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An abstract of the article "Biogas Impact Mitigation Through Biocovers: Lab Tests and Analysis in Situ for the Characterization of Filtering Media" by Isabella Pecorini and colleagues is presented.

An abstract of the article "BMP Analysis and Decision Tools for the Comparison of Different Management and Treatment Scenarios of Food Waste Form Large Retailers" by Isabella Pecorini and colleagues is presented.

Abstract: Based on the results of previous studies, the efficiency of a Brayton/Hirn combined cycle fuelled with a clean syngas produced by means of biomass gasification and equipped with CO2 removal by chemical absorption reached 33.94%, considering also the separate CO2 compression process. The specific CO2 emission of the power plant was 178kg/MWh. In comparison with values previously found for an integrated coal gasification combined cycle (ICGCC) with upstream CO2 chemical absorption (38–39% efficiency, 130kg/MWh specific CO2 emissions), this configuration seems to be attractive because of the possibility of operating with a simplified scheme and because of the possibility of using biomass in a more efficient way with respect to conventional systems. In this paper, a life cycle assessment (LCA) was conducted with presenting the results on the basis of the Eco-Indicator 95 impact assessment methodology. Further, a comparison with the results previously obtained for the LCA of the ICGCC was performed in order to highlight the environmental impact of biomass production with fossil fuels utilisation. The LCA shows the important environmental advantages of biomass utilisation in terms of reduction of both greenhouse gas emissions and natural resource depletion, although an improved impact assessment methodology may better highlight the advantages due to the biomass utilisation. [Copyright &y& Elsevier]

Performance analysis and life cycle assessment (LCA) of an integrated gasification combined cycle (IGCC) fed with biomass with upstream CO2 chemical absorption has been carried out. The main working conditions have been determined by mean of partial exergetic analysis. A sensitivity analysis with respect to the CO2 absorbing solution composition has also been carried out. The reachable efficiency ranges between 35% and 36%, depending on gas turbine technology level. In comparison with efficiency values previously found for an IGCC fed with coal with upstream CO2 chemical absorption (38–39%), the configuration studied seems to be attractive because of the possibility of operating with a simplified scheme (without H2S removal process) and at atmospheric pressure and for the possibility of using biomass in a more efficient way with respect to conventional combustion systems. Due to the lower efficiency, the specific CO2 emission results higher (170 kg/MW h) with respect to the cycle fed with coal and CO2 removal (130 kg/MW h). Moreover, the CO2 balance has been determined with respect to the entire life cycle of the plant, including the construction, operation, dismantling and the biomass growing phases. [Copyright &y& Elsevier]

A new carbon dioxide separation system based on CO2 absorption in aqueous solutions of alkaline salts (sodium and potassium carbonate) was studied with reference to semi-closed gas turbine/combined cycle (SCGT/CC), and compared to results obtained with existing technologies. Use of calcium hydroxide for the regeneration of the exhaust solution was studied in order to obtain a tail-end product, calcium carbonate in the form of precipitated calcium carbonate (PCC) with a wide spread and continuously growing market. The alkali CO2 absorption process was compared with a conventional amine absorption process (DEA+MDEA), referring to the same SCGT/CC based on the same CO2 removal efficiency. The comparison allows foregrounding of the possible goals of the CO2 alkali absorption process with respect to previous amine cycle analyses. The modeling approach focuses on a thermodynamical and economical first comparison of the proposed cycle to previous studies carried out on CO2 absorption (Energy Convers. Manage. 40 (1999) 1917; Absorption of CO2 with amines in a semi closed GT cycle: plant performance and operating costs, ASME Paper 98-GT-395, American Society of Mechanical Engineers ASME Publishing, New York, 1998; Greenhouse Gas Control Technologies Conference, Interlaken, Switzerland, Pergamon, Oxford, 1999). [Copyright &y& Elsevier]

Industrial districts are highly characteristic of Italian industry structure, with energy implication due to both electrical and thermal energy demand. The present study represents an environmental methodology approach applied to an area in the Tuscany region characterized by the presence of a high net power output cogeneration plant connected to paper mill processes. The cogeneration unit is based on a innovative gas turbine characterized by low atmospheric environmental impact. Additional impact due to cogeneration plant installation was evaluated in comparison with pollutant concentration levels due to existent energy conversion processes, using atmospheric diffusional models. A comparison was also made with respect to pollutant concentration contribute due to ordinary road and highway traffic emissions existent in the area. [ABSTRACT FROM AUTHOR]

