Pollutant content in marine debris and characterization by thermal decomposition

Marine debris (MDs) produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (plastics), leading to a gradual accumulation in the coastal and marine environment. Characterization of the MDs has been done in terms of their pollutant content: PAHs, ClBzs, ClPhs, BrPhs, PCDD/Fs and PCBs. The results show that MDs is not a very contaminated waste. Also, thermal decomposition of MDs materials has been studied in a thermobalance at different atmospheres and heating rates. Below 400–500 K, the atmosphere does not affect the thermal degradation of the mentioned waste. However, at temperatures between 500 and 800 K the presence of oxygen accelerates the decomposition. Also, a kinetic model is proposed for the combustion of the MDs, and the decomposition is compared with that of their main constituents, i.e., polyethylene (PE), polystyrene (PS), polypropylene (PP), nylon and polyethylene-terephthalate (PET).Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain). The author also thanks the Ministry of Economy, Industry and Competitiveness (Spain) for a Ph.D. grant (BES-2014-069473)

Marine debris occurrence and treatment: A review

Marine debris produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (as plastics, which are the most abundant type of marine debris), leading to a gradual, but significant accumulation in the coastal and marine environment. Along that time, marine debris is a significant source of chemical contaminants to the marine environment. Once extracted from the water, incineration is the method most widely used to treat marine debris. Other treatment methods have been tested, but they still need some improvement and so far have only been used in some countries. Several extraction and collection programs have been carried out. However, as marine debris keep entering the sea, these programs result insufficient and the problem of marine debris will continue its increase. The present work addresses the environmental impact and social aspects of the marine debris, with a review of the state of the art in the treatments of this kind of waste, together with an estimation of the worldwide occurrence and characteristics.Support for this work was provided Spanish Ministry of Culture and Sport and by the CTQ2013-41006-R project from the Ministry of Economy and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain)

Recyclability of four types of plastics exposed to UV irradiation in a marine environment

Plastics are the most abundant products in the world and therefore also represent the largest volume of materials found in the sea. Their resistance to degradation makes them dangerous for the marine environment. In this study, the degradation of the four main plastics (Nylon, Polyethylene (PE), Polypropylene (PP), Polyethylene terephthalate (PET)) found in the sea was observed for 6.5 months as they were exposed to UV irradiation in a marine environment. Data on changes in the physical and chemical properties of each of them were collected in order to evaluate the possibilities of material (mechanical) recycling. A thermobalance was used to look for differences in the thermal decomposition of the plastics during this time. In addition, the mechanical properties of each plastic were studied. Results showed that both thermal and mechanical properties were affected, causing a weakening of the material which became less elastic and more rigid. Furthermore, SEM and AFM images were obtained: they showed cracks, flakes and granular oxidation as well as a loss of homogeneity on the surface of the samples. These changes make mechanical recycling unfeasible, since the quality of the recycled material is insufficient to ensure a high virgin material substitution rate.This work was supported by the CTQ2016-76608-R project of the Ministry of Economy, Industry and Competitiveness (Spain) and the PROMETEOII/2014/007 project of the Valencian Community Government (Spain). The author M.E. Iñiguez also thanks the Ministry of Economy, Industry and Competitiveness (Spain) for a Ph.D. grant (contract grant number BES-2014-069473)

Effect of Sodium Chloride and Thiourea on Pollutant Formation during Combustion of Plastics

