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1.
Ecotoxicol Environ Saf ; 202: 110910, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800245

RESUMO

Microplastics (MPs) are ubiquitous in the environment and more abundant in the marine environment. Consequently, increasing focus has been put on MPs in oceans and seas, while little importance has been attached to their presence in freshwaters and soils. Therefore, this paper aimed to provide a comprehensive review of the occurrence, analysis and ecotoxicology of MPs. The abundance and distribution of MPs in several typical freshwater systems of China were summarized. It suggested that the surface water of Poyang Lake contained the highest concentration of 34 items/L MPs among all the 8 freshwater systems, and the content of MPs in sediments were higher than that of the surface water. Net-based zooplankton sampling methods are the most frequently utilized sampling methods for MPs, and density separation, elutriation and digestion are three major pretreatment methods. Fourier transform infrared spectroscopy, Raman spectroscopy and pyrolysis-gas chromatography coupled to mass spectrometry are often used to identify the polymer types of MPs. Besides, MPs might damage the digestive tract of various organisms and negatively inhibit their growth, feeding and reproduction. The ways of human exposure to MPs are by ingestion, inhalation and dermal exposure, digestive and respiratory system might be adversely influenced. However, potential health risks of MPs to humans are remained insufficiently researched. Overall, by showing the presence of MPs in freshwaters and soils as well as possible ecotoxicological effects on the environment and humans, this paper provided a framework for future research in this field.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais/análise , Microplásticos/análise , Animais , China , Ecotoxicologia , Monitoramento Ambiental/métodos , Poluentes Ambientais/toxicidade , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lagos/química , Microplásticos/toxicidade , Oceanos e Mares , Plásticos/química , Solo , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Zooplâncton
2.
PLoS One ; 15(7): e0236579, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735596

RESUMO

The pollution of the natural environment, especially the world's oceans, with conventional plastic is of major concern. Biodegradable plastics are an emerging market bringing along potential chances and risks. The fate of these materials in the environment and their possible effects on organisms and ecosystems has rarely been studied systematically and is not well understood. For the marine environment, reliable field test methods and standards for assessing and certifying biodegradation to bridge laboratory respirometric data are lacking. In this work we present newly developed field tests to assess the performance of (biodegradable) plastics under natural marine conditions. These methods were successfully applied and validated in three coastal habitats (eulittoral, benthic and pelagic) and two climate zones (Mediterranean Sea and tropical Southeast Asia). Additionally, a stand-alone mesocosm test system which integrated all three habitats in one technical system at 400-L scale independent from running seawater is presented as a methodological bridge. Films of polyhydroxyalkanoate copolymer (PHA) and low density polyethylene (LD-PE) were used to validate the tests. While LD-PE remained intact, PHA disintegrated to a varying degree depending on the habitat and the climate zone. Together with the existing laboratory standard test methods, the field and mesocosm test systems presented in this work provide a 3-tier testing scheme for the reliable assessment of the biodegradation of (biodegradable) plastic in the marine environment. This toolset of tests can be adapted to other aquatic ecosystems.


Assuntos
Ambiente Controlado , Oceanos e Mares , Plásticos/metabolismo , Biodegradação Ambiental , Cadeia Alimentar , Sedimentos Geológicos/química , Plásticos/química , Plásticos/isolamento & purificação , Água do Mar/química , Temperatura
3.
PLoS One ; 15(8): e0236410, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797095

RESUMO

The use and management of single use plastics is a major area of concern for the public, regulatory and business worlds. Focusing on the most commonly occurring consumer plastic items present in European freshwater environments, we identified and evaluated consumer-based actions with respect to their direct or indirect potential to reduce macroplastic pollution in freshwater environments. As the main end users of these items, concerned consumers are faced with a bewildering array of choices to reduce their plastics footprint, notably through recycling or using reusable items. Using a Multi-Criteria Decision Analysis approach, we explored the effectiveness of 27 plastic reduction actions with respect to their feasibility, economic impacts, environmental impacts, unintended social/environmental impacts, potential scale of change and evidence of impact. The top ranked consumer-based actions were identified as: using wooden or reusable cutlery; switching to reusable water bottles; using wooden or reusable stirrers; using plastic free cotton-buds; and using refill detergent/ shampoo bottles. We examined the feasibility of top-ranked actions using a SWOT analysis (Strengths, Weaknesses, Opportunities and Threats) to explore the complexities inherent in their implementation for consumers, businesses, and government to reduce the presence of plastic in the environment.


