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Background: The respiratory symptoms in welding workers have been appeare by increasing use of welding various poisoning gases and fumes in machine industry. It is necessary to evaluating of frequency of respiratory symptoms with scientific methods. Methods and Materials: In this historical cohort study, 60 non-smoker welding workers with history of at least 6 months work in welding, and 60 non-smoker office workers who were not expoused to respiratory pollution were selected from machine industry factories of Arak. Data was gathered by questionnaire. Occupationalist performed physical exams and spirometery. Data was statistically analyzed. Results: There was a significant relationship between sore throat (p=0.02), cough (p=0.04), spectrum (p=0.01), and dyspnea (p=0.007) with working in welding. But in symptoms such as rinite, hoarsening, nasal congestion, epistaxis, respiratory assessment and spirometery results difference was not significant. Conclusion: Symptoms of upper respiratory tract stimulation in welding workers were significantly more than non-expoused workers.

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Background: Hospital wastewater usually contains pathogenic micro-organisms, drugs, radio active materials, and toxic chemical elements that in case of being disposed without filtration, will result in pollution and spread of diseases. Therefore, evaluating the status of wastewater disposal in hospitals is necessary for proper planning. Materials and Methods: In a cross-sectional descriptive study in 2008, data collection was done by means of interviews, observations, and questionnaires in all hospitals of Markazi Province. Noticing the 33 items in the questionnaire, the overall conditions of the hospitals and the methods of using the sewage system were studied, and at the same time, filtration installations and wastewater disposal systems were inspected. Results: Of all the 19 hospitals, 10 used a conventional method of direct disposal of sewage to subterranean shafts, and of the 4 hospitals with filtration installations, three were practically out of order or were not efficient. Five of the hospitals were directly linked to the city sewage system without any pre-filtration. None of the hospitals had a specialized operator of sewage filtration and disposal system. Conclusion: Wastewater disposal in hospitals of Markazi Province is not desirable therefore, such acts as conducting more specific surveys, creating a positive attitude in planners, and providing sufficient funds for filtering wastewater in some of the hospitals are suggested.

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Background: Solid waste is one of the environmental pollution. Therefore the aim of this study was to survey of knowledge, attitude and practice of student and teachers about weast management for developing methods of educational in Arak city.

Materials and Methods: This is a cross sectional and analytical study that was carried out on 1739 student and 149 teacher in school of Arak city in 2012. sampling with cluster and data collection with questionnaire including knowledge, attitude, practice and appropriate resource of education for waste management. Finally data analyzed with statistical tests.

Results: The mean knowledge and attitude student was 4.1±1.9 (out of 8) and was 20.63±5.9 (out of 35) respectively. Based on most educational methods for weast management viewpoint of student book 441 student (29% ) but impact of internet very low interest 487 (32%) of student. Moreover the most educational methods based on level of education significant difference was observed (p=0.001).

Conclusion: Due to a level of knowledge and attitude of student and accsses to educational resourse and huge of weaste in school educational program planned via book, teacher and peer education for student recommended.

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Background: As dental solid waste are among the most important environmental pollutants due to its high contents of toxic and hazardous agents, suitable treatment and management of it are of great importance. The objective of this study was to quantity & quality analyses of dental solid waste and associated management practices in the general dentistry offices in the city of Arak.

Materials and Methods: 15 samples of solid waste were taken from the 5 selected general dentistry offices, classified into 66 components and 4 fractions, and then the quantity & quality characteristics were evaluated. Management practices of the solid waste were also investigated by using a questionnaire.

Results: According to the results, per capita and the average generation rate of each dentistry office were 66.71 g/day-patient and 1340.45 g/day, respectively. Potential infectious, domestic-type, chemical & pharmaceutical, and toxic wastes consisted of 54.25%, 35.14%, 8.19%, and 2.14% of the waste generated, respectively. 10 components including latex gloves, nylon & plastic, saliva & blood-contaminated kleenex, paper & cardboard, used ampoules, saliva ejector tubes, gypsum, food waste, saliva & blood-contaminated dental rolls, and nylon gloves were responsible for more than 80% of the total waste generated, respectively.

Conclusion: Each fraction of dental solid waste (toxic, chemical & pharmaceutical, potential infectious and domestic-type wastes) should be separately collected and disposed of according to the related criteria.