A novel procedure for nylon 6 and nylon 6,6 polyamide (PAs) microplastics (MPs) quantification is described for the first time. The overall procedure, including quantification of poly(ethylene terephthalate) (PET), was tested on wastewater treatment plant (WWTP) sludges. The three polymers account for the largest global share of synthetic textile microfibers, being possibly the most common MPs released upon laundering in urban wastewaters. Therefore, measuring their content in WWTP sludges may provide an accurate picture of the potential risks associated with both the inflow of these MPs in natural water bodies and the practice of using WWTP sludges as agricultural soil amendment. The novel procedure involves PAs depolymerization by acid hydrolysis followed by derivatization of the monomers 6-aminohexanoic acid (AHA) and hexamethylene diamine (HMDA) with a fluorophore. Reversed-phase HPLC analysis with fluorescence detection results in high sensitivities for both AHA (LOD = 8.85·10–4 mg/L, LOQ = 3.73·10–3 mg/L) and HMDA (LOD = 2.12·10–4, LOQ = 7.04·10–4 mg/L). PET quantification involves depolymerization, in this case by alkaline hydrolysis, followed by HPLC analysis of its comonomer terephthalic acid. Eight sludge samples from four WWTPs in Italy showed contamination in the 29.3–215.3 ppm and 10.6–134.6 ppm range for nylon 6 and nylon 6,6, respectively, and in the 520–1470 ppm range for PET. ga1 • The first analytical method for nylon 6 and nylon 6,6 polyamide (PAs) microplastics. • Overall method includes poly(ethylene terephthalate) (PET), nylon6, and nylon6,6. • PAs and PET are the most common textile microfibers polluting natural water bodies. • Contamination in complex matrices is measured with high accuracy and sensitivity. • Contamination by PET and PAs in wastewater treatment plant sludges was quantified. [ABSTRACT FROM AUTHOR]

Fish meal (FM) is an industrial product, mainly obtained from whole wild-caught fish, that is used as a high protein feedstuff component in aquaculture and intensive animal farming. Contamination of FM by microplastics (MPs), the synthetic polymer particles known to be nearly ubiquitous in the marine environment, is a likely consequence of their ingestion by zooplankton and other small marine animals that through the food chain end up in the fish commercialized not only for direct human consumption but also for the industrial production of FM. Unfortunately, analytical tools for quantifying contamination of FM by synthetic polymers are not available. A newly developed procedure described here allows quantification of the total amounts of polyolefins (including ethene and propene homo- and copolymers), polystyrene (PS), and poly(ethylene terephthalate) (PET), respectively, in FM. The multi-step procedure involves a sequence of solvent extractions, hydrolytic treatments to remove the biogenic matrix mainly consisting of proteins and some lipids, and selective depolymerization for PET. The gravimetric and SEC-UV techniques employed for the quantification of polyolefins and PS, respectively, only allowed to estimate their concentration in FM at around or below 100 mg/kg each, a more accurate quantification being prevented by the interference from the organic matrix and, in the case of polyolefins, by the limited sensitivity of the quantification by gravimetry. On the other hand, the contamination by PET MPs could accurately be quantified at 12.9 mg/kg based on the dry FM mass. Ways to overcome the sensitivity limitations for PS and polyolefins by using e.g. pyrolysis-GC/MS are highlighted. Image 1 • A new analytical method allows quantification of microplastics (MPs) in Fish meal. • Different polymers types are separated and analyzed in a multi-step procedure. • The total content of each polymer is measured by simple gravimetry or HPLC analysis. • Poly(ethylene terephtalate) (PET) can be quantified in FM with high sensitivity. • Polyolefin and polystyrene can also be detected but sensitivity should be improved. The first reported analytical procedure for identifying and quantifying the main polymer types as potential contaminant microplastics in fish meal. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) quantification in benthic marine sediments is typically performed by time-consuming and moderately accurate mechanical separation and microscopy detection. In this paper, we describe the results of our innovative Polymer Identification and Specific Analysis (PISA) of microplastic total mass, previously tested on either less complex sandy beach sediment or less demanding (because of the high MPs content) wastewater treatment plant sludges, applied to the analysis of benthic sediments from a sublittoral area north-west of Leghorn (Tuscany, Italy). Samples were collected from two shallow sites characterized by coarse debris in a mixed seabed of Posidonia oceanica, and by a very fine silty-organogenic sediment, respectively. After sieving at <2 mm the sediment was sequentially extracted with selective organic solvents and the two polymer classes polystyrene (PS) and polyolefins (PE and PP) were quantified by pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS). A contamination in the 8–65 ppm range by PS could be accurately detected. Acid hydrolysis on the extracted residue to achieve total depolymerization of all natural and synthetic polyamides, tagging of all aminated species in the hydrolysate with a fluorophore, and reversed-phase high performance liquid chromatography (HPLC) (RP-HPLC) analysis, allowed the quantification within the 137–1523 ppm range of the individual mass of contaminating nylon 6 and nylon 6,6, based on the detected amounts of the respective monomeric amines 6-aminohexanoic acid (AHA) and hexamethylenediamine (HMDA). Finally, alkaline hydrolysis of the residue from acid hydrolysis followed by RP-HPLC analysis of the purified hydrolysate showed contamination by polyethylene terephthalate (PET) in the 12.1–2.7 ppm range, based on the content of its comonomer, terephthalic acid. [ABSTRACT FROM AUTHOR]

