Pedestrian road crossing behavior (PEROB): Development and psychometric evaluation

Objective: The aim of this study was to develop a theory-based questionnaire to measure road crossing attitudes and potentially risky pedestrian behavior.

Methods: A cross-sectional validation study was carried out on a total sample of 380 young adults aged 18 to 25 years who live in Tehran, Iran. Data were collected from January 27 to May 20, 2015, using a self-administered structured pool of 76 items that was developed from research on the theory of planned behavior. A panel of subject-matter experts evaluated the items for content validity index and content validity ratio, and the questionnaire was pretested. Exploratory factor analysis (EFA) was performed to test construct validity. The Cronbach's alpha coefficient and intraclass correlation coefficient (ICC) analyses were done to assess internal consistency and stability of the scale.

Results: From the initial 76 items, 38 items were found to be appropriate for assessing the pedestrian road crossing behavior (PEROB) of young adults in Tehran. A 9-factor solution revealed an exploratory factor analysis that jointly accounted for 63.8% of the variance observed. Additional analyses also indicated acceptable results for the internal consistency with Cronbach's alpha value ranging from 0.67 to 0.88 and ICC values ranging from 0.64 to 0.96.

Conclusions: This psychometric evaluation of a self-administered instrument resulted in a reliable and valid instrument to assess young adult pedestrians' self-reported road crossing attitudes and behaviors in Tehran. Further development of the instrument is needed to assess its applicability to other road users, particularly older pedestrians.     

Adsorptive removal of phosphate by the bimetallic hydroxide nanocomposites embedded in pomegranate peel

This study aimed to fabricate new and effective material for the efficiency of phosphate adsorption.Two types of adsorbent materials,the zirconium hydroxides embedded in pomegranate peel(Zr/Peel) and zirconium-lanthanum hydroxides embedded in pomegranate peel(Zr-La/Peel) were developed.Scanning electronic microscopy(SEM),x-ray photoelectron spectroscopy(XPS) and x-ray diffraction(XRD) were evaluated to give insight into the physicochemical properties of these adsorbents.Zr-La/Peel exceeded the a...     

Importance of nutrient availability for soluble microbial products formation during a famine period of activated sludge: Evidence from multiple analyses

Much remains unknown about compositional variations in soluble microbial products (SMP) with the shift of the substrate condition from a feast to a famine phase in biological treatment systems. This study demonstrated that the formation of SMP could be suppressed by up to 75% during the famine phase with the addition of essential nutrients. In contrast, presence of electron acceptor did not play any significant role during the stress condition, showing the similar amounts of SMP (r?=?0.98, p?<?0.05) formation between the bioreactors supplied with air and N₂. The SMP formed in the famine phase was more bio-refractory in the famine versus the feast phase with a linear correlation shown between the production and their aromatic structures in the composition (R²?>?0.95). The fluorescence excitation–emission matrix coupled with parallel factor analysis (EEM-PARAFAC) revealed the presence of four different fluorescent components, including two protein-like (C1 and C4), fulvic-like (C2), and humic-like (C3) components, in the SMP and bEPS formed at different conditions. Both C1 and C4 showed increasing trends (R²?>?0.95) with the length of starvation in the bioreactors without essential nutrients. Nutrient availability was found to be a key factor to quench the production of large-sized biopolymers. This study provides a wealth of information on operation conditions of activated sludge treatment systems to minimize large sized SMP molecules (particularly proteins), which typically exert many environmental concerns to effluent organic matter quality.     

Heavy metal concentrations in roadside soil and street dust from Petra region,Jordan

Concentrations of Cd, Cu, Fe, Pb, and Zn were measured in the samples of street dust and surface roadside soil before Jordan switched to unleaded fuel usage. The samples were collected from Petra, the most tourist-attractive site in Jordan. The samples were analyzed for heavy metals by atomic absorption spectrophotometry. Our results show that the distribution of metals in the soil samples is affected by wind direction in the investigated area. The highest level of metals was found in the eastern parts of the roads due to the westerly-dominant wind in the studied area. The contamination levels of metals decrease as the distance from the edge of the road increases. In the roadside soil samples, the means for the concentrations of the metals at 1 m from the east side of the main road are 1.0, 19.1, 3791.4, 177.0, and 129.0 mg kg^?1 for Cd, Cu, Fe, Pb, and Zn, respectively. In the samples of street dust, the means of the concentrations of the metals in the investigated area are 9.7, 11.8, 4694.4, 31.6, and 24.8 mg kg^?1 for Cd, Cu, Fe, Pb, and Zn, respectively. In conclusion, the lithogenic origins (traffic emissions) are responsible for the diffusion of these metals in the studied region.     

Heavy metal mobility and potential availability in animal manure: using a sequential extraction procedure

In this study, dairy cow manure, goat manure, and chicken manure were collected from three farms and analyzed to find out the concentration of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn. The concentration and potential of mobility and availability of heavy metals were studied in the animal manure samples. BCR Sequential extraction procedure was used to determine the binding forms of the metals. In this study, pseudo total concentrations of Mn and Zn were found out to be predominant in all the types of animal manure samples. According to the results, it was traced that Cr, Cu, and Ni were observed to be at the second highest level while Cd, Co, and Pb were seen at the lowest level in all the manure samples. When extractable amounts of heavy metals are taken into consideration, it is seen that the amount of the mobile fractions of heavy metals except for Cr and Ni are higher in comparison with that of immobile fraction in all the animal manure samples. It was also viewed that Mn, Cd, and Zn are more available in dairy cow manure and chicken manure whereas Cd, Co, and Mn are more available in goat manure.     

