafish were evaluated with two environmental relevant concentrations of PE particles (0.5 and 5 mg L-1) using integrated biomarker response (IBR) index through a 14-d exposure. Co-exposure induced significant antioxidative stress than either PE or TBBPA alone when exposed to 0.5 mg L-1 of MPs. After 7-d depuration, the IBR value for combination treatments [TBBPA + PE (L)] was 3-fold compared with that in MP-free groups, indicating the coexistence might exert a prolonged adverse effects on aquatic organisms. These results highlight the probability of risk from microbead pollution in freshwater, where toxic compounds can be adsorbed on microbeads in a considerable amount resulting in potential adverse effects towards aquatic organisms.


Assuntos
Cosméticos/química , Microplásticos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Bifenil Polibromatos/toxicidade , Polietileno/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Adsorção , Animais , Antioxidantes/metabolismo , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/metabolismo , Sinergismo Farmacológico , Biomarcadores Ambientais/efeitos dos fármacos , Retardadores de Chama/análise , Retardadores de Chama/toxicidade , Água Doce/química , Microplásticos/análise , Microesferas , Bifenil Polibromatos/análise , Polietileno/análise , Poluentes Químicos da Água/análise
6.
Mar Pollut Bull ; 151: 110859, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32056641

RESUMO

Microplastic ingestion by intertidal fauna is a well-documented phenomenon, with emphasis on the physiological consequences of microplastic exposure. However, the behavioural effects of microplastic ingestion have not been explored to the same degree, even in species with documented microplastic ingestion. In this study, the predator-avoidance emergence response of Littorina littorea was assessed and related to microplastic levels within the samples. This is a novel approach to microplastic behavioural experiments, whereby current environmental L. littorea microplastic levels are assessed, rather than levels vastly in excess of those recorded under field conditions. The results showed no difference in emergence likelihood or emergence latency related to microplastic abundance, sex, or treatment. However, L. littorea size did have a significant effect on emergence likelihood and emergence latency, with smaller individuals emerging faster and more frequently. This study shows that microplastics, at their current environmental levels, do not seem to affect L. littorea emergence behaviour.


Assuntos
Monitoramento Ambiental , Gastrópodes/fisiologia , Microplásticos/análise , Poluentes Químicos da Água/análise , Animais , Comportamento Animal/efeitos dos fármacos , Ingestão de Alimentos , Microplásticos/toxicidade , Plásticos , Poluentes Químicos da Água/toxicidade
7.
Environ Pollut ; 260: 114059, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32004970

RESUMO

Ingestion of microplastics by marine organisms has been well documented, but their interaction with chemical pollutants has not been sufficiently addressed. The aim of this study was to determine the individual and combined effects of chlorpyrifos (CPF) and polyethylene microplastics (MP) on the survival, fecundity, feeding and egg viability of Acartia tonsa, a calanoid copepod widely distributed in planktonic communities. The median lethal concentration obtained for CPF was higher (LC50 = 1.34 µg/L) than for the combination with MP (LC50 = 0.37 µg/L), or CPF-loaded MP (LC50 = 0.26 µg/L). Significant effects were also observed for feeding and egg production (EC50 = 0.77 and 1.07 µg/L for CPF, 0.03 and 0.05 µg/L for CPF combined with MP, 0.18 and 0.20 µg/L for CPF-loaded MP). No significant effects were observed in the exposure to 'virgin' MP. This study confirms the role of MP as vectors of pollutants to marine organisms and supports the increased availability of certain toxicants carried out by MP. The effects observed in fitness-related responses suggest potential damage to A. tonsa populations. The comparison of the results obtained here with environmental concentrations indicates that the combined exposure to CPF and MP could constitute a risk to A. tonsa in the natural environment.