Thermal decomposition of different samples containing a mixture of plastics (polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and nylon) combined with NaCl and metal oxides (Fe2O3, CuO) was studied under an air atmosphere at 850 °C using a reactor, followed by analysis of the evolved products. Combustion runs were performed to study how the presence of such compounds influences the production of pollutants. Here, we report the analyses of the emissions of the main gases, as well as volatiles and semivolatiles, including polyaromatic hydrocarbons (PAHs), polychlorinated benzenes and phenols, and polybrominated phenols. Results show that the production of chlorinated pollutants did not increase in the presence of NaCl, but the presence of other metals during the decomposition led to the production of a great amount of pollutants. In this regard, the emission of chlorinated phenols increased from 110 to ca. 250 mg/kg when the sample included a small quantity of a transition metal oxide. Additionally, the presence of an inhibitor—thiourea (TUA)—was tested. Results confirm that adding TUA to the sample reduced these emissions to a considerable extent, with the emission of chlorinated phenols amounting to 65 mg/kg.This research was funded by Ministry of Economy, Industry and Competitiveness (Spain) grant number CTQ2016-76608-R, and by Valencian Community Government (Spain) grant number PROMETEOII/2014/007. The author M.E. Iñiguez was also funded by Ministry of Economy, Industry and Competitiveness (Spain) contract grant number BES-2014-069473

Microplastics in Spanish Table Salt

Marine debris is widely recognized as a global environmental problem. One of its main components, microplastics, has been found in several sea salt samples from different countries, indicating that sea products are irremediably contaminated by microplastics. Previous studies show very confusing results, reporting amounts of microparticles (MPs) in salt ranging from zero to 680 MPs/kg, with no mention of the possible causes of such differences. Several errors in the experimental procedures used were found and are reported in the present work. Likewise, 21 different samples of commercial table salt from Spain have been analyzed for MPs content and nature. The samples comprise sea salts and well salts, before and after packing. The microplastic content found was of 50–280 MPs/kg salt, being polyethylene-terephthalate (PET) the most frequently found polymer, followed by polypropylene (PP) and polyethylene (PE), with no significant differences among all the samples. The results indicate that even though the micro-particles might originate from multiple sources, there is a background presence of microplastics in the environment.Support for this work was provided by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain). The author M.E. Iñiguez also thanks the Ministry of Economy, Industry and Competitiveness (Spain) for a Ph.D. grant (contract grant number BES-2014-069473)

Including coronary ostia in patient-specific 3D models of the whole aortic valve apparatus, derived from TEE, for biomechanical simulations

There is an increasing interest in the numerical modeling and simulation of the aortic valve behavior and functioning, on the different stages involved as healthy, stenotic or replacement procedure. As echocardiography is a ubiquitous and economic modality, the geometric model construction based on such images is therefore of major interest. In this paper, a new patient-specific approach for modeling the complete aortic valve apparatus - derived from parameters extracted from 3D transesophageal echocardiographs -that includes for the first time the left ventricle outflow tract and the coronary ostia, both crucial for proper assessment of valve biomechanical behavior, is presented. An innovative method for characterizing coronary pressures from patient-specific clinical data, to be used as boundary conditions for the numerical simulation is also described. Results from experiments were presented to evaluate the novel aspects of the model, that permits to compare the existing models (non-coronary model NCM) and the proposed new coronary model (CM). Variations of displacement and stress on each leaflet prove the need of considering leaflet asymmetry. Computed quantities in the results sections are within the range of physiological data. This permits to conclude that the proposed aortic valve apparatus model of the aortic valve apparatus improves on previous ones by considering this extremely complex structure in greater detail.Xunta de Galicia | Ref. IN606A-2017/02

Pollution in the Marine Environment: Plastics, Microplastics and Organic Pollutants

