ABSTRACT
Background: inhalation of radon and its short-lived decay products is one of the most significant sources of exposure to natural radiation. Radon is the second cause of lung cancer in the populations. The present study was carried out under the projects of national radon, with the aim of determining the concentration of indoor in the city of Qom located in the central semi-arid region of Iran
Materials and Methods: radon measurements were carried out in 123 dwellings using passive sampling with CR-39 detectors for 90 days. The map of radon concentration distribution was prepared using Arc GIS software and the statistical analysis was performed with SPSS version 20
Results: indoor radon concentrations in Qom dwellings ranged from 15-259 Bq m[-3]. The arithmetic mean of indoor radon concentrations on basement, ground floors, first floors and second and upper floors were 123.43, 87.94, 63.72 and 40.69 Bq m[-3], respectively
Conclusion: a correlation was found between the distances from fault zones and measured indoor radon concentration. In most of cases, radon values were lower in well- ventilated dwellings in comparison with poorly-ventilated ones. Moreover, high radon concentration levels were observed in basements. The results indicated that in 30 places [24.3% of cases], the radon concentrations were higher than the reference levels recommended by the World Health Organization [100 Bq m[-3]]
ABSTRACT
Arak waste stabilization pond facilities consist of two stabilization pond systems, module 1 and module 2. The existing facilities have had several problems in their operation. The objectives of this research were to evaluate the performance of stabilization ponds in wastewater treatment of the city of Arak, because of several problems in their operation, and to prepare a scheme of its upgrading, if necessary. Within the period of May to September 2007, analyses were carried out for both raw and treated wastewaters. Results of these investigations showed that the average effluent concentrations of BOD5, COD and SS taken from primary and secondary facultative ponds of module 1 were 91.5, 169, 114; and 70, 160, 123 mg/L, respectively. These results indicated that the effluent of the primary facultative ponds of module 1 were complied with the Iranian treated wastewater standards for agricultural reuse in terms of BOD5 and COD concentrations; hence the secondary facultative ponds could be changed to other primary facultative ponds in order to increase the capacity of wastewater treatment plant. For module 2, BOD5, COD, and SS average concentrations of treated wastewater for the secondary and tertiary facultative ponds were obtained as 69, 101, 77; and 76, 127, 78 mg/L, respectively. Thus the effluent of the secondary facultative pond was complied with the considered standards in terms of all studied parameters. Consequently, the tertiary facultative pond could be changed to other secondary facultative pond to upgrade both the quality and the quantity of treated wastewater
Subject(s)
ClimateABSTRACT
Due to having features such as toxicity, corrosiveness, ignitability, reactivity or other similar characteristics, hazardous wastes refer to the wastes that jeopardize man's health and environment. A study was required to identify the hazardous wastes in Tehran University of Medical Sciences [TUMS], since it plays an important role in the development of the country's education. The objective of this research was to provide a review of hazardous wastes production and its management at Tehran University of Medical Sciences. In this study, four schools that were in the central campus of Tehran University of Medical Sciences, Iran, were selected and the necessary data were gathered using a sampling, questionnaire, interviewing those in charge of the units, and referring to the available documents. The information includes the type and amount of waste, method of temporary storage, frequency of waste discharge, and method of final disposal of wastes. The obtained results indicate that approximately 2072 Kg of hazardous wastes are produced each year, excluding the uncontrolled waste water. Moreover, schools of dental, pharmacy, medicine, and public health produced approximately 993, 606, 256, 217 Kg/year, respectively, of hazardous wastes in the central campus. Also, the results show that, of total amount of annual hazardous waste that was 2.72 tons, 954, 848, 475, 427, 245, 49 Kg were wastes that the features infectious, toxicity, ignitability, carcinogenesis, corrosiveness, and reactivity, respectively. It is to be mentioned that hazardous solid wastes were manage with household solid waste and hazardous liquid waste were discharged into sink without any kind of control. Improper practice is evident from the point of waste production to final disposal