ABSTRACT
These minerals have been extensively used in industrial products such as cement-asbestos sheet and pipe, brake shoe, clutch, insulation materials, etc. Occupational and non - occupational exposures to this carcinogenic material have caused to develop several methods to evaluate airborne asbestos fibers. In this study, multiple microscopic method of determining the type and concentration of asbestos fibers has been used in an industry. The forty five personal samples on membrane filters [MCE] were collected of different processes of a manufacturing factory of cement-asbestos sheet. The half of each filter was prepared and then fibers counting were accomplished by ocular PCM and LCD images methods. Another part of filters was used for identification of asbestos fibers elements and types by scanning electron microscope method. Fibers concentration range were determined 0.009-0.243 fibers/cc by direct counting method [Ocular PCM], while by indirect method [LCD Images], results were 0.00-0.117 fibers/cc and statistical tests showed significant difference [p<0.02]. Study of elemental composition of fibers by scanning electron microscope confirmed that, the majority of fibers were chrysotile. Study of elemental composition of fibers by scanning electron microscope confirmed that majority of fibers are chrysotile. Due to limitation of study, use of 1.3 megapixels in indirect method, PCM direct method remains one the best methods of Asbestos fibers counting in Iran
ABSTRACT
Dust can be produced by almost all production processes in Portland cement factory. Dust exposure potentially can affect respiratory function. But evidence for respiratory effect of cement dust exposure has not been conclusive. In this study we assessed effect of cement dust exposure on respiratory function in a cement production factory. A respiratory symptoms questionnaire was completed and pulmonary function tests were carried out on 94 exposed and 54 non exposed workers at a cement factory in the east of Iran. Additionally, respirable dust level was determined by the gravimetric method. X-ray fluorescence [XRF] technique was performed to determine the silica phases and the SiO[2] contents of the bulk samples. The arithmetic means [AM] of personal respirable dust were 30.18 mg/m[3] in the crushing, 27 mg/m[3] in the packing, 5.4 mg/m[3] in the cement mill, 5.9 mg/m[3] in the kiln and 5.48 mg/m[3] in the maintenance that were higher than threshold limit value [TLV] of the American Conference of Governmental Industrial Hygienists [ACGIH] which is 5 mg/m[3]. This value in the unexposed group was 0.93 mg/m[3]. In this study cough, sputum, wheezing and dyspnea were more prevalent among exposed subjects. Exposed workers compared to the unexposed group showed significant reduction in Forced Expiratory Volume in one second [FEV[1]], Forced Vital Capacity [FVC], and Forced Expiratory Flow between 25% and 75% of the FVC [FEF[25-75%]] [P<0.05]. It can be concluded that in our study there was close and direct association between cement dust exposure and functional impairment among the cement factory workers