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1.
Chemosphere ; 249: 126564, 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32213389

RESUMO

Pb-based perovskite nanoparticles (PbPNPs) are amongst others used within highly efficient solar cells. PbPNPs can be released into the environment during their production, recycling or waste processing. In this study we investigated the fate and toxicity of PbPNPs on soil bacterial community under simulated natural environmental conditions across a range of pH, humic acid, and divalent cation concentrations. Increasing pH decreased PbPNPs-particle aggregation as well as Pb-ion release. The presence of only humic acid (HA) prevented the aggregation of PbPNPs-particles, whereas the presence of only divalent cations promoted the aggregation of PbPNPs-particles. The amount of Pb-ions released from the PbPNPs-particles was reduced in the presence of either HA or the divalent cations. Results of toxicity testing of PbPNPs by determining the metabolic potential of a bacterial community indicated that increasing pH alleviated particle toxicity. The presence of only HA reduced the toxicity of PbPNPs, while the presence of only divalent cations enhanced the particle toxicity. The coexistence of HA and divalent cations enhanced PbPNPs aggregation and reduced toxicity, with both Pb-ions and the interaction between the PbPNPs-particles and bacterial cells contributing to the toxic effects. Our study emphasized that environmental conditions play important roles that influencing the fate and toxicity of PbPNPs.

2.
Environ Pollut ; 261: 114117, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32062092

RESUMO

Whether toxicity of silver nanoparticles (AgNPs) to organisms originates from the nanoparticles themselves or from the dissolved Ag-ions is still debated, with the majority of studies claiming that extracellular release of Ag-ions is the main cause of toxicity. The objective of this study was to determine the contributions of both particles and dissolved ions to toxic responses, and to better understand the underlying mechanisms of toxicity. In addition, the pathways of AgNPs exposure to plants might play an important role and therefore are explicitly studied as well. We systematically assessed the phytotoxicity, internalization, biodistribution, and antioxidant responses in lettuce (Lactuca sativa) following root or foliar exposure to AgNPs and ionic Ag at various concentrations. For each endpoint the relative contribution of the particle-specific versus the ionic form was quantified. The results reveal particle-specific toxicity and uptake of AgNPs in lettuce as the relative contribution of particulate Ag accounted for more than 65% to the overall toxicity and the Ag accumulation in whole plant tissues. In addition, particle toxicity is shown to originate from the accumulation of Ag in plants by blocking nutrient transport, while ion toxicity is likely due to the induction of excess ROS production. Root exposure induced higher toxicity than foliar exposure at comparable exposure levels. Ag was found to be taken up and subsequently translocated from the exposed parts of plants to other portions regardless of the exposure pathway. These findings suggest particle related toxicity, and demonstrate that the accumulation and translocation of silver nanoparticles need to be considered in assessment of environmental risks and of food safety following consumption of plants exposed to AgNPs by humans.

3.
Sci Total Environ ; 708: 135134, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31796277

RESUMO

Organic-inorganic perovskite solar cells (PSCs) are promising candidates as photovoltaic cells. Recently, they have attracted significant attention due to certified power conversion efficiencies exceeding 23%, low-cost engineering, and superior electrical/optical characteristics. These PSCs extensively utilize a perovskite-structured composite with a hybrid of Pb-based nanomaterials. Operation of them may cause the release of Pb-based nanoparticles. However, limited information is available regarding the potential toxicity of Pb-based PSCs on various organisms. This study conducted a battery of in vitro and in vivo toxicity bioassays for three quintessential Pb-based PSCs (CH3NH3PbI3, NHCHNH3PbBr3, and CH3NH3PbBr3) using progressively more complex forms of life. For all species tested, the three different perovskites had comparable toxicities. The viability of Caco-2/TC7 cells was lower than that of A549 cells in response to Pb-based PSC exposure. Concentration-dependent toxicity was observed for the bioluminescent bacterium Vibrio fischeri, for soil bacterial communities, and for the nematode Caenorhabditis elegans. Neither of the tested Pb-based PSCs particles had apparent toxicity to Pseudomonas putida. Among all tested organisms, V. fischeri showed the highest sensitivity with EC50 values (30 min of exposure) ranging from 1.45 to 2.91 mg L-1. Therefore, this study recommends that V. fischeri should be preferably utilized to assess. PSC toxicity due to its increased sensitivity, low costs, and relatively high throughput in a 96-well format, compared with the other tested organisms. These results highlight that the developed assay can easily predict the toxic potency of PSCs. Consequently, this approach has the potential to promote the implementation of the 3Rs (Replacement, Reduction, and Refinement) principle in toxicology and decrease the dependence on animal testing when determining the safety of novel PSCs.