• A simple, sensitive & accurate analytical method for PET microplastics in sediments. • Polyester microplastics are found and quantified in marine and freshwater sediments. • The analytical protocol can be extended to complex environmental matrices. Microplastics are ubiquitous pollutants in marine and freshwater bodies. Poly(ethylene terephthalate) microfibers (PMFs) are among the main primary microplastics (as-produced polymer microparticles). Released in large amounts in laundry wastewaters, PMFs end up in freshwater and marine sediments due to their high density. PMFs are potentially hazardous pollutants for ecosystems and human health, being a deceiving food source for animal organisms at the base of the food chain (e.g. sediment and water filtrators, including edible shellfish and small crustaceans). This study describes a simple, sensitive and versatile procedure for quantifying the total mass of PET micro- and nano-particles in sediments. The procedure involves aqueous alkaline PET depolymerization with phase transfer catalysis, oxidation and fractionations to remove interfering species and pre-concentrate the terephthalic acid (TPA) monomer, and TPA quantification by reversed-phase HPLC. Recovery of TPA from a model sediment spiked with 800 ppm PET micropowder was 98.2 %, with limits of detection/quantification LOD = 17.2 μg/kg and LOQ = 57.0 μg/kg. Analyses of sandy sediments from a marine beach in Tuscany, Italy, showed contamination in the 370–460 μg/kg range, suggesting that a not negligible fraction of PET microfibers released in surface waters ends up in shore sediments. [ABSTRACT FROM AUTHOR]

Microplastics and nanoplastics represent one of the major environmental issues nowadays due to their ubiquitous presence on Earth, and their high potential danger for living systems, ecosystems, and human life. The formation of both microplastics and nanoplastics strongly depends on both the type of pristine materials and the degradation processes related to biological and/or abiotic conditions. The aim of this study is to investigate the effect of two of the most relevant abiotic parameters, namely temperature and light, taken under direct control by using a Solar box, on five types of reference polymers: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). A multi-analytical approach was adopted to investigate in detail the first steps of plastics degradation. Samples of plastic materials at different degradation times were analyzed by means of 1H NMR spectroscopy and thermal desorption gas chromatography mass spectrometry (TD-GC-MS) technique. Several minor molecular species released during degradation were consistently identified by both techniques thus providing a comprehensive view of the various degradation products of these five types of microplastics. [ABSTRACT FROM AUTHOR]

The aim of this work is to identify the current level of energy recovery through waste thermal treatment. The state of the art in energy recovery from waste was investigated, highlighting the differences for different types of thermal treatment, considering combustion/incineration, gasification and pyrolysis. Also different types of wastes – Municipal Solid Waste (MSW), Refuse Derived Fuel (RDF) or Solid Refuse Fuels (SRF) and some typologies of Industrial Waste (IW) (sludge, plastic scraps, etc.) – were included in the analysis. The investigation was carried out mainly reviewing papers, published in scientific journals and conferences, but also considering technical reports, to gather more information. In particular the goal of this review work was to synthesize studies in order to compare the values of energy conversion efficiencies measured or calculated for different types of thermal processes and different types of waste. It emerged that the dominant type of thermal treatment is incineration associated to energy recovery in a steam cycle. When waste gasification is applied, the produced syngas is generally combusted in a boiler to generate steam for energy recovery in a steam cycle. For both the possibilities – incineration or gasification – cogeneration is the mean to improve energy recovery, especially for small scale plants. In the case of only electricity production, the achievable values are strongly dependent on the plant size: for large plant size, where advanced technical solutions can be applied and sustained from an economic point of view, net electric efficiency may reach values up to 30–31%. In small-medium plants, net electric efficiency is constrained by scale effect and remains at values around 20–24%. Other types of technical solutions – gasification with syngas use in internally fired devices, pyrolysis and plasma gasification – are less common or studied at pilot or demonstrative scale and, in any case, offer at present similar or lower levels of energy efficiency. [ABSTRACT FROM AUTHOR]

• Extensive comparison of three modeling approaches for Taylor slug flows and their corresponding modeling output. • Investigation of the different flow regimes of a coflow arrangement accompanied by a sensitivity study on droplet characteristics. • Modeling guidelines for liquid-liquid and liquid-gas simulations at low capillary numbers. [Display omitted] In this work, a versatile modeling platform, employing computational fluid dynamics (CFD) techniques to simulate liquid-liquid and liquid-gas Taylor slug flow, is presented. This platform consists of three two-dimensional, axisymmetric models, whose output can be used in various applications for which examples are provided. Modeling guidelines to decrease the simulation time and to mitigate numerical artifacts occurring at low values of the Capillary number, called spurious currents, are discussed. Moreover, to test capabilities outside the Taylor slug flow regime, other flow regimes occurring in a coflow arrangement were investigated and a sensitivity analysis on the resulting droplet characteristics was performed. [ABSTRACT FROM AUTHOR]

