نشریه طب کار
سال ششم شماره 2 (پیاپی 15، تابستان 1393)

Ventilation plays a crucial role in reducing the number of air transmitted pathogens in isolated rooms. Determination of the suitable type of ventilation system and the proper ventilating rate has always been a challenge. Patients’ bed arrangement and the location of the staff are also expected to influence the occupational exposure of the staffs’ to harmful airborne particles. The purpose of this project was to determine the state of ventilation systems, patient’s bed and the location of the healthcare staff in these rooms, upon the risk to the staff being exposed to the airborne pollution in these places. Throughout this practical study, a single-bed hospital room, where a tuberculosis patient had been admitted, was chosen. Thereafter, 5 types of ventilation systems were applied for the experiment. Whilst applying various ventilating scenarios, a patient’s bed and a statue of a hypothetical healthcare staff were positioned in 2 different locations. During each of these experiments, 3 occupational samples were taken from the bio-aerosols in the room. The total density of the bio-aerosols in the patient’s room changes significantly (P<0.001) within different plans. The least amount of capacity and the worst aeration and the concentration of indoor air bio-aerosols meaningfully decreased (p<0.001) in comparison with the air of a room within which no ventilation system is utilized. When air is supplied via a vent on the ceiling and it is exhausted from a vent situated on a wall at the southern part of the room, the total density of the bio-aerosols reduced to 25cfu/m3 (application of 12 air changes per hour). The arrangement of patients’ bed caused 17.75% reduction in total density of the sampled pollutions from the air. Application of a system as determined in this study is recommended for isolated rooms

The use of exhaled breath condensate (EBC) biomarkers to evaluate exposure and disease in recent years gained attention in toxicology and occupational medicine. However, use of standard sampling apparatus is missing element in this procedure. Initial design of sampler was selected based on the water condensation system. The effect of sampler length, sampling time and temperature were studied in the condensate collection system. Samples from both smokers and non-smokers were acquired to determine the amount of malondialdehyde in exhaled breath condensates. Samples were analyzed by high-performance liquid chromatography (HPLC). Based on observed results, cooling at zero degree centigrade was selected for optimum sampling. However, 5°C temperature also had slightly less sample recovery in comparison with zero °C. A 25 cm length condenser also had the highest sampling efficiency in comparison with other condenser lengths (15 and 40 cm). EBC Malondialdehyde was measured by the constructed sampler in smokers and non-smokers. Smokers had higher amount of malondialdehyde in their EBC(p<0.05). In this study we designed, constructed and validated the simple and cost effective exhaled breath sampler for exhaled breath biomarkers study. Results indicated satisfactory repeatability and robustness. Smokers had higher level of EBC malondialdehyde as a marker of lipid peroxidation.

Exposure to high temperatures is common among workers in hot environments and can lead to physiological adverse effects. Heat radiation from hot surfaces and inflamed ways to get the most important heat is the exposure ways of the workers. The aim of this study was to evaluate the effectiveness of control methods of radiant heat in workers exposed in a blast furnace steel industry. In this study, two main solutions include reducing radiant heat to control the temperature of the hot surface of the design and installation of heat-absorbing water pipes in the body blast furnace and the control of emission radiation heat of the installation reflective shield in the work station were studied. WBGT index before and after implementation of the intervention based on standard methods for evaluating was measured the effectiveness of the interventions at the work station. Environmental radiation temperature distribution in the furnace area was drawn before and after the intervention. Environmental parameters were measured using the WBGT meter manufactured by Casella Co. Evaluation of the effectiveness of interventions based on physiological strain index to measure skin temperature, heart rate before and after the intervention was performed in 20 workers according to standard methods. Data analysis was performed using SPSS software. The effectiveness of interventions, use of thermal absorbents in the body of the furnace and reflective shield exposed in a straight exposure line, radiation temperature and work station WBGT index was decreased 20, 3/9°C and 18.6 and 2.5°C respectively. Combination of control measures radiation temperature and work station WBGT index was decreased respectively by 26.5 and 5.2°C. After applying heat absorbing and reflective shield, mean skin temperature of workers and heart rate was declined 2.6°C and 3.6 bpm respectively. Use of thermal absorbents in the body of blast furnace was more effective due to the intervention of the heat radiation source. However, the combination control measures have the best performance to reduce thermal stress and strain caused by thermal radiation in the blast furnace workers.

