Heavy metal contamination in feathers of Western Reef Heron (Egretta gularis) and Siberian gull (Larus heuglini) from Hara biosphere reserve of Southern Iran

The main objectives of article were monitor the metal concentrations of cadmium, lead, copper, zinc, cobalt, and iron, in the feather of shorebirds species, Western Reef Heron (Egretta gularis) and Siberian Gull (Larus heuglini) from Hara Biosphere Reserve of Southern Iran; and identify any relationships between species. Assaying heavy metals by using Shimadzu AA 680 flame atomic absorption spectrophotometer, the results were given as micrograms per gram dry weight. The concentrations of heavy metal were found to follow the order of iron>zinc>copper>lead>cadmium>cobalt for E. gularis and of iron>zinc>lead>copper>cadmium>cobalt for L. heuglini. Also, they showed that the cadmium, copper, and cobalt concentrations were higher in females than in the males, while the lead concentration for E. gularis and L. heuglini was higher in males. The cadmium concentration means they were measured as1.16 and 1.37 μg/g for E. gularis and L. heuglini, respectively, whereas the lead concentration means 7.04 and 5.48 μg/g for E. gularis and L. heuglini, respectively. The concentrations of nonessential trace elements in E. gularis and L. heuglini were generally comparable to values reported in other studies. The average levels of lead we observed in these birds were greater than 5 μg/g dry weight in the feather that is known to be associated with adverse behavioral or reproductive effects. Data analysis showed that there was a positive correlation between copper and zinc (P?相似文献   

A mathematical model to predict the composition and generation of hospital wastes in Iran

The aim of this study is to investigate the quality and quantity of hospital wastes in Iran. The generated hospital wastes have been estimated by the number of hospitals and the number of active beds in each province of Iran in 2001. All data and information have been gathered from: (i) Iran Statistics Center, (ii) literature review, and (iii) hospital waste investigations for an average hospital. Physical analyses have been conducted in terms of various materials (plastic, textile, paper, metal, and others) and components (biological, infectious, medical, and regular wastes). Based on the above-mentioned investigation and information, a mathematical model has been developed to calculate the generation of (infectious) hospital wastes for any desired year. Utilizing the model, generated infectious hospital wastes has been estimated as 698,937 tones for 2008 (short-term) and 3,494,387 tones for 2028 (long-term period). If the real infectious wastes are collected separately, then the generated infectious wastes will be reduced by 15.1% of the above-mentioned amount (139,787 tones for 2008, and 698,877 tones for 2028). Results of physical analysis show the components of the hospital waste as: (a) infectious, 67.3%; (b) medical, 8.8%; (c) biological, 1.8%; and (d) common municipal wastes, 22.1%. An appropriate collection method requires training the staff at hospitals along with preparation of the required facilities. Of course, both of these requirements are cost intensive.     

Occupational Cognitive Failures and Safety Performance in the Workplace

Introduction. The majority of industrial accidents occur because of human errors. Human error has different causes, however, in all cases cognitive abilities and limitations of human play an important role. Occupational cognitive failures are cognitively-based human errors that occur at work. The aim of this study was to examine the relationship between occupational cognitive failures and safety consequences. Method. Personnel of a large industrial company in Iran filled out an occupational cognitive failure questionnaire (OCFQ) and answered questions on accidents. Univariate and multiple logistic regression analysis were used to determine the relationship between cognitive failures and safety consequences. Results. According to developed regression models, personnel with a high rate of cognitive failure, in comparison to low rate, have a high risk of minor injury involvement (OR 5.1, 95% CI [2.62, 10.3]); similar results were for major injury and near miss. Discussion. The results of this study revealed usefulness of the OCFQ as a tool of predicting safety-related consequences and planning preventive actions.     

Multiple dimensions of work-related risk factors and their relationship to work ability among industrial workers in Iran

Objectives. The present study was designed to investigate the simultaneous effects of physical, psychosocial and other work-related risk factors on the work ability index (WAI) score among industrial workers. Methods. This study used a cross-sectional design with a questionnaire survey. A total of 280 workers were included in the study. Data were collected using three questionnaires including the Persian version of the WAI, the Persian version of the job content questionnaire and an author-developed measure (to assess work-related factors, health-related factors and socio-demographic characteristics). Results. The majority of the participants were young, but they had poor WAI scores (mean 37.3?±?6.4) and 44.3% of them had poor or moderate work ability. Occupational accidents and injuries were found to be the strongest predictors of WAI scores. Additionally, there was a strong association between WAI scores and supervisor support, skill discretion, occupational training, sleep quality, work nature and educational level. Conclusions. Intervention programs should focus on improving supervisor support, sleep quality, job skills and knowledge and on decreasing physical and mental work demands. Additionally, implementing a comprehensive occupational health and ergonomics program for controlling and reducing hazardous working environments and occupational injury rates should be considered.     

Optimizing stabilization of waste-activated sludge using Fered-Fenton process and artificial neural network modeling (KSOFM,MLP)

Sludge management is a fundamental activity in accordance with wastewater treatment aims. Sludge stabilization is always considered as a significant step of wastewater sludge handling. There has been a progressive development observed in the approach to the novel solutions in this regard. In this research, based on own initially experimental results in lab-scale regarding Fered-Fenton processes in view of organic loading (volatile-suspended solids, VSS) removal efficiency, a combination of both methods towards proper improving of excess biological sludge stabilization was investigated. Firstly, VSS removal efficiency has been experimentally studied in lab-scale under different operational conditions taking into consideration pH [Fe²⁺]/[H₂O₂], detention time [H₂O₂], and current density parameters. Therefore, the correlations of the same parameters have been determined by utilizing Kohonen self-organizing feature maps (KSOFM). In addition, multi-layer perceptron (MLP) has been employed afterwards for a comprehensive evaluation of investigating parameters correlation and prediction aims. The findings indicated that the best proportion of iron to hydrogen peroxide and the optimum pH were 0.58 and 3.1, respectively. Furthermore, maximum retention time about 6 h with a hydrogen peroxide concentration of 1,568 mg/l and a current density of 650–750 mA results to the optimum VSS removal (efficiency equals to 81 %). The performance of KSOFM and MLP models is found to be magnificent, with correlation ranging (R) from 0.873 to 0.998 for the process simulation and prediction. Finally, it can be concluded that the Fered-Fenton reactor is a suitable efficient process to reduce considerably sludge organic load and mathematical modeling tools as artificial neural networks are impressive methods of process simulation and prediction accordingly.     

Benzene removal by nano magnetic particles under continuous condition from aqueous solutions

Benzene removal evaluated using Fe304 nano continuous condition. A 44 initial benzene concentration, from aqueous solutions was magnetic particles （NM） in factorial design including NM dose, contact time and pH was investigated in 16 experiments （Taguchi OA design）. The results indicated that all factors were significant and the optimum condition was： pH 8, NM dose of 2000 mg.L-1, benzene concentrations of 100 mg.L-1 and contact time of 14min. The maximum benzene uptake and distribution ratio in the optimum situation were 49.4mg.g-1 and 38.4L.g-1, respectively. The nano particles were shown to capture 98.7% of the benzene in optimum batch condition and 94.5% in continuous condition. The isotherm data proved that the Bmnauer-Emmett-Teller model fit more closely and produced an isotherm constant （b） less than one, indicating favorable adsorption. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature, and thereby, NM can be employed repeatedly in water and wastewater management.     

Hydraulic characteristics of open-channel flow with partially-placed double layer rigid vegetation

Environmental Fluid Mechanics - Vegetation in watercourses can influence different aspects of flow structure, subsequently affecting many processes of flow, such as pollutant transportation,...