Iranian Journal of

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Background and Objectives: In the recent years Municipal Solid Waste (MSW) has been one of the most important environmental concerns to throughout regions of Iran. Sound MSW management for any area needs to the reliable data in which present the actual MSW condition in that area. The aim of this study is express of integrated view of MSW in Iran.
Materials and Methods:  In this study we collect the data from various municipal regions of Iran, to represent the roughly integrated view of MSW management situation in Iran. In this paper quantity, average generation rate, physical composition, and types of disposal methods in all of municipal regions of Iran also were investigated.
Results: Results from this study has shown that the amount of MSW generated in all of the municipal regions of Iran was 10370798 tons per year, and the average generation rate of MSW was 0.64 kg/capita/day. Results showed that only 6% of MSW was recycled, 10% was treated at organic waste (composting) plants, and about 84% was disposed of in landfill.
Conclusion: According to obtained results from this study and compare  MSW composition of Iran to some countries, its found that MSW properties in Iran is near to MSW properties in Low-income countries. Since the most of MSW in Iran contain organic fraction, there is a high potential to develop of composting industry.

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Background and Objectives: Atmospheric transport is a key mode of microbial dispersal and the transmission of airborne microbe can have significant impacts on human health. The main objective of this study was to determine the concentrations of airborne bacteria in a children.s hospital.
Materials and methods: Three sampling points were selected. Airborne bacteria were collected with 6 days interval at each location using Quick take 30® sampler at an sampling rate of 28.3 l min-1 from November 2007 to March2008.
Results: The results showed that the highest indoor density of bacteria was 429 CFU/m3 that founded in oncology ward. Bacteria identified were representative of normal flora of the skin, respiratory and gastrointestinal tracts.
Conclusion:Our analysis revealed that colony of bacteria in 14% in patient room exceeded available guideline value for indoor air quality. That 11% cases was found in the oncology ward.

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Backgrounds and Objectives:Today, One of the most important environmental issues is solid waste Produced in Dentistry That because of the presence of hazardous, toxic and pathogen agents has special importance. In this survey, solid waste produced in Hamadan Dentistry laboratories and practical dentist offices is studied.
Materials and Methods: In this descriptive study, from 24 Dentistry laboratories in Hamedan 5 offices and from 27 practical dentist offices 5 offices were selected in simple random way. From each offices 3 sample at the end of successive working day (Sunday, Monday and Tuesday) were analyzed. Samples were manually sorted into different 41 components and by means of laboratory scale were measured. Then, measured components were classified based on characteristic and hazardous potential.
Results: Total annual waste produced in Dentistry laboratories and practical dentist offices in Hamaden is 15921.79 and 8677.56 Kg respectively. Production percentages of domestic type, chemical and pharmaceutical waste, potentially infectious and toxic wastes in practical dentist offices were 91.14, 6.7, 2.14 and 0.02 respectively. Dentistry laboratories solid waste comprises of 94.47 percent domestic type and 5.53 percent chemical and pharmaceutical waste. Main components of produced analyzed wastes were 2 components that consist of more than 80 percents of total dental solid waste. So, waste reduction, separation and recycling plans in the offices must be concentrated on these main components.
Conclusion: In order to waste suitable management, it is suggested that in addition to educate waste producer for waste reduction, separation and recycling in the offices, each section of dental waste (toxic, chemical and pharmaceutical, potentially infectious and domestic type wastes) separately and according to related criteria are managed.

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Backgrounds and Objectives: in recent years, mobile bed biological reactors have been used progressively for municipal and industrial wastewaters treatment. Dissented experiment is a trial that significant changes will accrue for influent variables in the process, and generally used for identification of the effective factors and optimization of the process. The scope of this study was determination of the optimized conditions for the MBBR process by using of Taguchi method.
Materials and Methods: Reactor start up was done by using of the recycled activated sludge from Ahwaz wastewater treatment plant. After that and passing the acclimation period, with hydraulic residence time equal to 9 hours matched for 1000, 2000 and 3000 mg/l based on COD respectively, for optimization determination of the acclimated microbial growth, the variables change (pH, nitrogen source, chemical oxygen demand and salinity) were determined in 9 steps, and all of the results were analyzed by Qualitek -4 (w32b).
Results:In this study, organic load removal based on COD was 97% and best optimized condition for MBBR were (inf. COD=1000 mg/l, pH= 8, salinity = 5% and the Nitrogen source= NH4CL)
Conclusion: Based on our finding, we may conclude that Taguchi method is on of the appropriate procedure in determination the optimized condition for increasing removal efficiency of MBBR.

