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Plastic recycling is an effective strategy to solve the shortage of national resources and improve the ecological environment. Herein, a novel approach was proposed to identify different colored plastics using laser-induced breakdown spectroscopy (LIBS) by neighborhood component analysis (NCA) and support vector machine (SVM). Six kinds of plastics (PVC, POM, ABS, PP, PA, and PE) with multiple colors were used to verify the feasibility of this method. Firstly, the types of plastics were classified by SVM, and the average accuracy about 97% was obtained. Then the same type of plastics with multiple colors was classified by SVM, and more than 99% average accuracy was acquired. However, the average accuracy of PVC by SVM was only 82%. To improve the average identification accuracy of PVC, the neighborhood component analysis (NCA) was used for feature selection by evaluating the weights of spectral lines. The spectral lines of focus elements (hydrogen (H), potassium (K), carbon (C), etc.) with higher weight were used as the input of SVM. The average accuracy of NCA-SVM was 91%, which higher than 9% and 5% with SVM and principal component analysis (PCA) combined with SVM (PCA -SVM), respectively. The results demonstrated that LIBS with the SVM and NCA-SVM can acquire high accuracy identification of different plastics, as well as recognition of the same type of plastics with different colors.

Plastics play an important role in manufacture and our daily life. In order to realize fast classifications of plastics products, this paper proposes a method using laser-induced breakdown spectroscopy (LIBS) combined with principal component analysis (PCA) and K_nearest neighbor algorithm (kNN) to achieve highly-accurate classification of plastic products with a small amount of data training.After dimensionality reduction by PCA, the higher the dimensionality reduction, the higher the average recognition accuracy of samples, but the rising trend tends to be flat. When the original data of each sample is reduced to less than 10 dimensions, the classification accuracy of classifying the same kind of samples produced by different manufacturers into different categories is significantly higher than that of classifying the same kind of samples produced by different manufacturers into one category. However, when the data is reduced to more than 10 dimensions, there is little difference between the two classification methods, when reduced to 20 dimensions, the average recognition accuracy is 99.6%.In the aspect of improving classification efficiency, after dimensionality reduction by PCA, the training time of the model is reduced from 369 s to 168 s, and the time of classifying a single sample is reduced from 0.1 s to less than 0.02 s. This work provides an effective method for rapid automatic classification in the process of plastic manufacturing and recycling.

We report an accurate recognition of ten different types of postconsumer plastics, including five extensively used basic plastics, by laser-induced breakdown spectroscopy (LIBS). Ratiometric and correlational analysis have been performed for the classification in which C/H ratio yielded partial discrimination while an excellent correlation has been observed between the intensity of the carbon peak with carbon single bonds. Additionally, a 3D correlational approach using the emission intensities of carbon, hydrogen, oxygen and nitrogen lines successfully segregated all the plastics. Finally, we report findings from partial least squares- discriminant analysis (PLS-DA) that demonstrates classification accuracies of over 93 %. We envision that the high classification accuracy is shown here will encourage further validation studies leading to routine application of LIBS for screening and identification of post-consumer plastics. • LIBS technique has demonstrated the identification of post-consumer plastics with an accuracy of 93 %. • Carbon peak intensity shows a strong correlation with the number of the carbon atoms. • 3D correlation of the atomic intestines has revealed excellent classification among the samples. • Feature selection combined with PLS-DA model resulted in identification accuracies over 89%. [ABSTRACT FROM AUTHOR]

Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 μm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds. Nontargeted chemical analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was used to compare the chemical profiles of leachates. After leaching for 12 days, DOC was 4.0 times higher in the micron TTP leachate than in the centimeter TTP leachate, and TDN was 2.6 times higher. The total GC×GC/TOF-MS chromatographic feature peak area was 2.9 times greater in the micron TTP leachate than the centimeter TTP leachate, and similarly, the total relative abundance of 54 tentatively identified compounds was 3.3 times greater. We identified frequently measured tire-related chemicals, such as 6PPD, N-cyclohexyl-N'-phenylurea (CPU), and hexa(methoxymethyl)melamine (HMMM), but nearly 50% of detected chemicals were not previously reported in tire literature or lacked toxicity information. Overall, the results demonstrate that smaller TTP have a greater potential to leach chemicals into aquatic systems, but a significant portion of these chemicals are not well-studied and require further risk assessment., 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 © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Plastic debris is thought to be widespread in freshwater ecosystems globally 1 . However, a lack of comprehensive and comparable data makes rigorous assessment of its distribution challenging 2,3 . Here we present a standardized cross-national survey that assesses the abundance and type of plastic debris (>250 μm) in freshwater ecosystems. We sample surface waters of 38 lakes and reservoirs, distributed across gradients of geographical position and limnological attributes, with the aim to identify factors associated with an increased observation of plastics. We find plastic debris in all studied lakes and reservoirs, suggesting that these ecosystems play a key role in the plastic-pollution cycle. Our results indicate that two types of lakes are particularly vulnerable to plastic contamination: lakes and reservoirs in densely populated and urbanized areas and large lakes and reservoirs with elevated deposition areas, long water-retention times and high levels of anthropogenic influence. Plastic concentrations vary widely among lakes; in the most polluted, concentrations reach or even exceed those reported in the subtropical oceanic gyres, marine areas collecting large amounts of debris 4 . Our findings highlight the importance of including lakes and reservoirs when addressing plastic pollution, in the context of pollution management and for the continued provision of lake ecosystem services., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

This paper presents the abundance and ubiquitous presence of microplastics in a protected coastal zone located in the southeast of Spain: The Mar Menor lagoon, an important tourist destination in this region. Seventeen sampling sites, corresponding to both intertidal and backshore points, were collected during winter 2017 and 2018, being situated in different protected areas according to international, European and Spanish environmental policies. The main objectives of the study were to examine microplastics in both protected and non-protected areas, and to test the importance of local activities on their presence. Northwest samples reported higher average microplastic concentrations than samples collected in the southeastern part of the coastal lagoon, likely due to the extensive use of sludge from wastewater treatment plants besides the fragmentation of low density polyethylene from plastic greenhouses, being microplastic films also higher for northwest than for southeast samples. Moreover, large inter-site differences observed in microplastic concentrations also demonstrated that local activities, mainly tourism and fishery, may play an important role as microplastic sources. The extensive amount of 17 different polymer types identified in this paper, much higher than most reported in similar studies, together with the variety of colors of microplastics most of them in a fragmented form (59.4%) and mainly detected in urban beaches, should be related to the geographical situation of this coastal lagoon, together with enormous environmental passives accumulated over the past 50 years. Only polyvinyl ester resins proved to be statistically higher in non-protected than in protected zones, probably related to their use in manufacturing boat hulls, although sources and pathways for microplastics are always difficult to assess. Measures to avoid microplastic pollution should be taken through educational programs, with also a clear commitment from plastic producers and transformers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

At present, the study of microplastic sources is in a relatively preliminary stage due to the complexity of microplastic features in the environment. Based on a literature review, we developed a source-specific classification system for the quantitative analysis of microplastic sources. The classification system includes ten types of microplastics based on morphology and composition and can identify their main sources and the associated probabilities. To reflect the complexity of types and sources in the regional combination of microplastics, we first propose a microplastic diversity index (D 1-D '(MP)). We use the South China Sea as an example to carry out quantitative source analysis and calculate the diversity index. Eight types of microplastics were found, mainly consisting of maritime coatings (type "Gran_coat") (33.0%) and synthetic fibers (type "Fib_thin") (29.6%). We also found that the diversity increased with offshore distance. In addition, we partitioned surface microplastics globally according to a two-dimensional microplastic abundance-diversity index. We believe that these indicators can effectively reflect pollution status and ultimately lead to different types of control measures. In the future, additional indicators for the characterization of microplastics must be included in the classification system to establish a one-to-one source analysis system for microplastic characteristics and source apportionment. In general, our study may provide new insights into the establishment of more accurate and quantitative source apportionment techniques and effective pollution control., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Despite concerns regarding the environmental impacts of microplastics, knowledge of the incidence and levels of synthetic particles in large marine vertebrates is lacking. Here, we utilize an optimized enzymatic digestion methodology, previously developed for zooplankton, to explore whether synthetic particles could be isolated from marine turtle ingesta. We report the presence of synthetic particles in every turtle subjected to investigation (n = 102) which included individuals from all seven species of marine turtle, sampled from three ocean basins (Atlantic [ATL]: n = 30, four species; Mediterranean (MED): n = 56, two species; Pacific (PAC): n = 16, five species). Most particles (n = 811) were fibres (ATL: 77.1% MED: 85.3% PAC: 64.8%) with blue and black being the dominant colours. In lesser quantities were fragments (ATL: 22.9%: MED: 14.7% PAC: 20.2%) and microbeads (4.8%; PAC only; to our knowledge the first isolation of microbeads from marine megavertebrates). Fourier transform infrared spectroscopy (FT-IR) of a subsample of particles (n = 169) showed a range of synthetic materials such as elastomers (MED: 61.2%; PAC: 3.4%), thermoplastics (ATL: 36.8%: MED: 20.7% PAC: 27.7%) and synthetic regenerated cellulosic fibres (SRCF; ATL: 63.2%: MED: 5.8% PAC: 68.9%). Synthetic particles being isolated from species occupying different trophic levels suggest the possibility of multiple ingestion pathways. These include exposure from polluted seawater and sediments and/or additional trophic transfer from contaminated prey/forage items. We assess the likelihood that microplastic ingestion presents a significant conservation problem at current levels compared to other anthropogenic threats., (© 2018 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.)

