Microbiome Development of Seawater-Incubated Pre-production Plastic Pellets Reveals Distinct and Predictive Community Compositions

Plastics of various chemistries pollute global water bodies. Toxic chemicals leach with detrimental and often unpredictable impacts on the surrounding ecosystems. We found that seawater leachates of plastic pre-production pellets from 7 recycle categories are acutely toxic to stage II barnacle nauplii; lethal concentration 50 (LC50s) were observed in 24-h leachates from dilutions ranging from 0.007 to 2.1 mg/mL of seawater. Based on previous observations that macro-organismal settlement on fouling management coatings of various toxicities can be used to predict the toxicity of the coating, we hypothesized that interaction of plastic pre-production pellets with emerging microbiomes would exhibit patterns indicative of the chemistry at the pellet surface. We used amplicon sequencing of bacterial 16S ribosomal RNA genes to characterize the microbiomes that developed from 8 through 70 days on pellets exposed to the same flowing ambient seawater. Diversity and composition of the microbiomes colonizing plastic pellets changed over time and varied with plastic type. Microbial taxa belong to taxonomic groups known to consume hydrocarbons, to be prevalent following marine oil spills, or to live on fouling management surfaces. Microbiomes were still distinct between plastic types at Day 70, suggesting that differences in the physicochemical characteristics of the underlying plastics continue to exert variable selection of surface microbial communities. A random forest-based sample classifier correctly predicted 93% of plastic types using microbiome compositions. Surface microbiomes have promise for use in forensically identifying plastic types and potential toxicities.

The effect of plastic type on the yield and quality of lignite and plastic waste pyrolysis products

Lignite is a low rank coal which has great potential in South Kalimantan. However, it has not been used optimally due to its low quality. One of the ways to improve it is pyrolysis. Pyrolysis is the thermal decomposition of organic material in the absence of oxygen which will produce three products (char, tar and gas). Pyrolysis can make lignite into liquid fuel (pyrolysis liquid), but it still requires improvement due to the need for pure hydrogen donors. Plastic waste has a higher hydrogen/carbon ratio than coal. This material can be used as an additive in the pyrolysis process because it is rich in hydrogen. The samples of plastic waste used were ppolyethylene (PE), ppolypropylene (PP), and polystyrene (PS). Samples of lignite and plastic (plastic composition was 25 wt%) were used for every experiment, and pyrolysis was carried out with a holding time of 60 minutes at 500°C. The pyrolysis liquid obtained is then analyzed for its yields and properties (density, kinematic viscosity, heating value). The most feasible result for fuel alternative was obtained with the addition of PE.

CHARACTERIZATION OF CLAY MATERIALS USED FOR POTTERY PURPOSES FROM RENDENG, MALO, BOJONEGORO

Clay material from Rendeng, Malo, Bojonegoro was studied by mineralogy and physicochemical characterization to evaluate its potential suitability as a raw material in pottery application. X-ray Diffraction (XRD) and Fourier Transform-Infrared (FTIR) spectrometry were used to establish the mineralogy composition. Meanwhile the physical properties were identified by particle size distribution and consistency limits. Chemical composition was carried out by X-ray Fluorescence Spectrometer (XRF). The results of XRD characterization revealed that clay from Rendeng Village, Malo, Bojonegoro contained kaolin, quartz, and feldspar. Physical characterization shows that clay material is a less plastic type based on Atterberg method. Based on the chemical compositions indicated that SiO2, Al2O3, CaO, and Fe2O3 were abundance oxides. Therefore, clay from Desa Rendeng was only suitable for the pottery purposes because most of its mineral compositions did not meet the quality requirements for making advanced ceramics.