Abstract: An innovative biogas upgrading method that, differs from the currently employed commercial techniques, allows also to capture and store the separated CO2 is investigated. This process, named Alkali absorption with Regeneration (AwR), consists in a first step in which CO2 is separated from the biogas by chemical absorption with an alkali aqueous solution followed by a second step in which the spent absorption solution is regenerated for reuse in the first step of the upgrading process and the captured CO2 is stored in a solid and thermodynamically stable form. The latter process is carried out contacting the spent absorption solution, rich in carbonate and bicarbonate ions, with a waste material – air pollution control (APC) residues from Waste-to-Energy plants – characterized by a high content of calcium hydroxide and leads to the precipitation of calcium carbonate and to the regeneration of the alkali hydroxide content of the solution. The process was tested in a specifically designed pilot plant fed with 20 m3 h−1 (gas at standard conditions of 273 K and 1001 kPa) of landfill gas. Results showed that a high CH4 content in the outlet gas can be obtained using a 3.8 mol L−1 NaOH aqueous solution with a solution/landfill gas ratio of about 9 L m−3 (gas at standard conditions of 273 K and 1001 kPa). The regeneration process proved to be feasible, but its efficiency was limited by several factors to maximum values in the range of 50–60 %, showing to decrease with higher NaOH concentrations in the absorption solution. Absorption tests with regenerated load solutions after appropriate NaOH makeup, did not show appreciable differences with respect to raw solutions. [Copyright &y& Elsevier]

Abstract: In this paper, two alternative thermo-chemical processes for waste treatment were analysed: high temperature gasification and gasification associated to plasma process. The two processes were analysed from the thermodynamic point of view, trying to reconstruct two simplified models, using appropriate simulation tools and some support data from existing/planned plants, able to predict the energy recovery performances by process application. In order to carry out a comparative analysis, the same waste stream input was considered as input to the two models and the generated results were compared. The performances were compared with those that can be obtained from conventional combustion with energy recovery process by means of steam turbine cycle. Results are reported in terms of energy recovery performance indicators as overall energy efficiency, specific energy production per unit of mass of entering waste, primary energy source savings, specific carbon dioxide production. [Copyright &y& Elsevier]

Abstract: Waste management systems are a non-negligible source of greenhouse gases. In particular, methane and carbon dioxide emissions occur in landfills due to the breakdown of biodegradable carbon compounds operated on by anaerobic bacteria. The conventional possibilities of reducing the greenhouse effect (GHE) from waste landfilling consists in landfill gas (LFG) flaring or combustion with energy recovery in reciprocating engines. These conventional treatments are compared with three innovative possibilities: the direct LFG feeding to a fuel cell (FC); the production of a hydrogen-rich gas, by means of steam reforming and CO2 capture, to feed a stationary FC; the production of a hydrogen-rich gas, by means of steam reforming and CO2 capture, to feed a vehicle FC. The comparison is carried out from an environmental point of view, calculating the specific production of GHE per unit mass of waste disposed in landfill equipped with the different considered technologies. [Copyright &y& Elsevier]

Eco-toxicity investigation of polymer materials was considered extremely necessary for their potential menace, which was widely use as mulching materials in agricultural. In this study, polyethylene (PE), polystyrene (PS) and synthetic biomaterials-Ecoflex and cellulose were applying into soil cultivated with two potential indicator plants species: oat (A v ena sati v a) and red radish (Raphanus sativum). Variety of chemical, biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm. The F-value of biomass, pH, heavy metal and electoral conductivity of Raphanus behaved significant different from T0. Significant analysis results indicated biodegradation was fast in PE than PS, besides, heavy metals were dramatically decrease in the end implied the plant absorption may help decrease heavy metal toxicity. The increase value at T2 of Dehydrogenase activity (0.84 higher than average value for Avena & 0.91 higher for Raphanus), Metabolic Index (3.12 higher than average value for Avena & 3.81 higher for Raphanus) means during soil enzyme activity was promoted by biodegradation for its heterotrophic organisms' energy transportation was stimulated. Statistics analysis was carried on Biplot PC1 (24.2% of the total variance), PC2 (23.2% of the total variance), versus PC3 (22.8% of the total variance), which indicated phosphatase activity and metabolic index was significant correlated, and high correlation of ammonium and protease activity. Furthermore, the effects were more evident in Raphanus treatments than in Avena , suggesting the higher sensitivity of Raphanus to polymers treatment, which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds. [Display omitted] Variety of chemical, biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm. Biodegradation was fast in PE than PS, besides, heavy metals were dramatically decrease in soil at the end of experiment implied the plant absorption of metal may help decrease heavy metal toxicity of soil. During experiments, soil enzyme activity was promoted by polymer biodegradation for its heterotrophic organisms' energy transportation was stimulated. The effects were more evident in Raphanus treatments than in Avena , suggesting the higher sensitivity of Raphanus to the polymers treatment, which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds [ABSTRACT FROM AUTHOR]