Thin films of various polymers are currently used for wrapping various food products and illicit drugs worldwide. In thin films, polyvinyl chloride is the third most widely used polymer after the polyethylene and polypropylene. These films usually contain harmful plasticizers such as adipates, phthalates, and citrates along with other additives. Plasticizers adversely affect the human health and therefore, their migration in foodstuff must be monitored carefully. By considering all these facts, this study summarizes the utilities of non-destructive ATR-FTIR spectroscopy in the identification of base polymer as well as plasticizers in various cling films and application of multivariate analysis in the identification and classification of the cling films to their respective groups. In the present research, a considerable transfer of plasticizers from the wrapping material is observed. A spectral library is developed for all 22 cling film samples for further comparison of the unknown sample. The obtained results are promising, especially for classification purposes. The multivariate method significantly provides 100% of cross-validation classification along with 99.13% discrimination. In this study, we have developed a method to compare or link a cling film which somebody uses and found that there is a transfer of plasticizers and other additives into the food and if the manufacturing company disown that this specific cling film does not belong to our company. In such type of cases, this method could link the suspected cling film to their manufacturers with precision and accurateness. The chronic effect of plasticizers on human health can also be linked to the type of cling film the accused was using consistently., (Copyright © 2018 Elsevier B.V. All rights reserved.)

During the last decades, biopolymers experienced a renaissance. The increasing limitation of fossil resources in combination with a public demand for environmental-friendly and sustainable processes has led to the formation of a market for biobased plastics. Especially non-biodegradable bioplastics are very interesting materials, as they combine the benefits of reduced carbon footprint during production and increased resource efficiency with the persistence to microbial degradation. Consequently, persistent biomass-derived plastic materials are highly promising to substitute conventional fossil-based plastics in applications, which require durability and longevity. Non-biodegradable bioplastics derived from renewable resources represent 57% of all bioplastics with partially biobased polyethylene terephthalate currently leading the market, followed by biobased polyamides and fully biomass-derived polyethylene. An exceptional biopolymer with thermoplastic properties was discovered only two decades ago, when-for the first time-polythioesters were synthesized by microbial fermentation. Though synthesized by bacteria, it turned out that polythioesters are non-biodegradable by microorganisms in contrast to all other biopolymers and thus, represent a novel non-biodegradable bioplastic material. This review gives an overview about the recent development and progress regarding bioplastics with special focus on persistent bioplastics. We describe the generation of the respective monomers from biomass-derived substrates and summarize the current status of production, which range from the laboratory-scale up to large-scale industrial processes.