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Backgrounds and Objectives:Today the crisis rising from over consumption energy and materialand environmental pollution pose serious problems that challenges present resources of man.Sustainable development is probably an inevitable strategy for human being in such a way that theleast possible damage be inflicted to the environment.In this way, the role played by universities in reaching the objectives of sustainable development is crucial. In this paper, we examine the present state of consumption energy resources (Electricity and natural gas) in the central main campus of Tehran University and so we calculate the extent of environmental pollutants resulted of these energy consumptions.
Materials and Methods: For surveying of our objectives the first step is a survey of the current state of campus by way of reexamination of Gas and Electricity bills and distribution of a questionnaire. Second is an estimate of the entering pollutants to the environment with online software in site of http://www.abraxasenergy.com/emissions.
Results:annual consumption of 16.5 million KWHS of electricity along with 4312392 m3 of naturalgas leads to 0.0218 million tones Co2, 778 kg VOCS, 374.6 tones NOX, 2.41 tones CO, 65.341 tones So2, 93 kg Mercury compounds and 868 kg particles.
Conclusion: It is shown that there is no objective effort and green management in this part ofuniversity officials. This project suggests that the implementation of green management in the framework of programs such as green university can be crucial in reaching the objectives.

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Backgrounds and Objectives: 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.
Materials and Methods: 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.
Results: The obtained results indicate that approximately 2072 Kg of hazardous wastes are produced each year, excluding the uncontrolled wastewater. 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.
Conclusion: 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.

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Backgrounds and Objectives: Polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous pollutants which have carcinogenic and mutagenic properties and accumulated in environment by different actions, therefore treatment of them is important. Biological treatments are simple and cheep technologies. This technology was recommended as a cost- effective method for treatment of these pollutants. In order to investigate the trend of pollution reduction of petroleum hydrocarbons in bioremediation, the phenanthrene biodegradation&aposs model in contaminated soils was studied.
Materials and Methods: Firstly, PAHs capable degrading bacteria was isolated from petroleum contaminated soils and then their ability for biodegradation of phenanthrene was assessed in slurry phase. After that by using Acinetobacter which have the most potential of removing phenanthrene from soil, the biodegradation model was investigated in bench scale.
Results: Phenantherene removal efficiency was obtained 99.4% for 100 mg/kg and 96 % for 500 mg/kg concentrations in 33 and 60 days biodegradation period respectively. Phenantherene reduction rate varied from 2.99 to 8.86 and 1.4 to 11.09 mg/kg/day for 100 and 500 mg/kg concentrations, respectively.
Conclusion: Rate of phenantherene removal is depended on primary concentration of contamination and by increasing of primary concentration, phenantherene removal rate was increased. Also removal efficiency followed zero and first order kinetic model with good correlation.

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Backgrounds  and Objectives:  Over than 70% of solid wastes is consisted of food wastes with high putrecibility in Iran.  Due to this regard, construction of composting factories for sanitary disposal or fertilizer production from solid wastes was very appreciated in our country. The objective of this research was to study on the quality and comparing of the compost produced by Khomain and Tehran compost factories.
Materials and Methods: This study was accomplished on the compost produce from Khomain and Tehran compost factories about 9 months. For investigation of chemical qualities of these materials, some indexes such as percentage of organic materials, carbon, nitrogen, phosphorus, potash and heavy metals consists of lead, cadmium, mercury and chromium were measured. Microbial quality of these compost materials were defined by assessing of the amounts of coliforms bacteria, salmonella bacteria and parasites ova.
Results: The average amounts of some indexes in compost of Khomain and Tehran were been: organic materials % (37.77, 29.80), carbon %( 22.14, 18.12), nitrogen% (2.08, 1.6), lead (229.6, 59.44 ppm), and chromium (70.2, 19.75), respectively. The microbial quality of these compost samples were agreement with class B of USEPA guidelines.
Conclusion: This study showed that quality of organic materials percent in Tehran's samples was better than Khomain's samples, but these indexes on these samples were lower than the grade No.2 of compost. The percentage of carbon, nitrogen and potash in these samples were desirable but, phosphorus amount were not in sufficient. The heavy metals especially lead and chromium in Tehran's samples were higher than Khomain's samples, but these samples were usually in agreement with guidelines of compost. Due to the defined microbial qualities, these samples could be used as well as amendment agents for poor soil.