Assuntos
Monitoramento Ambiental , Plásticos/toxicidade , Rios/química , Poluentes Químicos da Água/toxicidade , Comportamento do Consumidor , Técnicas de Apoio para a Decisão , Poluição Ambiental , Humanos , Plásticos/química , Reciclagem , Resíduos/análise , Poluentes Químicos da Água/química
4.
PLoS One ; 15(8): e0231933, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32818952

RESUMO

Financing municipal solid waste (MSW) services is one of the key challenges faced by cities in developing countries. This study used plastic waste, a constituent of MSW, to explore the possibility of generating revenue for financing MSW management in the municipalities of Nepal. The results of this study suggest that plastic material recovery could generate revenue, which is equivalent to 1.38 times of the plastic-waste-related management cost when collection efficiency reaches 66.7%. An increase in 1% of recovery rate and collection efficiency could cover an additional 4.64% and 2.06% of the costs of managing plastic waste, respectively. In addition, an increase in tax on imported plastic materials could also motivate recovery of plastic waste for recycle and reuse. An additional 1% tax on plastic imports would be sufficient to cover plastic-related waste management when plastic waste recovery and collection efficiency rates are low. This plastic recovery- revenue exercise could be expanded to other materials such as paper and metal to fully understand the possibility of sustainable financing of MSW management and reducing environmental harm in developing countries like Nepal.


Assuntos
Reciclagem/métodos , Resíduos Sólidos/economia , Gerenciamento de Resíduos/métodos , Cidades , Países em Desenvolvimento , Nepal , Plásticos/análise , Plásticos/química , Reciclagem/economia , Eliminação de Resíduos/economia , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Gerenciamento de Resíduos/economia
5.
Chemosphere ; 260: 127589, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32682135

RESUMO

Although recycled plastics provide a low-cost and environmentally friendly alternative for many applications, their desirability is significantly limited by the presence of unpleasant odors from volatile organic compounds (VOCs). In this work, a headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) method was optimized to analyze volatile compounds from an odorous recycled plastic resin which was roughly composed of 85-90% polypropylene (PP) and 15-10% high-density polyethylene (HDPE). A large variety of aliphatic hydrocarbons and 13 additive residues were detected. Statistical tools were employed to screen the VOCs and successfully identified three components, i.e., 2,4-dimethyl-heptane, 4-methyl-octane and octamethylcyclotetrasiloxane (D4), which were significantly related to the odor intensity of the recycled plastic resin (p-values < 0.05). 2,4-Dimethyl-heptane has a strong, pungent plastic smell, which is very similar to the odor of the recycled resin. It is identified as a major source of the odor. Past relevant research has not been able to establish a direct link between an odorous compound and the undesirable odor of recycled plastic until now. 4-Methyl-octane was highly corelated to 2,4-dimethyl-heptane and somewhat contributed to the odor. D4 does not have an odor, but it may serve as an indicator of some odorous residues from personal care products.


