Production of natural and recycled aggregates: the environmental impacts of energy consumption and CO<Subscript>2</Subscript> emissions

Natural aggregates (NA) are crushed and processed in crushing plants after the extraction stage in quarries. In the present study, the aggregates are divided into three scenarios, depending on the production methods. The first scenario considers the production of NA, the second scenario deals with the production of recycled aggregates (RA) with respect to construction and demolition waste, and the third scenario, which is a hybrid scenario, handles the combination of NA and RA by assuming a 50% mixing percentage. In this research, we assess the environmental impacts on the production of aggregates via each scenario, using life cycle assessment; in addition, energy consumption and CO₂ emissions are considered as the environmental variables. We conclude that Iran’s current policy with an annual energy consumption of 1.48 million tons of oil equivalent (toe) can have a footprint of 2.88 million tons of CO₂ eq emissions per year (the first scenario). Achieving 30 and 36% reduction in annual energy consumption and CO₂ emissions, respectively, by the third scenario compared to the first scenario indicates the destructive effect of the first scenario from the environmental outlook.     

Methane biofiltration in the presence of ethanol vapor under steady and transient state conditions: an experimental study

Methane (CH₄) removal in the presence of ethanol vapors was performed by a stone-based bed and a hybrid packing biofilter in parallel. In the absence of ethanol, a methane removal efficiency of 55 ± 1% was obtained for both biofilters under similar CH₄ inlet load (IL) of 13 ± 0.5 g_CH4 m^?3 h^?1 and an empty bed residence time (EBRT) of 6 min. The results proved the key role of the bottom section in both biofilters for simultaneous removal of CH₄ and ethanol. Ethanol vapor was completely eliminated in the bottom sections for an ethanol IL variation between 1 and 11 g_ethanol m^?3 h^?1. Ethanol absorption and accumulation in the biofilm phase as well as ethanol conversion to CO₂ contributed to ethanol removal efficiency of 100%. In the presence of ethanol vapor, CO₂ productions in the bottom section increased almost fourfold in both biofilters. The ethanol concentration in the leachate of the biofilter exceeding 2200 g_ethanol m^?3 _leachate in both biofilters demonstrated the excess accumulation of ethanol in the biofilm phase. The biofilters responded quickly to an ethanol shock load followed by a starvation with 20% decrease of their performance. The return to normal operations in both biofilters after the transient conditions took less than 5 days. Unlike the hybrid packing biofilter, excess pressure drop (up to 1.9 cmH₂O m^?1) was an important concern for the stone bed biofilter. The biomass accumulation in the bottom section of the stone bed biofilter contributed to 80% of the total pressure drop. However, the 14-day starvation reduced the pressure drop to 0.25 cmH₂O m^?1.     

Strong correlations between metal in mollusk soft tissue and nonresistant sediment fraction: a tool for biomonitoring intertidal zone of the Persian Gulf,Iran

Cadmium (Cd) and lead (Pb) were determined in three species of mollusks and associated sediment. Samples were collected from two locations along the intertidal zone of the Persian Gulf near Bandar Abbas. The study was conducted during the spring of 2011, 10 sediment samples and 15 mollusks from each of the following species: Saccostrea cucullata, Solen brevis, and Callista umbonella, were simultaneously collected. Soft tissue, shell, and sediment were tested for metals using an atomic absorption spectrophotometer. Geochemical fractions of the sediment were examined for metals using a sequential extraction technique. Our results indicate that over half of Cd and Pb in the sediment had natural origins. Independent sample t test showed statistically significant (p?<?0.05) inter-tissue differences in accumulation of Cd and Pb. Soft tissue of C. umbonella contained highest levels of Cd. Pb accumulation was highest in S. brevis shell. Significant correlations (p?<?0.05) were found between Cd in the soft tissue of C. umbonella and its levels in the geochemical fractions of the sediment. Lead levels in the resistant geochemical fractions of the sediment and S. brevis shell were significantly correlated. Our results suggest that soft tissue of C. umbonella and shell of S. brevis are reliable biomonitoring tools for Cd and Pb, respectively.     

Hazardous waste site identification using aerial photography: A pilot study in Burlington County,New Jersey,USA

The objective of the project was to identify all hazardous waste sites in Burlington County, New Jersey that could be detected on existing, medium-scale aerial photographs of the county. The complete set of over 1000 black- and-white stereopairs at a scale of 1:12,000 was carefully examined for initial identification of possible sites. All suspicious sites were examined again on color transparencies of the county at the same 1:12,000 scale. Out of the 1094 black- and-white photos, 250 required further checking on color transparencies using a zoom stereoscope. This examination resulted in a final identification of 67 sites, the locations of which were delineated on 1:24,000 USGS maps. The use of air photo interpretation techniques provided an effective procedure for identifying waste sites quickly as well as providing a useful demonstration program for county and state officials.     

