Ecological risk assessment of metal and hydrocarbon pollution in sediments from an urban tropical estuary: Tijuca lagoon (Rio de Janeiro,Brazil)

Environmental Science and Pollution Research - Urban tropical lagoons are often impacted by eutrophication, metal, and polycyclic aromatic hydrocarbon (PAH) contamination, but the toxicity of their...     

Characterization of composites based on expanded polystyrene wastes and wood flour

This paper aims to evaluate the potential for the use of recycled expanded polystyrene and wood flour as materials for the development of wood plastic composites. The effects of wood flour loading and coupling agent addition on the mechanical properties and morphology of wood thermoplastic composites were examined. In addition, a methodology for the thermo-mechanical recycling of expanded polystyrene waste was developed. The results show that the mechanical properties decreased as the wood flour loading increased. On the other hand, the use of poly(styrene-co-maleic anhydride), SMA, as a coupling agent improved the compatibility between the wood flour and polystyrene matrix and the mechanical properties subsequently improved. A morphological study revealed the positive effect of the coupling agent on the interfacial bonding. The density values obtained for the composites were compared with the theoretical values and showed agreement with the rule of mixtures. Based on the findings of this work, it appears that both recycled materials can be used to manufacture composites with high mechanical properties and low density.     

Applications of chitosan to the roots and shoots change the accumulation pattern of cadmium in Talinum patens (Talinaceae) cuttings

Environmental Science and Pollution Research - Chitosan induces tolerance to abiotic stress agents in plants. However, studies on the different application forms of this biopolymer are limited....     

Copaiba oil and vegetal tannin as functionalizing agents for açai nanofibril films: valorization of forest wastes from Amazonia

The applicability of cellulose nanofibrils (CNFs) has received attention due to their attractive properties. This study proposes the functionalization of açai CNFs with copaiba oil and vegetal tannins to produce films with potential for packaging. Bio-based films were evaluated by vapor permeability, colorimetry, and mechanical strength. CNFs were produced by mechanical fibrillation, from suspensions of bleached açai fibers and commercial eucalipytus pulp. Moreover, copaiba oil and vegetal tannin were added to the CNFs to produce films/nanopapers by casting from both suspensions with concentrations of 1% (based on CNF dry mass). The bulk densities of the eucalyptus CNF films were higher (1.126–1.171 g cm^?3) compared to the açai CNF ones. Films from eucalyptus and açai pulps containing copaiba oil and tannins presented higher Tonset and Tmax, respectively (312 and 370 °C). Films with açaí CNFs functionalized with copaiba oil and tannin showed the lowest permeability value (370 g day^?1 m^?2). Films produced with eucalyptus pulp, and eucalyptus pulp functionalized with copaiba oil highlighted by superior mechanical strength, achieving 133.8 and 121.4 MPa, respectively. The evaluation of colorimetry showed a greater tendency to yellowing for açai films, especially those functionalized with vegetal tannins. Besides the low cost, functionalized vegetal-based nanomaterials could have attractive properties, with potential for application as some kind of packaging, for transporting basic products, such as breads, flours, or products with low moisture content, enabling efficient utilization of forest wastes.

     

Historical and Geological Evidence for Seismic Origin of Newly Recognized Landslides in Southeastern Sicily, and Its Significance inTerms of Hazard

Old, large, and dormant landslides were unexpectedly found in southeastern Sicily, a territory of known seismicity but commonly considered as landslide-free or almost so. Purposely undertaken investigations revealed that: (1) these landslides are scarcely compatible with the local geoclimatic environment; (2) they usually show low-angle basal shear surfaces, despite the fact that the properties of the forming material are generally good; (3) they fulfill the known relationships between earthquake magnitude and epicenter–landslide distance; (4) sources coeval with high-energy historical earthquakes occurred in 1169, 1542 and 1693 testify to the occurrence of earthquake-triggered landsliding; and (5) documentary material (presented here for the first time) correlates with certainty a specific landslide to the 1693 earthquake. This geological and historical evidence, accompanied by the absence of contrasting elements, leads us to conclude that these landslides are earthquake-triggered. Because of their typological and geometrical characteristics, nearly all landslides can be reactivated, which has serious implications in terms of hazard, particularly with respect to lines of communication. Obviously, every action aimed at preventing or mitigating risks must start from the awareness of the causative processes, a condition substantially unsatisfied at the moment in SE Sicily. The paper concludes by emphasizing the opportunity not to trust excessively beliefs that, although shared, have never been really checked.     

Norovirus GII.17 Associated with a Foodborne Acute Gastroenteritis Outbreak in Brazil, 2016

Foodborne transmission gastroenteritis (AGE) outbreak occurred during a celebration lunch in July, 2016, Brazil. All stool samples tested were positive for noroviruses (NoV) and phylogenetic analysis revealed that strains were genetically close to GII.17 Kawasaki_2014. These findings indicated circulation of NoV GII.17 Kawasaki_2014 in the Brazilian population, associated with AGE outbreak.     

Detection and Molecular Characterization of Gemycircularvirus from Environmental Samples in Brazil

Gemycircularvirus (GemyCV) is a group of viruses which has been recently proposed as a new viral genus detected in fecal and environmental samples around the world. GemyCVs have been detected in human blood, brain tissue, cerebrospinal fluid, and stool sample. In the present study, we demonstrate for the first time, through molecular detection and characterization, the presence of GemyCVs in environmental samples from Brazil. Our results show a percentage of positivity ranging from 69 (25/36) to 97 % (35/36) in river water samples collected in Manaus, Amazon region, and wastewater from a wastewater treatment plant located in Rio de Janeiro, respectively, revealing GemyCVs as an important environmental contaminant.     

Ecotoxicity Evaluation of the Biodegradable Polymers PLA,PBAT and its Blends Using <Emphasis Type="Italic">Allium cepa</Emphasis> as Test Organism

Biodegradable polymers are considered a feasible option to minimize the environment impacts of high disposal of solid waste. Nevertheless, environmental safety of these materials is a few explored issue. In this context, this study evaluated ecotoxicological effects in soil of the biodegradable materials poly(lactic acid)-PLA, poly(butylene adipate co-terephthalate)-PBAT and their blends compatibilized with a chain extender. The tool used for this analysis was the bioassay with Allium cepa as test organism. The studied materials were not phytotoxic, cytotoxic, genotoxic nor mutagenic for meristematic cells of A. cepa.     

Comparison of the Effect of Plasticizers on PHBV—and Organoclay—Based Biodegradable Polymer Nanocomposites

The aim of this work was to evaluate the effect of different plasticizers on the morphology, crystallization, and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/organomodified montmorillonite (OMt) nanocomposites. We investigated three different plasticizers: dioctyl phthalate (DOP), a commonly used additive in the polymer industry, and two natural and biodegradable plasticizers: epoxidized soybean oil (ESO) and triethyl citrate (TEC). The nanocomposites with 3 wt% OMt were obtained by melt processing in an internal mixer. The plasticizers were used alone or in combination with clay in a concentration of 10 wt%. X-ray diffraction and scanning electron microscopy results revealed a partially intercalated structure. The degree of crystallinity was higher for all of the samples compared to neat PHBV, although the melting temperature decreased with the use of plasticizers combined with OMt. The impact strength results were dependent on the interaction between the components of the system. Triethyl citrate was the most effective plasticizer due to its more pronounced interaction with the PHBV matrix, which yielded improvements in processing conditions and PHBV’s flexibility and impact properties.