A review is presented of the manufacture and use of different types of plastic, and the effects of pollution by these materials on animal, human and environmental health, insofar as this is known. Since 2004, the world has made as much plastic as it did in the previous half century, and it has been reckoned that the total mass of virgin plastics ever made amounts to 8.3 billion tonnes, mainly derived from natural gas and crude oil, used as chemical feedstocks and fuel sources. Between 1950 and 2015, a total of 6.3 billion tonnes of primary and secondary (recycled) plastic waste was generated, of which around 9% has been recycled, and 12% incinerated, with the remaining 79% either being stored in landfills or having been released directly into the natural environment. In 2015, 407 million tonnes (Mt) of plastic was produced, of which 164 Mt was consumed by packaging (36% of the total). Although quoted values vary, packaging probably accounts for around one third of all plastics used, of which approximately 40% goes to landfill, while 32% escapes the collection system. It has been deduced that around 9 Mt of plastic entered the oceans in 2010, as a result of mismanaged waste, along with up to 0.5 Mt each of microplastics from washing synthetic textiles, and from the abrasion of tyres on road surfaces. However, the amount of plastics actually measured in the oceans represents less than 1% of the (at least) 150 Mt reckoned to have been released into the oceans over time. Plastic accounts for around 10% by mass of municipal waste, but up to 85% of marine debris items - most of which arrive from land-based sources. Geographically, the five heaviest plastic polluters are P. R. China, Indonesia, Philippines, Vietnam and Sri Lanka, which between them contribute 56% of global plastic waste. Larger, primary plastic items can undergo progressive fragmentation to yield a greater number of increasingly smaller 'secondary' microplastic particles, thus increasing the overall surface area of the plastic material, which enhances its ability to absorb, and concentrate, persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs), with the potential to transfer them to the tissues of animals that ingest the microplastic particles, particularly in marine environments. Although fears that such microparticles and their toxins may be passed via food webs to humans are not as yet substantiated, the direct ingestion of microplastics by humans via drinking water is a distinct possibility - since 92% of samples taken in the USA and 72% in Europe showed their presence - although any consequent health effects are as yet unclear. Foodstuffs may also become contaminated by microplastics from the air, although any consequent health effects are also unknown. In regard to such airborne sources, it is noteworthy that small plastic particles have been found in human lung tissue, which might prove an adverse health issue under given circumstances. It is also very striking that microplastics have been detected in mountain soils in Switzerland, which are most likely windborne in origin. Arctic ice core samples too have revealed the presence of microplastics, which were most likely carried on ocean currents from the Pacific garbage patch, and from local pollution from shipping and fishing. Thus, sea ice traps large amounts of microplastics and transports them across the Arctic Ocean, but these particles will be released into the global environment when the ice melts, particularly under the influence of a rising mean global temperature. While there is a growing emphasis toward the substitution of petrochemically derived plastics by bioplastics, controversy has arisen in regard to how biodegradable the latter actually are in the open environment, and they presently only account for 0.5% of the total mass of plastics manufactured globally. Since the majority of bioplastics are made from sugar and starch materials, to expand their use significantly raises the prospect of competition between growing crops to supply food or plastics, similarly to the diversion of food crops for the manufacture of primary biofuels. The use of oxo-plastics, which contain additives that assist the material to degrade, is also a matter of concern, since it is claimed that they merely fragment and add to the environmental burden of microplastics; hence, the European Union has moved to restrict their use. Since 6% of the current global oil (including natural gas liquids, NGLs) production is used to manufacture plastic commodities - predicted to rise to 20% by 2050 - the current approaches for the manufacture and use of plastics (including their end-use) demand immediate revision. More extensive collection and recycling of plastic items at the end of their life, for re-use in new production, to offset the use of virgin plastic, is a critical aspect both for reducing the amount of plastic waste entering the environment, and in improving the efficiency of fossil resource use. This is central to the ideology underpinning the circular economy, which has common elements with permaculture, the latter being a regenerative design system based on 'nature as teacher', which could help optimise the use of resources in town and city environments, while minimising and repurposing 'waste'. Thus, food might be produced more on the local than the global scale, with smaller inputs of fuels (including transportation fuels for importing and distributing food), water and fertilisers, and with a marked reduction in the use of plastic packaging. Such an approach, adopted by billions of individuals, could prove of immense significance in ensuring future food security, and in reducing waste and pollution - of all kinds.

