Corrigendum: The presence of microplastics in commercial salts from different countries

This is the final version. Available from Springer Nature via the DOI in this recordThe article to which this is the corrigendum is in ORE at http://hdl.handle.net/10871/27394This corrects the article published in Scientific Reports Vol. 7, article 46173; published online: 06 April 2017; updated: 26 June 2017 DOI: 10.1038/srep46173

The presence of microplastics in commercial salts from different countries

This is the final version of the article. Available from Springer Nature via the DOI in this record.The corrigendum to this article is in ORE at http://hdl.handle.net/10871/34751The occurrence of microplastics (MPs) in saltwater bodies is relatively well studied, but nothing is known about their presence in most of the commercial salts that are widely consumed by humans across the globe. Here, we extracted MP-like particles larger than 149 μm from 17 salt brands originating from 8 different countries followed by the identification of their polymer composition using micro-Raman spectroscopy. Microplastics were absent in one brand while others contained between 1 to 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The particle size (mean ± SD) was 515 ± 171 μm. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Fragments were the primary form of MPs (63.8%) followed by filaments (25.6%) and films (10.6%). According to our results, the low level of anthropogenic particles intake from the salts (maximum 37 particles per individual per annum) warrants negligible health impacts. However, to better understand the health risks associated with salt consumption, further development in extraction protocols are needed to isolate anthropogenic particles smaller than 149 μm

Microplastics in eviscerated flesh and excised organs of dried fish

There is a paucity of information about the occurrence of microplastics (MPs) in edible fish tissues. Here, we investigated the potential presence of MPs in the excised organs (viscera and gills) and eviscerated flesh (whole fish excluding the viscera and gills) of four commonly consumed dried fish species (n=30 per species). The MP chemical composition was then determined using micro-Raman spectroscopy and elemental analysis with energy-dispersive X-ray spectroscopy (EDX). Out of 61 isolated particles, 59.0% were plastic polymers, 21.3% were pigment particles, 6.55% were non-plastic items (i.e. cellulose or actinolite), while 13.1% remained unidentified. The level of heavy metals on MPs or pigment particles were below the detection limit. Surprisingly, in two species, the eviscerated flesh contained higher MP loads than the excised organs, which highlights that evisceration does not necessarily eliminate the risk of MP intake by consumers. Future studies are encouraged to quantify anthropogenic particle loads in edible fish tissues

Abundance and characteristics of microplastics in commercial marine fish from Malaysia

Plastic debris is widespread and ubiquitous in the marine environment and ingestion of plastic debris by marine organisms is well-documented. Viscera and gills of 110 individual marine fish from 11 commercial fish species collected from the marine fish market were examined for presence of plastic debris. Isolated particles were characterized by Raman spectroscopy, and elemental analysis was assessed using energy-dispersive X-ray spectroscopy (EDX). Nine (of 11) species contained plastic debris. Out of 56 isolated particles, 76.8% were plastic polymers, 5.4% were pigments, and 17.8% were unidentified. Extracted plastic particle sizes ranged from 200 to 34,900 μm (mean = 2600 μm ±7.0 SD). Hazardous material was undetected using inorganic elemental analysis of extracted plastic debris and pigment particles. The highest number of ingested microplastics was measured in Eleutheronema tridactylum and Clarias gariepinus, suggesting their potential as indicator species to monitor and study trends of ingested marine litter