Assuntos
Clorpirifos/toxicidade , Copépodes/fisiologia , Microplásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Plásticos , Polietileno
8.
Chemosphere ; 248: 126065, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32045975

RESUMO

Two isoforms of Glutathione S-Transferase (GST) genes, belonging to mu (Dp-GSTm1 and Dp-GSTm2) and sigma (Dp-GSTs1 and Dp-GSTs2) classes, were cloned and characterised in the freshwater Daphnia pulex. No signal peptide was found in any of the four GST proteins, indicating that they were cytosolic GST. A highly conserved glutathione (GSH) binding site (G-site) occurred in the N-terminal sequence, and a substrate binding site (H-site), interacting non-specifically with the second hydrophobic substrate, was present in the C-terminal. A Tyr residue, for the stabilization of GSH, was found to be conserved in the analysed sequences. The secondary and tertiary structures indicated that these genes possess the typical cytosolic GST structure, including a conserved N-terminal domain with a ßαßαßßα motif. The µ loop (NVGPAPDYDR and NFIGAEWDR in Dp-GSTm1 and Dp-GSTm2, respectively) was identified between the ßαß (ß1α1ß2) and αßßα motifs (α2ß3ß4α3) in the N-terminal domain. The expressions of Dp-GSTs1, Dp-GSTs2, and Dp-GSTm1 were higher in other age groups compared to the newly-born neonates (1 d); however, the expression of Dp-GSTm2 first increased and then decreased with age. Gene expression was significantly reduced by high concentration (1 and 2 mg/L) of 75 nm polystyrene nanoplastic. However, nanoplastic exposure at the predicted environmental concentration (1 µg/L) had a low effect. Exposure of mothers to nanoplastic (1 µg/L) elevated the Dp-GSTs2 level in their neonates. These results improve our understanding on the response of different types of Daphnid GST to environmental contaminants, especially nanoplastic.


Assuntos
Daphnia/metabolismo , Glutationa Transferase/metabolismo , Microplásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Sítios de Ligação , Água Doce/química , Expressão Gênica , Glutationa/metabolismo , Poliestirenos/metabolismo
9.
Environ Pollut ; 259: 113937, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31952101

RESUMO

In recent years, reports of plastic debris in the gastrointestinal (GI) tract of fish have been well documented in the scientific literature. This, in turn, increased concerns regarding human health exposure to microplastics through the consumption of contaminated fish. Most of the available research regarding microplastic toxicity has focused on marine organisms through direct feeding or waterborne exposures at the individual level. However, little is known about the trophic transfer of microplastics through the aquatic food chain. Freshwater zooplankton Daphnia magna (hereafter Daphnia), and the fathead minnow Pimephales promelas (FHM), are well-known model species used in standard toxicological studies and ecological risk assessments that provide a simple model for trophic transfer. The aim of this study was to assess the tissue translocation, trophic transfer, and depuration of two concentrations (20 and 2000-part ml-1) of 6 µm polystyrene (PS) microplastics particles between Daphnia and FHM. Bioconcentration factors (BCF) and bioaccumulation factors (BAF) were determined. Fluorescent microscopy was used to determine the number of particles in the water media and within the organs of both species. Throughout the five days of exposure, PS particles were only found within the GI tract of both species. The BCF for Daphnia was 0.034 ± 0.005 for the low concentration and 0.026 ± 0.006 for the high concentration. The BAF for FHM was 0.094 ± 0.037 for the low concentration and 0.205 ± 0.051 for the high concentration. Between 72 and 96 h after exposure all microplastic particles were depurated from both species. The presence of food had a significant effect on the depuration of microplastic particles from Daphnia but not for FHM. Based on the low BCF and BAF values for both species, rapid depuration rates, and null translocation of microplastic particles to organs and tissues from the GI tract, there is a low probability that microplastics will bioconcentrate and bioaccumulate under environmental conditions.


Assuntos
Cyprinidae/metabolismo , Daphnia/metabolismo , Microplásticos/metabolismo , Poliestirenos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Humanos , Microplásticos/toxicidade , Plásticos , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade
10.
Arch Environ Contam Toxicol ; 78(3): 495-500, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31989187

RESUMO

The effects of microplastic pollution on sea urchins has received little attention despite their ecological and economical importance. This is the first study to focus on adult sea urchins (Arbacia punctulata). These organisms were exposed to storm-like sediment resuspension of microplastic concentrations (9-µm polystyrene 25,000 spheres L-1) combined with salinity reductions (salinity 25 vs. 33) associated with high precipitation. Urchins were exposed to these parameters for 24 h before assessing righting times and for 48 h before assessing oxygen consumption rates. No significant impacts on urchin physiology were observed showing resilience to short-term exposures of storm-like induced microplastics and salinity. No microplastic particles blocked the madreporite pores indicating the active removal of particles by cilia and pedicellariae. Gut tissue samples indicated consumption of microplastics. Studies on more species are urgently required to determine their responses to plastic pollution to inform management decision-making processes.