• Plastic debris photo-degradation releases harmful VOCs in the environment. • VOCs are characterized by gas chromatography/mass spectrometry. • VOC profile can be exploited to characterize plastic debris. • Polystyrene-based plastic debris emits aromatic compounds. • Polyethylene-/polypropylene-based plastic debris emits oxygenated hydrocarbons. Environmental pollution associated to plastic debris is gaining increasing relevance not only as a threat to ecosystems but also for its possible harmful effects on biota and human health. The release of toxic volatile organic compounds (VOCs) is a potential hazard associated with the environmental weathering of plastic debris. Artificial aging of reference polymers (polystyrene, polypropylene, polyethylene terephthalate, high and low density polyethylene) was performed in a Solar Box at 40 °C and 750 W/m2. The volatile degradation products were determined before and after 1, 2, 3 and 4 weeks of aging using a validated analytical procedure combining headspace (HS) with needle trap microextraction (NTME) and gas chromatography/mass spectrometry (GC–MS). A progressive increase in VOCs was observed during artificial photo-degradation, whose chemical profile resulted polymer-dependent and included carbonyls, lactones, esters, acids, alcohols, ethers, aromatics. The amount of extractable fraction in polar solvents generally showed a similar trend. The same analytical procedure was used to determine VOCs released from plastic debris collected at a marine beach. All samples released harmful compounds (e.g. acrolein, benzene, propanal, methyl vinyl ketone, and methyl propenyl ketone), supporting the initial hypothesis that microplastics represent an unrecognized source of environmental pollution. [ABSTRACT FROM AUTHOR]

In this study, the sources, abundance, and ecological implications of microplastic (MP) pollution in Volturno, one of the main rivers in southern Italy, were explored by investigating the MP concentration levels in sediments collected along the watercourse. The samples were sieved through 5- and 2-mm sieves and treated with selective organic solvents. The polymer classes polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), nylon 6 (PA6), and nylon 6,6 (PA66) were quantified using pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS) and high-performance liquid chromatography (HPLC). Furthermore, a 16S rRNA metagenomic analysis was performed using next-generation sequencing in Ion Torrent™ to explore the bacterial taxonomy and ecological dynamics of sediment samples. The MPs were detected in all samples collected from the study area. PP and PET were the most abundant and frequently detected polymer types in the analysed samples. The total MP concentration ranged from 1.05 to 14.55 ppm (parts per million), identifying two distinct data populations: high- and low-MP-contaminated sediments. According to the Polymer Hazard Index (PHI), MP pollution was categorised as hazard levels III and IV (corresponding to the danger category). Metagenomic data revealed that the presence of MPs significantly affected the abundance of bacterial taxa; Flavobacteraceae and Nocardiaceae , which are known to degrade polymeric substances, were present in high-MP-contaminated sediments. This study provides new insights into the ecological relevance of MP pollution and suggests that microorganisms may serve as biomarkers of MP pollution. [Display omitted] • Microplastic (MP) quantification in sediments was achieved using Py-GC/MS and HPLC. • MP pollution was highly variable along the river continuum. • Bacterial taxonomic abundance in sediment was altered by MP contamination. • Microbial biomarkers of river sediment MP pollution dynamics were identified. [ABSTRACT FROM AUTHOR]

Air pollution related to traffic emissions pose an especially significant problem in cities; this is due to its adverse impact on human health and well-being. Previous studies which have aimed to quantify emissions from the transportation sector have been limited by either simulated or coarsely resolved traffic volume data. Emissions inventories form the basis of urban pollution models, therefore in this study, Global Positioning System (GPS) trajectory data from a taxi fleet of over 15,000 vehicles were analyzed with the aim of predicting air pollution emissions for Singapore. This novel approach enabled the quantification of instantaneous drive cycle parameters in high spatio-temporal resolution, which provided the basis for a microscopic emissions model. Carbon dioxide (CO 2 ), nitrogen oxides (NO x ), volatile organic compounds (VOCs) and particulate matter (PM) emissions were thus estimated. Highly localized areas of elevated emissions levels were identified, with a spatio-temporal precision not possible with previously used methods for estimating emissions. Relatively higher emissions areas were mainly concentrated in a few districts that were the Singapore Downtown Core area, to the north of the central urban region and to the east of it. Daily emissions quantified for the total motor vehicle population of Singapore were found to be comparable to another emissions dataset. Results demonstrated that high-resolution spatio-temporal vehicle traces detected using GPS in large taxi fleets could be used to infer highly localized areas of elevated acceleration and air pollution emissions in cities, and may become a complement to traditional emission estimates, especially in emerging cities and countries where reliable fine-grained urban air quality data is not easily available. This is the first study of its kind to investigate measured microscopic vehicle movement in tandem with microscopic emissions modeling for a substantial study domain. [ABSTRACT FROM AUTHOR]