Stagnation Zone Near a Corner in Viscoplastic Fluid Flow

The shape, size and location of the stagnation zone between flat non-parallel walls that make up the corner of a tube with non-circular cross-section through which a phase change material of the Bingham plastic type flows is investigated. We show that the stagnant area is bounded by a convex meniscus whose size depends on the degree of plasticity and the vertex angle. The maximum and minimum energy dissipation occurs at the wall and at the bisectrix, respectively. The stagnant zone can be altogether avoided by modifying the shape of the wall in the corner area. A new design of the cross-section of the tube that allows reducing or eliminating this area to optimize the mass transport is developed. Two optimal solutions a vertex with a straight cut and a concavely curved vertex are proposed.

A Regional Approach For Health Risk Assessment of Toxicants in Plastic Food Containers

Plastic food containers are being used popularly, generating a waste of about 115 million tons in Vietnam. Such waste is causing environmental and health issues. This study conducted a field survey with 309 local people and selected 59 samples out of 135 plastic food containers collected in Go Vap district, Vietnam. Collected plastic samples identified compositions were PET 13.6 %, PP 28.8 %, PS 16.9 %, and 40.7 % X. Although most people are aware of the toxicity of plastics, plastics are still widely used due to their convenience and price with easy use and purchase. Collected plastic samples were classified based on the plastic type using recycling code and quantitatively analyzed with X-ray fluorescence spectroscopy method to assess concentrations of Cd, Sb, Pb, Hg, Sn, Cr, Br, Cl, and S. Most of these collected plastic samples (91.5 %) were found to contain 8/9 hazardous substances and most elements contained in these plastics were below their standard thresholds. However, elements Cl and Sb exceeded their safe thresholds, reached the highest concentrations of 1990.3 ppm and 469.2 ppm, respectively. Thus, additional health risks need to be assessed using the USEtox model. Finally, this study proposed a screening process to assess the risk of toxicity of elements contained in plastic food containers through ISO 31000:2018.

Bacterial Abundance, Diversity and Activity During Long-Term Colonization of Non-biodegradable and Biodegradable Plastics in Seawater

The microorganisms living on plastics called “plastisphere” have been classically described as very abundant, highly diverse, and very specific when compared to the surrounding environments, but their potential ability to biodegrade various plastic types in natural conditions have been poorly investigated. Here, we follow the successive phases of biofilm development and maturation after long-term immersion in seawater (7 months) on conventional [fossil-based polyethylene (PE) and polystyrene (PS)] and biodegradable plastics [biobased polylactic acid (PLA) and polyhydroxybutyrate-co-hydroxyvalerate (PHBV), or fossil-based polycaprolactone (PCL)], as well as on artificially aged or non-aged PE without or with prooxidant additives [oxobiodegradable (OXO)]. First, we confirmed that the classical primo-colonization and growth phases of the biofilms that occurred during the first 10 days of immersion in seawater were more or less independent of the plastic type. After only 1 month, we found congruent signs of biodegradation for some bio-based and also fossil-based materials. A continuous growth of the biofilm during the 7 months of observation (measured by epifluorescence microscopy and flow cytometry) was found on PHBV, PCL, and artificially aged OXO, together with a continuous increase in intracellular (3H-leucine incorporation) and extracellular activities (lipase, aminopeptidase, and β-glucosidase) as well as subsequent changes in biofilm diversity that became specific to each polymer type (16S rRNA metabarcoding). No sign of biodegradation was visible for PE, PS, and PLA under our experimental conditions. We also provide a list of operational taxonomic units (OTUs) potentially involved in the biodegradation of these polymers under natural seawater conditions, such as Pseudohongiella sp. and Marinobacter sp. on PCL, Marinicella litoralis and Celeribacter sp. on PHBV, or Myxococcales on artificially aged OXO. This study opens new routes for a deeper understanding of the polymers’ biodegradability in seawaters, especially when considering an alternative to conventional fossil-based plastics.