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Backgrounds and Objectives:Skin cancer is the most frequent malignancy in Iran. Exposure to the excessive ultraviolet radiation is an important factor in creating skin tumors. The purpose of this study is to determine how the ultraviolet index has been distributed in all townships throughout the country, to determine different kinds of skin cancer and to evaluate a geographical distribution of skin cancers with regard to the UV geographical distribution.
Materials and Methods: This study is ecologic, descriptive and analytical in nature. A total number of 6921 skin cancer cases registered at the Center for Disease Control of Iran in 2004 were thoroughly analyzed and UV data were collected from the world wide web. With the help of ArcGIS software and SPSS, the statistical analysis was done.
Results:The incidence rates were 10.13 for the total skin cancer, 7.53 for basal cell carcinoma, 1.79 for squamous cell carcinoma and 0.39 for malignant melanoma per 100000 population of Iran. The mean ultraviolet index differed from 9 in July to 3 in January. The correlation between the skin cancer incidence at the level of districts and ultraviolet index was not significantly observed.
Conclusion:Skin cancer is a public health problem in Iran. Further research in this regard would lead to skin cancer registration improvement and more understanding of different climatic, cultural and behavioral factors in developing skin tumors. With this knowledge the possibility of more effective prevention of the most prevalent cancer in Iran can be created.

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Background and Objectives:Fanavaran petrochemical company is located on the shore of Persian Gulf on west south of Iran, Imam Khomeini Bandar, petrochemical special economic zone with of 25 hectares area. Two units of this company, methanol unit with production capacity 1000000 tons/years and monoxide carbon unit with 140000 tons/years were studied for determination and emission factories of SO2, CO2, CO, NO, NO2, NOx Gases.
Materials and methods: With attention to project goals, for implementation of this project 14 months took into from April 2008 till June2009.For goals provide of mentioned research on this basis,case sampling were done from 3 emission sources by using of direct reading device of gas concentration according to standard methods of United State Environmental Protection Agency.
Results: Results of the study indicate that concentration of issued pollutant gases from these units is in the level lower than Iran department of environment standard level. The total amount of emission Factory of SO2, CO2, CO, NO, NO2, NOx gases diffused from these units are11.7×10-6 , 81/8×10-6, 0.14×10-6, 431.5×10-6, 19.2×10-6 , 681.2×10-6kg /tons million production in a year respectively.
Conclusion:Parameters which optimization is performed in accordance with them, include of additional air percentage, exit air temperature from pre heater, and fuel type, in fact with regarding these 3 factors. effects, the work is done in a manner that the amount of pollutants diffusion is near to minimum and the selected best fuel.

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Backgrounds and Objective: Surfactants are one of the largest pollutants which exist in urban and industrial wastewaters. Large quantities of surfactants have entered to the environment since last decade due to increased use of synthetic detergent in industrial and home consumptions.In this study, the efficiency of UV/H2O2 process in removal of linear alkylbenzane sulfonate (LAS) from aqueous solutions was investigated.
Materials and Methods: In this study methylene blue active substane(MBAS)method and spectrometery were used to determine anion and residual surfactant respectively. In this study important variables were H2O2 concentration, initial concentration of surfactant, pH and duration of UV radiation. The effect of UV/H2O2 process on the degradation of LAS was analyzed statistically by using Multiple Linear Regression test.
Results: The resulted showed that after 20 minute, ultraviolet radiation solely removed 38.44 percent of Anionic detergent, Hydrogen peroxide showed no significant removal of detergent solution in the time course study. The efficiency of UV/H2O2 process in 10, 20 and 30 minute were to 86.2, 90 and 96.5 %, respectively.
Conclusion: The results showed that the efficiency of ultraviolet radiation and hydrogen peroxide process in anionic detergent was not significant thoogh it was considerable in combination process (UV/H2O2).