Plants play a fundamental role in maintaining coastal dunes but also accumulate littered microplastics (MPs). Migration tests suggest that naturally weathered MPs can leach out a broader range of potentially phytotoxic chemicals than virgin MPs. Thus, assessing MPs effects on plants using beached-collected particles rather than virgin ones is critically important. Here, the effects on plants of leachates from two pools of beach-collected and virgin MPs, high-density polyethylene (HDPE) and polypropylene (PP), and their mixture, were explored combining toxicity tests and chemical analyses. Phytotoxicity of MP leachates at different dilutions was evaluated under standard laboratory conditions using test species and under environmentally realistic conditions using the dune species Thinopyrum junceum. Leachates from beached PP and HDPE adversely affected all species, and the extent of these effects varied according to polymer type, concentration, and species. Virgin MPs had weaker effects than beached ones. Several potentially phytotoxic oxidized compounds were detected in water by GC/MS analysis, and their amount estimated. Results indicate that the molecular species leaching from beached MPs - at ppm concentration levels for the individual chemical species - can inhibit plant growth, and the effects of leachates from mixtures of degraded MPs can differ from those from individual polymers, highlighting the need for further investigation of MPs consequences for coastal ecosystems. [Display omitted] • Leachates from beached PP and HDPE microplastics (MPs) were tested on plants. • MPs released many potentially phytotoxic oxidized degradation compounds. • Their amounts were determined by thermal desorption-GC-MS after SPE. • Leachates from beached MPs reduced seed germination and early plant growth. • Dune plants exposure to beached MPs is a potential threat to coastal ecosystems. [ABSTRACT FROM AUTHOR]

• Accelerated ageing of reference microplastics in artificial seawater was performed. • Solvent extraction of chemical species leached out in the water was developed. • GC/MS qualitative and semi-quantitative analysis were performed. • Leachates from plastic debris collected in natural environment were characterized. • The toxicity of the leachates and formation pathways of the polymers were highlighted. Microplastics are the particulate plastic debris found almost everywhere as environmental contaminants. They are not chemically stable persistent pollutants, but reactive materials. In fact, synthetic polymers exposed to the environment undergo chemical and physical degradation processes which lead not only to mechanical but also molecular fragmentation, releasing compounds that are potentially harmful for the environment and human health. We carried out accelerated photo-oxidative ageing of four reference microplastics (low- and high-density polyethylene, polypropylene, and polystyrene) directly in artificial seawater. We then made a characterization at the molecular level along with a quantification of the chemical species leached into water. Gas chromatography/mass spectrometry analyses performed after selective extraction and derivatization enabled us to identify more than 60 different compounds. Analysis of the leachates from the three polyolefins revealed that the main degradation products were mono- and dicarboxylic acids, along with linear and branched hydroxy acids. The highest amount of leached degradation species was observed for polystyrene, with benzoic acid and phenol derivatives as the most abundant, along with oligomeric styrene derivatives. The results from reference microplastics were then compared with those obtained by analyzing leachates in artificial seawater from aged plastic debris collected in a natural environment. The differences observed between the reference and the environmental plastic leachates mainly concerned the relative abundances of the chemical species detected, with the environmental samples showing higher amounts of dicarboxylic acids and oxidized species. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present paper we report the exclusive microbial preparation of polyhydroxyalkanoates (PHA) containing 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV) and 4-hydroxybutyrate (4HB) as comonomers through the use of unexpensive carbon sources such as whey from dairy industry. Polymers were produced by growing H. pseudoflava DSM 1034 in minimal medium supplemented with sucrose, lactose or whey without any co-substrate added. The chemical and physical properties of the polymers were fully characterized by GPC, DSC, TGA analyses and the composition by GC and 1H NMR examinations to especially confirm the content of different monomeric units. The presence of 4HB units into PHA samples is particularly aimed in thermoplastic applications where greater flexibility is required and conventional rigid PHAs tend to fail. Usually the insertion of 4HB into chain backbone consisting of 3-hydroxyalkanoates requires expensive carbon sources mostly of petrochemical origin. According to our study the production of P(3HB-co-3HV-co-4HB) terpolymer can be obtained directly by the use of lactose or waste raw materials such as cheese whey as carbon sources. Although the amount of 4HB in the produced terpolymers was usually low and not exceeding 10% of the total molar composition, a PHA containing 18.4% of 4HB units was produced in 1 step fermentation process from this structurally unrelated carbon sources. The crystallinity of the terpolymer is basically to be markedly affected with respect to that of conventional PHAs, thus obtaining a comparatively less rigid material and easier to be processed. [ABSTRACT FROM AUTHOR]

Abstract: Environmentally degradable polymers and plastics (EDPs) are a group of polymeric materials experiencing a rapid growth in number as well as in their applications and quantities used. The assessment of their key characteristic – degradability, including eventually biodegradability as the ultimate stage, is scientifically and technically a challenging issue and has led to differing interpretations in the past. In order to standardize techniques and criteria a number of standards were established by different standardization bodies which are also used as a basis for certification schemes. An up-to-date inventory of the rapidly growing standardization body is presented with basic interpretation to help guide the non-expert. A basic introduction to EDPs and polymer degradation is added for clarity. [Copyright &y& Elsevier]

