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1

Synthesizing nano silica nanoparticles from barley grain waste: effect of temperature on mechanical properties

100%
Akhayere E., Kavaz D., Vaseashta A.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 4
In this investigation we report the synthesis of nano silica (NS) nanoparticles from barley grass waste – an environmental burden – using varying temperatures during preparation. The temperatures used during the investigation were 400, 500, 600, and 700ºC, and we studied its effects on the mechanical properties of the NS nanoparticles for use in environmentally friendly applications. Furthermore, the NS nanoparticles resulting from high temperature synthesis were characterized using various characterization methodologies such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) spectrometry analysis. The result of the various characterizations revealed the presence of elemental Si, C, and O in the synthesized nanoparticles. Using XRF, we observed that higher amounts of SiO2 particles from NS were obtained at 600ºC and 700ºC, also resulting in higher strength in the mechanical properties. Furthermore, using the Brunauer-Emmett-Teller (BET) methodology, we were able to measure the surface area corresponding to 150 m2/g. Additional methodologies were used, such as differential scanning calorimetric (DSC), thermo gravimetric analysis (TGA), SEM, and tensile analysis. The results of this study showed improved and stable mechanical properties with the increase in temperature during synthesis.
2

Modeling river ecosystem vulnerability assessments due to climate change: case study of Armenia

100%
Aleksanyan A. S., Khudaverdyan S. K., Vaseashta A.
Polish Journal of Environmental Studies
|
2015
|
tom 24
|
nr 2
Water resources are an integral part of the global hydrologic cycle and are considered among the natural systems most vulnerable to climate change. Research indicates that severe problems related to water will affect the globe around 2030, which will further intensify to attain its peak by 2100 unless a different water management trajectory is strategically implemented. To conduct an accurate climate change impact assessment it is necessary to conduct parametric analysis for vulnerability to assess for each system by constructing a conceptual hydrogeological model that is then transferred to a mathematical model of overall water resources. We present here a case study outlining plausible impacts of climate change on water resources of Armenia, particularly on river ecosystems. Based on this initial study, we propose certain recommendations for the future to reduce, if not reverse in its entirety, the vulnerability trajectory. We further conclude that vulnerability assessment of water resources resulting from climate change, as proposed here, can be applied for different countries and will be of considerable interest worldwide.
3

Environmental risk assessment of heavy metal pollution in Armenian river ecosystems: case study of Lake Sevan and debed rivercatchment basins

88%
Gevorgyan G. A., Mamyan A. S., Hambaryan L. R., Khudaverdyan S. K., Vaseashta A.
Polish Journal of Environmental Studies
|
2016
|
tom 25
|
nr 6
Investigating the mechanisms behind the impact of heavy metal pollution on aquatic ecosystems is urgently required. Due to increasing growth in the mining sector, pollution has become a serious threat to water resources and aquatic biodiversity and is causing unfavorable environmental changes and human health hazards. The aim of the present study was to investigate and assess the environmental risks of heavy metal pollution of river ecosystems in the Lake Sevan and Debed River catchment basins in Armenia, and a thorough study of their qualitative and quantitative parameters. Water samples were taken from the risky river sites of the Sevan and Debed basins in May and August 2013 and 2014. Investigations showed that due to mining and metallurgical industrial activities and the insufficient management of industrial waste and wastewater, the river ecosystems in these territories were exposed to heavy metal pollution, the degree of which in some sites of the Sotq, Masrik (Lake Sevan catchment basin), Debed, Alaverdi, Akhtala, and Chochkan (Debed River catchment basin) rivers may have posed health risks to aquatic life as well as to humans (at least in the case of river water used for drinking purposes). The results of a phytoplankton community study revealed that a decrease in the species diversity of planktonic algae in the investigated rivers was mainly conditioned by the impact of heavy metal pollution induced by mining and metallurgical industrial activities in the Lake Sevan and Debed River catchment basins.
4

Monitoring water contaminants: a case study for the Republic of Moldova

76%
Nastasiuc L., Bogdevici O., Aureliu O., Culighin E., Sidorenko A., Vaseashta A.
Polish Journal of Environmental Studies
|
2016
|
tom 25
|
nr 1
Water quality monitoring is a major issue toward maintaining safety and security for many countries. Due to many contaminants present in surface water in the Republic of Moldova, groundwater monitoring has become an exclusive source of drinking and potable water for many cities. In this investigation, we determined chemical contaminants in groundwater bodies of the Prut River basin for groundwater classification. For this investigation, monitoring wells were sampled by several field trials. The results of the chemical analysis have been used for the preliminary identification, characterization, and classification of groundwater bodies. The chemical content of water shows the current status of groundwater bodies under investigation, thus validating the study on the importance of groundwater monitoring. We examined several heavy metals in the groundwater from a national monitoring network. One hotspot (contaminated region) is the old Chismichioi pesticide deposit, which was studied for the assessment of actual status of the surrounding territory. It is also one of the largest deposits of toxic substances in the Low Danube Euro region. The following spectrum of persistent organic pollutants was identified in the samples: DDE, DDD, DDT, a-HCH, b-HCH, and g-HCH. Several other toxic organic substances were also studied at this site, including PAHs, triazine pesticides, and some other heavy metals. The general conclusion about the situation around the Chismichioi deposit is that the level of pollution from the time of the origination (in 1979) has not changed, in general. The zones with high pollution levels should be eliminated and recommendations have been made for the mitigation of the negative impacts to the environmental and water resources in this area of Moldova. At the conclusion of this extensive investigation, similar studies are planned for other locations and surface water sources. This will provide a valuable tool for the Republic of Moldova and may be extended to other regions as well.
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