physical exercise could induce lipid peroxidation as a result of oxidative stress. And intake of antioxidant compound may alleviate this stress by enhancing antioxidant defense. This study aimed to investigate the effect of vitamin E supplementation as an antioxidant on the lipid peroxidation and serum total antioxidant capacity following exhaustive continuous aerobic exercise in wistar rats. 28 wistar rats aged 4 month were assigned randomly into one of 4 groups: rest, rest vitamin E, continuous aerobic exercise, and continuous aerobic exercise-vitamin E. The supplement groups, were administrated a dose of 250 IU per one kilogram of daily intake food for one month of supplementation. All groups were subjected a familiarization treadmill protocol for two weeks. Finally, rats in continuous aerobic exercise groups exercised at 70% vo2 max. The running speed was 20 m/min at a gradient 5%. Serum malon dealdehyde (MDA) and total antioxidant capacity (TAC) were measured. Data were analyzed by one way ANOVA and sheffe post hoc at P<0.05 level. The MDA increased significantly following continuous aerobic exercise (P<0.05) but vitamin E could not decrease significantly the elevated response of MDA following exercise. However The TAC was higher significantly in continuous aerobic vitamin E group compare to the rest group (P<0.01). vitamin E supplementation despite of enhancement of the antioxidant capacity cannot prevent lipid peroxidation following continuous aerobic exercise in wistar rats.

Silicosis as a most important work-related lung disease is generated of inhalation crystalline silica dust. Chemicals health risk assessment is essential to decide on priorities for control action and reduce the risk to an acceptable level. The aim of this study is evaluate worker's exposure to crystalline silica (quartz) and determine the qualitative and quantitative health risk level. In this cross– sectional descriptive, analytical study, the total, respirable and crystalline silica dust was measured. Total and respirable dust measured by gravimetric method and crystalline silica amounts measured based on X-ray diffraction technique by NIOSH7500 method. Semi- quantitative risk assessment methods for Occupational Safety and Health Association of Singapore was used for Health risk assessment. The results showed that the average exposure of workers to total dust was 7.38±5.15, respirable 4.35±3.5 and crystalline silica 0.21±0.19 milligrams per cubic meter. Worker's exposure to crystalline silica in production units, including crusher, presses, ball mill, mucilage production and spray dryer are higher than Iran occupational exposure level. Also, the mean of total dust, respirable and crystalline silica in the different units, showed significant differences (p≥0.05). The result showed the high level of Risk in crusher, presses ball mill and glazing production units. Crystalline silica amount and risk level of risk is high in crusher, presses, ball mill and mucilage production and the exposure control measures are necessary.

One of the ways of transmission of infectious diseases is person to person transmission which hairdressers have an important role in this field. The aim of this study was to determine the knowledge, attitude and practice of female hairdressers about health and diseases related to hairdressing profession in 1391 in Yazd. This study was a descriptive study that was done randomly on 60 female hairdressers (12% of total female hairdressers in Yazd). The tool of gathering data was a questionnaire that its reliability and validity was determined and after completing, was analyzed by using SPSS 16 and Excel. Demographic data revealed that most hairdressers were less than 30 years old, diploma and have the experience more than 10 years. The results also showed that the age has not significant difference with the knowledge, attitude and performance of hairdressers (P>0.05), education level has a significant difference only with attitude. Work experience has a significant difference with attitudes and knowledge (P<0.05), so with increasing of work experience from less than 5 years to over 10 years, the knowledge and attitudes of hairdressers were increased. There was also a significant correlation between knowledge and attitudes about health and occupational diseases related to professional hairdressing, but there was not a significant correlation between knowledge and attitude with performance (P>0.05). The results of this study showed that the hairdressers have high knowledge, attitudes and performance.

Wastewater treatment workers may be exposed to a wide range of chemical pollutants and biological contaminants such as bacteria and fungi. The aim of this study was to investigate the potential work-related respiratory disorders in workers of 10 wastewater treatment of petrochemical industries in Iran. This cross-sectional study was carried out on 198 employees of wastewater treatment plants and 99 non-exposed (referents) employees. American thoracic society (ATS) standard questionnaire was used for investigation of respiratory symptoms. Pulmonary function parameters were measured using a calibrated Vitalograph. The data were analyzed by SPSS version 16. The result of this study showed that odds ratio of cough, phlegm, productive cough, wheezing, and breathlessness in exposed group were 2.94, 1.10, 1.95, 0.82 and 1.97 times higher than reference subjects. Additionally mean values of most parameters of pulmonary function tests (PFT) were significantly lower in exposed individuals than in referent subjects (P<0.05). Significant increase in prevalence of respiratory symptoms and decrement in PFTs in wastewater treatment workers may be attributed to their exposure to bioaerosols.