Occupational exposure of a medical school staff to formaldehyde in Tehran

Cadavers are preserved in a fixing solution containing formalin. Formaldehyde [FA] released from formalin is inhaled by the personnel in the anatomy laboratory. Exposed personnel have reported respiratory problems and various symptoms. Due to the toxicity of FA as a strong irritant and carcinogen and also lack of a national study assessing occupational exposure to FA in gross anatomy labs in Iran, the present study aimed at occupational monitoring of personnel exposed to FA and evaluating relevant symptoms in them. A total of 20 subjects [all the staff] working in a gross anatomy lab and 20 library personnel were considered for occupational monitoring of exposure to FA during three months with various climatic conditions. They were also monitored for respiratory symptoms. Air sampling and analysis of its FA content were conducted according to the NIOSH method No.2016. Symptoms of cases and controls [library personnel] with active and passive exposure to formaldehyde were also studied by a self-report questionnaire. In the first stage of monitoring with ventilation [supply-exhaust] system on, the exposure of personnel [Mean +/- SE] was 306 +/- 21ppb. In the second stage of monitoring the personnel's exposure was 317 +/- 26ppb with only the ventilation supply system on and in the final monitoring stage this rate was 698 +/- 34ppb with the ventilation system [supply and exhaust] off. In this study, personal's exposure level to FA was higher than the indoor concentration, and the individual exposure levels of instructors were higher than those of the students. Exposure of library personnel in the adjacent department [central library] was about 50ppb. Most important complaints reported by actively exposed staff members and library personnel were the unpleasant odor [68%], cough [64%], throat irritation and runny nose [56%], burning and itching of nose [52%] and irritating eyes [48%]. Considering the level of exposure of all subjects in this study and existence of clinical symptoms, better control of the exhaust system in the gross anatomy lab and use of a more efficient ventilation system are recommended to protect the staff and instructors of the Anatomy Department

Serum malondialdehyde and urinary neopterin levels in glass sandblasters exposed to crystalline silica aerosols

The aim of this cross-sectional study was to explore the association of crystalline silica aerosols exposure with malondialdehyde in blood serum and urinary neopterin and explore their potential as biomarkers of their external exposure. Nonsmoking and healthy male glass sandblasters and control population were randomly selected for this study. All groups were monitored for their personal exposure to crystalline silica according to NOISH method No. 7601. High Performance Liquid Chromatography [HPLC] was used to for analysis of malondialdehyde of blood serum and urinary neopterin, and creatinine in all study participants. The mean of personal exposure to crystalline silica aerosols in glass sanbalsters was 164 microg/m3 [SD: 112] compared with less than 0.006 mg/m3 for control group that was even below detection limit. The mean of blood serum malondialdehyde of sandblasters [49.08 +/- 19.05micromole/l] was significantly higher than that of control population 1.92 +/- 0.33 micromole/l [p<0.001]. Urinary neopterin of sandblasters was 10.85 +/- 3.61 mmole/mole creatinine which was also significantly higher than control group 4.71 +/- 1.88 mmole/mole creatinine [p<0.001]. Correlation between occupational exposures of glass sandblasters to crystalline silica with blood serum malondialdehyde was significant [r2=0.279, p<0.01]. Malondialdehyde of blood serum and urinary neopterin could be regarded as biomarkers of exposure to crystalline silica aerosols

Risk assessment of workers exposed to crystalline silica aerosols in the East Zone of Tehran

