مجله بهداشت و ایمنی کار
سال سوم شماره 4 (زمستان 1392)

Bioaeroslos released from wastewater treatment plants may contain pathogens existing in the sewage which could endanger the health of workers. The aim of this study was to evaluate the status of bioaerosol emissions form in a sanitary wastewater treatment plant. This cross-sectional study was carried out in different units of a sanitary wastewater treatment plant. For this purpose، air samples were collected on blood agar and dextro agar in an Andersen single-stage sampler with flow of 28. 3 lit/min for 10 minutes. Collected samples were shipped to the lab immediately and incubated for 48 hours. Then، incubated samples were counted for colonies concentration. Based on the result of this study، the mean density of bacterial and fungal bioaerosols in all wastewater treatment plants were 412. 86±23. 30 and 53. 72±23. 99 CFU/m3، respectively. Microbial contamination of the air within a kilometer away from the site (control areas) was 17 times less than its average density. Wastewater treatment processes can contaminate the air surrounding the plant، particularly with bacteria bioaerosols. Therefore، it is necessary to control the emissions and protect the health of workers against risks arising from exposure to bioaerosols.

One of the most important threats for employees working in chemical industries is exposing to the chemical materials. Lack of precaution and control regulations during working with chemicals can have irreparable consequences. So، in order to achieve an effective control program، it is necessary to have an appropriate assessment of the procedures involving exposure to the chemicals. William-fine method can provide an acceptable insight into hazard risk rate. In this study، a combination of AHP and William-fine adopted to achieve a model for chemicals exposure risk assessment in oil and gas industry. The numbers were extracted from questionnaire، and then، they weighted entered to assessment the model. Finally، they were presented quantitatively with protection layer. Result and The results revealed that the quantitative amount of consequence، probability and exposure was 83. 2، 8. 45، and 2. 2، respectively. Generally، the chemical exposure risk number was 1546 which shows that reforming plans are in highly priorities from an economical point of view. William-fine method has the benefit of an accurate chemical exposure by combination of effect severity، exposure probability and detriment rate، and also minimization of personal judgments during the assessment.

Manual dexterity impairment due to wearing latex and nitrile gloves among health care employees and laboratory personnel can be a remarkable problem because of its adverse outcomes. The present study was conducted to “compare the effect of using latex and nitrile laboratory gloves on hand dexterity”. In a semi experimental study design، 30 university were students randomly selected from Urmia University of medical sciences. Subjects assigned in three experimental conditions، such as the control condition (without gloves)، with latex glove and with nitrile gloves. Then، dexterity level of fine finger and gross of the subjects were calculated using the Purdue pegboard test. Repeated measures one-way ANOVA test and T-test and Pearson’s correlation coefficient were used for statistical analysis. The result showed that the differences between three groups of laboratory conditions from the level of gross and fine finger dexterity were statistically significant (p‹0. 05). As the latex gloves showed significant and positive effect on gross and fine finger dexterity comparable with nitrile gloves and control group but there was no significant difference between the gross and fine finger dexterity of nitrile gloves when comparing with the control group. In other words، the nitrile gloves had not negative effect on gross and fine finger dexterity. Considering that there was no significant difference in the score of both fine finger and gross hand dexterity while using nitrile gloves as compared to the control condition (without gloves)، means that use of nitrile gloves has no adverse effect on hand dexterity; therefore، using nitrile gloves is recommended as a alternative for the latex gloves، considering the additional advantage of no allergic reaction in this gloves.

PAHs are organic compounds with benzenic rings that releas from hot asphalt as incomplete combusting. These compounds are one of the major concern in scientific societies، workplace and environment due to their stability، bioaccumulation، carcinogenic and mutagenic effects. Since asphalt workers are exposed to PAHs frequently in their job، in this study it was attempted to evaluate respiratory exposure of asphalt workers to PAHs in their breathing zone. In this study air samples of the asphalt workers were collected in accordance with the NIOSH 5506 method using PTFE filter and XAD-2 adsorbent. The ultrasonic bath and acetonithrile are used in order to extract the analytes from the filter and adsorbent. Also، the samples were analyzed by HPLC-UV. In all samples، Finisher assistance and oilman with 1754. 48 ng/m3، 24. 65 ng/m3 had maximum and minimum exposed to ∑PAH، respectively. Among the PAHs compounds، which asphalt workers exposed to، Naphtalene had the highest concentration. Among different asphalt workers tasks، screedman expoused to PAHs، had a significant difference. Evaluation of Polycyclic aromatic hydrocarbons concentrations in the breathing zone of asphalt workers indicated that exposure to these compounds were below the occupational exposure limits recommended by NIOSH، OSAH، ACGIH and Iranian OEL. Due to the highly carcinogenic potential of some of these compounds and absence of occupational exposure limits for these compounds، likes Chrysene and Benzo (a) Anthracene، it is strictly recommended to employ engineering controls and using suitable PPEs. This study also indicated that the exposure to PAHs in the most asphalt workers tasks had significant differences، and it can be due to proximity of the workers to the source of hot asphalt and also exposure to the exhaust gases that releasesd from the construction machinery.

