مجله بهداشت و ایمنی کار
سال نهم شماره 3 (پاییز 1398)

Along with the extensive production and use of various pesticides for controlling pests and enhancing the production of agricultural crops, there is a growing concern about the adverse effects of these toxic materials on human health. Therefore, the development of sensitive, selective, and accurate methods for continuous assessment of pesticides concentration in occupational and environmental fields and comparing them with national and international standards is of great importance. This study was aimed at synthesis and application of molecularly imprinted polymer as a selective sorbent for residue determination of two pyrethroid isomers in biological samples.  

The MIP particles were prepared by a non-covalent approach using permethrin as a template, chloroform as progen solvent, methacrylic acid as functional monomer and ethyleneglycol dimethacrylate as cross-linker, at 55 °C for 18 hours in an oil bath. Field emission scanning electron microscopy was used to investigate the morphology and size of polymer particles. Afterward, the critical parameters, which could affect the recognition properties of synthesized MIP, were investigated and optimized under the selected operational ranges for the highest adsorption and recycling yield in solid-phase extraction of permethrin in biological samples

using precipitation polymerization technique, uniform and spherical particles with the nano-ranged diameter (less than 21.2 nanometers) were obtained. Under the optimized condition, the designed molecularly imprinted solid-phase extraction (MISPE) technique exhibited great potential for the extraction of pesticide isomers in the real sample. More than 93 % of the recovery obtained from spiked urine samples. The linear calibration curve was obtained from 20-120 μg.L-1 (R2=0.99) and the detection limit was less than 6 ppb for both isomers. The presence of interferences had no effect on the selectivity of the method up to 100-fold.

employing the molecular imprinted solid-phase extraction method along with the high-performance liquid chromatography technique resulted in a selective and sensitive approach, suitable for quantitative monitoring of the desired pesticide in complex biological samples.

Despite nanofibers have attracted great interests for filtering particulate matters from the air stream, fewer studies have been done on the feasibility of their use in the removal of gas pollutants, while the both pollutants are present in the most workplaces. Toluene is a toxic and mutagenic substance, and chronic exposure to its low levels can lead to a wide range of adverse health effects on people who exposed. The purpose of this study was to produce polymer /single-walled carbon nanotube hybrid nanofibers by electrospinning technique and doing plasma surface treatment and evaluating their removal efficiency of toluene from air stream.  

The nanofiber layers were fabricated by electrospinning solution containing polyacrylonitrile polymer (PAN) and single-walled carbon nanotube (SWNT) with a 99: 1 ratio under following conditions: applied voltage 20 kV, distance between needle and collector: 10 cm, injection rate: 1 ml / h; needle diameter: 18 gauge and drum speed ranging from 1000 to 500 rpm. The surface of the manufactured nanofibers was treated by cold-plasma with a radio frequency power supply (13.56 MHz with a power of 20 watts), argon gas and operating pressure of 0.2 torr. Test conditions was prepared according to standard ISO 10121-1: 2014, which provides a method for testing the performance of gas-phase air filter for a variety of flat sheet media. In order to measure the concentration of toluene, the First check – handheld multi gas VOC detector equipped with a PID detector was used. The morphology characteristics of the fibers was performed using the analysis of scanning electron microscope images. Infrared spectroscopy-Fourier transform was used to identify organic compounds and functional groups in nanofibers.

The results of the analysis of the images showed that the mean diameter of the fiber was 169.16 ± 7.19 nm and the mean coefficient of variation was 0.23. The uniform and bead nanofibers were obtained. The thickness, porosity and air permeability coefficient of test media was 0.15 mm, 43% and 5.75 Darcy, respectively. The mean removal efficiency of PAN / SWNT nanofiber treated with plasma was 98% and the mean pressure drop was 100 Pascal. The FTIR spectrum of the test filter media showed that the peaks appearing at certain wavelengths related to the vibration of C-H aliphatic groups of C-C and C=O bands related to PAN polymer and carbon nanotubes.

Removal of toluene was achieved through the fabrication of PAN/SWNT hybrid nanofibers treated with plasma. Uniform nanofibers were obtained and showed the proper removal efficiency and low pressure drop.

Determining the VO2 max of individuals is of great importance. The VO2 max refers to the maximum oxygen that can be consumed in the body in one minute and depends on factors such as physical conditions, environmental parameters, and physiological characteristics of the individual.. Noise and heat are among the factors influencing VO2 max (also called maximal oxygen uptake or maximal aerobic capacity), which affects the performance of respiratory system, via different ways. Therefore, the purpose of this study was to investigate the simultaneous effect of noise and heat on VO2 max in Ahvaz university of medical sciences’ students  

The present study was conducted on 50 volunteer students from the Ahvaz Jundishapur University of Medical Sciences, Iran. The VO2 max index was measured using the ergometer bicycle test and the Astrand protocol in nine modes of exposure to heat (21, 38 and 48°C), WBGT (18.34, 32.46 and 41.25°C)   and noise (75, 85 and 95 dB (A)). In order to carry out the test according to the Astrand protocol, the person pedaled on the bike for six minutes at a constant load and a speed of 50 rpm to increase the heart rate to more than 120 beats per minute. The heart rate was monitored while working with the ergometer bike using a Polar branded sensor mounted below the individual chest. SPSS vol.22 software, Friedman test and paired t-test were used to analyze the data.