Antimony induces oxidative stress and cell death in normal hepatocytes

Antimony (Sb) accumulates in the liver which is one of the target organs for metal-mediated toxicity. Although toxicity of Sb was previously investigated, the precise mechanism of Sb-induced hepatotoxicity remains to be determined. The aim of this study was to examine the role of oxidative stress, and mitochondria in the induction of cell death by Sb. Our results showed that liver cell lysis induced by Sb is mediated by reactive oxygen species (ROS) formation, lipid peroxidation and decline of mitochondrial membrane potential (MMP). Antimony-induced ROS formation, lipid peroxidation and reduction of MMP were significantly diminished by antioxidants and ROS scavengers such as dimethyl sulfoxide and mannitol; mitochondrial permeability transition (MPT) pore sealing agents such as carnitine and trifluoperazine; and adenosine triphosphate (ATP) generator, L-glutamine. Antimony-induced ROS formation, lipid peroxidation and fall in MMP were potentiated by glutathione (GSH) depletion via n-bromoheptane. MPT pore sealing agents and ATP generator inhibited hepatotoxicity, indicating Sb-activated cell death via mitochondrial pathway. Pretreatment of hepatocytes with antioxidants and ROS scavengers also blocked cell death induced by Sb, whereas GSH depletion enhances Sb-induced cell death, suggesting that oxidative stress may be directly involved in the reduction of MMP. These findings contribute to a better understanding of the mechanisms that mediate Sb-induced cell death in isolated rat hepatocytes.     

Survey of discomfort glare from the headlamps of cars widely used in Iran

Objective: On 2-lane roads, discomfort glare can cause annoyance, discomfort, inconvenience, stress, and fatigue to drivers, posing a risk of accidents. The aim of this study is to evaluate discomfort glare from the headlamps of cars widely used in Iran.

Methods: The discomfort glare of new vehicles including Pride Saba model GTX, Pride Model 131SL, Samand Soren, Peugeot 405, Megane, and Peugeot Pars was examined at distances of 5 to 100 m at a background luminance of 50 cd/m² (late twilight/early dawn lighting) and 1 cd/m² (nighttime) using Schmidt-Clausen and Bindels model and de Boer's subjective scale.

Results: According to the de Boer scale, at a background luminance of 50 cd/m², the discomfort glare for all studied vehicles was between 1.98 and 4.05 in high-beam mode and between 3.5 and 5.4 in low-beam mode. At a background luminance of 1 cd/m², discomfort glare was between 0.41 and 2.48 in high-beam mode and between 1.93 and 3.84 in low-beam mode. In high-beam mode, the average levels of discomfort glare of these vehicles gradually increased when the distance between cars was reduced by up to about 20 m. In low-beam mode, there was no discomfort glare up to a vehicle distance of 40 m. In addition, at an angle of 1.15°–5.73° between the line of sight and light of vehicles in high-beam mode, the level of discomfort glare was increased, but at an angle of 5.73°–22.9° the level of discomfort glare was reduced. In low-beam mode at an angle of 2.86°–22.9°, the level of discomfort glare was almost identical. The results show that in high-beam mode and with a 100-m distance between vehicles as well as in low-beam mode at intervals of less than 40 m between cars, discomfort glare is created.

Conclusion: It can be concluded that by providing solutions such as installing road lighting system, an increase in luminance of roads, separating or widening road lanes, increasing the lateral distance between vehicles, and increasing the angle between lighted vehicles and drivers can noticeably reduce discomfort glare.     

Drivers of local people’s participation in sustainable natural resource management: a case study in central Iran

The driving forces behind natural resource management (NRM) vary among countries. Most NRM programmes focus on biophysical drivers such as soil, water and vegetation, with little attention directed towards the nuanced sociocultural and religious drivers of sustainable natural resource management (SNRM) practices. This paper explores those understudied drivers that influence local people’s participation (LPP) in SNRM in Isfahan, Iran. Using a multi-stage stratified sampling method, we selected 200 natural resource experts and natural resource users to complete a questionnaire about their perceptions of SNRM. Results reveal that sociocultural and religious beliefs are the major drivers of SNRM. The results also indicate that subsidiary drivers include: a sense of responsibility towards SNRM; the conviction that natural resources belong to God and should therefore be preserved; participation to preserve natural resources because of training courses and media influence; a long-established custom of preserving natural resources; and the specific impact of environmental television programmes. Demographic analysis finds a significant relationship between educational level and LPP in SNRM. This study’s results therefore suggest that natural resource managers would benefit from a deeper understanding of the local sociocultural and religious contexts that motivate people to participate in SNRM.     

Positive environmental effects of the coronavirus 2020 episode: a review

Environment, Development and Sustainability - The outbreak of COVID-19 has made a global catastrophic situation that caused 1,039,406 deaths out of 35,347,404 infections, and it will also cause...     

A critical review of state-of-the-art electrocoagulation technique applied to COD-rich industrial wastewaters

Environmental Science and Pollution Research - Electrocoagulation (EC) is one of the emerging technologies in groundwater and wastewater treatment as it combines the benefits of coagulation,...