The Effect of Microwave Irradiation on the Flotation of the Selected Polymers as a Potential Solution for Plastic Recycling

Journal of Polymers and the Environment - The separation of an individual plastic from a plastics mix is crucial in plastic recycling management. The selected plastics available in municipal and...     

Flow injection online spectrophotometric determination of uranium after preconcentration on XAD-4 resin impregnated with nalidixic acid

In this work, spectrophotometer was used as a detector for the determination of uranium from water, biological, and ore samples with a flow injection system coupled with solid phase extraction. In order to promote the online preconcentration of uranium, a minicolumn packed with XAD-4 resin impregnated with nalidixic acid was utilized. The system operation was based on U(VI) ion retention at pH 6 in the minicolumn at flow rate of 15.2 mL min^?1. The uranium complex was removed from the resin by 0.1 mol dm^?3 HCl at flow rate of 3.2 mL min^?1 and was mixed with arsenazo III solution (0.05 % solution in 0.1 mol dm^?3 HCl, 3.2 mL min^?1) and driven to flow through cell of spectrophotometer where its absorbance was measured at 651 nm. The influence of chemical (pH and HCl (as eluent and reagent medium) concentration) and flow (sample and eluent flow rate and preconcentration time) parameters that could affect the performance of the system as well as the possible interferents was investigated. At the optimum conditions for 60 s preconcentration time (15.2 mL of sample volume), the method presented a detection limit of 1.1 μg L^?1, a relative standard deviation (RSD) of 0.8 % at 100 μg L^?1, enrichment factor of 30, and a sample throughput of 42 h^?1, whereas for 300 s of the preconcentration time (76 mL of sample volume), a detection limit of 0.22 μg L^?1, a RSD of 1.32 % at 10 μg L^?1, enrichment factor of 150, and a sampling frequency of 11 h^?1 were reported.     

Climatology of atmospheric circulation patterns of Arabian dust in western Iran

Being in vicinity of vast deserts, the west and southwest of Iran are characterized by high levels of dust events, which have adverse consequences on human health, ecosystems, and environment. Using ground based dataset of dust events in western Iran and NCEP/NCAR reanalysis data, the atmospheric circulation patterns of dust events in the Arabian region and west of Iran are identified. The atmospheric circulation patterns which lead to dust events in the Arabian region and western Iran were classified into two main categories: the Shamal dust events that occurs in warm period of year and the frontal dust events as cold period pattern. In frontal dust events, the western trough or blocking pattern at mid-level leads to frontogenesis, instability, and air uplift at lower levels of troposphere in the southwest of Asia. Non-frontal is other pattern of dust event in the cold period and dust generation are due to the regional circulation systems at the lower level of troposphere. In Shamal wind pattern, the Saudi Arabian anticyclone, Turkmenistan anticyclone, and Zagros thermal low play the key roles in formation of this pattern. Summer and transitional patterns are two sub-categories of summer Shamal wind pattern. In summer trough pattern, the mid-tropospheric trough leads to intensify the surface thermal systems in the Middle East and causes instability and rising of wind speed in the region. In synthetic pattern of Shamal wind and summer trough, dust is created by the impact of a trough in mid-levels of troposphere as well as existing the mentioned regional systems which are contributed in formation of summer Shamal wind pattern.     

Screening of human health risk to infants associated with the polychlorinated biphenyl (PCB) levels in human milk from Punjab Province,Pakistan

This study assessed the polychlorinated biphenyl (PCB) levels in human milk and its associated health risk to infants from rural and urban settings of five districts of Punjab Province, Pakistan. The ∑₃₄PCB concentrations ranged from 30.9 to 68.3 ng g^?1 on lipid weight (l.w.) basis. The ∑₈DL-PCB concentrations were ranged from 0.29 to 1.35 ng g^?1 l.w., (mean 6.2 ± 8.7 ng g^?1 l.w.), with toxicity equivalent to polychlorinated dibenzodioxins (PCDDs) ranging from 8.58 × 10^?6 to 0.05 ng TEQ g^?1 l.w. The spatial trend of PCB levels in human milk revealed higher bioaccumulative levels for urban mothers as compared with rural counterparts. The estimated daily intake (EDI) values of DL-PCBs to infants through trans-mammary transfer were considerably higher than tolerable daily intake limits established by WHO (i.e., 1–4 pg TEQ kg^?1 bw) and other globally recognized organizations. Similarly, the hazard quotient values for TEQ ∑₈DL-PCBs (range 1.21 to 79.87) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. The ∑₃₄PCB levels were found to be negatively correlated with mother’ age (r = ?0.31; p = 0.02), parity (r = ? 0.85; p = 0.001), and infant’ birth weight (r = ? 0.73; p = 0.01). The present study suggests undertaking comprehensive public health risk assessment studies and firm regulatory measures to safeguard human health risks.