The mean VO2 max in the second test condition (heat:21°C ,  WBGT : 18.34°C ,noise:85 dB)  and the third test condition (heat:21°C ,WBGT : 18.34°C ,noise:95 dB) were not significantly different from the first (normal) mode, but the VO2 max value significantly decreased (P<0.001) from the third mode to higher levels with increasing the levels of heat and noise.

Since one of the objectives of ergonomics is to create an environment in consistent with human capacities, it is essential to have knowledge of VO2 max. Regarding the effect of heat and noise on VO2 max of individuals and also the direct relationship between VO2 max and PWC) Physical Work Capacity (, in order to protect the health of individuals and increase their productivity, it is necessary to carry out control measures in warm and noisy environments.

Evaluating environmental risks in the oil and gas industry is essential to prevent irreparable damage to the environment. Using classical methods for prioritizing environmental risks does not achieve high-reliable results. Therefore, the aim of this study is to minimize the limitations of classical methods in a typical oil and gas production zone, by using fuzzy logic and Multi Attribute Decision Making (MADM) approach.  

After forming an identification and assessment team including experienced experts from different organizational units in a region of exploitation of oil and gas, values of each risk factor (likelihood of occurrence, severity and detectability) related to identified environmental risks are determined according to their qualitative opinions represented by linguistic variables. Relative weights of the risk factors are calculated by applying the group Analytic Hierarchy Process (AHP) in a fuzzy environment on expert opinions. Then, fuzzy aggregation in the linear form by considering the weight of the risk factors and a method that is developed based on the center of gravity are employed in evaluation and ranking of the risks.

In this study, the severity factor has the most important contribution in risk assessment compared to the other risk factors, since it has the highest relative weight. Raw sewage aspect resulted from absence of appropriate treatment system has the highest priority and spilling over of acid that is caused by chiller cleaning stands at the second position in the identified environmental risks.

The results demonstrate that although the proposed methodology requires greater time than classical methods, it is able to determine the risk ranking more practically because of minimizing the limitations of classical

high sensitivity to judgmental errors, considering some risks in the same index group and ignoring uncertainty in experts’ opinions. Proposed method is a proper alternative for classical environmental risk assessment technique, and capable of prioritization and evaluation risks in terms of safety and health.

Nowadays, accidents are regarded as a main risk factor for both human and economic of countries. The triggerring cause of most accident is human error. In the healthcare setting, human errors can lead to injuries and even death of patients and damage the reputation of healthcare staff. Human errors in healthcares can occur during various activities including diagnosis of a disease, drug administration, and also during the use of various appliances. Therefore, it is of critical importance to identify these errors and assess their risks.  Accordingly, the main aim of the present study was to identify and assess human errors possible to occur during the use of the ventilator device in neonatal units of  educational hospitals of Hamedan University of Medical Sciences.  

This qualitative study was conducted using PUEA technique in 2017. The required data associated with the function and operation of the ventilator were gathered by investingating documents, observing the operater while using it, and interviewing with the operator. Hierarchical task analysis (HTA) was used for determining the main tasks and subtasks performed for operating the device. The identified errors were categorized into seven groups, namely planning, functional, checking, retrieval, communication, and selection errors. The PUEA method was utilized in exploring the causes of errors, the possibility of error recovery, and associated risks.

Functional error was the most prevalent one (72.7 %), whereas communication error was the least prevalent one (3.03 %).  Omission and commission were the most frequent functional error. Moreover, 42.2 percent of errors had roots in lapse and slip and 12.1 percent were of knowledge-based type. Moreover, it was impossible for 79.7 percent of errors to be recovered. About 54.53 percent of errors had severe or catastrophic consequences.

As the risk of accidents occurring in healthcare organizations is unacceptable, it is a necessity to identify these errors and evaluate their risks. As it is costly to replace the purchased devices with less error prone devices, human error analysis should be performed in the design phase and before purchasing the devices. Moreover, errors with an unacceptable risk should be controlled based on their probable causes.

Work-related musculoskeletal disorders (WMSDs) are any disorders or injuries to the musculoskeletal system due to working procedure or conditions. WMSDs is one of the main causes of occupational injuries and disability in advanced and developing countries. The present study was conducted to evaluate the prevalence of musculoskeletal disorders in drivers in order to achieve complete results with high statistical power, using meta-analysis method.