Assuntos
Arbacia/efeitos dos fármacos , Exposição Ambiental/análise , Sedimentos Geológicos/química , Microplásticos/toxicidade , Água do Mar/química , Poluentes Químicos da Água/toxicidade , Animais , Arbacia/fisiologia , Modelos Teóricos , Salinidade , Fatores de Tempo
11.
Environ Pollut ; 259: 113896, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31918148

RESUMO

Microplastics are plastic fragments of particle sizes less than 5 mm, which are widely distributed in marine and terrestrial environments. In this study, earthworms Eisenia fetida were exposed to 100 and 1000 µg of 100 nm and 1300 nm fluorescent polystyrene microplastics (PS-MPs) per kg of artificial soil for 14 days. Uptake or accumulation of PS-MPs in earthworm intestines, histopathological changes, oxidative stress, and DNA damage were assessed to determine the toxicological effects of PS-MPs on E. fetida. The results showed that the average accumulated concentrations in the earthworm intestines were higher for 1300 nm PS-MPs (0.084 ± 0.005 and 0.094 ± 0.003 µg/mg for 100 and 1000 µg/kg, respectively) than for 100 nm PS-MPs (0.015 ± 0.001 and 0.033 ± 0.002 µg/mg for 100 and 1000 µg/kg, respectively). In addition, histopathological analysis indicated that the intestinal cells were damaged after exposure to PS-MPs. Furthermore, PS-MPs significantly changed glutathione (GSH) level and superoxide dismutase (SOD) activity. The GSH levels were 86.991 ± 7.723, 165.436 ± 4.256-167.767 ± 18.642, and 93.590 ± 4.279-173.980 ± 15.523 µmol/L in the control, 100 nm, and 1300 nm PS-MPs treatment groups. In addition, the SOD activities were 10.566 ± 0.621, 9.039 ± 0.787-9.408 ± 0.493, and 7.959 ± 0.422-9.195 ± 0.327 U/mg protein for the control, 100 nm, and 1300 nm PS-MPs treatment groups, respectively, indicating that oxidative stress was induced after PS-MPs exposure. Furthermore, the comet assay suggested that exposure to PS-MPs induced DNA damage in earthworms. Overall, 1300 nm PS-MPs showed more toxic effect than 100 nm PS-MPs on earthworms. These findings provide new insights regarding the toxicological effects of low concentrations of microplastics on earthworms, and on the ecological risks of microplastics to soil animals.


Assuntos
Microplásticos , Oligoquetos , Poliestirenos , Poluentes do Solo , Animais , Microplásticos/toxicidade , Oligoquetos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poliestirenos/toxicidade
12.
Environ Pollut ; 259: 113898, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31927275

RESUMO

Microplastics (MPs) are contaminants of increasing concern due to their abundance, ubiquity and persistence over time. However, knowledge about MP distribution in fresh waters and their effects on freshwater organisms is still scarce, and there is virtually no information about their potential influence on ecosystem functioning. We used a microcosm experiment to examine the effects of MPs (fluorescent, 10-µm polystyrene microspheres) at different concentrations (from 0 to 103 particles mL-1) on leaf litter decomposition (a key process in stream ecosystems) and associated organisms (the caddisfly detritivore Sericostoma pyrenaicum), and the extent to which MPs were attached to leaf litter and ingested and egested by detritivores, thus assessing mechanisms of MP trophic transfer. We found that MPs caused detritivore mortality (which increased 9-fold at the highest concentration) but did not affect their growth. Analysis of fluorescence in samples suggested that MPs were rapidly ingested (most likely through ingestion of particles attached to leaf litter) and egested. Leaf litter decomposition was reduced as a result of increasing MP concentrations; the relationship was significant only in the presence of detritivores, but microbially-mediated decomposition showed a similar trend. Our findings provide novel evidence of harmful effects of MPs on aquatic insects and stream ecosystem functioning, and highlight the need for the standardization of methods in future experiments with MPs in order to allow comparisons and generalizations.