4.
Ecotoxicol Environ Saf ; 188: 109882, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31698175

RESUMO

Microplastics attract widespread attention, including for their potential to transport toxic chemicals in the form of plasticisers and associated hydrophobic organic chemicals, such as polybrominated diphenyl ethers (PBDEs). The aims of this study were to investigate how nylon (polyamide) microplastics may affect PBDE accumulation in snails, and the acute effects of nylon particles and PBDEs on survival, weight change and inherent microbiome diversity and community composition of the pond snail Lymnaea stagnalis. Snails were exposed for 96 h to BDEs-47, 99, 100 and 153 in the presence and absence of 1% w/w nylon microplastics in quartz sand sediment. No mortality was observed over the exposure period. Snails not exposed to microplastics lost significantly more weight compared to those exposed to microplastics. Increasing PBDE concentration in the sediment resulted in an increased PBDE body burden in the snails, however microplastics did not significantly influence total PBDE uptake. Based on individual congeners, uptake of BDE 47 by snails was significantly reduced in the presence of microplastics. The diversity and composition of the snail microbiome was not significantly altered by the presence of PBDEs nor by the microplastics, singly or combined. Significant effects on a few individual operational taxonomic units (OTUs) occurred when comparing the highest PBDE concentration with the control treatment, but in the absence of microplastics only. Overall within these acute experiments, only subtle effects on weight loss and slight microbiome alterations occurred. These results therefore highlight that L. stagnalis are resilient to acute exposures to microplastics and PBDEs, and that microplastics are unlikely to influence HOC accumulation or the microbiome of this species over short timescales.


Assuntos
Éteres Difenil Halogenados/metabolismo , Lymnaea/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo , Animais , Carga Corporal (Radioterapia) , Exposição Ambiental/análise , Retardadores de Chama/análise , Retardadores de Chama/metabolismo , Retardadores de Chama/toxicidade , Éteres Difenil Halogenados/análise , Éteres Difenil Halogenados/toxicidade , Lymnaea/metabolismo , Lymnaea/microbiologia , Nylons/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
5.
Chemosphere ; 239: 124731, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31499303

RESUMO

The fish bioconcentration factor (BCF) is an important aspect within bioaccumulation assessments. Several factors have been suggested to influence BCF values - including species, developmental stage, mixture exposure, and calculation method. However, their exact contribution to variance in BCF values is unknown. Within this study we assessed the relative impact of these test characteristics on BCF values and analyzed the reproducibility of aquatic exposure bioconcentration tests. Linear mixed effects analyses were performed on a newly develop database to investigate the relationship between the response variable (i.e. lipid normalized log BCF values) and several test characteristics as fixed effects. Lower BCF values were observed for substances that were simultaneously applied with high molecular weight polycyclic aromatic hydrocarbons compared to single substance exposure (with an average difference of -0.81 log BCF). Also, lower BCFs upon kinetic determination were observed compared to steady-state BCFs (log BCF -0.27), and lower BCFs for species from the Ostariophysi subcohort level (log BCF -0.17 to -0.15). In addition, data analysis showed high variation within BCF values for single substances (average SD = log BCF 0.21), which questions the robustness of the current bioaccumulation assessments. For example, the 95% confidence range of a BCF value of 2500 ranges from 953 ('not-bioaccumulative') to 6561 ('very bioaccumulative'). Our results show that the use of one single BCF leads to a high uncertainty in bioaccumulation assessments. We strongly recommend that within future bioconcentration studies, the used experimental design and test conditions are described in detail and justified to support solid interpretation.


