Survey of quantity and management condition of end-of-life tires in Iran: a case study in Tabriz

Journal of Material Cycles and Waste Management - Once a tire is removed from a vehicle without the possibility of being remounted for continued on-road use, it is defined as waste and called...     

Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination

Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils’ calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions.     

Challenges of higher education related to e-learning in developing countries during COVID-19 spread: a review of the perspectives of students,instructors, policymakers,and ICT experts

The COVID-19 pandemic brought about many critical issues in all aspects such as economy, environment, health, and lifestyle, but people always try to find some response to crisis in different conditions. E-learning is defined as an elaborate response aiming at continuing education during the COVID-19 pandemic. It seems that developed countries have established and adjusted their technological infrastructures for the transition from a face-to-face education to a digital one. In contrast, developing countries were not completely prepared for this transition. Improper and deficient technological and practical fundamentals have been causing problems for all students, instructors, and other involved individuals. Therefore, we reviewed the challenges that have arisen from e-learning during the COVID-19 outbreak in different parts of tertiary education focusing on underprivileged countries.

     

Enhanced Ni phytoextraction by effectiveness of chemical and biological amendments in sunflower plant grown in Ni-polluted soils

A greenhouse study was conducted as a completely randomised design in a factorial arrangement to assess how inoculation of AMF (arbuscular mycorrhizal fungus) and application of EDTA (ethylenediaminetetracetic acid) as biological and chemical amendments can affect the Ni (nickel) phytoremediation in Ni-polluted soils using sunflower plant. The results showed that the inoculation of AMF increased root colonisation while applying EDTA and high level of Ni decreased it. Microbial incubation has a positive effect on both shoot and root dry yields; however, co-application of Ni and EDTA demoted the growth rate. Shoot nutrients uptake of plants decreased as Ni levels increased. In inoculated plants, shoot uptake of Zn, Fe and Mn was higher in all Ni levels than non-inoculated plants. Ni uptake in plant shoots and roots increased with applying both AMF and EDTA. However, the mean Ni concentration and uptake in inoculated plants along with applying EDTA are higher in sunflower shoots than in roots. As Ni levels increased, Ni extraction and uptake efficiencies increased; it can be concluded co-application of EDTA and AMF was effective in increasing phytoextraction potential of sunflower plants in Ni-contaminated sites. This study highlights that AMF could be suitable for cleaning Ni-polluted areas and it could significantly contribute to phytoremediation technology.     

Assessment of human health risks and pollution index for heavy metals in farmlands irrigated by effluents of stabilization ponds

Areas contaminated with heavy metals can pose major risks to human health and ecological environments. The aims of this study are to assess human health risk and pollution index for heavy metals in agricultural soils irrigated by effluents of stabilization ponds in Birjand, Iran. The results revealed that the levels of Cr, Mn, Zn, Fe, Cu, Cd, and Pb were in range of 70.3–149.65, 355–570, 31.15–98.45, 23,925–29,140, 22.75–25.95, 0.17–6.51, and 8.5–23.5 mg/kg in topsoils, respectively. Total hazard index values from heavy metals through three exposure routes for adults and children were 9.13E−01 and 1.10, respectively, indicating that there was non-carcinogenic risk for children. The total risk of carcinogenic metals (Cr, Cd, and Pb) through the three exposure routes for adults and children was 1.06E−04 and 9.76E−04, respectively, which indicates that the metals in the soil will not induce carcinogenic risks to these age groups. Pollution levels of heavy metals in soil samples including enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and geo-accumulation index (Igeo) showed heavy metal contamination of agricultural soils. The results of the present study provide basic information about heavy metal contamination control and human health risk assessment management in the study area.     

An assessment of metal contamination risk in sediments of Hara Biosphere Reserve,southern Iran with a focus on application of pollution indicators

The aim of this study was to assess the pollution status of metals in sediments of Hara Biosphere Reserve using pollution indicators. For this purpose, sediment samples from nine locations were collected and characterized for metal content (Pb, Cr, Zn, Cu, and Fe) using the total digestion technique. Comparison of metal concentrations with that of sediment quality guidelines (SQGs) demonstrated no association with negative biological effects for Cu and Zn, while the values of Pb and Cr mainly illustrated to have association with negative biological effects. The results of the geo-accumulation index (I _geo) indicated no contamination for Cr, Cu, Zn, and Fe, while the values of Pb demonstrated to have moderate contamination based on I _geo values. The analysis of the enrichment factor (EF) showed no enrichment for Cu and Zn and minor enrichment for Pb and Cr. Similar results were also found for quantification of contamination (QoC) analysis, where the values of Cu and Zn demonstrated to have a geogenic source of contamination, while the values of Pb and Cr mainly illustrated to have an anthropogenic source of contamination. According to EF and QoC calculations, the values of Cu and Zn were derived mainly from natural processes and exposure of material from the earth’s crust, while the values for Pb and Cr were enriched by anthropogenic activities. The results of the contamination factor (C _f ⁱ ) demonstrated low contamination levels for Fe, Cr, Zn, and Cu and moderate contamination levels for Pb. The pollution load index (PLI), showing the overall contamination of metals, demonstrated moderate pollution status in the study area.     

In Vitro and In Vivo Anticancer Activity of Ferula Gummosa Essential Oil Nanoemulsions (FGEO-NE) for the Colon Cancer Treatment

This survey was performed to aim of synthesize Nano emulsion from Ferula gummosa essential oil (FEGO-NE) and to evaluate its anti-tumor effect. First, Ferula gummosa essential oil was analyzed by GC–MS method, and then the Nano emulsion was synthesized as O/W and after characterization by DLS, Zeta potential, AFM, FESEM and TEM methods, its toxicity was evaluated by MTT method. Then its pro-apoptotic effects were evaluated by qPCR (Caspase3, 9, Bax and Bcl-2) method and AO/PI staining. The cancer induction model was used to evaluate the antitumor effects in Balb/C mice. The anti-angiogenic and antioxidant effects were evaluated by qPCR (VEGF, CAT and SOD) method. The results of physicochemical studies showed the formation of droplet with dimensions of 24.6 nm, dispersion index of 0.41 and zeta potential of ? 28.5 mV with a spherical morphology. The Nano emulsion synthesized at a concentration of 2.9 μg/mL inhibited about 50% of ht-29 cells, while up to a concentration of 4 μg/mL showed no inhibitory effect on normal cells. Increase of caspase 3, 9 and Bax and decrease of BCL-2 gene expression along with increase of apoptotic cells in AP/PI staining confirmed induction of apoptosis by FEGO-NE. The FEGO-NE showed an inhibitory effect on angiogenesis and an additive effect on the expression of antioxidant genes. In addition, the reduction of tumor volume (69.72% in 14 days) in samples treated with FEGO-NE was confirmed. The results of this study showed that FEGO-NE by various mechanisms are able to inhibit cancer cells and have a reducing effect on induced tumors in the in vivo model. These results suggest FEGO-NEs as a suitable candidate for cancer therapy studies.