Single and joint oxidative stress–related toxicity of sediment-associated cadmium and lead on Bellamya aeruginosa

Environmental Science and Pollution Research - The biotoxicity of heavy metals in sediments toward benthic organisms has evoked great concern for the health of freshwater ecosystems. This study...     

Computer professionals and Carpal Tunnel Syndrome (CTS).

Carpal Tunnel Syndrome (CTS) is an important problem among computer professionals. Hence the prevalence of CTS among computer professionals and risk factors were studied. 648 subjects were selected from 4,276 computer professionals from 21 companies by with simple random sampling method. CTS was diagnosed based on clinical features. The prevalence of CTS was found to be 13.1% (95% CI 10.5-15.7%). Subjects with over 8 years of computer work, over 12 hrs of work per day and system administrators were at a higher risk for CTS (OR 3.3, 4.9 and 2.5 respectively). Flexed or extended hand position had higher risk for CTS. Higher risk for CTS was found with higher exposure to computer work. Ergonomic considerations are important in facilitating proper positioning of hand while working with a computer. Further studies on CTS risk factors among computer professionals are essential for planning prevention.     

Using self‐determination theory to understand the relationship between calling enactment and daily well‐being

This paper contributes to the calling literature by using self‐determination theory—a theory that makes distinctions between different types of motivation—in order to gain a better understanding of how enacting a calling may relate both positively and negatively to well‐being. We use a daily diary method novel to the calling field and a sample with a distinctive calling, Church of England clergy. We expect daily calling enactment to relate positively to daily well‐being via more autonomous forms of motivation (intrinsic and identified motivation) and negatively via less autonomous forms (introjected motivation). Furthermore, we consider how the relationship between calling enactment and motivation may be moderated by perceived competence. The hypotheses were tested using multi‐level structural equation modeling. There was strong support for calling enactment relating positively to well‐being, and this relationship was fully mediated by intrinsic and identified motivation; the hypothesized negative pathway, from calling enactment, to introjected motivation, to well‐being, was not supported. However, perceived competence was found to moderate some of the relationships between calling and the motivation types, where calling enactment is linked to lower introjected motivation at high levels of competence. Copyright © 2015 John Wiley & Sons, Ltd.     

Ultrasound-assistant preparation of Cu-SAPO-34 nanocatalyst for selective catalytic reduction of NO by NH3

The influence of the various preparation methods of Cu-SAPO-34 nanocatalysts on the selective catalytic reduction of NO with NH₃ under excess oxygen was studied. Cu-SAPO-34 nanocatalysts were prepared by using four techniques: conventional impregnation (IM), ultrasound-enhanced impregnation (UIM), conventional deposition precipitation (DP) using NaOH and homogeneous deposition precipitation (HDP) using urea. These catalysts were characterized in detail by various techniques such as N₂-sorption, XRD, TEM, H₂-TPR, NH₃-TPD and XPS to understand the catalyst structure, the nature and the dispersed state of the copper species, and the acid sites for NH₃ adsorption. All of the nanocatalysts showed high activities for NO removal. However, the activities were different and followed the sequence of Cu-SAPO-34 (UIM) > Cu-SAPO-34 (HDP) > Cu-SAPO-34 (IM) > Cu-SAPO-34 (DP). Based on the obtained results, it was concluded that the NO conversion on Cu-SAPO-34 nanocatalysts was mainly related to the high reducibility of the isolated Cu^2 + ions and CuO species, the number of the acid sites and the dispersion of CuO species on SAPO-34.     

Development of thermochromic strips as a water pasteurization indicator

Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding,scaling in the vessels, removal of useful minerals and blandness of taste etc. Water can be made safe for drinking simply by heating at 65℃ for 6 minutes. A colour indicating strip was developed which changes colour from red to purple at 67℃. Use of this strip can help in pasteurizing water without the above problems and with considerable energy saving.     

Effect of mercury and arsenic from industrial effluents on the drinking water and comparison of the water quality of polluted and non-polluted areas: a case study of Peshawar and Lower Dir

The purpose of the present study was to find out the sources of mercury and arsenic pollution of water in the industrial area of Peshawar, the capital of Khyber Pakhtunkhwa, Pakistan. Samples of effluents, mud, and water were collected from the target area (industrial area of Peshawar), the area of water supply source, and from the less polluted area, the Lower Dir district, as the control. Hg was determined by the cold vapor generation technique, while arsenic was determined using the electrothermal atomic absorption technique. Data of the water from the industrial area were compared with that of the source area, control area, as well as with the WHO and some international drinking water quality standards. The results show that some parameters, i.e., TDS, DO, pH, and hardness, were more than the permissible limits. Textile and glass industries were found to be the major sources of Hg and As pollution. Downstream dilution of these contaminants was also observed.     