Assuntos
Ecotoxicologia/métodos , Peixes , Poluentes Químicos da Água/farmacocinética , Animais , Bioacumulação , Exposição Ambiental/análise , Cinética , Peso Molecular , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
6.
Chemosphere ; 245: 125612, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31864948

RESUMO

Humic substances are the dominant dissolved organic matter fraction in the aqueous phase of environmental media. They would inevitably react with chemicals released into the environment. The influence of dissolved humic acid (DHA) on the dissolution and dispersion of copper oxide nanoparticles (CuO NPs, 50 nm, 49.57 mg L-1) was therefore investigated in the present study. In addition to dispersing CuO NPs and reducing the size of the aggregates, the amount of released Cu from CuO NPs was found to increase over time with increasing concentrations of DHA, 96% of which was present as organic complexes after 72 h. At DHA concentrations exceeding 16.09 mg C L-1, the complexation coefficients of DHA with Cu and the adsorptivity of CuO NPs to DHA were both reduced due to increased homo-conjugation of DHA as promoted by negative charge-assisted H-bond. Although the adsorption capacity of DHA kept increasing up to 57.07 mg C L-1, the hydrodynamic diameter and ζ-potential were similar and the percentages of total released Cu continued to increase linearly to 4.92% at higher levels of DHA (30.13-57.07 mg C L-1). Thereupon, DHA promoted the dissolution of CuO NPs in a concentration-dependent fashion. The driving force was complexation of Cu by DHA, rather than the balancing between the exposed and the covered surface area of the CuO NPs due to DHA adsorption. Our findings facilitate understanding the underlying mechanisms on how DHA impacts the CuO NPs environmental behavior (or fate) as well as on their kinetics.

7.
Nanotoxicology ; : 1-16, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31775550

RESUMO

We systematically investigated how the combinations of size, shape and the natural organic matter (NOM)-ecocorona of gold (Au) engineered nanoparticles (ENPs) influence the attachment of the particles to algae and physical toxicity to the cells. Spherical (10, 60 and 100 nm), urchin-shaped (60 nm), rod-shaped (10 × 45, 40 × 60 and 50 × 100 nm), and wire-shaped (75 × 500, 75 × 3000 and 75 × 6000 nm) citrate-coated and NOM-coated Au-ENPs were used. Among the spherical particles only the spherical 10 nm Au-ENPs caused membrane damage to algae. Only the rod-shaped 10 × 45 nm induced membrane damage among the rod-shaped Au-ENPs. Wire-shaped Au-ENPs caused no membrane damage to the algae. NOM ecocorona decreased the membrane damage effects of spherical 10 nm and rod-shaped 10 × 45 nm ENPs. The spherical Au-ENPs were mostly loosely attached to the cells compared to other shapes, whereas the wire-shaped Au-ENPs were mostly strongly attached compared to particles with other shapes. NOM ecocorona determined the strength of Au-ENPs attachment to the cell wall, leading to the formation of loose rather than strong attachment of Au-ENPs to the cells. After removal of the loosely and strongly attached Au-ENPs, some particles remained anchored to the surface of the algae. The highest concentration was detected for spherical 10 nm Au-ENPs followed by rod-shaped 10 × 45 nm Au-ENPs, while the lowest concentration was observed for the wire-shaped Au-ENPs. The combined effect of shape, size, and ecocorona controls the Au-ENPs attachment and physical toxicity to cells.

8.
Environ Pollut ; 255(Pt 2): 113304, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31586909

RESUMO

Suitable methods and fit-for-purpose techniques are required to allow characterization of carbon-based nanomaterials (CB-NMs) in complex matrices. In this study, two methods were developed; a method for extraction and characterization of CB-NMs in biological media and a method for fractionation of natural organic matter (NOM) coated CB-NMs in environmental matrices. The former method was developed by extracting carbon nanotubes (CNTs: sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 600 nm) from eggshells and characterizing the extracted CB-NMs in terms of particle size distribution using asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS). The latter method was developed using AF4-MALS to fraction NOM-coated CNT (sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 300 nm) in a simulated natural surface water and provide information about the size distribution of the CB-NM-NOM complexes. The developed AF4-MALS method successfully fractioned the CB-NM-NOM complexes based on hydrodynamic size and provided the size distribution of the complexes. The NOM corona did not shift significantly the median size of the CB-NMs. It influenced however the size distribution of the nanoplastics and CNTs. The sample preparation method failed to extract the CNTs (recovery < 20%) from the matrices of the eggshells while being successful for extracting the nanoplastics (recoveries > 60%). The AF4-MALS fractogram showed that the extraction method did not significantly influence the size distribution of the nanoplastics of 60 and 200 nm size, whereas the peak of 600 nm nanoplastics shifted towards a smaller hydrodynamic size. In conclusion, the developed sample preparation method followed by the developed AF4-MALS method can be applied for extraction, separation and characterization of CB-NMs in biological and environmental matrices. Thus, the methods have a high potential to be methods of choice to investigate CB-NMs in future studies.