     

Environmental factors affecting the frequency of road traffic accidents: a case study of sub-urban area of Pakistan

Road traffic accidents (RTAs) are among the life-threatening issues facing rural as well as sub-/urban communities. Several factors contribute to RTAs ranging from human to technical and natural/environmental impacts. Anthropogenic air pollution and corresponding environmental factors also increase the probability of RTAs. Current study reports the relationship of the weather conditions to RTAs. The study establishes the relevancy of different weather conditions like rainfall, temperature, fog, and wind storm with the incidences of RTAs in rural and urban settings of Vehari, Punjab—Pakistan. The results of the study showed that rainfall, severe coldness, fog, and heat conditions were directly related with the occurrence of RTAs. The percentage of RTAs which occurred due to fog, rainfall, temperature, and other weather-related factors was 34, 25, 21, and 20%, respectively. The age of the driver significantly correlated (R²?=?0.60) with RTAs; the drivers in the age group 40–60 years caused the least RTAs during their drive. Since the smaller vehicles were involved in maximum RTAs, it relates negatively (R²?=?0.82) to vehicles power. Among different vehicles motor bikes were involved in most (42%) of the reported RTAs. Therefore, during severe weather conditions, vehicles with smaller size and young drivers must be dealt with carefully while interacting (crossing, overtaking, and maneuvering) on the roads regardless of rural or urban conditions. Factors including civic sense, traffic education, vehicle size, drivers’ maturity, road conditions, and environmental impacts may be considered while designing traffic rules and traffic aware campaigns specific for developing countries such as Pakistan.

     

Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide,diazinon in rainbow trout,Oncorhynchus mykiss: innate immunity components and immune-related genes

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2 g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5 g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4 g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4 g GB/kg diet (p < 0.05). In fish fed 1 and 2 g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4 g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2 g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2 g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4 g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

     

A metric-based assessment of climate and tourism in major cities of Pakistan

Environment, Development and Sustainability - Tourism plays an essential role in the economic development of a country and has become a growing phenomenon of global importance. The climate change...     

Household waste behaviours among a community sample in Iran: An application of the theory of planned behaviour

Understanding the factors influencing recycling behaviour can lead to better and more effective recycling programs in a community. The goal of this study was to examine factors associated with household waste behaviours in the context of the theory of planned behaviour (TPB) among a community sample of Iranians that included data collection at time 1 and at follow-up one year later at time 2. Study participants were sampled from households under the coverage of eight urban health centers in the city of Qazvin. Of 2000 invited households, 1782 agreed to participate in the study. A self-reported questionnaire was used for assessing socio-demographic factors and the TPB constructs (i.e. attitude, subjective norms, perceived behavioural control, and intention). Furthermore, questions regarding moral obligation, self-identity, action planning, and past recycling behaviour were asked, creating an extended TPB. At time 2, participants were asked to complete a follow-up questionnaire on self-reported recycling behaviours. All TPB constructs had positive and significant correlations with each other. Recycling behaviour at time 1 (past behaviour) significantly related to household waste behaviour at time 2. The extended TPB explained 47% of the variance in household waste behaviour at time 2. Attitude, perceived behavioural control, intention, moral obligation, self-identity, action planning, and past recycling behaviour were significant predictors of household waste behaviour at time 2 in all models. The fact that the expanded TPB constructs significantly predicted household waste behaviours holds great promise for developing effective public campaigns and behaviour-changing interventions in a region where overall rates of household waste reduction behaviours are low. Our results indicate that educational materials which target moral obligation and action planning may be particularly effective.     

Jettability of reactive nylon materials for additive manufacturing applications

An inkjet printing process has been suggested for producing nylon 6 in an additive manufacturing approach and this paper reports on the jettability of molten reactive materials made by caprolactam with activator and catalyst to study the feasibility of the approach in an inkjet system. The materials physical properties which are important for jetting were characterized and then the melt supply behaviour in the system was studied and finally jetting trials were monitored to investigate the effect of parameter settings on the stability of the jet array. It was found that the surface tension and viscosity of all materials were within the suitable range. However, with the catalyst mixtures, microcrystals of the undissolved salt of the catalyst complex were found to influence the melt supply behaviour considerably. The mixtures had a narrower range of parameters where stability occurred compared with caprolactam. Monitoring the jet stability recommended a suitable range of jetting parameters for the deposition stage of researching the new approach. A higher level of instability was observed with the catalyst mixture especially when jetting with multiple nozzles due to the microcrystals.