Assuntos
Odorantes/análise , Resinas Sintéticas/química , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Plásticos/química , Polietileno/química , Polipropilenos/química , Reciclagem
6.
Chemosphere ; 260: 127650, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32693263

RESUMO

In recent years, the composite pollution of microplastics with organic pollutants and heavy metal ions in the water environment, including their combined toxicity, has received increasing attention. However, the mechanism underlying the joint effect of antibiotics and heavy metals on the surface behavior of microplastics has not been reported. The primary purpose of this article was to analyze the adsorption of levofloxacin (OFL) onto polyvinyl chloride (PVC) in an aqueous solution. The adsorption behavior was studied using kinetics, thermodynamics, and isotherm models, and the effects of several environmental factors, such as ionic strength, fulvic acid, and heavy metals, were determined. The adsorption kinetics and isotherms models indicated that the whole adsorption process was controlled by both intraparticle and outer diffusion, as well as chemical adsorption, which was the dominant mechanism. Based on the results of the thermodynamic experiment, the adsorption process was a nonspontaneous and exothermic reaction process. Furthermore, the presence of Cu2+, Zn2+, and Cr3+ ions significantly promoted the adsorption of OFL, but the presence of Cd2+ and Pb2+ ions inhibited its adsorption. At the same time, the presence of the ionic strength and fulvic acid remarkably restricted the adsorption process. These findings confirmed that electrostatic interactions, ion exchange, intermolecular hydrogen bonds, and halogen bond cooperation were the main adsorption mechanisms. This paper mainly discusses the interaction between combinations of pollutants with microplastics, which provides theoretical guidance for the interface behavior, migration and transformation of marine microplastics in the actual environment.


Assuntos
Levofloxacino/química , Metais Pesados/química , Microplásticos/química , Poluentes Químicos da Água/química , Adsorção , Antibacterianos , Difusão , Poluentes Ambientais , Íons , Cinética , Concentração Osmolar , Plásticos/química , Cloreto de Polivinila , Termodinâmica , Água/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-32640873

RESUMO

Each year, large amounts of plastic waste are generated and must be appropriately disposed. In this work, we studied the feasibility of using plastics as wetland substrates as an alternative plastic waste disposal method and the ability of the constructed wetland to remove pharmaceuticals and personal care products (PPCPs) from contaminated water. Wetland microcosms were constructed using polycarbonate, polyethylene terephthalate, quartz sand, and ceramsite substrates. Lake water spiked with methyl-paraben, ibuprofen, triclosan, 4-methybenzylidene camphor, carbamazepine, and 17α-ethinyl estradiol at 5 µg L-1 was continuously loaded to the microcosms with a hydraulic retention time of approximately 11 days. After 70 days, methyl-paraben, triclosan, and 4-methybenzylidene camphor were effectively removed regardless of the substrate. However, ibuprofen, carbamazepine, and 17α-ethinyl estradiol were partially removed, and the removal efficiency was the best in wetlands with ceramsite substrate. Carbamazepine was the most persistent among the tested compounds. Phospholipid fatty acid (PLFA) analysis revealed that ceramsite supported the highest microbial biomass per bulk volume of substrate followed by quartz sand, polycarbonate, and polyethylene terephthalate, which might be related to the PPCP removal potential of the wetland microcosms.


Assuntos
Cosméticos/análise , Preparações Farmacêuticas/análise , Plásticos/química , Resíduos Sólidos , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Áreas Alagadas , China , Estudos de Viabilidade , Água Doce/microbiologia
8.
Chemosphere ; 259: 127402, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593819

RESUMO

Plastic waste has caused severe environmental problems. Some additives in plastics, like organophosphates, enter the environment with plastic waste, causing significant harm to plants and creatures. However, the primary method of recycling phosphorus-containing plastic, especially polycarbonate and acrylonitrile-butadiene-styrene copolymer (PC/ABS), is a mechanical method, which not only does not effectively separate plastics and organophosphates but also tends to cause polymer degradation during recycling. In order to overcome these problems, we proposed an efficient and sustainable approach to recycle of phosphorus-containing plastic. In this method, N, N-dimethylcyclohexylamine (DMCHA), a switchable hydrophilicity solvent (SHS), was used to react with and extract organophosphates in plastic, achieving the goal of complete separation of plastic and organophosphates. PC/ABS can be recovered by precipitation. Dissolved organophosphates can also be easily recovered due to the switching characteristics of SHS. Both of recovered materials were of high purity and were close to virgin materials. This technique is an easy and efficient approach to separate plastic and organophosphates, which has excellent application prospects in recycling phosphorus-containing plastic.


