Nanoparticles and interfaces with toxic elements in fluvial suspended sediment

Studies examining nanoparticles (NPs) and hazardous elements (HEs) contained in suspended sediments (SSs) are vital for watershed administration and ecological impact evaluation. The biochemical consequence of titanium-nanoparticles (Ti-NPs) from SSs in Colombia's Magdalena River was examined utilizing an innovative approach involving nanogeochemistry in this study. In general, the toxicity and the human health risk assessment associated with the presence of some Ti-NPs + HEs in SSs from riverine systems need to be determined with a robust analytical procedure. The mode of occurrence of Ti-NPs, total Ti and other elements contained within SSs of the Magdalena River were evaluated through advanced electron microscopy (field emission scanning electron microscope-FE-SEM and high resolution transmission electron microscope-HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS); X-Ray Diffractions (XRD); and inductively coupled plasma-mass spectrometry (ICP-MS). This work showed that enormous quantities of Ti-NPs were present in the river studied and that they displayed diverse geochemical properties and posed various possible ecological dangers. Ti-NP contamination indices must be established for measuring the environmental magnitudes of NP contamination and determining contamination rank among rivers. Finally, SS contamination guidelines must be recommended on an international level. This study contributes to the scientific understanding of the relationship of HE and Ti-NP dynamics from SSs in riverine systems around the world

Dispersion of hazardous nanoparticles on beaches around phosphogypsum factories

Anthropogenic occurring nanoparticles (NPs) have been one of the principal catalytic components of marine pollution throughout its history. The phosphogypsum (PG) factories present environmental risks and evident marine pollution in different parts of the world. Many of these factors continue to operate, however, some have already been abandoned by the private sector. The general objective of this manuscript is to analyze the real nanoparticles (NPs) present on a beach in southern Brazil to illustrate the need to create public policies and projects for environmental recovery. This work focused on real representative sampling of suspended sediments (SSs), and on a modern analytical procedure via advanced electron microscopes (field emission scanning electron microscope-FE-SEM and high resolution transmission electron microscope-HR-TEM coupled with an energy dispersive X-ray microanalysis system-EDS) to analyze NPs containing hazardous elements (HEs). The results presented in this work demonstrate who the size, morphology, among other physical-geochemical characteristics influence in the adsorption of HEs by the NPs and their respective agglomerates. This study is of great importance for carrying out the application of advanced techniques and methods to better understand the formation and transport of NPs on beaches, which allows assisting in the management of waste from plaster factories on a global scale

A realistic study of 3D composition of carbon nanotubes and carbonaceous nanocompounds from different soils around coal power plant

Information on the effects of multi-walled carbon nanotubes (MWCNTs) on topsoil around coal power plants (CPPs) is still very limited. In the present work, the influences of MWCNTs on potential hazardous elements (PHEs) and environmental carbonaceous compounds in agrarian topsoil around CPPs of Latin America were investigated. The environmentally elevated proportions of MWCNTs and PHEs can cause damage to developing a fetus. The ecological impacts of industrial energy byproducts generated by MWCNTs were also studied. The surface morphologies of MWCNTs and PHEs detected in topsoil samples were analyzed by advanced electron microscopy in a combination of energy dispersive X-ray spectroscopy (EDS). The alterations could be originated due to the different geophysical constituents and superficial structure, which in turn disturbed their geoavailability in studied topsoil. It was found that a large amount of MWCNTs and amorphous carbonaceous matters, which are responsible for adsorbing PHEs, existed in soils around CPPs. Hence, these findings could be used to better understand the geochemical properties of PHEs near CPPs

Chemical composition and minerals in pyrite ash of an abandoned sulphuric acid production plant

The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly, the characterization of submicron, ultrafine and nanoparticles, in coal-derived roasted pyrite ash remain to be resolved. In this work we provide essential data on the chemical composition and nanomineralogical assemblage of roasted pyrite ash. XRD, HR-TEM and FE-SEM were used to identify a large variety of minerals of anthropogenic origin. These phases result from highly complex chemical reactions occurring during the processing of coal pyrite of southern Brazil for sulphur extraction and further manufacture of sulphuric acid. Iron-rich submicron, ultrafine and nanoparticles within the ash may contain high proportions of toxic elements such as As, Se, U, among others. A number of elements, such as As, Cr, Cu, Co, La, Mn, Ni, Pb, Sb, Se, Sr, Ti, Zn, and Zr, were found to be present in individual nanoparticles and submicron, ultrafine and nanominerals (e.g. oxides, sulphates, clays) in concentrations of up to 5%. The study of nanominerals in roasted pyrite ash from coal rejects is important to develop an understanding on the nature of this by-product, and to assess the interaction between emitted nanominerals, ultra-fine particles, and atmospheric gases, rain or body fluids, and thus to evaluate the environmental and health impacts of pyrite ash materials