A novel method, calcium hypochlorite (CHC) treatment, was proposed for separation of hazardous poly(vinyl chloride) (PVC) plastic from mixed plastic wastes (MPWs) by froth flotation. Flotation behavior of single plastic indicates that PVC can be separated from poly(ethylene terephthalate) (PET), poly(acrylonitrile-co-butadiene-co-styrene) (ABS), polystyrene (PS), polycarbonate (PC) and poly(methyl methacrylate) (PMMA) by froth flotation combined with CHC treatment. Mechanism of CHC treatment was examined by contact angle measurement, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Under the optimum conditions, separation of PVC from binary plastics with different particle sizes is achieved efficiently. The purity of PC, ABS, PMMA, PS and PET is greater than 96.8%, 98.5%, 98.8%, 97.4% and 96.3%, respectively. Separation of PVC from multi-plastics was further conducted by two-stage flotation. PVC can be separated efficiently from MPWs with residue content of 0.37%. Additionally, reusing CHC solution is practical. This work indicates that separation of hazardous PVC from MPWs is effective by froth flotation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Since recycling of materials is widely assumed to be environmentally and economically beneficial, reliable sorting and processing of waste packaging materials such as plastics is very important for recycling with high efficiency. An automated system that can quickly categorize these materials is certainly needed for obtaining maximum classification while maintaining high throughput. In this paper, first of all, the photographs of the plastic bottles have been taken and several preprocessing steps were carried out. The first preprocessing step is to extract the plastic area of a bottle from the background. Then, the morphological image operations are implemented. These operations are edge detection, noise removal, hole removing, image enhancement, and image segmentation. These morphological operations can be generally defined in terms of the combinations of erosion and dilation. The effect of bottle color as well as label are eliminated using these operations. Secondly, the pixel-wise intensity values of the plastic bottle images have been used together with the most popular subspace and statistical feature extraction methods to construct the feature vectors in this study. Only three types of plastics are considered due to higher existence ratio of them than the other plastic types in the world. The decision mechanism consists of five different feature extraction methods including as Principal Component Analysis (PCA), Kernel PCA (KPCA), Fisher's Linear Discriminant Analysis (FLDA), Singular Value Decomposition (SVD) and Laplacian Eigenmaps (LEMAP) and uses a simple experimental setup with a camera and homogenous backlighting. Due to the giving global solution for a classification problem, Support Vector Machine (SVM) is selected to achieve the classification task and majority voting technique is used as the decision mechanism. This technique equally weights each classification result and assigns the given plastic object to the class that the most classification results agree on. The proposed classification scheme provides high accuracy rate, and also it is able to run in real-time applications. It can automatically classify the plastic bottle types with approximately 90% recognition accuracy. Besides this, the proposed methodology yields approximately 96% classification rate for the separation of PET or non-PET plastic types. It also gives 92% accuracy for the categorization of non-PET plastic types into HPDE or PP., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Dental materials, especially in restorative dentistry, must not only be cost-effective, they must also meet many other requirements: biocompatibility, durability, excellent shade and light effects, abrasion resistance, hardness, mechanical strength under pressure, chemical resistance, surface density, ease of manufacture, and easy intraoral maintenance.

Plastic debris on six beaches near the Nakdong River Estuary, South Korea, was sampled in May and September 2012 and classified into three size classes, large microplastics (1-5 mm), mesoplastics (5-25 mm), and macroplastics (>25 mm). The relationships among the abundances of the size classes were then examined. The abundances of each size category in May (before rainy season) and in September (after rainy season) were 8205 and 27,606 particles/m(2) for large microplastics, 238 and 237 particles/m(2) for mesoplastics, and 0.97 and 1.03 particles/m(2) for macroplastics, respectively. Styrofoam was the most abundant item both in microplastic and mesoplastic debris, while intact plastics were most common in macroplastic debris. The abundances of meso- and micro-plastics were the most strongly correlated. There was a higher correlation between the abundances of macro- and meso-plastics than between macro- and micro-plastics., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Plastic is a broad name given to the different types of organic polymers having high molecular weight and is commonly derived from different petrochemicals. Plastics are generally not biodegradable or few are degradable but in a very slow rate. Day by day, the global demand of these polymers is sharply increasing; however, considering their abundance and potentiality in causing different environmental hazards, there is a great concern in the possible methods of degradation of plastics. Recently, there have been some debates at the world stage about the potential degradation procedures of these synthetic polymers and microbial degradation has emerged as one of the potential alternative ways of degradation of plastics. Alternatively, some scientists have also reported many adverse effects of these polymers in human health, and thus, there is an immediate need of a potential screening of some potential microbes to degrade these synthetic polymers. In this review, we have taken an attempt to accumulate all information regarding the chemical nature along with some potential microbes and their enzymatic nature of biodegradation of plastics along with some key factors that affect their biodegradability.