Marine debris (MDs) produces a wide variety of negative environmental, economic, safety, health and cultural impacts, thus further research should focus on these kinds of waste. The present work has three main purposes: First, characterization of the MDs has been carried out in terms of their plastic composition, and their pollutant content (PAHs, ClBzs, ClPhs, BrPhs, PCDD/Fs and PCBs). Thermogravimetry has been used to identify the main constituents of the debris, using kinetic modelling to fit the proportion of each plastic. The decomposition of MDs is compared with that of their neat constituents, i.e. polyethylene (PE), polystyrene (PS), polypropylene (PP), nylon and polyethylen-tereftalate (PET). Furthermore, the analysis of pollutants in the samples reveal that MDs is not a highly contaminated waste. In addition, thermal decomposition of MD materials has been studied in a thermobalance at different atmospheres and heating rates. Second, a method for reusing the MDs is presented, consisting on the hydrothermal carbonization (HTC) of the wastes and the seawater where they are found. The plastics, once removed from the sea, cannot usually be recycled or reused. This debris has high net calorific value (NCV) what makes them suitable as a fuel. For this reason, a mixture of plastic materials was treated by HTC using seawater as a solvent, to examine the characteristics of the final products obtained and to test the feasibility of converting marine plastic debris to fuel. Results showed that an increase in the temperature of the process reduces the content of the inorganic anions and increases the NCV of the hydrochar (HTC char). The content of inorganic compounds in the HTC-liquor was measured, which increases as the process temperature rises. Organic compounds were also analyzed, being amides, alcohols and alkanes the major compounds in all cases. Finally, worried about the way in which these plastics reach the human being, microplastics where measured in sea products, more specifically in salt samples. In this sense, 21 different samples of commercial table salt from Spain have been analyzed for MP content and nature. The samples comprise sea salts and rock salts, before and after packing. Results indicate that even though the micro-particles might originate from multiple sources, there is a background presence of microplastics in the environment.Ministry of Economy, Industry and Competitiveness (Spain) grant numbers CTQ2016-76608-R and BES-2014-069473; University of Alicante (Spain) grant number UAUSTI10-06

Temporal patterns of reciprocity in communication networks

Human communication, the essence of collective social phenomena ranging from small-scale organizations to worldwide online platforms, features intense reciprocal interactions between members in order to achieve stability, cohesion, and cooperation in social networks. While high levels of reciprocity are well known in aggregated communication data, temporal patterns of reciprocal information exchange have received far less attention. Here we propose measures of reciprocity based on the time ordering of interactions and explore them in data from multiple communication channels, including calls, messaging and social media. By separating each channel into reciprocal and non-reciprocal temporal networks, we find persistent trends that point to the distinct roles of one-to-one exchange versus information broadcast. We implement several null models of communication activity, which identify memory, a higher tendency to repeat interactions with past contacts, as a key source of temporal reciprocity. When adding memory to a model of activity-driven, time-varying networks, we reproduce the levels of temporal reciprocity seen in empirical data. Our work adds to the theoretical understanding of the emergence of reciprocity in human communication systems, hinting at the mechanisms behind the formation of norms in social exchange and large-scale cooperation.publishedVersionPeer reviewe

Treatment of small vessel disease with the paclitaxel drug-eluting balloon: 6-month angiographic and 1-year clinical outcomes of the Spanish multicenter registry

Background: small vessel disease (SMD) remains a major challenge because of the increased risk of restenosis. We sought to assess the efficacy and safety of a paclitaxel-eluting balloon (PEB) in patients with SMD. Methods and results: one-hundred and four patients with native coronary lesions in small vessels treated by using a PEB were included in this prospective multicenter registry. In each case, after regular balloon dilatation, a larger PEB was inflated for a minimum of 45-60 seconds. Patients were 65 ± 10 years old, 43% diabetic, and 58% presented acutely. Angiographic success was 93% (7% bailout BMS implantation due to coronary dissection). The rate of major adverse cardiac events (MACE) at 12 months was 4.8% (1.9% cardiac death, 1.0% MI, and 2.9% TLR). One definite stent thrombosis was reported at 6 months in a patient with bailout BMS implantation. At 7 months, late loss was 0.31 ± 0.2 mm. Bail-out BMS after DEB use, was an independent predictor of MACE, HR 18.74, 95%CI (2.58-135.84) and TLR, HR 30.99, 95%CI (2.79-344.07). Conclusion: the use of this PEB for the treatment of SMD provides excellent 1-year outcomes with only 4.8% MACE. The need for a bailout BMS was a strong predictor of MACE and TLR