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Backgrounds and Objectives: Anthraquinone dyes such as reactive blue29 in water resources and industrial wastewater effluents are one of the most environmental setbacks in many countries. Various methods have been considered to remove these dyes One of which is adsorption.
Materials and Methods: All adsorption experiments were conducted in different pHs and various concentrations of adsorbents. The initial concentration of reactive blue 29 chosen in this study was 30mg/L.Adsorption isotherms were determined and correlated with Longmuir, Freundlich and BET models.
Results: The maximum adsorption capacity of reactive blue 29 onto single wall carbon nanotubes was 496mg/g.Results showed that the best pH for adsorption was 5 followed by pH3 and 8. Kinetic study showed that the equilibrium time for adsorption of RB 29 to SWCNT is 4 hr.
Conclusion:According to the results obtained BET isotherm fitted well the experiment. It shows the adsorption of reactive blue 29 onto single wall carbon nanotubes is multilayers and the mechanism of SWCNTs adsorption toward RB29 is based on weak van der waals forces.

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Backgrounds and Objectives: Phenol and phenolic compounds are widely used in industry and daily liFe, and are of high interest due to stability in the environment, dissolution ability in water and health problems. In this regard, phenol removal from water is of high importance. The purpose of this study was to investigate the efficiency of photodegradation process for removal of phenol from aqueous system by use of Fe-doped TiO2 nanoparticles prepared by sol-gel method.
Materials and Methods: Phenol concentrations of 5, 10, 50 and 100 mg/L were prepared and exposed to UV and Fe-doped TiO2, separately and simultaneously. Also the effect of initial phenol concentration, Fe-doped TiO2 loading and pH were studied. Various doses of photocatalist investigated for Fe- doped TiO2 were 0.25, 0.5 and 1 g/L. pH was studied at three ranges, acidic (pH=3), neutral (pH=7) and alkaline (pH=11).
Results: Maximum degradation was obtained at acidic pH, 0.5 g/L of Fe-doped TiO2 for all of phenol concentrations. With increasing initial concentration of phenol, photocatalytic degradation decreased. In comparison with Fe-doped TiO2/UV process, efficiency of UV radiation alone was low in phenol degradation (% 64.5 at 100 mg/l of phenol concentration). Also the amount of phenol adsorbed on the Fe-doped TiO2 was negligible at dark conditions.
Conclusion: Results of this study showed that Fe(III)- doped TiO2 nanoparticles had an important effect on photocatalytic degradation of high initial phenol concentration when Fe(III)-doped TiO2/ UV process applied.

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Background and Objectives: Not paying attention to management and control of medical wastes in different stages of production, keeping, gathering, transporting and finally eliminating them all have been creating various setbacks such that the environment and human's health are in danger with the relevant consequences. This descriptive cross-sectional study was performed in Vali-e Asr, Amir Kabir, Taleghani, Amir Al-Momenin and Imam Khomeini hospitals of Arak city in 2009. In this research the current condition of gathering, maintaining, transportation and final elimination of hospital wastes of Arak city was investigated .Eventually an appropriate model was introduced.
Material and Methods: Solid wastes were separated, weighed and registered in two sequential intervals. In order to get acquaintance with the management procedure of medical solid wastes in the hospitals studied, a questionnaire approved byW.H.O was used. The questions were then replied by the Managers and Hygiene Experts worked at hospitals and their responses were recorded.
Results: The investigations conducted in 5 hospitals reveal that the average per annual was2.9 Kg in 24 hours per active bed and 4.6 Kg for each patient. This volume consists of 60% for semi-home solid wastes, 39% for infectious solid wastes, 0.34% for sharp wastes, 0.28% for the pathologic and 0.38% for medicinal and chemical solid wastes.
Conclusion: According to the results obtained in this study, in order to reduce pollution create in the hospitals, action should be taken to deal with pollutants at their source of generation. The staff members involved in waste collection and transportation should practice all the personal protection measures.finaly it also should be considered that,success in medical waste management wouldn't be achievable unless all groups of medical staff involved cooperate and participle.