Assuntos
Monitoramento Ambiental , Nanotubos de Carbono/química , Plásticos/química , Fracionamento por Campo e Fluxo , Luz , Tamanho da Partícula , Espalhamento de Radiação , Água
9.
Commun Biol ; 2: 382, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31646185

RESUMO

Plastic nanoparticles originating from weathering plastic waste are emerging contaminants in aquatic environments, with unknown modes of action in aquatic organisms. Recent studies suggest that internalised nanoplastics may disrupt processes related to energy metabolism. Such disruption can be crucial for organisms during development and may ultimately lead to changes in behaviour. Here, we investigated the link between polystyrene nanoplastic (PSNP)-induced signalling events and behavioural changes. Larval zebrafish exhibited PSNP accumulation in the pancreas, which coincided with a decreased glucose level. By using hyperglycemic and glucocorticoid receptor (Gr) mutant larvae, we demonstrate that the PSNP-induced disruption in glucose homoeostasis coincided with increased cortisol secretion and hyperactivity in challenge phases. Our work sheds new light on a potential mechanism underlying nanoplastics toxicity in fish, suggesting that the adverse effect of PSNPs are at least in part mediated by Gr activation in response to disrupted glucose homeostasis, ultimately leading to aberrant locomotor activity.

10.
Environ Res ; 178: 108713, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31518961

RESUMO

Titanium dioxide nanoparticles (TiO2NP) are increasingly released in soil ecosystems, while there is limited understanding of the impacts of TiO2NP on soil bacterial communities. Here we investigated the effects of TiO2NP on the taxonomic composition and functional profile of a soil bacterial community over a 60-day exposure period. In short-term exposure (1-day), contradictory effects on the taxonomic composition of soil bacterial communities were found after exposure to a low realistic environmental concentration of TiO2NP at 1 mg/kg as compared to the effects induced by medium and high concentrations of TiO2NP at 500 and 2000 mg/kg. After long-term exposure (60-day), the negative effects of TiO2NP at the low concentration disappeared, and the inhibition by TiO2NP of the abundance of core taxa was enhanced along with increasing exposure concentrations. However, although significant alterations were observed in the taxonomic composition over time and exposure concentrations, no significant change was observed in the community functional profile as well as enzyme activity after 60-day exposure, indicating that functional redundancy likely contributed to the bacterial community tolerance after the exposure to TiO2NP. Our study highlighted the importance of assessing bacterial community compositional and functional responses in assessing the environmental risk of nanoparticles on soil ecosystems.

11.
Sci Total Environ ; 691: 36-44, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31306875

RESUMO

Although it is widely acknowledged that a decline of freshwater biodiversity jeopardizes the functioning of freshwater ecosystems, the large number of (human-induced) pressures jointly acting on these systems hampers managing its biodiversity. To disentangle the magnitude and the temporal effects of these single and interacting pressures, experiments are required that study how these pressures affect the structuring of natural communities. We performed experiments with naturally assembled invertebrate communities in 36 experimental ditches to assess the single and joint effects of environmentally relevant concentrations of two commonly co-occurring stressors: fertilizer inputs and neonicotinoid insecticides, in this case thiacloprid. Specifically, we explored whether these agrochemicals result in sustained changes in community structure by inspecting divergence, convergence and short- /long-lived dissimilarity of communities, when compared to a control treatment. Our results indicate strong impacts on the abundance of different taxa by exposure to the agrochemicals. However, we found no effect of any treatment on total abundance, taxon richness or convergence/divergence (measured as beta dispersion) of the communities. Moreover, we found contrasting responses when both joint stressors were present: when considering abundance of different taxa, we observed that fertilizer additions reduced some of the thiacloprid toxicity. But when assessing the community structure, we found that exposure to both stressors consistently resulted in a more dissimilar community compared to the control. This dissimilarity was persistent up to four months after applying the agrochemicals, even though there was a turnover in taxa explaining this dissimilarity. This turnover indicates that the persistent dissimilarity can potentially be attributed to a rippling effect in the community rather than continued toxicity. Such shifts in natural freshwater invertebrate communities, months after the actual exposure, suggests that stressors may have important long-term repercussions for which may subsequently lead to changes in ecosystem functioning.