Assuntos
Ecossistema , Insetos , Microplásticos , Rios , Animais , Insetos/efeitos dos fármacos , Microplásticos/toxicidade , Folhas de Planta/química
13.
Environ Pollut ; 259: 113892, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31931412

RESUMO

Hydroponic experiments were conducted to study the effects of microplastic particles of polystyrene (PS) and polytetrafluoroethylene (PTFE) on arsenic (As) content in leaves and roots of rice seedlings, and the changes in root vigor and physiological and biochemical indicators under single or combined PS and PTFE with As(III) treatment. Rice biomass decreased with increasing concentrations of PS, PTFE, and As(III) in the growth medium. The highest root (leaf) biomass decreases were 21.4% (10.2%), 25.4% (11.8%), and 26.2% (16.2%) with the addition of 0.2 g L-1 PS, 0.2 g L-1 PTFE, and 4 mg L-1 As(III), respectively. Microplastic particles and As(III) inhibited biomass accumulation by inhibiting root activity and RuBisCO activity, respectively. The addition of As(III) and microplastic particles (PS or PTFE) inhibited photosynthesis through non-stomatal and stomatal factors, respectively; furthermore, net photosynthetic rate, chlorophyll fluorescence, and the Chl a content of rice were reduced with the addition of As(III) and microplastic particles (PS or PTFE). Microplastic particles and As(III) induced an oxidative burst in rice tissues through mechanical damage and destruction of the tertiary structure of antioxidant enzymes, respectively, thereby increasing O2- and H2O2 in roots and leaves, inducing lipid peroxidation, and destroying cell membranes. When PS and PTFE were added at 0.04 and 0.1 g L-1, respectively, the negative effects of As(III) on rice were reduced. Treatment with 0.2 g L-1 PS or PTFE, combined with As(III), had a higher impact on rice than the application of As(III) alone. PS and PTFE reduced As(III) uptake, and absorbed As decreased with the increasing concentration of microparticles. The underlying mechanisms for these effects may involve direct adsorption of As, competition between As and microplastic particles for adsorption sites on the root surface, and inhibition of root activity by microplastic particles.


Assuntos
Arsênico , Microplásticos , Oryza , Plântula , Poluentes do Solo , Arsênico/toxicidade , Peróxido de Hidrogênio/metabolismo , Microplásticos/toxicidade , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade
14.
Ecotoxicol Environ Saf ; 190: 110133, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31896473

RESUMO

Microplastics (MP) are receiving increased attention as a harmful environmental pollutant, however information on the reproduction toxicity of MP in terrestrial animals, especially mammals, is limited. In this experiment, we investigated the impact of polystyrene microplastics (micro-PS) on the reproductive system of male mice. Healthy Balb/c mice were exposed to saline or to different doses of micro-PS for 6 weeks. The results showed that micro-PS exposure resulted in a significant decrease in the number and motility of sperm, and a significant increase in sperm deformity rate. We also detected a decrease in the activity of the sperm metabolism-related enzymes, succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH), and a decrease in the serum testosterone content in the micro-PS exposure group. We found that micro-PS exposure caused oxidative stress and activated JNK and p38 MAPK. In addition, we found that when N-acetylcysteine (NAC) scavenges ROS, and when the p38 MAPK-specific inhibitor SB203580 inhibits p38MAPK, the micro-PS-induced sperm damage is alleviated and testosterone secretion improves. In conclusion, our findings suggest that micro-PS induces reproductive toxicity in mice through oxidative stress and activation of the p38 MAPK signaling pathways.


Assuntos
Microplásticos/toxicidade , Estresse Oxidativo/fisiologia , Poliestirenos/toxicidade , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Acetilcisteína/farmacologia , Animais , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Plásticos , Reprodução/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Espermatozoides/metabolismo
15.
Toxicol Lett ; 324: 75-85, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31954868

RESUMO

With the increased distribution of microplastics in the environment, the potential for harmful effects on human health and ecosystems have become a global concern. Considering that polyethylene microplastics (PE-MPs) are among the most produced plastics worldwide, we administered PE-MPs (0.125, 0.5, 2 mg/day/mouse) by gavage to mice (10 mice/sex/dose) for 90 days. Compared to control, the body weight gain was significantly reduced in the male mice, and the proportion of neutrophils in the blood stream clearly increased in both sexes of mice. Persistence of a PE-MPs-like material and migration of granules to the mast cell membrane and accumulation of damaged organelles were observed in the stomachs and the spleens from the treated dams, respectively. Additionally, the IgA level in the blood stream was significantly elevated in the dams administered with PE-MPs compared to control, and the subpopulation of lymphocytes within the spleen was altered. Following, we performed an additional study to screen the effects of PE-MPs on reproduction and development (5 mice/sex/dose). Importantly, number of live births per dam, the sex ratio of pups, and body weight of pups was notably altered in groups treated with PE-MPs compared to the control group. Additionally, PE-MPs affected the subpopulation of lymphocytes within the spleen of the offspring, as did in the dams. Therefore, we propose that reproductive and developmental toxicity testing is warranted to evaluate the safety of microplastics. Additionally, we suggest that the IgA level may be used as a biomarker for harmful effects following exposure on microplastics.