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MicrosoftInternetExplorer4 Background and Objectives: Nosocomial infection is the cause of deaths, morbidity, higher costs and increased length of stay in hospitals. Correct and appropriate use of antiseptic and disinfectants play an important role in reducing infections. In this study the efficacy of antiseptics on bacteria causing hospital infections has been studied.
Materials and Methods: This study was conducted in the laboratory of Imam Khomeini Hospital of Uremia. In this study the Antimicrobial activity of Descocid, Korsolex basic, Mikrobac forte and persidin 1% was studied against bacteria causing hospital infections such as Enterobacter aeruginosa 1221 (NCTC 10006), Staphylococcus epidermidis (PTCC: 1435 (Cip81.55) and Pseudomonas aeruginosa Strain PAO1. Sensitivities of bacteria were determined by Minimum inhibitory Concentration (MIC) and Minimum bactericidal Concentration (MBC) antiseptics. In the second stage, the concentration of antiseptics was prepared according to the manufacturer's suggested protocol and the effect of antimicrobial agents were studied at the certain concentration and contact time.
Result: All disinfectants (Descocid, Korsolex basic, Mikrobac forte) concentration and contact time, Accordance with the manufacturer's brochure, had inhibitory effect on all bacteria. That this is consistent with the manufacturer's brochure. Persidin one percent in concentration of from 2 and 4 V/V % and exposure time 5 minutes could not inhibit the growth of bacterial. But at concentrations of 10 and 20% respectively 15 and 30 minutes exposure time, all three types of bacteria can be inhibited, which is consistent with the manufacturer's claims.
Conclusion: In this study, the efficacy of antiseptics was determined with the Micro-dilution method recommended by the NCCLS. Korsolex basic, weakest antiseptics (the highest MIC) for the inhibition of three bacteria was determined. But Between all four antiseptics (according to manufacturer concentration), Only one percent Percidine 2 and 4 V/V %  in consumer dilution and 5 minutes exposure time failed to inhibit the growth of Pseudomonas aeruginosa, Staphylococcus epidermidis and Enterobacter aeruginosa.

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MicrosoftInternetExplorer4 Background and Objectives: Guilan province, with unique environmental values ​​of the Caspian Sea is located in the southwest of Caspian Sea. Disposal of untreated domestic sewage, industrial and agricultural surface water cause pollution of the Caspian Sea region and endanger the health of swimmers. This study performed to determine the microbial contamination of coastal water in Guilan. 
Materials and Methods: In this work, 21 sampling point in the Caspian Sea littoral provinces of Guilan were selected and microbial contaminations were assessed using   microbial indicators of fecal and total coliform. Parameters such as pH, temperature, and turbidity also monitored during the year. In this study, 122 samples were taken and then analyzed by statistical software.
Results: The results showed that the average values of total coliform and fecal coliform were 234.8 and  60 MPN per 100 ml, respectively. The fecal pollution appeared to be high in some stations. Also significant relationship between temperature, turbidity and microbial contamination was observed (P< 0.05).
Conclusion: The results revealed high total coliform in the two stations. The average fecal coliform of six stations were higher than the local standards.

 

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MicrosoftInternetExplorer4 Background and Objectives: Heavy metals including antimony and cobalt as two contaminant factors leach from polyethylene terephthalate packages into water under some conditions. Therefore, their detection was concerned at different storage conditions.
Materials and Methods: Five time-temperature treatments were carried out for 5 water samples. Storage conditions were defined as following: at outdoor and sunlight ambient temperature, room temperature, and at 40˚C at different intervals for 8 weeks, at 65˚C for 6 weeks and 80˚C for 7 days. Detection was performed by ICP-AES method and the data analysis was processed by SPSS software.
Results: Antimony concentration increased by storage time at all temperatures and for all samples, however enhancing proportion was different in samples. At outdoor, 40˚C and room temperature, concentration increase was below the MCL by the end of storage period. But at 65˚C and 85˚C, antimony concentration exceeded MCL by study time and the difference between samples 4 and 5, for example, was significant (p≤0.05). Cobalt concentration at the beginning and during the study was also too less and lower than the detection limit.
Conclusion: By increasing temperature and time, leaching of antimony into water increases. Moreover, sunlight has effect but not noticeable at the temperature of present study. In this study, blue or clear packaging had no significant effect on antimony leakage (P>0.05).

