Mechanistic aspects of poly(ethylene terephthalate) recycling–toward enabling high quality sustainability decisions in waste management

Environmental Science and Pollution Research - Since plastic waste pollution is a severe environmental concern in modern life, the demand for recycling poly(ethylene terephthalate) (PET) has...     

On integration of policies for climate and global change

Currently envisaged mitigation of greenhouse gases (GHG) emissions will be insufficient to appreciably limit climate change and its impacts. Adaptation holds the promise of ameliorating the impacts on a small subset of systems being affected. There is no question that both will be needed. However, climate change is only part of a broader multi-stress setting of global through to local changes. Privileging climate related policies over other concerns leads to tragic outcomes. Climate policies need to be designed for and integrated into this broader and challenging context. This paper focuses on placing climate change within the broader context of global change and the importance of aligning climate policy objectives with the myriad other policies that still need to be implemented if our primary goal is improving human welfare rather than limiting our focus to climate change and its impacts.     

Toward a high-rate enhanced biological phosphorus removal process in a membrane-assisted bioreactor.

A membrane enhanced biological phosphorus removal (MEBPR) process was studied to determine the impact of hydraulic retention time (HRT) and solids retention time (SRT) on the removal of chemical oxygen demand (COD), nitrogen, and phosphorus from municipal wastewater. The MEBPR process was capable of delivering complete nitrification independent of the prevailing operating conditions, whereas a significant improvement in COD removal efficiency was observed at longer SRTs. In the absence of carbon-limiting conditions, the MEBPR process was able to achieve low phosphorus concentrations in the effluent at increasingly higher hydraulic loads, with the lowest HRT being 5 hours. The MEBPR process was also able to maintain optimal phosphorus removal when the SRT was increased from 12 to 20 days. However, at higher suspended solids concentrations, a substantial increase was observed in carbon utilization per unit mass of phosphorus removed from the influent. These results offer critical insights to the application of membrane technology for biological nutrient removal systems.     

High-risk behaviors while driving: A population-based study from Iran

Objective: Traffic injuries are becoming one of the most important challenges of public health systems. Because these injuries are mostly preventable, the aim of this study is to evaluate the four main high-risk behaviors while driving.

Methods: This cross-sectional study was conducted on a random sample from the population of Mashhad, Iran, in 2014. A checklist and a previously validated questionnaire for the transtheoretical stages of change model (TTM) were used for data collection. Statistical analyses were performed using SPSS 11.5 software with P <.05 statistically significant.

Results: Totally 431 individuals were included with a mean age of 30 ± 11.3 years. Forty-three percent (183) were male. The TTM model revealed that participants were mostly in pre-actional phases regarding not using a cell phone while driving (80%), fastening the driver's seat belt (66%), front seat belt (68%), and rear seat belt (85%) The penalty was a protective factor only for using cellphone (odd ratio [OR] = 0.82, 95% confidence interval [CI], 0.68–0.98). Lower education (OR = 0.12, 95% CI, 0.01–0.94) and male gender (OR = 0.35, 95% CI, 0.14–0.83) were indicative of lower rates of fastening the front and rear seat belts.

Conclusion: The stages of change model among study participants is a proper reflection of the effectiveness of the current policies. More serious actions regarding these high-risk behaviors should be considered in legislation.     

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.     

Fullerenes toxicity and electronic properties

Nanotechnology globally represents a new direction within scientific development, where the atomic and electronic properties of molecules are used in a unique fashion to produce and construct new and exotic materials and products. Fullerenes (Bucky balls, C₆₀) constitute a particular group within the field of nanotechnology. Fullerenes find applications in medicine, industrial chemistry and electronics. However, there are several unanswered questions about fullerenes and their toxicological properties. Most toxicological studies on fullerenes evolve around the in vitro and in vivo aspects of pristine C₆₀ along with chemically modified C₆₀ molecules. We reviewed toxicology reports on C₆₀. We bring a critical and challenging evaluation of the electronic and quantum properties of C₆₀ molecules in context with the implications on cellular factors and metabolites. The evaluation shows that the reactivity and quantum chemical properties of C₆₀ can have unexpected effects in the cell, by principally absorbing metabolites, such as OH^? and H⁺ ions and alter its reactivity. We thus challenge the present view of C₆₀ solely based on empirical studies, based on the electronic properties of C₆₀ that vary considerably with their size and reaction path. A further example of this is the absorption of divalent zinc ions, which shows an increase in reactivity of the C₆₀ that presents an important pattern of chemical state, reactivity and toxicological potential. The results evaluate the toxicological potential of C₆₀ from a different angle than conventional, by applying a blend of critical review of the findings on C₆₀ toxicity, their chemical and electronic properties.     

A study on chemical properties of groundwater and soil in ophiolitic rocks in Firuzabad, east of Shahrood, Iran: with emphasis to heavy metal contamination

In order to assess the chemical properties of groundwater and soil in ophiolitic zone of Firuzabad, in east of Shahrood, Iran, 10 soil samples with regard to sensitive points (vicinity to mine, ophiolitic rocks, and villages) and 10 groundwater samples including nine samples from springs, and also one sample from a well in a village of the study area were taken. These samples were analyzed in laboratories using inductively coupled plasma method. The soil samples were also evaluated for grain size. The obtained results show that most of heavy and major elements were exceeding the permissible levels in soil and water samples in the study area. On the subject of soil quality, concentrations of elements Cr, Mn, Fe, Ca, Mg, Ca, Ni, and Zn are above permissible levels. Enrichment factor and index of geoaccumulation have been calculated for heavy and major elements of all soil samples. According to the obtained results, it may be argued that soil samples are contaminated in relation to the above-mentioned indices. Comparing the concentrations of elements with results of grain size analysis illustrates that the concentrations of Cr, Ni, Fe, Mg, and Co are positively correlated with sand fraction and the concentrations of Al, P, Mn, and Pb are directly proportional with clay fraction in soil samples. The study on water contamination suggests that concentrations of elements Cr, Ni, and Mg in groundwater samples of the study area are above the permissible levels. Some indices like metal index and heavy metal pollution index show that most of the water samples include heavy metal contamination.     

Physical development trend and green space destruction in developing cities: a GIS approach

Green spaces considered natural remnants in urban environments play a key role in promoting environmental quality and forming a sustainable city. Nowadays, development of urban spaces has taken a hasty growth. In the meanwhile, the natural green spaces are severely damaged. The current study aims at investigating the trend of changes in green space of Tabriz City, the second large industrial city in Iran, on the basis of landscape ecology principles. In order to prepare the land-cover maps, Landsat TM and IRS LISS-III of the years 1989 and 2006 were applied. Alongside, landscape percentage metrics, the largest patch index, number of patches, patch density, edge density, total edge, class area and landscape shape index were also used to analyse the changes. Metric analysis of the landscape within the studied years revealed that a large part of the region has enjoyed a rapid growth (equivalent to 64.5 %) in constructions. As the obtained results showed, the smallest landscape percentage (3.9 %) in the study area is belonged to the municipal green space, while the largest landscape percentage (66 %) is allocated to the barren land. This shows that the constructions have not balanced with creation of new green spaces, and the lack of green space per capita continues to be felt.