Central Giant Cell Granuloma of the Mandible: Clinical Observation

The Giant central cell granuloma (GCCG) is a benign intra-osseous lesion of the neo-plastic type. It appears mainly in the mandible, but can be observed in the maxilla and small bones of the hand and foot, with a predilection for the female sex and prevalence at a young age. Its diagnosis is clinical and radiological, confirmed by histological examination. The differential diagnosis is biological because it has a wide range of morphologies and a misinterpretation with other giant cell lesions can often occur. The authors present a case of the Giant central cell granuloma in a 62-year-old woman developing for 3 years after dental extractions. The most favorable treatment for giant cell granulomas is surgical whose main objective is to prevent recurrences.

Pengaruh Penambahan Serat Limbah Plastik HDPE terhadap Kuat Tekan pada Mortar

Mortar merupakan bahan konstruksi yang umum digunakan pada gedung maupun jalan. Beberapa konstruksi yang menggunakan mortar antara lain Lane Concrete (LC), spesi, perekat bata ringan, plester dinding, acian instan, pemasangan kramik, dan lain-lain. Serat limbah plastik HDPE (High Density Polyethylene) pada penelitian ini adalah bahan campuran sebagai pengikat dan pengganti semen. Plastik HDPE merupakan salah satu jenis plastik yang jika dilihat secara visual tergolong pekat, dimana pemakaian jenis plastik ini biasanya digunakan untuk botol minuman. Jenis plastik HDPE mudah untuk di daur ulang. Penelitian ini diharapkan dapat mengurangi jumlah limbah plastik yang ada di Indonesia. Tujuan penelitian ini adalah untuk mengkaji pengaruh pencampuran serat limbah plastik HDPE dengan variasi terhadap kuat tekan dan berat mortar. Serat yang digunakan sebanyak 0%, 2%, 4%, dan 6% terhadap berat semennya. Penelitian ini dilakukan untuk memperoleh kuat tekan mortar pada umur 7 hari dan 28 hari dengan menggunakan benda uji kubus dengan dimensi 15 cm × 15 cm × 15 cm. Hasil pengujian menunjukkan bahwa kuat tekan tertinggi untuk mortar serat pada variasi serat 2% di umur 28 hari yaitu sebesar 14,47 MPa. Kuat tekan mortar pada umur 7 dan 28 hari berturut-turut mengalami kenaikan sekitar 11%. Sedangkan pada penambahan serat, kuat tekan mortar mengalami penurunan seiring dengan semakin banyaknya campuran serat. Mortar serat mengalami penurunan berat dari 7696 gram menjadi 7640 gram, 7422 gram, dan 7280 gram, masing-masing untuk 2%, 4%, dan 6% serat pada umur 28 hari. Mortar is a construction material commonly used in building and road infrastructure. Some constructions that use mortar include Lane Concrete (LC), species, light brick adhesives, wall plaster, mechanical installation, and others. HDPE plastic waste fiber (High density polyethylene) in this study is a mixture of materials as binders and cement substitutes. HDPE plastic is one type of plastic that when viewed visually is classified as concentrated, where the use of this type of plastic is usually used for beverage bottles. The HDPE plastic type is easy to recycle. In 2015, global plastic waste in the world was recorded at 2.5 billion tons per year, so this research is expected to reduce the amount of plastic waste in Indonesia. The purpose of this study was to analyze the effect of mixing HDPE plastic waste fibers on compressive strength and mortar weight. This HDPE variations of 0%, 2%, 4%, and 6% is used from the weight of the cement. This study was carried out to obtain the compressive strength at the ages of 7 days and 28 days using cube specimens with dimensions of 15 cm × 15 cm × 15 cm. Based on the results of the test, the highest compressive strength for mortar at of 2% fiber variation at 28 days is 14.47 MPa. The compressive strength of mortar at the age of 7 and 28 consecutive days increased by 11%. While the addition of fibers, compressive strength of mortar decreases with the increasing number of fiber mixtures. Fiber mortar decreased in weight from 7696 grams to 7640 grams, 7422 grams, and 7280 grams, for fiber of 2%, 4%, and 6% respectively. Mortar is a construction material commonly used in building and road infrastructure. Some constructions that use mortar include Lane Concrete (LC), species, light brick adhesives, wall plaster, mechanical installation, and others. HDPE plastic waste fiber (High density polyethylene) in this study is a mixture of materials as binders and cement substitutes. HDPE plastic is one type of plastic that when viewed visually is classified as concentrated, where the use of this type of plastic is usually used for beverage bottles. The HDPE plastic type is easy to recycle. In 2015, global plastic waste in the world was recorded at 2.5 billion tons per year, so this research is expected to reduce the amount of plastic waste in Indonesia. The purpose of this study was to analyze the effect of mixing HDPE plastic waste fibers on compressive strength and mortar weight. This HDPE variations of 0%, 2%, 4%, and 6% is used from the weight of the cement. This study was carried out to obtain the compressive strength at the ages of 7 days and 28 days using cube specimens with dimensions of 15 cm × 15 cm × 15 cm. Based on the results of the test, the highest compressive strength for mortar at of 2% fiber variation at 28 days is 14.47 MPa. The compressive strength of mortar at the age of 7 and 28 consecutive days increased by 11%. While the addition of fibers, compressive strength of mortar decreases with the increasing number of fiber mixtures. Fiber mortar decreased in weight from 7696 grams to 7640 grams, 7422 grams, and 7280 grams, for fiber of 2%, 4%, and 6% respectively.