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MicrosoftInternetExplorer4 Background and Objectives: Irrigation of agricultural crops using wastewater will increase, in some cases, their growth by 40 to 60 percent. However, this has a high risks for human health because of the presence of higher number of pathogenic organisms. The main purpose of this study was to investigate the feasibility use of Fenton and modified Fenton with copper for the disinfection of raw wastewater.
Materials and Methods: After primarily laboratory physicochemical and biological analysis, the disinfection process was performed in three different phases in each process. First, the disinfectants were injected separately, then we performed disinfection using Fe++ and cu++ ions combined with hydrogen peroxide in order to determine synergistic effect of each catalyst. Direct method was used for fecal coliforms counting. 
Results: Hydrogen peroxide maximum efficiency for inactivation of fecal coliforms was only 0.66log inactivation. Fenton and modified Fenton with copper ions showed a remarkable effect on the bacterial inactivation so that Fenton and modified Fenton with 1 and 2 mg/l of Cu++ inactivated coliforms by 4.73, 3.28, and 4.88 log respectively.
Conclusion: Application of HP alone for the disinfection of raw wastewater is not practicable due to low observed efficiency. However, its combination with ions such as Fe++ and Cu++ increases HP performance in disinfection and has a notable synergistic effect on HP  disinfection power, where, in the presence of each catalyst, hydrogen peroxide can reduce the fecal coliforms of raw wastewater to meet the Iranian Environmental Protection Agency Standards.

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MicrosoftInternetExplorer4 Background and Objective: Dioxins and Furans are dangerous and highly toxic compounds entering to the environment from natural and manmade sources. Having high stability and half-life, these compounds remain for a long period in the medium and bring about severe effects on human beings and the environment. The aim of this study was to identify dioxins and furans emission sources in Iran and to estimate their contribution in emission rate.
‌Materials and Methods: First, we identified the emission sources of dioxins and furans and then necessary data was gathered by referring to the authorized organizations and filling the prepared UNEP questionnaires. We used Excel software to analyze the data collected.
Results: According to the results obtained, total dioxins and furan emission in Iran in 2010, was 1957 g TEQ/yr out of this amount, 705.8 g TEQ is emitted to the atmosphere and 643.2 g TEQ is residual ash. Therefore, dioxins and furans emission rate was 26.4 µg TEQ/capita in Iran. The most rates of emissions were associated with uncontrolled open burning (732.8 g TEQ/yr) and ferrous and nonferrous metal production (635.7 g TEQ/yr) such as cupper, iron, and steel.
‌Conclusion: Our findings showed that the emission rate of Dioxins and Furans is much higher in Iran compared with other countries and appropriate management strategies are required to control these dangerous pollutants.

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Backgrounds and Objectives: Medical waste management is one of the important issues in solid waste managment in each community. This research was carried out to study the quantity, quality and the management practices of solid wastes of hospitals in Zanjan City in 2011. Materials and Methods: In the present study, the hospital wastes were categoried and weighted into four main categories. Waste management pattern was studied based on a checklist extracted from national guidelines. Then, hospitals were ranked from very poor to excellent classes. For data analysis, Excel soft ware was used. Results: Waste generation rate was on average 2.402± 0.163 Kg/bed.day in the studied hospitals. The generation rate of domestic waste, infectious waste, sharp wastes, and chemical - pharmacological waste was 1.432±0.059, 0.926±0.096, 0.029±0.0055, and 0.015±0.002 kg/day.bed respectively. The status of the waste management practices was determined as average. Conclusion: Waste generation rate in the hospitals of Zanjan was lower compared with the expected average value in other cities (e.g. 2.71 Kg/bed.day in Tehran). The percentage of medical waste in Zanjan hospitals was 34, which is higher than W.H.O. recommendations. Therefore, it is strongly recommended to reform and monitor certain solid waste management practices in order to reduce health and environmental issues.