This study is a systematic review and meta-analysis. In this study, the articles extracted from national and international databases, including Scientific Information Database (SID), Science Direct, PubMed (using the word MESH), Pre Quest, Scopus, Google Scholar, Iran Medix, SID, and MedLib. The main keywords for the search were Prevalence, Musculoskeletal and Drivers. The time for selecting articles was from 2000 to 2017. Data were analyzed using meta-analysis (random effect model). I2 and Q indexes were used to calculate heterogeneity. All statistical analysis was performed using STATA 14 software.

In this study, 22 articles were entered into the meta-analysis process. The sample size was 7706 people with mean of 350 people in each study. The prevalence of musculoskeletal disorders in different organs of drivers was as follows: 26.19% (CI: 38-14.30), 18.07% (CI: 25.99-10.16), and 5.75% (CI: 8.273.22) in neck, shoulder, wrist / hand, and elbow respectively. The highest prevalence was related to low back pain 41.63% (confindence Interval (CI): 33.09-50.17), and the lowest prevalence was related to elbow disorder 7.45% with (CI: 95.46-9.43). The significance level was set at 0.05.

The results of this study show that the prevalence of pains in the back, neck, and shoulder are high among drivers. Also, due to the high prevalence of predicting the incidence of impaired driving. in order to control and reduce these disorders, appropriate design of seats and equipment of vehicles, conducting periodic examinations of drivers,performing proper exercise, and considering adequate rest time in working hours are recommended. Ergonomics and occupational health education programs are also recommended to reduce the risk of developing musculoskeletal disorders associated with driving.

Nowadays, working in any computer work stations, named visual display terminal (VDT), was widespread and has become popular in our lives. Due to the increasing trend of using computers in the administrative and social institutions, prevalence of eye-related signs of working with computers is still increasing and it is one of the most important health issues. Computer jobs are low-mobility and require little energy to do physical work, but require more cognitive processing and mental focus. Visual fatigue is an occupational hazard for people working with computers. Eye fatigue has symptoms such as headaches, job discomfort, and eye pain the purpose of this study was to have a systematic review on eye fatigue, dry eye and eye blink among people working with visual terminals.  

Internet search databases and search engines were used to find articles with focusing on the impact of risk factors on eye indexes on computer users. In this study, related articles were obtained from websites, including: PubMed, Google Scholar, Scopus and Web of Sciences. The keywords were used to search in these websites were: computer user, eye fatigue, dry eye and eye blink. Accordingly, after finding 115 relevant articles from the related sites, 17 articles were finally selected.

Findings show that using computer cause many problems in the eye. Duration of using the computer, the type of work with the computer, the mental load, the distance from the monitor, and also long-term use of the computer without break in during work can cause dry and fatigue eye in users, which is one of the most common ocular problems among computer users.

According to the finding and results recommended to reduce of dry and fatigue eye, distance of users from the monitors, be more than 50cm, use 20-20-20 law to rest user’s eyes, and  Positioning the monitor be 15-20 degrees below the user’s line of sight. Also, too much focus on the screen reduces blinking and resulting in dry eyes. In order to prevent dryness of the surface of the eye, it is recommended that the eyelid be optional even if possible. Increasing the contrast of the monitor can be helpful in reducing stress and strain on the eye while working with a computer and using glasses instead of lenses to correct refractive errors and one of the ways to control and improve dry eye is using artificial tears by computer users.

Nearly a third of people work in jobs that use voice to be part of their work. Teachers as the largest group of professional vocal users, are at risk of vocal disorders. The aim of this study was to investigate the effect of different risk factors on vocal disorders in teachers.  

This is a cross-sectional and descriptive-analytic study that was conducted on 73 primary and secondary male and female school teachers in Saveh in 2017 by random sampling. The researcher-made questionnaire on risk factors affecting verbal disorders with the aim of identifying risk factors and a Voice Handicap Index (VHI) questionnaire (30 items) aimed at evaluating verbal disorders and symptom questionnaire were used in this study. All of them have been shown to be valid and reliable in previous studies. Data were analyzed using t-test and chi square statistical tests by SPSS ver.24.

The reliability of the researcher-made questionnaire on the risk factors affecting vocal disorders was confirmed by Cronbach’s alpha (0.736) and its validity was confirmed by the experts regarding the adequacy of the number of questions, the lack of ambiguity and the assessment of content fitness. According to our gathered data, vocal disorders were observed in 55% of the teachers. Also the results showed the rate of vocal disorders in female teachers is far higher than male teachers. Functional disturbance of vocal cords and allergy as general risk factors, teaching tools and poor air quality as environmental risk factors and inadequate vocal rest and job stress as occupational risk factors contributed to increasing vocal disorders in teachers. Among the symptom associated with verbal disorders in teachers, vocal fatigue and hoarseness were more common in comparison with other symptoms.

Due to the prevalence of vocal disorders in half of the teachers and the impact of general, environmental and occupational risk factors, it is necessary to identify and control the risk factors of vocal disorders in teachers. It can also be concluded that teachers can enjoy a healthy voice by considering the principles of ergonomics and occupational health.