Most of the analytical studies focused on microplastics (MPs) are based on the detection and identification of the polymers constituting the particles. On the other hand, plastic debris in the environment undergoes chemical and physical degradation processes leading not only to mechanical but also to molecular fragmentation quickly resulting in the formation of leachable, soluble and/or volatile degradation products that are released in the environment. We performed the analysis of reference MPs–polymer micropowders obtained by grinding a set of five polymer types down to final size in the 857–509 μm range, namely high- and low-density polyethylene, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (PET). The reference MPs were artificially aged in a solar-box to investigate their degradation processes by characterizing the aged (photo-oxidized) MPs and their low molecular weight and/or highly oxidized fraction. For this purpose, the artificially aged MPs were subjected to extraction in polar organic solvents, targeting selective recovery of the low molecular weight fractions generated during the artificial aging. Analysis of the extractable fractions and of the residues was carried out by a multi-technique approach combining evolved gas analysis–mass spectrometry (EGA–MS), pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS), and size exclusion chromatography (SEC). The results provided information on the degradation products formed during accelerated aging. Up to 18 wt% of extractable, low molecular weight fraction was recovered from the photo-aged MPs, depending on the polymer type. The photo-degradation products of polyolefins (PE and PP) included a wide range of long chain alcohols, aldehydes, ketones, carboxylic acids, and hydroxy acids, as detected in the soluble fractions of aged samples. SEC analyses also showed a marked decrease in the average molecular weight of PP polymer chains, whereas cross-linking was observed in the case of PS. The most abundant low molecular weight photo-degradation products of PS were benzoic acid and 1,4-benzenedicarboxylic acid, while PET had the highest stability towards aging, as indicated by the modest generation of low molecular weight species. [ABSTRACT FROM AUTHOR]

Pollution from microplastics (MPs) has become one of the most relevant topics in environmental chemistry. The risks related to MPs include their capability to adsorb toxic and harmful molecular species, and to release additives and degradation products into ecosystems. Their role as a primary source of a broad range of harmful volatile organic compounds (VOCs) has also been recently reported. In this work, we applied a non-destructive approach based on selected-ion flow tube mass spectrometry (SIFT-MS) for the characterization of VOCs released from a set of plastic debris collected from a sandy beach in northern Tuscany. The interpretation of the individual SIFT-MS spectra, aided by principal component data analysis, allowed us to relate the aged polymeric materials that make up the plastic debris (polyethylene, polypropylene, and polyethylene terephthalate) to their VOC emission profile, degradation level, and sampling site. The study proves the potential of SIFT-MS application in the field, as a major advance to obtain fast and reliable information on the VOCs emitted from microplastics. The possibility to obtain qualitative and quantitative data on plastic debris in less than 2 min also makes SIFT-MS a useful and innovative tool for future monitoring campaigns involving statistically significant sets of environmental samples. Image 1 • VOCs released from plastic debris were analyzed non-destructively by SIFT-MS. • Aged polymeric materials were characterized based on their SIFT-MS spectra. • PCA analysis of spectra correlated VOC profile, degradation level and sampling site. • SIFT-MS provided fast and reliable information on the VOCs emitted by microplastics. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are considered one of the most widespread pollutants in all ecosystems worldwide. In the environment, MPs can undergo hydrolysis and/or oxidation, resulting in the release of low-molecular weight degradation products, along with additives, and adsorbed organic pollutants. In this study, the morphological, chemical, and thermal changes of microplastics obtained from two biodegradable plastics, polylactic acid and Mater-Bi®, and a recycled plastic, recycled-polyethylene terephthalate, were examined after accelerated ageing under photo-oxidative conditions in synthetic seawater in a Solarbox system, and after thermal treatment in the dark. Thermal properties were studied by thermogravimetric analysis, differential scanning calorimetry, and evolved gas analysis-mass spectrometry. Compositions and changes of chemical components of the polymers were evaluated by attenuated total reflection-Fourier transform infrared spectroscopy and pyrolysis-gas chromatography-mass spectrometry. The leachable fractions and degradation products released in synthetic seawater by degraded MPs were characterized by gas chromatography-mass spectrometry. This study allowed us to identify hydrolysis as the main degradation pathway of the polymers under analysis, and to characterize not only the oligomers and degradation products released in the water as a consequence of degradation, but also additives used in plastic item formulations. This study improves our understanding of these polymers' behavior under accelerated ageing conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Virgin and environmentally aged polypropylene (PP) micropowders (V-PP and E-PP, respectively) were used as reference microplastics (MPs) in comparative photo- and thermo-oxidative ageing experiments performed on their mixtures with a natural ferrous sand (NS) and with a metal-free silica sand (QS). The ferrous NS was found to catalyze the photo-oxidative degradation of V-PP after both UV and simulated solar light irradiation. The catalytic activity in the V-PP/NS mixture was highlighted by the comparatively higher fraction of photo-oxidized PP extracted in dichloromethane, and the higher carbonyl index of the bulk polymer extracted with boiling xylene, when compared with the V-PP/QS mixture. Similarly, NS showed a catalytic effect on the thermal degradation (at T = 60 °C) of E-PP. The results obtained indicate that, under suitable environmental conditions (in this case, an iron-containing sediment or soil matrix, combined with simulated solar irradiation), the degradation of some types of MPs could be much faster than anticipated. Given the widespread presence of iron minerals (including the magnetite and iron-rich serpentine found in NS) in both coastal and mainland soils and sediments, a higher than expected resilience of the environment to the contamination by this class of pollutants is anticipated, and possible routes to remediation of polluted natural environments by eco-compatible iron-based minerals are envisaged., (© 2024. The Author(s).)