Objectives: To identify and classify disposable hospital products containing polyvinyl chloride (PVC), including the search and evaluation of cost-effective sustainable alternative products free of PVC., Methods: A descriptive observational analysis was performed, after classifying the latest research in major databases, and disposable products that could contain PVC. These were divided into 5 groups: cannulas, catheters, tubes, bags, and equipment, purchased in the period 2008-2009, differentiating between the technical and economic assessment of the materials., Results: In the analysis of the composition of 492 articles selected, 234 (47.5%) contained PVC, and 19.4% were considered PVC-free alternatives, with only 11.3% of these being economically viable., Conclusions: This study highlights the advantages of the classification of PVC products, by showing that safe and efficient alternatives exist for some product lines that are consistent with patient safety and quality in the work by doctors., (Copyright © 2011 SECA. Published by Elsevier Espana. All rights reserved.)

This review of 68 studies compares the methodologies used for the identification and quantification of microplastics from the marine environment. Three main sampling strategies were identified: selective, volume-reduced, and bulk sampling. Most sediment samples came from sandy beaches at the high tide line, and most seawater samples were taken at the sea surface using neuston nets. Four steps were distinguished during sample processing: density separation, filtration, sieving, and visual sorting of microplastics. Visual sorting was one of the most commonly used methods for the identification of microplastics (using type, shape, degradation stage, and color as criteria). Chemical and physical characteristics (e.g., specific density) were also used. The most reliable method to identify the chemical composition of microplastics is by infrared spectroscopy. Most studies reported that plastic fragments were polyethylene and polypropylene polymers. Units commonly used for abundance estimates are "items per m(2)" for sediment and sea surface studies and "items per m(3)" for water column studies. Mesh size of sieves and filters used during sampling or sample processing influence abundance estimates. Most studies reported two main size ranges of microplastics: (i) 500 μm-5 mm, which are retained by a 500 μm sieve/net, and (ii) 1-500 μm, or fractions thereof that are retained on filters. We recommend that future programs of monitoring continue to distinguish these size fractions, but we suggest standardized sampling procedures which allow the spatiotemporal comparison of microplastic abundance across marine environments.

We investigated the plastics ingested by short-tailed shearwaters, Puffinus tenuirostris, that were accidentally caught during experimental fishing in the North Pacific Ocean in 2003 and 2005. The mean mass of plastics found in the stomach was 0.23 g per bird (n=99). Plastic mass did not correlate with body weight. Total PCB (sum of 24 congeners) concentrations in the abdominal adipose tissue of 12 birds ranged from 45 to 529 ng/g-lipid. Although total PCBs or higher-chlorinated congeners, the mass of ingested plastic correlated positively with concentrations of lower-chlorinated congeners. The effects of toxic chemicals present in plastic debris on bird physiology should be investigated., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Plastic debris is a worldwide threat to marine environments and Portugal is not immune to it. Though never quantified, items of all sizes can be found in the Portuguese coastline; therefore the objective of this work is the identification of main size classes in stranded plastic debris. Beaches sediment was sampled and in the laboratory plastic items were sorted in 11 classes from <1 to >10mm, counted and weighted. Plastic size ranged from 50 μm to 20 cm and microplastics (<5mm) were the majority (72%). Most plastic fits in the smaller size classes, due to expected high residence time in the sea enhancing degradation processes, which increase surface exposure and potentially persistent organic pollutants (POP) adsorption. These results point out the important contribution of microplastics to marine debris pollution, its risks, and the need to set a higher focus on this size class., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Plastics constitute a large material group with a global annual production that has doubled in 15 years (245 million tonnes in 2008). Plastics are present everywhere in society and the environment, especially the marine environment, where large amounts of plastic waste accumulate. The knowledge of human and environmental hazards and risks from chemicals associated with the diversity of plastic products is very limited. Most chemicals used for producing plastic polymers are derived from non-renewable crude oil, and several are hazardous. These may be released during the production, use and disposal of the plastic product. In this study the environmental and health hazards of chemicals used in 55 thermoplastic and thermosetting polymers were identified and compiled. A hazard ranking model was developed for the hazard classes and categories in the EU classification and labelling (CLP) regulation which is based on the UN Globally Harmonized System. The polymers were ranked based on monomer hazard classifications, and initial assessments were made. The polymers that ranked as most hazardous are made of monomers classified as mutagenic and/or carcinogenic (category 1A or 1B). These belong to the polymer families of polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrenic copolymers. All have a large global annual production (1-37 million tonnes). A considerable number of polymers (31 out of 55) are made of monomers that belong to the two worst of the ranking model's five hazard levels, i.e. levels IV-V. The polymers that are made of level IV monomers and have a large global annual production (1-5 million tonnes) are phenol formaldehyde resins, unsaturated polyesters, polycarbonate, polymethyl methacrylate, and urea-formaldehyde resins. This study has identified hazardous substances used in polymer production for which the risks should be evaluated for decisions on the need for risk reduction measures, substitution, or even phase out., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Laser induced breakdown spectroscopy (LIBS) was applied for the detection of trace elements in non-degradable part of plastics known as insoluble organic material, obtained from thermal and catalytic degradation of plastics. LIBS signal intensity for each metal measured in the test sample was unique and different. The capability of this technique is demonstrated by analyzing various trace metals present inside plastics and also compared with ICP results. The metal concentration (ppm) measured with LIBS and verified by ICP for Ag (901), Al (522), Fe (231), Co (628), V (275), Ni (558), Pb (325), Mn (167) and Cd (378) are higher than permissible safe limits.