Epidemiology of occupational accidents among Iranian insured workers

Work-related accidents are considered as a major health problem worldwide. The aim of present study was to determine the epidemiological pattern of occupational accidents among workers insured by the Iranian Social Security Organization (ISSO) between 2001 and 2005.Subjects consisted of all workers and drivers who had a work-related accident during 2001–2005 and were registered in the Iranian Social Security Organization (ISSO) database according to the inspection reports. An ordinal logistic regression model (proportional odds regression model) was used to assess the concurrent effects of independent variables on accident outcomes.Overall, 86,437 work-related accidents were investigated. The accidents were more frequent in metal workplaces and electrical industries, respectively. More than half of the accidents were due to incautious activities. Workers’ age (age at the time of accident) (OR = 0.99, CI: 0.989–0.994), gender (OR = 1.3, CI: 1.191–1.683), marital status (OR = 1.25, CI: 1.143–1.675) as well as accident setting (OR = 1.88, CI: 1.728–1.975) had significant effect on accident outcomes. Pattern of occupational injuries in Iran was consistent with the global pattern for accident outcomes.     

Heavy metals distribution and risk assessment in soils affected by tannery effluents

Effluents collected from tanneries in Sialkot showed considerably higher levels of heavy metals. Sodium (12 660.91 mg/L) among macronutrients and Cr (592.20 mg/L) among heavy metals were found in the highest concentrations. Effluent parameters, i.e. biological oxygen demand (BOD; 12.40), chemical oxygen demand (COD; 16.53), Cd (5.90), Cr (592.20) and Fe (18.59) were the respective times higher than Pakistan National Environmental Quality Standards and their continuous unchecked discharge into agricultural soils poses a potential risk. Mean concentrations (mg/L) of Cr (592.20), Ni (2.66), Mn (1.16), Fe (37.17), Zn (0.90), Cd (0.59) and Pb (1.18) in this study exceeded levels recorded to date from different tanning hubs in Pakistan. Factor analysis/principal components analysis (FA/PCA) for the effluent parameters resulted in six varimax factors, i.e. VF1 (salinity, electrical conductivity, total dissolved solids, chloride, phosphate, BOD and COD; including characteristic tannery effluent features), VF2 (pH, Cr and alkalinity; tanning operations), VF3 (Cd and Pb; dyeing processes), VF4 (Mn and Fe; finishing operations), VF5 (Ni; retaining processes) and VF6 (hardness, Ca and Cu; bating processes). Cluster analysis performed on metal data resulted in three clusters confirming metal–metal relations obtained either from FA/PCA or a correlation matrix. The results of this study are useful for heavy metal source apportionment, assessment of risk to peripheral soils and the future management of environments around tanneries.     

Sol-gel immobilisation of methyl parathion degrading bacteria isolated from agricultural areas of Pakistan

The following areas are discussed in this paper: immobilisation of bacterial consortium in sol-gel; methyl parathion degradation and bioremediation applications; evaluation of indigenous bacterial isolates of contaminated soils. Bacterial strains were isolated from agricultural areas of Pakistan which were contaminated with methyl parathion. A bacterial consortium of seven (out of 64) Enterobacteriaceae isolates including Citrobacter, Enterobacter and Proteus vulgaris capable of degrading methyl parathion (enzyme activity ranging 410–675 mU mL^?1 for individual isolates and 982 mU/mL for consortium) was selected and subsequently immobilised in tetraethyl orthosilicate (TEOS) and sodium-silicate-based sol-gel matrices. Cell viability of suspended and immobilised bacterial consortium was monitored using a minimal salt medium supplemented with methyl parathion. The results indicate that sol-gel immobilisation can be helpful to increase the shelf life of methyl parathion degrading bacterial strains along with preservation of biological activity for bioremediation applications in field.     

Lead(II) and cadmium(II) removal from aqueous solution using processed walnut shell: kinetic and equilibrium study

The biosorption potential of processed walnut shell for Pb(II) and Cd(II) ions from aqueous solutions was explored. The effects of pH, contact time, initial ion concentration, and amount of dried adsorbent were studied in batch experiments. The maximum adsorption was achieved within the pH range 4.0–6.0. The equilibrium data were well fitted by the Langmuir isotherm model. The maximum monolayer adsorption capacities were found to be 32?g?kg^?1 and 11.6?g?kg^?1 for Pb(II) and Cd(II) ions, respectively. Kinetic data were best described by the pseudo-second-order model. The structural features of the adsorbent were characterized by Fourier transform infrared spectroscopy, which confirmed the involvement of hydroxyl (–OH), carboxyl (–COO^–), and carbonyl (C=O) groups in metal sorption. This readily available adsorbent is efficient in the uptake of Pb(II) and Cd(II) ions from an aqueous solution and could be used for the treatment of wastewater streams bearing these metal ions.