Spatial assessment of soil salinity in the Harran Plain using multiple kriging techniques

The Harran Plain is located in the southeastern part of Turkey and has recently been developed for irrigation agriculture. It already faces soil salinity problems causing major yield losses. Management of the problem is hindered by the lack of information on the extent and geography of the salinization problem. A survey was carried out to delineate the spatial distribution of salt-affected areas by randomly selecting 140 locations that were sampled at two depths (0 to 30 and 30 to 60 cm) and analyzed for soil salinity variables: soil electrical conductivity (EC), soluble cations (Ca^2+, Mg²⁺, Na⁺, and K⁺), soluble anions (SO ₄ ^2? , Cl^?), exchangeable Na⁺ (me 100 g^?1) and exchangeable sodium percentage. Terrain attributes (slope, topographical wetness index) were extracted from the digital elevation model of the study area. Variogram analyses after log transformation and ordinary kriging (OK) were applied to map spatial patterns of soil salinity variables. Multivariate geostatistical methods—regression kriging (RK) and kriging with external drift (KED)—were used using elevation and soil electrical conductivity data as covariates. Performances of the three estimation methods (OK, RK, and KED) were compared using independent validation samples randomly selected from the main dataset. Soils were categorized into salinity classes using disjunctive kriging (DK) and ArcGIS, and classification accuracy was tested using the kappa statistic. Results showed that soil salinity variables all have skewed distribution and are poorly correlated with terrain indices but have strong correlations among each other. Up to 65 % improvement was obtained in the estimations of soil salinity variables using hybrid methods over OK with the best estimations obtained with RK using EC_0–30 as covariate. DK–ArcGIS successfully classified soil samples into different salinity groups with overall accuracy of 75 % and kappa of 0.55 (p?<?0.001).     

Assessment of organochlorine pesticides and plasticisers in the Selangor River basin and possible pollution sources

A study on the quality of water abstracted for potable use was conducted in the Selangor River basin from November 2008 to July 2009. Seven sampling sites representing the intake points of water treatment plants in the basin were selected to determine the occurrence and level of 15 organochlorine pesticides (OCPs), six phthalate esters (PAEs) and bisphenol A (BPA). Results indicated OCPs were still detected regularly in 66.1 % of the samples with the Σ₁₅OCPs ranging from 0.6–25.2 ng/L. The first data on PAEs contamination in the basin revealed Σ₆PAEs concentrations were between 39.0 and 1,096.6 ng/L with a median concentration of 186.0 ng/L while BPA concentration ranged from <1.2 to 120.0 ng/L. Although di-n-butyl phthalate was detected in all the samples, concentrations of di-ethyl(hexyl)phthalate were higher. Sampling sites located downstream recorded the highest concentrations, together with samples collected during the dry season. Comparison of the detected contaminants with the Department of Environment Water Quality Index (DOE-WQI) showed some agreement between the concentration and the current classification of stream water. While the results suggest that the sites were only slightly polluted and suitable to be used as drinking water source, its presence is cause for concern especially to the fragile firefly “Pteroptyx tener” ecosystem located further downstream.     

Compost and sulfur affect the mobilization and phyto-availability of Cd and Ni to sorghum and barnyard grass in a spiked fluvial soil

Soil reclamation via additives can cause contradictory effects on the mobilization of toxic elements in soils under dry and wet conditions. Therefore, our aim was to investigate the impact of compost and sulfur in two rates (1.25 and 2.5%) on fractionation, mobilization, and phyto-availability of cadmium (Cd) and nickel (Ni) to sorghum (dry soil) and barnyard grass (wet soil) in a fluvial soil spiked with 25 mg Cd or 200 mg Ni/kg soil. Compost decreased the solubility and mobilization of Cd (especially in dry soil) and Ni (in both soils). Sulfur increased the solubility of Cd (31% in dry soil—49% in wet soil) and Ni (4.6% in wet soil—8.7% in dry soil). Sulfur altered the carbonate fraction of Cd to the soluble fraction and the residual fraction of Cd and Ni to the non-residual fraction. Compost decreased Cd and increased Ni in sorghum, but enhanced Cd and degraded Ni in grass. Sulfur increased Cd and Ni in both plants, and the increasing rate of Cd was higher in grass than in sorghum, while Ni was higher in sorghum than in grass. These results suggest that compost can be used as an immobilizing agent for Cd in the dry soil and Ni in the wet soil; however, it might be used as mobilizing agent for Cd in the wet soil and Ni in the dry soil. Sulfur (with rate 2.5%) can be used for enhancing the phyto-extraction of Cd and Ni (especially Cd) from contaminated alkaline soils.     

Analysis of the traffic injury severity on two-lane,two-way rural roads based on classification tree models

Two-lane, two-way roads constitute a major portion of the rural roads in most countries of the world. This study identifies the factors influencing crash injury severity on these roads in Iran. Classification and regression trees (CART), which is one of the most common methods of data mining, was employed to analyze the traffic crash data of the main two-lane, two-way rural roads of Iran over a 3-year period (2006–2008). In the analysis procedure, the problem of three-class prediction was decomposed into a set of binary prediction models, which resulted in a higher overall accuracy of the predictions of the model. In addition, the prediction accuracy of the fatality class, which was nearly 0% in some of the previous studies, increased significantly. The results indicated that improper overtaking and not using a seatbelt are the most important factors affecting the severity of injuries.