Assuntos
Organismos Aquáticos/fisiologia , Ecossistema , Monitoramento Ambiental , Fertilizantes/análise , Inseticidas/análise , Invertebrados/fisiologia , Neonicotinoides/análise , Poluentes Químicos da Água/análise , Animais , Biodiversidade , Água Doce
12.
Sci Total Environ ; 689: 133-140, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31271982

RESUMO

Some metal-based engineered nanoparticles (ENPs) undergo fast dissolution and/or aggregation when they are released in the environment. The underlying processes are controlled by psychochemical/biological parameters of the environment and the properties of the particles. In this study, we investigated the interaction between algal cells and zero valent copper nanoparticles (Cu0-ENPs) to elucidate how the cells influence the dissolution and aggregation kinetics of the particles and how these kinetics influence the cellular uptake of Cu. Our finding showed that the concentration of dissolved Cu ([Cu]dissolved) in the supernatant of the culture media without algal cells was higher than the [Cu]dissolved in the media with algal cells. In the absence of the cells, dissolved organic matter (DOC) increased the dissolution of the particle due to increasing the stability of the particles against aggregation, thus increasing the available surface area. In the presence of algae, Cu0-ENPs heteroaggregated with the cells. Thus, the available surface area decreased over time and this resulted in a low dissolution rate of the particles. The DOC corona on the surface of the particles increased the heteroaggregation of the particles with the cells and decreases the uptake of the particles. Our findings showed that microorganisms influence the fate of ENPs in the environment, and they do so by modifying the dissolution and aggregation kinetics of the Cu0-ENPs.


Assuntos
Clorofíceas/metabolismo , Cobre/metabolismo , Nanopartículas Metálicas , Clorofíceas/efeitos dos fármacos , Liberação Controlada de Fármacos , Substâncias Húmicas/análise , Cinética , Solubilidade
13.
Chemosphere ; 227: 366-370, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30999176
14.
Environ Pollut ; 249: 638-646, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30933761

RESUMO

Microplastics (<5 mm) are distributed ubiquitously in natural environments. The majority of microplastics in aquatic environments are shown to have rough surfaces due to various weathering processes (secondary microplastics; SMP), while laboratory studies predominantly utilise pristine microplastics (primary microplastics; PMP). Here we present the results from a study comparing the chronic effects of pristine PMP and artificially weathered SMP to three different Cladoceran species (Daphnia magna, Daphnia pulex, Ceriodaphnia dubia). We assessed the impact of PMP and SMP on reproductive output using various measured parameters, including time of first brood, size of first brood, size of first three broods, cumulative number of neonates, total number of broods and terminal length of test animals. Our results show that reproductive output of all species declined in a dose-dependent manner. The No Observed Effect Concentration (NOEC) was less than the lowest tested concentration (102 p/mL) for at least one measured endpoint for all species and both PMP and SMP. Further, it was inferred that species sensitivity varied inversely with body size for most endpoints, resulting in C. dubia being the most sensitive species; and D. magna being the least sensitive species under study. In addition, PMP appeared to have greater toxic potential as compared to SMP. This study is the first to directly compare the chronic toxicity of both pristine and weathered microplastic particles on three freshwater toxicological model organisms. Our results indicate that sensitivity in reproduction and growth to microplastics may differ between species and type of microplastic exposed; highlighting the importance of using multiple species and structural types of particles.


Assuntos
Cladóceros/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Nanopartículas/toxicidade , Plásticos/toxicidade , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais
15.
Chemosphere ; 226: 841-850, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30974377

RESUMO

The combined effects of pH, dissolved organic carbon (DOC) and Ca2+/Mg2+ on the dissolution and aggregation kinetics of zero valent copper engineered nanoparticles (Cu0 ENPs) were investigated. The dissolution and aggregation of the particles were studied in (a) synthetic aqueous media, similar in chemistry to natural surface waters, and (b) natural surface waters samples, for up to 32 or 24 h. The DOC stabilized the particles and prevented aggregation, and thus increased the available surface area. The higher available surface area in turn accelerated the dissolution of the particles. The presence of Ca2+/Mg2+, however, changed the aggregation and the dissolution of the DOC-stabilized particles. The influence of Ca2+/Mg2+ on DOC-stabilized particles was different at different pH's. In the absence of DOC, 10 mM of Ca2+/Mg2+ induced charge reversal on the particles and caused particle stability against aggregation. This subsequently increased particles dissolution. The results obtained with regard to dissolution and aggregation of the particles in natural surface waters were compared with those determined for the synthetic waters. This comparison showed that the behavior of the particles in the natural surface waters was mostly similar to the behavior determined for media at pH 9. Overall, the current study provides some novel insights into the simultaneous effects of physicochemical parameters of water on particle stability against aggregation and dissolution, and provides data about how the processes of aggregation and dissolution of Cu0 ENPs interact and jointly determine the overall particle fate.