Assuntos
Fósforo/química , Plásticos/química , Reciclagem/métodos , Acrilonitrila , Butadienos , Interações Hidrofóbicas e Hidrofílicas , Cimento de Policarboxilato , Polímeros , Poliestirenos , Solventes
9.
PLoS One ; 15(6): e0228811, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555686

RESUMO

Marine debris is currently a significant source of environmental and economic problems. Floating litter can be employed by marine organisms as a surface to attach to and use as spreading vector. Human activities are promoting the expansion of potentially harmful species into novel ecosystems, endangering autochthonous communities. In this project, more than 1,000 litter items were collected and classified from five beaches eastwards the port of Gijon, in Asturias, Spain. Next generation sequencing was employed to study biofouling communities attached to items of different materials. A dominance of DNA from Florideophyceae, Dinophyceae and Arthropoda was found, and four non-indigenous species (NIS) were identified. Results showed a clear preference of Florideophyceae and Bryozoa to attach on textile surfaces versus plastic ones. Considering that these taxa contain several highly invasive species described to date, these data emphasize the potential of textile marine debris as a vector for dispersal of NIS. Moreover, the closest beaches to the port contained a more similar biota profile than the farther ones, confirming that both plastic and textile marine litter can be vectors for species dispersal from ports.


Assuntos
DNA Ambiental/análise , Monitoramento Ambiental , Oceanos e Mares , Plásticos/química , Têxteis/análise , Poluentes Químicos da Água/química , Praias , Biofilmes , DNA Ambiental/genética , Sequenciamento de Nucleotídeos em Larga Escala
10.
Chemosphere ; 257: 127206, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32502737

RESUMO

Microplastics (MPs) could act as a vector for various kinds of pollutants due to their small size. Compared to nonpolar and nondegradabale MPs, the sorption of organic pollutants on polar and degradable MPs has been seldom studied. In this study, the sorption behavior of two nonpolar polycyclic aromatic hydrocarbons (PAHs, phenanthrene and pyrene), two polar derivates of PAHs (1-nitronapthalene and 1-napthylamine) and a heterocyclic chemical (atrazine) by three polar MPs including polybutylene succinate (PBS), polycaprolactone (PCL) and polyurethane (PU) and a typical nonpolar MP, polystyrene (PS) were investigated. The sorption followed the pseudo-second-order kinetics and sorption equilibrium was achieved within 5 days. Sorption isotherms could be well fitted by both Linear (R2>0.946) and Freundich models (R2>0.945) and the values of nonlinear index (n) from Freundlich model in most cases were close to 1, suggesting that hydrophobic partition was a primary process controlling the sorption. The sorption coefficients (Kd) of the five organic compounds ranged from 29. 6 to 1.42 × 105 (L/kg). The log KOC/log KOW of PAHs and derivates of PAHs on polar MPs were greater than 1, especially for 1-naphthylamine (1.30-1.40), confirming the great contribution of hydrogen bonding. PU contains a benzene ring and showed greater sorption compared the other two polar MPs, indicating the existence of π (n) -π electron donor-acceptor interactions. Morevoer, the sorption of phenanthrene and pyrene on PU were better fitted by Langmuir model and the maximum adsorption capacities were 1.06 × 104 and 5.87 × 103 mg/kg, respectively.