A Comparison of Microplastic in Fish From Australia and Fiji

Awareness surrounding plastic pollution has increased significantly in the past decade, leading to concerns on potential adverse effects on biota, including the consumption of microplastic by fish. Globally, plastic has been found in many species of fish, but little research has been undertaken in the southern hemisphere. We assessed the abundance and type of plastic in fish captured and sold for human consumption in Australia and Fiji. Fish (goatfish, sea mullet, paddletail, and common coral trout) had their gastrointestinal tracts dissected and microplastic quantified under a microscope. Plastic polymer types were confirmed using μ-FTIR. In Australia, plastic was found in 61.6% of fish gastrointestinal tracts, while in Fiji, 35.3% of fish had plastic. Fish from Australia had almost double the amount of plastic on average than fish caught in Fiji, with 1.58 (± 0.23) pieces per fish in Australia compared to 0.86 (± 0.14) in fish caught in Fiji. The types of plastic differed between countries, with fibers comprising 83.6% of microplastic pieces in fish from Australia whereas 50% of microplastic found in fish from Fiji was film. Polyolefin was the most abundant polymer type in both fibers from Australia and film from Fiji. We hypothesize variations in abundance and plastic type are a reflection of the population density and coastal geomorphology, but may also be a result of legislation and waste management strategies in the two countries. This work adds evidence to the pervasive presence of plastic in fish gastrointestinal tracts, reinforcing the urgent need for efficient plastic waste management, but also a better understanding of the impacts of microplastic on marine biota.

Effect of polymer type on the colonization of plastic pellets by marine bacteria

Plastic is omnipresent in the oceans and serves as a surface for biofilm-forming microorganisms. Plastic debris comprises different polymers, which may influence microbial colonization; here, we evaluated whether polymer type affects bacterial biofilm formation. Quantifying the biofilm on polyethylene (PE), polypropylene (PP) or polystyrene (PS) pellets by six marine bacterial strains (Vibrio,Pseudoalteromonas,Phaeobacter) demonstrated that each strain had a unique colonization behavior with either a preference for PS or PP over the other polymer types or no preference for a specific plastic type. PE, PP and PS pellets were exposed to natural seawater microbiota using free-living or total communities as inoculum. Microbial assembly as determined by 16S rRNA (V4) amplicon sequencing was affected by the composition of the initial inoculum and also by the plastic type. Known polymer and hydrocarbon degraders such as Paraglaciecola, Oleibacter and Hydrogenophaga were found in the plastic biofilms. Thus, on a community level, bacterial colonization on plastic is influenced by the microorganisms as well as the polymer type, and also individual strains can demonstrate polymer-specific colonization.