ABSTRACT
Growth of the plastics industry in recent decades has been dramatic. Poly Vinyl Chloride is one of the most widely used plastics in the world that granules in the thermal process decompose to Vinyl Chloride Monomer and is released in work air environment. This study aimed to evaluate occupational exposure and estimate workers' exposure with vinyl chloride monomer risk. A cross-sectional study of 100 workers at two Plastic factories in Tehran [A, B] was performed. Personal monitoring of workers to Vinyl Chloride Monomer was conducted by Optimized Method No.1007 from NIOSH. Atmospheric conditions, such as temperature, pressure, air velocity, and relative humidity were measured simultaneously along with personal monitoring. Quantitative risk assessment of workers was computed in the form of Standard Mortality Rate and incident rate cancer. Statistical analysis of data was conducted by SPSS version 19. Climatic parameters in the plant A and B for a relative humidity were 43.77 +/- 16.71 and 37.16 +/- 14.45% and temperature 20.95 +/- 3.34 and 21.05 +/- 2.20 degree C, air pressure 87.48 +/- 0.54 and 87.41 +/- 0.64 kPa and air velocity 0.13 +/- 0.08 and 0.10 +/- 0.06 meters per second were measured respectively. Occupational exposure to Vinyl Chloride Monomer plants A and B were 1.01 +/- 0.51 and 0.72 +/- 0.30 as ppm respectively. Quantitative risk of exposed workers based on Standard Mortality Rate was estimated 1.06 +/- 0.03 times of the population without exposure. Incident rate cancer based on accounting measures of integrated risk Information System was calculated per 1000 person exposure population. The correlation of Standard Mortality Rate and the risk of cancer incidence was statistically significant [R[2] :0.88]. Thirty one percent of workers had higher exposure to Vinyl Chloride Monomer than the occupational exposure limits [1 ppm]. In the present workers' exposure in this study is lower than international workforces reported in decades ago, but higher than studies recently published. The results clearly describes occupational hazard of workers in the current Iranian recession situation. The application of control system in the form of engineering control measure, especially in the coming years with projected economic growth, is justified for securing workers health and well-being.
ABSTRACT
To determine the surgical results of partially accommodative esotropia [PAET]. Thirty-eight patients with PAET scheduled for surgery from 2002 to 2008 were enrolled in a descriptive, analytic retrospective study. Patient characteristics including age, gender, refractive error, visual acuity, pre and post operative deviation, technique of surgery and follow up duration were recorded and analyzed. PAET accounted for 38.29% of accommodative esotropia. Mean age and refractive error [spherical equivalent] were 6.32 +/- 3.38 years and +4.1 +/- 1.98 diopters, respectively. The prevalence of amblyopia was 54.04% and patients were followed up for 18.76 +/- 13.58 months. Mean pre and post operative deviation were 30.87 +/- 10.3 and 2.05 +/- 5.7 PD, respectively [P< 0.001]. Mean amount of bilateral medial rectus recession was 5.48 +/- 0.66 mm. In 78.9% of patients, postoperative deviation was within 10PD of orthotropia. Residual esotropia and consecutive exotropia were seen in 18.4% and 2.6% of patients, respectively. Pre-operative deviation, refractive error and amblyopia had no significant effect on outcomes of surgery
ABSTRACT
Metal working fluids sprayed in air through lathe in form of oil mist, are considered as hazardous chemical pollutant. Metal working fluids are detrimental to skin and respiratory system and they possibly may produce carcinogenic effects. Due to increasing application of lathe machines in Iranian industries and unavailability of a sensitive analytic method, the objective of this study was to develop and validate a molecular spectroscopy for analysis of metal working fluids in the air. This study was conducted in two phases of method development and examination its validity. In the first phase, 10 ml of fresh mineral undiluted mineral oil were collected in cleaned glass vial and were used to prepare standard solutions. After pre-cleaning of the mineral oil by centrifuging at 5000g, standard solutions of oil were prepared from a spiked mixed cellulose filter using chilled pentane in concentration range of 1 to 200 ppm in series of 10 ml volumetric flax. Air-borne mineral oil were sampled from the breathing zone of workers on the mixed cellulose filter membranes and after extraction by pentane, mineral oil was determined by UV-spectroscopy in the wave length range of 190-380eta m. In the second phase of this study, the new method was validated through examination of coefficient of correlation of concentrations versus their respective absorptions and coefficient of variation and recovery tests. Standard concentrations of all bulk metal working fluids obtained from lathe operations had optimum absorptions in wave length range of 190-202 eta m. Linear concentration ranges of three standard solutions were in range of 5-100 ppm and with Pearson correlation of coefficient [r[2]] of 0.999, 0.997 and 0.998, respectively. Coefficient of variations of the three sets of standards for inter-day and intra-day variations were in the range of 3.4-6.6 and 5.4-8.6. Recoveries of known quantity of mineral oil added to standard solutions were in the range of 100 +/- 10. Developed method is capable of analyzing of air-borne mineral oil in the range of 0.09-3.66 mg/m[3]. The developed method is by far more sensitive than other routine methods and regarding the results of its validity, it can be considered as alternative method to previous ones