Assuntos
Poluentes Ambientais/química , Microplásticos/química , Adsorção , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Compostos Orgânicos , Fenantrenos , Plásticos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poliestirenos , Poliuretanos , Pirenos
11.
J Vis Exp ; (160)2020 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-32568225

RESUMO

Construction and demolition waste (CDW), including valuable materials such as plastics, have a remarkable influence on the waste sector. In order for plastic materials to be re-utilized, they must be identified and separated according to their polymer composition. In this study, the identification of these materials was performed using near-infrared spectroscopy (NIR), which identified material based on their physical-chemical properties. Advantages of the NIR method are a low environmental impact and rapid measurement (within a few seconds) in the spectral range of 1600-2400 nm without special sample preparation. Limitations include its inability to analyze dark materials. The identified polymers were utilized as a component for wood-polymer composite (WPC) that consists of a polymer matrix, low cost fillers, and additives. The components were first compounded with an agglomeration apparatus, followed by production by extrusion. In the agglomeration process, the aim was to compound all materials to produce uniformly distributed and granulated materials as pellets. During the agglomeration process, the polymer (matrix) was melted and fillers and other additives were then mixed into the melted polymer, being ready for the extrusion process. In the extrusion method, heat and shear forces were applied to a material within the barrel of a conical counter-rotating twin-screw type extruder, which reduces the risk of burning the materials and lower shear mixing. The heated and sheared mixture was then conveyed through a die to give the product the desired shape. The above-described protocol proved the potential for re-utilization of CDW materials. Functional properties must be verified according to the standardized tests, such as flexural, tensile, and impact strength tests for the material.


Assuntos
Materiais de Construção/análise , Plásticos/química , Resíduos/análise , Madeira/química
12.
Chemosphere ; 257: 127225, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505036

RESUMO

The role of plastic as a vector for bioaccumulation of hydrophobic organic pollutants has been widely studied. However, the interactions between microplastics (MPs) and crude oil, and the transfer kinetics of sorbed oil from ingested MPs into aquatic biota are largely unknown. In this study, interactions between MPs and crude oil in seawater and digestive tract mimic of aquatic biota have been examined. To mimic the living, transportation and cooking conditions of aquatic organisms, sorption and desorption behaviors were investigated under room temperature-bath (25 °C), ice-bath (0∼4 °C) and boiling water-bath (95∼100 °C), and pH was set as 4 and 7 for the simulated gut fluid. The results showed that sorption capacity of polyethylene (PE) MPs for crude oil in seawater was higher than that in intestinal tract, indicating more oil residue in aqueous phase of gut fluid in the present of organic particles. The sorption kinetics models were well fitted to the pseudo-order model, and isotherms models were well fitted to the Freundlich model. In addition, the results demonstrated that temperature played a significant effect on crude oil viscosity, and the sorption capacity under different temperatures was in the order of 25 °C > 95∼100 °C > 0∼4 °C, indicating that more oil was remained in aqueous phase at boiling water-bath and ice-bath. The increment of pH enhances the sorption capacities of PE MPs. Moreover, the desorption experiment has supplemented the current findings from the sorption experiments.


Assuntos
Microplásticos/química , Petróleo , Polietileno/química , Poluentes Químicos da Água/química , Adsorção , Organismos Aquáticos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Plásticos/química , Água do Mar/química , Poluentes Químicos da Água/análise
14.
Chemosphere ; 251: 126579, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443226

RESUMO

Brominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) are increasingly reported at significant levels in various matrices, including consumer goods that are manufactured from plastics containing certain brominated flame retardants. PBDD/Fs are known ligands for the aryl hydrocarbon receptor (AhR) but are not yet considered in the hazard assessment of dioxin mixtures. The aim of the present study was to determine if PBDD/Fs levels present in plastic constituents of toys could pose a threat to children's health. PBDD/Fs, unlike their chlorinated counterparts (PCDD/Fs), have not been officially assigned toxic equivalence factors (TEFs) by the WHO therefore, we determined their relative potency towards AhR activation in both human and rodent cell-based DR CALUX® bioassays. This allowed us to compare GC-HRMS PBDD/F congener levels, converted to total Toxic Equivalents (TEQ) by using the PCDD/F TEFs, to CALUX Bioanalytical Equivalents (BEQ) levels present in contaminated plastic constituents from children's toys. Finally, an estimate was made of the daily ingestion of TEQs from PBDD/Fs-contaminated plastic toys by child mouthing habits. It is observed that the daily ingestion of PBDD/Fs from contaminated plastic toys may significantly contribute to the total dioxin daily intake of young children.