Evaluating sulfates and nitrates as enemies of the recent constructions: Spectroscopic and thermodynamical study

Salt crystallization is one of the major problems currently faced by the field of architecture and construction. Its effects are devastating to the extent that they may even lead to loss of material. Although many innovative and resistant materials have been developed in the last years, in most of the constructions, salt crystallization is a persistent problem. Salts crystallizations are formed by the dissolution and subsequent precipitation of the soluble salts present in the material itself or due to the formation of new ones because of the reaction between original components of the building materials with salts coming from infiltration waters or with acid aerosols present in the atmosphere. Among others, some of the most common salts that can crystallize in the building materials are nitrates and sulfates. Both of them are soluble compounds, which can mobilize throughout the material easily, reprecipitate, and generate volume changes responsible for fissures, fractures, and even the loss of building material. In this work, a specific study of salts crystallizations in a recent construction erected in 2013 in Amorebieta (Basque Country, North of Spain) using a different kind of materials has been studied. The materials affected by salts are joint mortars, which in a first step were characterized by X‐ray diffraction and Raman microscopy to determine the mineralogical composition. In a second step, a soluble salts tests by ion chromatography was applied to approach quantitatively the impact of the salts. Finally, in a third step, the reactions that give rise to the decay products (thenardite, nitrocalcite, and/or epsomite mainly) were proposed and confirmed through a thermodynamic modellin

Effectiveness of disinfectant treatments for inactivating Piscirickettsia salmonis

This short communication investigated in vitro differences between commercial disinfectants types (n = 36), doses of application, and time of action in the elimination of Piscirickettsia salmonis, the most important bacterium affecting farmed salmon in Chile. Seven different treatments were examined, including active and inactive chlorine dioxides, glutaraldehyde, hypochlorite disinfectants and detergents, peracetic acid, peroxides and other miscellaneous methods A 3 replicate set of each of the sample groups was stored at 20 °C and 95% relative humidity and retested after 1, 5 and 30 min with varying doses (low, recommended and high doses). Multiple comparison tests were performed for the mean log CFU/ml among different disinfectant types, dose (ppm) and time of exposure (minutes) on the reduction of P. salmonis. Overall, disinfection using peracetic acid, peroxides, and both active and inactive chlorine dioxides caused significantly higher reduction of >7.5 log CFU/ml in samples, compared to other tested sanitizers. The lowest reduction was obtained after disinfection with hypochlorite detergents. As expected, as doses and time of action increase, there was a significant reduction of the overall counts of P. salmonis. However, at lowest doses, only use of paracetic acids resulted in zero counts. Implementation of effective protocols, making use of adequate disinfectants, may enhance biosecurity, and ultimately, mitigate the impact of P. salmonis in farmed salmon

Number Concentrations And Size Distributions Of Nanoparticles During The Use Of Hand Tools In Refurbishment Activities

Hand tools, such as a sledgehammer, are widely used in refurbishment activities; nonetheless, there is very little knowledge on nanoparticle generation. We measured particle number size distributions (PSDs) and concentrations (PNCs) in the 10–420 nm using a NanoScan scanning mobility particle sizer (SMPS) during the use of hand tools (i.e., sanding and removal of wall) in a real indoor refurbishment environment. Results indicated that refurbishment activities from removal of wall increased average PNCs by ~ 6 times over the background while it was ~ 1.5 times higher than sanding. The highest total PNC was 1.9 × 105 particles cm−3 that corresponded to removal of wall activities. For sanding activities, PNC was lower as the coat of the plaster was probably slightly wet. Moreover, comparison between the two principal activities showed a similar peak in the accumulation mode (~ 65 nm), with a monomodal pattern. Results suggest that removal of wall activities emitted nanoparticles with a 59% of contribution in the Aitken mode. According to these data, it can be inferred that the application of hand tools in refurbishment activities generates lower total PNC than using electromechanical equipment. This study may contribute to our understanding of nanoparticle generation in refurbishment activities