Tissue engineering represents an advanced therapeutic approach for the treatment of bone tissue defects. Polyhydroxyalkanoates are a promising class of natural polymers in this context thanks to their biocompatibility, processing versatility, and mechanical properties. The aim of this study is the development by computer-aided wet-spinning of novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)-based composite scaffolds for bone engineering. In particular, PHBV scaffolds are loaded with hydroxyapatite (HA), an osteoinductive ceramic, in order to tailor their biological activity and mechanical properties. PHBV blending with poly(lactide-co-glycolide) (PLGA) is also explored to increase the processing properties of the polymeric mixture used for composite scaffold fabrication. Different HA percentages, up to 15% wt., can be loaded into the PHBV or PHBV/PLGA scaffolds without compromising their interconnected porous architecture, as well as the polymer morphological and thermal properties, as demonstrated by scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. In addition, HA loading results in increased scaffold compressive stiffness to levels comparable to those of trabecular bone tissue, as well as in higher in vitro MC3T3-E1 cell viability and production of mineralized extracellular matrix, in comparison to what observed for unloaded scaffolds. The observed mechanical and biological properties suggest the suitability of the developed scaffolds for bone engineering., (© 2024 Wiley‐VCH GmbH.)

Different marine sponge species from Tethys Bay, Antarctica, were analyzed for contamination by polyester and polyamide microplastics (MPs). The PISA (Polymer Identification and Specific Analysis) procedure was adopted as it provides, through depolymerization and HPLC analysis, highly sensitive mass-based quantitative data. The study focused on three analytes resulting from the hydrolytic depolymerization of polyesters and polyamides: terephthalic acid (TPA), 6-aminohexanoic acid (AHA), and 1-6-hexanediamine (HMDA). TPA is a comonomer found in the polyesters poly(ethylene terephthalate) (PET) and poly(butylene adipate co terephthalate) (PBAT), and in polyamides such as poly(1,4-p-phenylene terephthalamide) (Kevlar™ and Twaron™ fibers) and poly(hexamethylene terephthalamide) (nylon 6 T). AHA is the monomer of nylon 6. HMDA is a comonomer of the aliphatic nylon 6,6 (HMDA-co-adipic acid) and of semi-aromatic polyamides such as, again, nylon 6 T (HMDA-co-TPA). Except for the biodegradable PBAT, these polymers exhibit high to extreme mechanical, thermal and chemical resistance. Indeed, they are used as technofibers in protective clothing able to withstand extreme conditions as those typical of Antarctica. Of the two amine monomers, only HMDA was found above the limit of quantification, and only in specimens of Haliclona (Rhizoniera) scotti, at a concentration equivalent to 27 μg/kg of nylon 6,6 in the fresh sponge. Comparatively higher concentrations, corresponding to 2.5-4.1 mg/kg of either PBAT or PPTA, were calculated from the concentration of TPA detected in all sponge species. Unexpectedly, TPA did not originate from PET (the most common textile fiber) as it was detected in the acid hydrolysate, whereas the PISA procedure results in effective PET depolymerization only under alkaline conditions. The obtained results showed that sponges, by capturing and concentrating MPs from large volumes of filtered marine waters, may be considered as effective indicators of the level and type of pollution by MPs and provide early warnings of increasing levels of pollution even in remote areas., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Stefania Giannarelli reports financial support was provided by Government of Italy Ministry of Education University and Research., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The total mass of individual synthetic polymers present as microplastic (MP < 2 mm) pollutants in the sediments of interconnected aquatic environments was determined adopting the Polymer Identification and Specific Analysis (PISA) procedure. The investigated area includes a coastal lakebed (Massaciuccoli), a coastal seabed (Serchio River estuarine), and a sandy beach (Lecciona), all within a natural park area in Tuscany (Italy). Polyolefins, poly(styrene) (PS), poly(vinyl chloride) (PVC), polycarbonate (PC), poly(ethylene terephthalate) (PET), and the polyamides poly(caprolactame) (Nylon 6) and poly(hexamethylene adipamide) (Nylon 6,6) were fractionated and quantified through a sequence of selective solvent extractions followed by either analytical pyrolysis or reversed-phase HPLC analysis of the products of hydrolytic depolymerizations under acidic and alkaline conditions. The highest concentrations of polyolefins (highly degraded, up to 864 µg/kg of dry sediment) and PS (up to 1138 µg/kg) MPs were found in the beach dune sector, where larger plastic debris are not removed by the cyclic swash action and are thus prone to further aging and fragmentation. Surprisingly, low concentrations of less degraded polyolefins (around 30 µg/kg) were found throughout the transect zones of the beach. Positive correlation was found between polar polymers (PVC, PC) and phthalates, most likely absorbed from polluted environments. PET and nylons above their respective LOQ values were found in the lakebed and estuarine seabed hot spots. The pollution levels suggest a significant contribution from riverine and canalized surface waters collecting urban (treated) wastewaters and waters from Serchio River and the much larger Arno River aquifers, characterized by a high anthropogenic pressure., (© 2023. The Author(s).)