Assuntos
Dibenzofuranos Policlorados/análise , Poluentes Ambientais/análise , Retardadores de Chama/análise , Plásticos/química , Jogos e Brinquedos , Dibenzodioxinas Policloradas/análise , Receptores de Hidrocarboneto Arílico/genética , Animais , Bioensaio , Linhagem Celular , Criança , Pré-Escolar , Dibenzofuranos Policlorados/toxicidade , Monitoramento Ambiental/métodos , Poluentes Ambientais/toxicidade , Retardadores de Chama/toxicidade , Cromatografia Gasosa-Espectrometria de Massas , Genes Reporter , Humanos , Luciferases/genética , Plásticos/normas , Dibenzodioxinas Policloradas/toxicidade , Ratos , Transfecção
15.
Chemosphere ; 253: 126787, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32464756

RESUMO

Microplastic (MP) accumulation in the environment has become an issue of human and environmental importance. Great efforts were made recently to identify the sources of MP exposure to humans and their release into the environment. Here, we employed spectroscopic techniques to identify and characterize MP in consumer plastic food containers that are, in huge quantity, used for food delivery and disposable plastic cups for daily drinking. We determined the average weight of isolated MP per pack to be 12 ± 5.12 mg, 38 ± 5.29 mg, and 3 ± 1.13 mg for the round-shaped, rectangular-shaped plastic container and disposable plastic cups, respectively, with various morphological features including cubic, spherical, rod-like as well as irregular shapes, which may either be consumed by humans or released into the environment. This study demonstrates that new plastic containers can be an important source of direct human and environmental exposure to microplastics. Most importantly, our results indicated that necessary attention must be given to morphological features of realistic MPs when evaluating their risks to humans and the environment.


Assuntos
Exposição Dietética/estatística & dados numéricos , Contaminação de Alimentos/estatística & dados numéricos , Embalagem de Alimentos , Microplásticos/análise , Exposição Ambiental , Monitoramento Ambiental , Humanos , Plásticos/química
16.
Ecotoxicol Environ Saf ; 196: 110551, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32244120

RESUMO

The widespread usage of plastic film increased the content of phthalic acid esters (PAEs) in the environment, causing PAE residue in vegetables and subsequently increasing health risks to humans when consuming them. In this work, the presence, distribution and risk assessment of 15 PAEs in soils and peppers from suburban plastic film pepper-growing greenhouses were investigated. The total PAE contents in soil and pepper samples ranged from 320.1 to 971.2 µg/kg (586.3 µg/kg on average) and from 196.6 to 304.2 µg/kg (245.4 µg/kg on average), respectively. Di (2-ethyl)hexyl, dibutyl and diisobutyl phthalates (DEHP, DnBP and DiBP, respectively) were the most abundant in both soil and pepper samples. Specifically, DEHP showed the highest content in soils, while the DnBP content was the highest in peppers. The total PAE content in soils from pepper-greenhouses was much lower than in the agricultural soils mulched with plastic films, but significantly higher than in the agricultural soils from open uncovered fields. The total PAE content in peppers decreased as the service life of plastic film greenhouses increased. Correlation analysis suggested that the difference in distribution and accumulation behaviors of individual PAEs in greenhouse systems was correlated with their physicochemical properties. The non-cancer and carcinogenic risks of priority PAEs show low risks of PAEs detected in pepper and soil samples from the suburban plastic film greenhouses to human health.