The term "crystalline silica" refers to crystallized form of SiO2 and quartz, as the most abundant compound on earth crust, is capable of causing silicosis and lung cancer upon inhaling large doses in course of occupational exposure. In this study, airborne respirable dust samples were collected on mixed cellulose filters [25 mm diameter, 0.8 mm pore size], by using a cyclone separator at the flow rate of 2.2 l/min for a maximum volume of 800 liters. Infrared absorption spectrometry was used according to the "National Institute of Occupational Safety and Health" [NIOSH] method No. 7602 for analysis of samples. Risk assessment techniques predictive of silicosis and lung cancer were employed. The geometric mean of workers' exposure to crystalline silica in ten industrial fields [stone milling and cutting, foundry work, glass manufacturing, asphalt, construction, sand and gravel mining, sand blast, ceramics, bricks and cement manufacturing] was in the range of 0.132 to 0.343 mg/m[3]. Mortality rate of silicosis was predicted to be in range of 1 to 52 per one thousand exposed individuals. Risk of lung cancer mortality in exposed workers in the east zone of Tehran based on geometric mean exposure of industrial activity and 45 years of exposure was in range of 50 to 129 per one thousand. In terms of risk assessment of silicosis mortality, cumulative exposure of 21 percent of population complied with the notion of acceptable risk. In regard to lung cancer mortality, 100 percent of the population were expected to have an unacceptable risk after 45 years of active work experience. This study is the first of its kind in Iran demonstrating a profile of exposure in different groups of workers in the east zone of Tehran's greater city, covering 5.5 million populations. Considering the total population of one hundred thousand workers exposed to quartz in east zone of Tehran and aging of the current young workforce, numerous cases of silicosis and lung cancer are forecasted in near future

Airborne microbial contamination of dental units

Occupational risk of dental personnel to microbial airborne contamination has been demonstrated through the increased prevalence of respiratory infections. The American Dental Association has suggested stringent protection for infectious agents present in dental aerosols. Materials and Occupational exposure of dentists to airborne microbial and mycological contamination in various locations of a dental school was monitored by sampling of air in close vicinity of their breathing zone. This sampler drew air at a flow rate of 10 liters/minute and for a 2-hour period and blew it at a high speed through a narrow slit over a solid nutrient agar plate. Immediately after sampling, the plates were placed in an incubator and incubated aerobically for 2 days at 37C. The total bacterial counts in the air of dental surgery rooms and in non-surgery rooms without direct involvements with dental operations were in the range of 120-280 cfu/m3 and 49-128 cfu/m3 respectively. Pathogenic Streptococcus haemolyticus and opportunistic Staphylococcus species were found in some locations of dental surgery rooms. There are no standards for acceptable levels of indoor air contamination with pathogenic microorganisms and since pathogenic Streptococcus haemolyticus and opportunistic Staphylococcus species were found in some areas of the dental school, the need for management of possible risk of infective hazards is recognized

new sampler and analysis method for BTEX in ambient air

Benzene, toluene, ethylbenzene and xylene [BTEX] compounds are components of motor vehicle fuel. BTEX are released from exhausts of vehicles and also evaporation from the fuel tank, carburetor and crank case of engines. BTEX are dangerous chemicals that participate in photochemical reactions and produce secondary air pollutants such as ozone, peroxyacethyl nitrate, free radicals and nitrogen oxides. BTEX in ambient air of metropolitan areas has been the subject of concern in many studies through elaborate "Environmental Protection Agency" [EPA] method. Level of BTEX in the ambient air of major Iranian cities, has not been measured in concentration range of part per billion [ppbv] due to the inadequate sensitivity of available gas chromatography systems. The aim of this study was to improve the sensitivity of gas chromatography by using a special sampler and thermal desorber [Micro-Packed Injector]. Our sampler consisted of a 5-centimeter stainless steel tube one millimeter in diameter packed with carbopacked B heat-conditioned samplers utilized for sampling atmospheric BTEX. It was subsequently injected to a custom-made thermal desorber [225C] which was assembled onto the injection port of a gas chromatography device for analysis. BTEX standard atmospheres were analyzed with a gas chromatograph flame ionization detector [GC-FID] with linear range detection of 27.5-275ppb, 23.1-223.6ppb, 20-320-ppb, and 20-320ppb respectively. The Micro-Packed Injector [MPI] installed on ordinary GC-FID improved linear range detection of BTEX from previous ppm detection to ppb range