Assuntos
Cobre/química , Água Doce/química , Nanopartículas Metálicas/química , Cálcio , Cátions Bivalentes/farmacologia , Concentração de Íons de Hidrogênio , Cinética , Magnésio , Compostos Orgânicos/farmacologia , Concentração Osmolar , Solubilidade
16.
Chemosphere ; 226: 774-781, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30965248

RESUMO

The impacts of nano- and microplastics (<100 nm and <5 mm, respectively) on terrestrial systems is to the present largely unexplored. Plastic particles are likely to accumulate in these systems primarily by the application of sewage sludge. The aim of the current study was to investigate the effects of three sizes of plastic particles (50, 500, and 4800 nm) on a terrestrial plant (cress; Lepidium sativum), using a standardized 72 h bioassay. Cress seeds were exposed to five different concentrations of plastics, ranging from 103 to 107 particles mL-1. Germination rate was significantly reduced after 8 h of exposure for all three sizes of plastics, with increased adverse effect with increasing plastic sizes. Seeds exposed to 4800 nm microplastics showed a germination rate decline from 78% in control to 17% in the highest exposure. No difference in germination rate occurred after 24 h of exposure, regardless of the size of the plastic used. Significant differences in root growth were observed after 24 h, but not after 48 or 72 h of exposure. Impacts on germination are likely due to physical blockage of the pores in the seed capsule by microplastics as shown by confocal microscopy of fluorescent microplastics. In later stages, the microplastics particularly accumulated on the root hairs. This is the first detailed study on the effect of nano- and microplastics on a vascular, terrestrial plant, and our results indicate short-term and transient adverse effects.


Assuntos
Lepidium sativum/efeitos dos fármacos , Plásticos/toxicidade , Sementes/efeitos dos fármacos , Brassicaceae , Germinação/efeitos dos fármacos , Tamanho da Partícula , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plásticos/metabolismo , Plásticos/farmacologia
17.
Environ Pollut ; 250: 669-675, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31035149

RESUMO

Even though microplastics are intensively studied, the focus of the research is mainly on relatively short term effects at high doses. Therefore there is a need to shift the focus toward more realistic, longer-term endpoints. Studies with a range of chemicals have shown that the response of populations often differs from studies in which a single organism is exposed in an individual container (as often described within standard ecotox screening assays). Here we investigate the impact of primary microplastics (1-5 µm in size) on a population of Daphnia magna. We first allowed a stable population of D. magna to develop over 29 d, after which the populations were exposed to microplastics for three weeks (concentrations ranging from 102 to 105 particles mL-1 and a control). We found a significant impact of microplastics on the total population of D. magna, with a reduction in the amount of adult daphnids. Importantly, when expressed as total biomass, exposure to 105 microplastics mL-1 resulted in a 21% reduction in total biomass compared to control. These results indicate that exposure to microplastics can result in significant adverse effects on the population of D. magna, including a reduction in the number of individuals as well as total biomass. Given the importance of D. magna in freshwater food webs, both as a grazer as well as a food source, this can potentially impact the functioning of the ecosystem.


Assuntos
Daphnia/efeitos dos fármacos , Plásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomassa , Daphnia/crescimento & desenvolvimento , Ecossistema , Água Doce/química , Plásticos/análise , Poluentes Químicos da Água/análise
18.
Artigo em Inglês | MEDLINE | ID: mdl-30871202