Assuntos
Feto/efeitos dos fármacos , Microplásticos/toxicidade , Polietileno/toxicidade , Reprodução/efeitos dos fármacos , Animais , Biomarcadores/sangue , Peso Corporal/efeitos dos fármacos , Feminino , Imunoglobulina A/sangue , Masculino , Camundongos , Camundongos Endogâmicos ICR
16.
Aquat Toxicol ; 220: 105396, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31927063

RESUMO

Fish studies report consumption of microplastics (MPs) in the field, and concern exists over associated risks. However, laboratory studies with adult fish are scarce. In this study, outbred and see-through Japanese medaka (Oryzias latipes) were fed diets amended with 500, 1000, or 2000 µg/g 10 µm fluorescent spherical polystyrene microplastics (MPs) for 10 weeks during their maturation from juveniles to spawning adults. No behavioral changes, growth differences, or mortalities occurred. In vivo examinations and histologic sections showed no evidence of translocation of MPs from the gut to other internal organs. Mature females experienced dose-dependent decreases in egg number. Scanning electron microscopic examination of gills and gut revealed MPs in both areas. Swollen enterocytes were observed on apices of gut folds only in exposed fish. These were particularly apparent in foreguts of the high exposure group. Enterocytes with eroded brush borders were found in foregut of high and medium exposure groups. Increased mucus production, in long strands and sheets, was seen over primary and secondary lamellae of gills. Histological analysis showed alteration in buccal cavity, kidney, and spleen. Thickening and roughening of epithelium in headgut and pharynx and cellular alterations in spleen occurred. Head kidney was the primary site of alteration. Glomerulopathy and nephrogenesis were observed in exposed fish, increasing in severity with exposure level.


Assuntos
Exposição Dietética/efeitos adversos , Microplásticos/toxicidade , Oryzias/crescimento & desenvolvimento , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Exposição Dietética/análise , Feminino , Brânquias/química , Brânquias/efeitos dos fármacos , Mucosa Intestinal/química , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Masculino , Microplásticos/análise , Poliestirenos/análise , Baço/química , Baço/efeitos dos fármacos , Baço/patologia , Poluentes Químicos da Água/análise
17.
Chemosphere ; 247: 125874, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31945722

RESUMO

Over 90% of microplastics that enter wastewater treatment plants end in the wasted activated sludge. The effect of microplastic abundance on the activated sludge anaerobic digestion has been rarely reported. This study investigated the methane production performance during anaerobic digestion with different abundance of microplastic doses (0, 1,000, 3,000, 6,000, 10,000, 30,000, 60,000, 100,000 and 200,000 polyester particle/kg activated sludge). The methane production was reduced to 88.53 ± 0.5%, 90.09 ± 1.2%, 89.95 ± 4.7%, 95.08 ± 0.5%, 90.29 ± 0.5%, 93.16 ± 0.8%, 92.92 ± 1.3%, and 92.72 ± 0.6% as compared with control after digestion for 59 days. The methane production of all conditions was fitted with the logarithm model (R2 > 0.95) and one-substrate model (R2 > 0.99). The predicted and actual methane production values of digestion for 59 days had high correlation in all conditions with R2 > 0.95. The analysis based on the biochemical methane potential test model indicated that the methane production potential (B0) and hydrolysis coefficient (k) decreased at nearly all tested conditions. The reactor digestate with microplastics retained higher organic matter and nutrient concentration and had slightly lower dewaterability than the control. The inhibition of methane production potential could be attributed to the incomplete digestion with the existence of microplastics. The microbial community showed no significant difference with and without microplastics.