Isolation and characterization of microplastics in marine foodstuff

Due to the persistence and ubiquity of plastic debris in the marine environment, these contaminants have become one of the major threats to the ecosystem. Disposed plastic debris may never degrade but instead breakdown to smaller particles, termed microplastic (MP). Microplastics have been previously detected in a wide array of organisms, however, MP loads in processed seafood products such as canned sardine and saltwater products such as commercial salt originating from various regions of the world has never been investigated. To extract MPs from organisms, an efficient digesting solution is required. In an attempt to select an optimum digesting solution, the efficiency of different oxidative agents (NaClO or H2O2), bases (NaOH or KOH), and acids [HCl or HNO3; concentrated and diluted (5%)] in digesting fish tissues at room temperature (RT, 25 °C), 40, 50, or 60 °C was assessed and those treatments that were efficient in digesting the biological materials (>95%) were evaluated for their compatibility with eight major plastic polymers (assessed through recovery rate, Raman spectroscopy analysis, and morphological changes). Following the selection of appropriate solution, the MP loads in 20 brands of canned sardine originating from 13 countries were assessed. In addition, the presence of MPs in 17 brands of commercial salts originating from 8 countries has been investigated. Among the tested solutions, NaClO, NaOH, and diluted acids did not efficiently digest the biological matrices. The H2O2treatment only at 50 °C resulted in satisfactory digestion efficiency, although it decreased the recovery rate of nylon-6 and nylon-66 and changed the colour of polyethylene terephthalate fragments. Concentrated HCl and HNO3 treatments at RT fully digested the fish tissues, but also had a destructive impact on most polymers, particularly nylon-6 and nylon-66. Potassium hydroxide solution was able to fully eliminate the biological matrices at all temperatures. However, at 50 and 60 °C, it reduced the recovery rate of polyethylene terephthalate and polyvinyl chloride, and changed the colour of nylon-66. According to our results, treating biological materials with 10% KOH solution and incubating at 40 °C was time and cost-effective, efficient in digesting biological materials, and had no impact on the integrity of the plastic polymers. Study on canned sardine has shown that plastic particles were absent in 16 brands while between 1 and 3 plastic particles per brand were found in the other 4 brands. Out of 21 extracted particles, 28.5% were plastic polymers, 42.8% were additives, 4.7% were non-plastic, and 23.8% were unidentified. The most abundant plastic polymers were polypropylene (33.3%) and polyethylene terephthalate (33.3%). The analysis of commercial salts for MP loads has revealed that MPs were absent in one brand while others contained between 1 and 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Although this study presents a low level of anthropogenic particles intake from the canned sardine (1 to 5 anthropogenic particles per individual per annum) and salts (maximum 37 particles per individual per annum) which warrants negligible health impacts on consumers, however, due to the progressive fragmentation of MPs in the environment, the number of MPs in these products tend to increase. As such, it is highly recommended that the quantification of MPs in foodstuffs to be included as one of the components of food safety management system

Combined convection heat transfer of nanofluids flow over forward facing step in a channel having a blockage

Numerical simulations of two dimensional laminar combined convection flows using nanofluids over forward facing step with a blockage are analyzed. The continuity, momentum and energy equations are solved using finite volume method (FVM) and the SIMPLE algorithm scheme is applied to examine the effect of the blockage on the heat transfer characteristics. In this project, several parameters such as different types of nanofluids (Al2O3, SiO2, CuO and ZnO), different volume fraction in the range of 1% - 4%, different nanoparticles diameter in the range of 25nm-80nm were used. Effects of different shapes of blockage (Circular, Square and Triangular) were studied. The numerical results indicated that SiO2nanofluid has the highest Nusselt number. The Nusselt number increased as the volume fraction and Reynolds number increase, while it decreases as the nanoparticles diameter increases. Circular blockage produced higher results compared to triangular and square one

Advanced 3Y-TZP bioceramic doped with Al2O3 and MnO2 particles potentially for biomedical applications: study on mechanical and degradation properties

The effectiveness of Al2O3 and MnO2 in enhancing mechanical properties and retarding degradation of 3 mol% yttria stabilized tetragonal zirconia polycrystalline (3Y-TZP) ceramic samples was evaluated by pressureless sintering at temperatures ranging from 1250 °C to 1550 °C with standard holding time of 2 h. It was observed that the inclusion of Al2O3 and MnO2 into 3Y-TZP was beneficial for the improvement of mechanical properties and ageing resistance. The optimum amounts of dopants were determined to be of 0.6 wt% Al2O3 and 0.4 wt% MnO2. Microstructural investigation revealed that at the same temperature, the tetragonal grain size was not influenced by the increase of dopant levels. With optimum dopants the 3Y-TZP ceramic (density 6.1 g/cm3) samples demonstrated the Vickers hardness of 11.6 GPa, fracture toughness, KIC of 9.8 MPa m1/2, flexural strength of 900 MPa and Young's modulus of 210 GPa. Furthermore, the efficacy of the dopants (MnO2 and Al2O3) in retarding low-temperature degradation of 3Y-TZP ceramic during exposure in Ringer's solution at 37 °C was also evaluated. Overall, the degradation rate and weight loss of 0.6 wt% Al2O3 and 0.4 wt% MnO2 ceramic samples were 0.66% in 8 weeks as compared to the undoped samples. The 3Y-TZP bioceramic doped with Al2O3 and MnO2 could be a potential candidate material for biomedical applications (e.g. hip implants) due to its improved mechanical properties and superior ageing resistance. Keywords: Bioceramic, 3Y-TZP, Mechanical properties, Degradation, Ringer's solution, Hip implan