RESUMO

Concerns about the adverse public health consequences of informal electronic waste (e-waste) recycling are increasing. This study adopted a cross-sectional study design to gain insights into health risks (cancer and non-cancer risks) associated with exposure to e-waste chemicals among informal e-waste workers via three main routes: Dermal contact, ingestion, and inhalation. The e-waste chemicals (PBDE and metals) were measured in the dust and top soils at e-waste sites (burning, dismantling, and repair sites). Adverse health risks were calculated using the EPA model developed by the Environmental Protection Agency of the United States. The concentrations of the e-waste chemicals and the health risks at the e-waste sites increased as the intensity of the e-waste recycling activities increased: control sites < repair sites < dismantling sites < burning sites. Dermal contact was the main route of exposure while exposure via inhalation was negligible for both carcinogenic and non-carcinogenic risks. Cumulative health risks via all routes of exposure (inhalation, ingestion, and dermal contact) exceeded the acceptable limits of both non-cancer effects and cancer risk at all e-waste sites. This indicates that overall the e-waste workers are at the risk of adverse health effects. Therefore, the importance of occupational safety programs and management regulations for e-waste workers cannot be over emphasised.


Assuntos
Resíduo Eletrônico/análise , Exposição Ambiental , Éteres Difenil Halogenados/toxicidade , Reciclagem , China , Estudos Transversais , Monitoramento Ambiental , Humanos , Nigéria , Medição de Risco
19.
Sci Total Environ ; 660: 1283-1293, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30743923

RESUMO

To promote the safer by design strategy and assess environmental risks of engineered nanoparticles (ENPs), it is essential to understand the fate of ENPs within organisms. This understanding in living organisms is limited by challenges in characterizing and quantifying ENPs in biological media. Relevant literature in this area is scattered across research from the past decade or so, and it consists mostly of medically oriented studies. This review first introduces those modern techniques and methods that can be used to extract, characterize, and quantify ENPs in biological matrices for (eco)toxicological purposes. It then summarizes recent research developments within those areas most relevant to the context and field that are the subject of this review paper. These comprise numerous in-situ techniques and some ex-situ techniques. The former group includes techniques allowing to observe specimens in their natural hydrated state (e.g., scanning electron microscopy working in cryo mode and high-pressure freezing) and microscopy equipped with elemental microanalysis (e.g., energy-dispersive X-ray spectroscopy); two-photon laser and coherent anti-Stokes Raman scattering microscopy; absorption-edge synchrotron X-ray computed microtomography; and laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The latter group includes asymmetric flow field flow fractionation coupled with ICP-MS and single particle-ICP-MS. Our review found that most of the evidence gathered for ENPs actually focused on a few metal-based ENPs and carbon nanotube and points to total mass concentration but no other particles properties, such as size and number. Based on the obtained knowledge, we developed and presented a decision scheme and analytical toolbox to help orient scientists toward selecting appropriate ways for investigating the (eco)toxicity of ENPs that are consistent with their properties.


Assuntos
Ecotoxicologia/métodos , Nanopartículas/análise , Ecotoxicologia/tendências , Terapia a Laser/métodos , Espectrometria de Massas/métodos , Microscopia Eletrônica , Nanopartículas/toxicidade , Nanotecnologia , Nanotubos de Carbono/toxicidade , Tomografia Computadorizada por Raios X/métodos
20.
Artigo em Inglês | MEDLINE | ID: mdl-30696044

RESUMO

Concerns about the adverse consequences of informal electronic waste (e-waste) recycling is increasing, because e-waste contains some hazardous substances such as polybrominated diphenyl ethers (PBDEs) which is used as flame retardants in electronics. There is dearth of information on the concentrations of PBDEs and the pattern of distribution at the various e-waste recycling sites in Nigeria. This study therefore measured the concentrations of 13 PBDE congeners, in top soils (0⁻10 cm) and in various dust samples from different e-waste recycling sites (burning, dismantling, repair). PBDE concentrations at e-waste sites were compared with the concentrations in samples from corresponding control sites in three study locations in Nigeria (Lagos, Ibadan, and Aba). There were significant differences in the level of PBDEs congeners between each of the e-waste recycling sites and the corresponding control sites. The levels of PBDEs at the e-waste recycling sites exceeded the levels at the controls sites by a factor of 100 s to 1000 s. In general, PBDE concentrations at the e-waste sites decreased with the intensity of the e-waste recycling activities: burning sites > dismantling sites > repair sites > control sites. Our results suggest that the informal e-waste recycling has negative impacts on the enviroment and human health.


Assuntos
Poeira/análise , Resíduo Eletrônico/análise , Éteres Difenil Halogenados/análise , Substâncias Perigosas/análise , Reciclagem , Poluentes do Solo/análise , Solo/química , Monitoramento Ambiental/métodos , Nigéria
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