Journal of Health and Safety at Work

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Introduction: Harmful effects of environmental pollutants and their environmental impacts necessitate revention of the pollution emission from various industries. Leather industry is one of the most polluting industries, with chromium compounds as an important contamination, widely used in the tanning process. The present study aimed to determine the causes of high chromium concentration from leather production process in Charmshahr industrial complex in Varamin city.
 

Methods and material: Continuous sampling was done from the wastewater in each plant for six months and the contaminations resulted from different stages of leather products were investigated. In this regard, for determining the chemical quality and pollution load of wastewater from tannery process, following parameters were examined: PH, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Chromium (III), and Chromium (VI). Analysis of data was conducted by SPSS and Excel softwares. The t-test was used for comparison with standards at significance level of P<0.05.
 

Results: The results indicated the existence of toxic pollutants such as Cr⁺³ and Cr⁺⁶ in leather wastewater, the relatively high level of organic loads with low biodegradability, high levels of COD, BOD, TDS and finally the complexity of the treatment of wastewater.

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Introduction: There are some tensions in occupational activities that are caused by harsh conditions and occupational violence is considered one of these tensions. Workplace violence is a global problem. Healthcare workers are globally exposed to the workplace violence more than any other workers. The aim of this study was to investigate the relationship between some individual and job variables with exposure to occupational violence among health care workers in the hospitals in Yazd province, Iran.
 

Material and Method: This cross-sectional, descriptive-analytical study was conducted in eight educational hospitals in Yazd province, Iran. Research population (600 participants) consisted of all healthcare personnel employed in hospitals affiliated to the Shahid Sadoughi University of Medical Sciences in Yazd and were selected by stratified sampling. The Negative Act Questionnaire-Revised (NAQ-R) was used to investigate occupational violence and data analysis was performed using multiple logistic regression tests.
 

Result: The average score of occupational violence was 19.3. Among individual factors, gender (male) and educational level (MSc degree), and among job factors, shift work (morning shift) and type of work environment (genecology and pediatrics wards) had significant relationships with the incidence of violence among the employees.
 

Conclusion: The importance of these findings is in planning and deployment of intervention measures using educational training with regard to the ways of preventing violence, decreasing the coworkers’ aggression, dealing with and increasing awareness about personal and civilian rights in order to reduce the phenomenon of violence among employees.

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Introduction: Fatigue, caused by prolonged standing activities, affects postural stability through disrupting somatosensory system functions. The application of sub-threshold mechanical vibration can enhance the sensitivity of the mechanical receptors in the sole of the feet. Improved sensory function leads to better movement control and balance. Therefore, this study investigated the effectiveness of vibration-based active insoles in reducing the impacts of fatigue on postural stability among military forces.
Material and Methods: Each of the 20 healthy male participants of the study completed three standing balance tests: 1) on both legs, 2) on one leg, and 3) on one leg with a cognitive secondary task for two states of the vibration system (on and off), before and after a fatigue protocol, on a force plate. The activity of leg muscles was also monitored by electromyography (EMG). The mean as a linear index (amount) and the sample entropy (SaEn) as a non-linear index (structure) related to the resultant distance of the body’s center of pressure (CoPRD) displacements, as well as the normalized percentage of the muscle activity level (linear envelope), were used for statistical analyses.
Results: Significant changes in most of the postural and muscular parameters were recorded after the fatigue protocol for the off-mode of the vibration system. Meanwhile, running the vibration system of active insoles was accompanied with no significant differences in the amount and structure of the CoPRD displacements, as well as the activity level of the lateral gastrocnemius and soleus muscles after fatigue, compared to the measurements before fatigue.
Conclusion: The findings confirm the effectiveness of applying sub-threshold mechanical vibration to the sole of the foot in improving standing balance by reducing the negative effects of fatigue on postural stability parameters. Therefore, it is suggested that the use of active insoles can be an effective, feasible, and accessible ergonomic intervention to address fatigue among military forces. 

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Introduction: The design of traffic signs should consider human cognitive abilities to enhance drivers’ understanding of the signs. Cognitive features, as one of the crucial principles of ergonomics, are among the influential factors in the design of signs. The present study aimed to evaluate the effect of graphic elements of eight new sign designs based on cognitive features on conveying the message “prohibition of using mobile phones.”
Material and Methods: This study was conducted in six driving schools in Tehran in 2013. One hundred seventy-four participants, with an average age of 23.5 and a standard deviation of six years, participated in this study. Participants were then presented with the designed signs through a colored questionnaire. They were instructed to evaluate the signs’ cognitive features including simplicity, concreteness, meaningfulness, and semantic closeness—using a Likert scale ranging from 0 to 100. 
Results: The results revealed that the average score of the cognitive features of the designed signs is higher than other traffic, industrial and pharmaceutical signs. In this study, “semantic closeness” was the best cognitive feature for predicting the message of the signs. The sign with the “hands-free” element had the best performance in transferring the message.
Conclusion: This research aimed to identify the most effective of eight proposed signs for banning mobile phone use while driving. Participants rated the sign featuring a button phone with a hands-free symbol as the top choice. Although most of the mobile phones in the market are of the touch screen type and the use of button phones has decreased a lot, the symbol of these phones as the dominant symbol still effectively conveys messages.