Assuntos
Produção Agrícola/métodos , Ácidos Ftálicos/análise , Plásticos/química , Poluentes do Solo/análise , Solo/química , Verduras/química , China , Dibutilftalato/análogos & derivados , Dibutilftalato/análise , Ésteres , Contaminação de Alimentos/análise , Humanos , Medição de Risco
17.
J Chromatogr A ; 1621: 461087, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32327226

RESUMO

As a new kind of green solvents for potential replacement of traditional volatile organic compounds, deep eutectic solvents (DESs) have been attracting more and more attention in various applications. In this work, three types of hydrophobic DESs were synthesized by simple mixing of trioctylmethyl ammonium chloride (used as hydrogen bond acceptor) with decanoic acid, ketoprofen and gemfibrozil (hydrogen bond donors), respectively, at different molar ratios. In order to evaluate the solvent characteristics of these DESs, some of the physical properties such as melting point, density, viscosity, and water contact angle were determined. Then, these hydrophobic DESs were used for the vortex-assisted liquid-liquid microextraction of bisphenol-type contaminants in water, followed by quantitative determination of bisphenols contents with high performance liquid chromatography (HPLC-FLD) coupled with fluorescence detection. For this purpose, four bisphenols, namely, 2, 2-bis(4-hydroxydiphenyl)propane (BPA), 2, 2-bis (4-hydroxyphenyl)butane (BPB), 4, 4'-(1-phenylethylidene)bisphenol (BPAP) and 4, 4'-cyclohexylidenebisphenol (BPZ) were selected as model contaminants. It was found that the enrichment factors of the proposed method were in the range from 97 to 112, depending on the structure of the analytes. Under optimal experimental conditions, the linearity ranges of the method varied from 0.3 to 700 µg L-1 with linear correlation coefficients (R2) higher than 0.996. The limit of detections (LODs) and limit of quantifications (LOQs) were in the range of 0.3-0.5 µg L-1 and 0.06-0.08 µg L-1, respectively. Furthermore, the developed method was successfully used in the extraction and determination of four bisphenols from food-contacted plastic samples.


Assuntos
Compostos Benzidrílicos/análise , Cromatografia Líquida de Alta Pressão/métodos , Alimentos , Interações Hidrofóbicas e Hidrofílicas , Fenóis/análise , Plásticos/química , Solventes/química , Compostos Benzidrílicos/urina , Fluorescência , Humanos , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Limite de Detecção , Microextração em Fase Líquida , Fenóis/urina , Reprodutibilidade dos Testes , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Poluentes Químicos da Água/análise
18.
Nature ; 580(7802): 216-219, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32269349

RESUMO

Present estimates suggest that of the 359 million tons of plastics produced annually worldwide1, 150-200 million tons accumulate in landfill or in the natural environment2. Poly(ethylene terephthalate) (PET) is the most abundant polyester plastic, with almost 70 million tons manufactured annually worldwide for use in textiles and packaging3. The main recycling process for PET, via thermomechanical means, results in a loss of mechanical properties4. Consequently, de novo synthesis is preferred and PET waste continues to accumulate. With a high ratio of aromatic terephthalate units-which reduce chain mobility-PET is a polyester that is extremely difficult to hydrolyse5. Several PET hydrolase enzymes have been reported, but show limited productivity6,7. Here we describe an improved PET hydrolase that ultimately achieves, over 10 hours, a minimum of 90 per cent PET depolymerization into monomers, with a productivity of 16.7 grams of terephthalate per litre per hour (200 grams per kilogram of PET suspension, with an enzyme concentration of 3 milligrams per gram of PET). This highly efficient, optimized enzyme outperforms all PET hydrolases reported so far, including an enzyme8,9 from the bacterium Ideonella sakaiensis strain 201-F6 (even assisted by a secondary enzyme10) and related improved variants11-14 that have attracted recent interest. We also show that biologically recycled PET exhibiting the same properties as petrochemical PET can be produced from enzymatically depolymerized PET waste, before being processed into bottles, thereby contributing towards the concept of a circular PET economy.