In real Conditions، pollution emission are mostly released as mixed components rather than a single pure emission of the chemicals. In this study، a miniature stirred tank bioreactor was optimized for treatment of waste gas containing BTX (benzene، toluene and xylene). The sludge of an oil refinery was sampled based on the assumption that it contains BTX-degrading microorganisms and used as microbial consortium. Also، silicone oil was added to improve removal efficiency. The operational parameters of the bioreactor were optimized during the study. The removal efficiency and elimination capacity of benzene، toluene and xylene vapors simultaneously in the presence of 10% silicone oil as an organic phase showed increasing trend up to the concentrations of 1730 mg/m3، 1710 mg/m3 and 1380 mg/m3، respectively. In these concentrations the removal efficiency and elimination capacity of benzene were 100% and 59 g/m3/h، toluene 100% and 58 g/m3/h and xylene 91% and 42 g/m3/h، respectively. The total removal efficiency and elimination capacity for BTX were 91 to 100% and 159 g/m3/h، respectively. It was shown that presence of 10% silicone oil increased 44. 5% in total removal efficiency of BTX. The microbiological experiments on the bioreactor media showed that three spices of Pseudomonas putida، Chryseobacterium and Ralstonia pickettii can be found، when BTX ware treated. This work revealed that two phase partition bioreactors (TPPBs) can be successful method for the treatment of streams contaminated with BTX.

According to the previous studies، about 90% of accidents in the workplace are due to the unsafe behaviors. In this study، the impact of personality traits، as a predictive factor on the unsafe acts was surveyed in a construction project of a car manufacturing company. In this study، personality traits and unsafe behavior rates were determined using NEO-Five Factor Inventory (NEO-FFI) and safety behavior sampling (SBS) technique. The Spearman correlation coefficient was used. To analyze the acquired results، the total population of the project was 243 people. The results showed that 31. 7% of workers’ behaviors were unsafe behaviors. The correlation between unsafe behaviors and the neuroticism and extroversion were direct and significant (p<0. 001). Assessment of the personality traits could be used as a predictive tool to identify employees with higher rates of unsafe behaviors and helps planning to reduce the accident rates.

Heat stress in workplaces cause multiple problems such as thermal stresses، thermal discomfort and in more severe cases may lead to accidents and diseases related to excessive heat. The aim of this study was to evaluate heat stress adopting WBGT Index in some small enterprise in Qom city and also to examine the relationship between WBGT and physiological indices. This Cross-sectional study was conducted in 25 small workshops in Qom city including of 10 indoor and 15 outdoor workshops in August 2012. WBGT were measured according to the ISO7243 standard. The physiological responses including pulse rate، systolic and diastolic blood pressure were measured among 25 workers (one from each workshop). The average WBGT index for indoor job were 27. 55 Ċ among auto body repair، 27. 45 Ċ in mechanics، 24. 64 Ċ in painters، 26. 73Ċ in welder and 25. 89 Ċ in manufacturing doors and windows makers. For outdoor jobs as auto body repair، mechanics and painters it was 30. 01 Ċ، and for welders and doors and windows makers 28. 52 Ċ. Compared to the standard of ISO7243 WBGT all small workshops were higher than threshold limit. Auto body repair (30. 22 Ċ) and painting (30. 03 Ċ) workshops had highest WBGT. Average WBGT in auto body repair (as a job with most exposed to the open space and solar radiation) with welder and doors and windows، showed statistically significant differences T-test using WBGT with pulse rate، systolic and diastolic blood pressure did not have statistically significant (P>0. 05). The findings indicated that workers are exposing to heat stress and doing more researches and representing preventive counter measures for the workers in this field are essential. Heat stress in almost all of the studied workplaces are higher than the recommended limits، and the outdoor workshops had the highest thermal stress، although heat stress did not show a significant correlation with the studied strains.

Possible contamination in nuclear medicine centers، in addition to health problems، affect the tests and much effort and cost is required for decontamination. Given the effects of ionizing radiation on human health، rules and regulations have been enacted to avoid contamination، that in working with radioactive materials should be followed to minimize them. After mapping of nuclear medicine centers in the province، areas that should be studied for measuring the amount of radioactive contamination were determined. The site selection for the tests were based on the area in which the possibility of further contamination were existance. After measuring the background count rate the radioactive contamination in studied areas were performed using Wipe Test. The mean level of background contamination in centers 1، 2 and 3 were 1. 75±0. 150 μCi، 4. 43±0. 615 μCi and 2. 47±0. 055 μCi، respectively. In center 1، only region of Hood pollution was much higher than the permissible limit. In center 2، radioactive contamination of the waiting room، patient rooms، warehouse radiotracer، control room، hood، desk and floor center was exceeded. Also، in center 3، contamination of the doorway، hallway patients، control room، hood، desk، sink، cabinets، room and floor imaging injection (control)، respectively، were higher than the permissible limits. In centers 1 and 2، most of the radioactive contamination occurred under the hood due to labeling of radiopharmaceuticals activity. Also، in center 3، the highest contamination rate belonged to patients’ corridor that could be due to frequent the area. According to this subject، necessary measures in this regard should be considered by the department responsible for health physics.