Lack of degradability and the closing of landfill sites as well as growing water and land pollution problems have led to concern about plastics. With the excessive use of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The interest in environmental issues is growing and there are increasing demands to develop material which do not burden the environment significantly. Biodegradation is necessary for water-soluble or water-immiscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires understanding of the interactions between materials and microorganisms and the biochemical changes involved. Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. This paper reviews the current research on the biodegradation of biodegradable and also the conventional synthetic plastics and also use of various techniques for the analysis of degradation in vitro.

Laser-Induced Breakdown Spectroscopy (LIBS) was applied for the identification of various kinds of plastics for management and recycling of plastic waste. In order to fingerprint these plastics, a laser-produced plasma emission was recorded for spectral analysis of various kinds of plastics. The plasma was generated by focusing a Nd:YAG laser radiation at wavelength = 1064 nm having laser energy = 40 mJ. The 6 main family of plastics tested are: Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polypropylenes (PP), Polystyrene (PS), Polyethylene Terephthalate (PET) and Polyvinyl chloride (PVC). The capability of this technique is demonstrated by the analysis of the major constituents carbon and hydrogen present in polymer matrices. The LIBS signal intensity measured for carbon and hydrogen was detrimental for the fingerprinting of various kinds of plastics. The C/H line intensity ratio was 1.68, 1.51, 1.42, 1.16, 1.01 and 0.91 for HDPE, LDPE, PS, PP, PET and PVC respectively. The detection limits of carbon and hydrogen were found to be approximately 6 micro g/g by applying 20 laser shots. The unique features of LIBS are: it is a simple, rapid, remote, real-time analysis without sampling requirements. The study demonstrated that LIBS could be applied as a best tool for sorting out different kinds plastics on a fast scale for waste management. The health hazards of different kinds of plastics are also described.

Waste to energy conversion is based on the classification of waste. In-flight catering wastes resulting from Egypt Airlines economy class passengers were classified. The solid waste stream generated contains plastic, paper, left-over waste food and aluminum. The type of meal served varies according to the period of flight and so the quantity and content of the waste stream. It was found that the waste generation rate varied from 61.3 to 265 g according to the meal type. Breakfast snack meal generates the highest weight of waste which recorded an average of 265 g. Plastic waste generated varied from 39.6% to 64.6% by weight for the various types of meals served. A total amount of 725 tons were generated annually from organic waste (paper, plastic and food waste) among which a non combustible 39.4 tons of aluminum. The calorific value for each generated item is calculated and the total energy potential reached up to 14.3 TJ annually.

Where is the best place to turn for help with plastics material selection? Sources of data and expertise are outlined here.

Polycationic derivatives of polynorbornene with different non-cytotoxic counterions, have been prepared by organometallic polymerization of methyleneammonium norbornene and subsequent exchange of the counterion. In this paper the effect of the counterion on the polycationic polymer binding onto plasmid DNA was studied via different ethidium bromide assays, heparin displacement and protection against degradation by DNAse. According to the nature of the counterions and consequently the size of the polymer particles, their complexation with the DNA led to aggregates with variable binding affinity for the plasmid. The relative transfection efficiency of each polyplex was compared, on the basis of reporter gene expression, in cells in culture. The nature of the counterion was seen to affect gene delivery. The order of transfection efficiency of the counterions studied at equivalent charge ratios (NH3+/PO4-) is lactobionate, acetate, chloride. The results obtained with the polynorbornene methyleneammonium lactobionate and acetate are particularly encouraging., (copyright 2004 Elsevier B.V.)