Assuntos
Hidrolases/química , Hidrolases/metabolismo , Plásticos/química , Plásticos/metabolismo , Polietilenotereftalatos/química , Polietilenotereftalatos/metabolismo , Engenharia de Proteínas , Reciclagem , Actinobacteria/enzimologia , Burkholderiales/enzimologia , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Dissulfetos/química , Dissulfetos/metabolismo , Ensaios Enzimáticos , Estabilidade Enzimática , Fusarium/enzimologia , Modelos Moleculares , Ácidos Ftálicos/metabolismo , Polimerização
19.
Ecotoxicol Environ Saf ; 195: 110495, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32213368

RESUMO

The widespread use of phthalate esters (PAEs) in plastic products has made them ubiquitous in environment. In this study, 93 soil samples were collected in 31 plastic-sheds from one of China's largest vegetable production bases, Shouguang City, Shandong Province, to investigate the pollution characteristics and composition of PAEs in soils. Eleven PAEs were detected in the soil samples with the total concentration of 756-1590 µg kg-1 dry soil. Di (2-ethylhexyl) phthalate (DEHP), bis (2-n-butoxyethyl) phthalate (DBEP), di-isobutyl phthalate (DiBP) and di-n-butyl phthalate (DBP) were the main pollutants with the highest concentrations. Moreover, soil properties, including pH, total organic carbon (TOC), soil enzyme activities, and soil microbial community characteristics, were monitored to explore the associated formation mechanisms. The concentration of PAEs in the plastic-shed vegetable soils was regionalized and the contamination degree in different regions was related to soil microbial characteristics and soil enzyme activities. Phthalate ester is positively correlated with catalase and sucrase, and negatively correlated with dehydrogenase and urease. Furthermore, some tolerant and sensitive bacteria were selected, which possibly could be used as potential indicators of PAE contamination in soil. Dimethyl phthalate (DMP) and DBP also had greater effects on the soil microbial community than other PAEs. The results will provide essential data and support the control of PAEs in plastic-shed vegetable soils in China.


Assuntos
Enzimas/análise , Microbiota/efeitos dos fármacos , Ácidos Ftálicos/análise , Plásticos/química , Poluentes do Solo/análise , Solo/química , Agricultura , China , Cidades , Dibutilftalato/análogos & derivados , Dibutilftalato/análise , Microbiologia do Solo , Verduras/crescimento & desenvolvimento
20.
J Food Sci ; 85(4): 1098-1104, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32147835

RESUMO

Newly developed magnetic carbon particles prepared from coffee grounds were used as the sorbent for the magnetic solid-phase extraction of eight phthalic acid esters (PAEs) from plastic bottled water prior to their analysis by GC-MS. The method, which uses coffee-ground particles coated with iron oxide, was validated, and exhibited linearities for the eight PAEs, with coefficients of determination above 0.998 in the 0.005 to 0.1 mg/L concentration range. Limits of detection and limits of quantification of 0.00003 to 0.002 mg/L and 0.0001 to 0.005 mg/L, respectively, were achieved, with recoveries (%) ranging between 77% and 120%, and relative standard deviations for intra- and interday precisions below 16.3% at three fortification levels. No PAE residues were detected when the developed and validated method was applied to 10 real plastic bottled water samples. Taken together, the developed magnetic solid-phase extraction method is a useful tool for monitoring phthalate esters in aqueous samples. PRACTICAL APPLICATION: The development of a new, inexpensive, and efficient magnetic sorption material derived from spent coffee grounds, and its ability to determine phthalate esters in aqueous solutions was described by GC-MS/MS. The developed magnetic solid-phase extraction method is a useful tool for monitoring phthalate esters in aqueous samples.


Assuntos
Coffea/química , Água Potável/análise , Ésteres/isolamento & purificação , Magnetismo/métodos , Ácidos Ftálicos/isolamento & purificação , Plásticos/isolamento & purificação , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Carbono/química , Ésteres/química , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Magnetismo/instrumentação , Ácidos Ftálicos/análise , Plásticos/química , Sementes/química , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/química
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