Assuntos
Anaerobiose/efeitos dos fármacos , Microplásticos/toxicidade , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/toxicidade , Reatores Biológicos , Hidrólise , Metano/biossíntese , Plásticos , Esgotos , Águas Residuárias
18.
Chemosphere ; 247: 125903, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31958647

RESUMO

The partial nitrification efficiency response to the presence of cadmium (Cd2+) and microplastics was investigated. Microplastics polyvinylchloride (PVC) abundance was 0-10,000 particles/L, and Cd2+ concentration was 0-10 mg/L. Cd-only inhibited the NH4+-N oxidation rate 1.21, 1.23, and 1.18 times with concentrations at 1, 5, and 10 mg/L, respectively. PVC-only inhibited NH4+-N oxidation rate 1.01, 1.21 and 1.05 times with PVC abundance at 1000, 5000 and 10,000 particles/L, respectively. The ammonia oxidation rate was improved with the co-existence of PVC and Cd2+ at the conditions PVC1000 and PVC5000, which could be attributed to the PVC. PVC at 1000 particles/L could act as carrier and mitigate the negative effect of Cd2+ to the partial nitrification process. Moreover, the partial nitrification process was largely inhibited with PVC abundance at 10,000 particles/L. First-order kinetic models could simulate the NH4+-N, NO2-N, and NO3--N changes in the partial nitrification process.


Assuntos
Microplásticos/toxicidade , Nitrificação/efeitos dos fármacos , Cloreto de Polivinila/toxicidade , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/toxicidade , Amônia , Reatores Biológicos , Cádmio , Cinética , Nitrogênio , Oxirredução , Plásticos
19.
Environ Pollut ; 260: 113978, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31991353

RESUMO

Understanding the effects of plastic debris on marine ecosystems is essential in encouraging decision-makers to take action. The present study investigates the effect of a 24 h experimental exposure to high density polyethylene (HDPE) microplastics (MPs) of different sizes (4-6, 11-13 and 20-25 µm) and at three concentrations (0.1, 1 and 10 mg MP.L-1) on the development and locomotor activity of early stages of Pacific oyster, Crassostrea gigas. The bivalve embryo-larval assay (NF ISO 17244, 2015) was used in this study but with additional toxicity criteria: developmental arrests, abnormal D-larvae, maximum speed and swimming trajectory. Copper (Cu), was used as a positive control. Our results show that smaller MPs (4-6 and 11-13 µm) induced higher rates of malformations and developmental arrests than the larger ones (20-25 µm). In addition, a dose-dependent decrease of maximum swimming speed was observed for larvae exposed to MPs of 4-6 and 11-13 µm. On the other hand, there was no significant difference in swimming speed with the largest MPs size tested (20-25 µm). For all three sizes of MPs, there was a decrease in straight-line swimming trajectories, and an increase in circular trajectories. This abnormal swimming behaviour could affect larvae survival as well as colonization of new habitats.


Assuntos
Crassostrea/fisiologia , Microplásticos/toxicidade , Polietileno/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecossistema , Larva , Tamanho da Partícula , Plásticos , Natação
20.
Chemosphere ; 244: 125500, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31809926

RESUMO

Microplastics (MPs) are contaminants of increasing concern; they are abundant, ubiquitous and persistent over time, representing potential risks for organisms and ecosystems. However, such risks are still virtually unknown for amphibians, despite the particular attention that these organisms often receive because of their global decline. We examined the effects of MPs (fluorescent, 10-µm polystyrene microspheres) at different concentrations (from 0 to 103 particles mL-1) on tadpoles of the common midwife toad, Alytes obstetricans, using a microcosm experiment. We assessed MP effects on tadpole feeding, growth and body condition, as well as their ingestion and egestion of MPs (estimated through fluorescence). Additionally, we explored whether MPs became attached to periphyton (the main food source for these tadpoles, thus potentially representing a major way of MP ingestion), and the effect of MPs on periphyton growth (which may translate into altered freshwater ecosystem functioning). Our results showed significant effects on all the examined variables, and caused tadpole mortality at the highest concentration; also, fluorescence indicated the presence of MPs in tadpoles, tadpole faeces and periphyton. This suggests that MPs can be an important source of stress for amphibians in addition to other pollutants, climate change, habitat loss or chytrid infections, and that amphibians can be a major transfer path for MPs from freshwater to terrestrial ecosystems.


Assuntos
Anuros/fisiologia , Ecossistema , Larva/efeitos dos fármacos , Microplásticos/toxicidade , Animais , Água Doce/química , Larva/crescimento & desenvolvimento , Perifíton/efeitos dos fármacos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
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