A new technology for automatic sorting of plastics, based upon optical identification of fluorescence signatures of dyes, incorporated in such materials in trace concentrations prior to product manufacturing, is described. Three commercial tracers were selected primarily on the basis of their good absorbency in the 310-370 nm spectral band and their identifiable narrow-band fluorescence signatures in the visible band of the spectrum when present in binary combinations. This absorption band was selected because of the availability of strong emission lines in this band from a commercial Hg-arc lamp and high fluorescence quantum yields of the tracers at this excitation wavelength band. The plastics chosen for tracing and identification are HDPE, LDPE, PP, EVA, PVC and PET and the tracers were compatible and chemically non-reactive with the host matrices and did not affect the transparency of the plastics. The design of a monochromatic and collimated excitation source, the sensor system are described and their performances in identifying and sorting plastics doped with tracers at a few parts per million concentration levels are evaluated. In an industrial sorting system, the sensor was able to sort 300 mm long plastic bottles at a conveyor belt speed of 3.5 m.sec(-1) with a sorting purity of -95%. The limitation was imposed due to mechanical singulation irregularities at high speed and the limited processing speed of the computer used.

TPEs provide medical designers with a broad spectrum of soft-feel, hygienic materials that can readily fulfill accepted medical industry standards with the exception of body implants. Ultimate performance is a combination of tailor-made formulations coupled with innovative design that captures the capability of the material's properties and thermoplastic processing techniques, including combination with other polymers by coinjection moulding or coextrusion.

When spraying, the drift is a restricting factor which reduces the efficiency of pesticides treatments and increases their impact on the environment. The use of anti-drift nozzles is the most common technique to reduce the drift effect. The basic principle of all anti-drift nozzles is to produce bigger droplets (Imag DLO, 1999) being less sensitive to the wind. The increase of the droplets' size is possible whether by reducing the spraying pressure (anti-drift fan nozzle) or by injecting air in the nozzle (air injection nozzles). This study aims at comparing the performances of the main anti-drift nozzles available on the Belgian market (Teejet DG and AI, Albuz ADI and AVI, Hardi ISO LD et AI). The study made it possible to compare thirteen different nozzles' sets according to their trademark, type and material. The study is based on the analysis of macroscopic parameters (flowrate, transversal distribution and individual distribution) as well as on the analysis of microscopic parameters (spraying deposit on artificial target). The evolution of these parameters is analysed according to the nozzle's wear. The wear is carried out artificially according to the "ISO 5682-1" standard (ISO 5682-1, 1996). The results confirmed the major influence of the manufacturing material on the nozzles' wear, ceramic being the most resistant material. Macroscopic as well as microscopic parameters variated according to the utilization time without any direct correlation. Indeed, most parameters variate in an uncertain way. It was however possible to establish a correlation between the wear time and the recovering rate and flowrate parameters. The utilization length is different depending on the type of nozzle, air injection nozzles being more resistant. At last, the analysis of microscopic parameters (spraying deposit) (Degré A., 1999), shows that the number of impacts is stable depending on the wear, while the size of impacts and the recovering rate increase.

One of the tasks of the Scientific Committee for Food (SCF) is to advise the Commission of the European Communities (CEC) on the safety-in-use of monomers, other starting substances and additives used in food packaging materials. This advice forms the basis of Community Directives for the regulation of food packaging materials by a system of positive lists of substances authorized for use. The SCF considers the available migration and toxicity data and classifies each substance into one of ten lists, reflecting whether or not there are adequate data and whether the data indicate the potential for adverse effects. This paper describes the SCF classification system and discusses the rationale behind the SCF approach to toxicity testing and evaluation of food packaging materials, with particular emphasis on the recent change which took place in 1990 when the Committee issued a new set of guidelines. These guidelines outlined a new tiered approach to toxicity testing, based on the principle that the greater the potential human exposure to a substance, the more toxicity data are required to make a sound health assessment.