REMOVAL OF ARSENIC FROM AQUEOUS SOLUTION BY PHOTOCATALYTIC UV IRRADIATION

The purpose of this research was to investigate the photocatalytic removal of arsenic from aqueous solution using UV/TiO2 process in a batch system. A 120 W UV lamp with irradiation 247 nm wave lenght inside a quartz jacket was submerged in the reactor to provide better irradiation of water samples in the presence of TiO2 nanoparticles. The optimum dosage of TiO2 was obtained equal to 1 g/L, with variation TiO2 dosage at constant pH and initial concentrations of arsenic. The effect of pH, contact time and initial concentration of arsenic was studied at the constant amount of TiO2(1g/L). The results showed that photocatalytic removal efficiency increased with increasing reaction time and TiO2 dosage. In addition, it was found that removal efficiency of arsenic decreased by increasing initial arsenic concentration and pH. In conclusion the results showed that UV/TiO2was an effective method in removal of arsenic from aqueous solutions

REMOVAL OF ARSENIC FROM AQUEOUS SOLUTION BY PHOTOCATALYTIC UV IRRADIATION

The purpose of this research was to investigate the photocatalytic removal of arsenic from aqueous solution using UV/TiO2 process in a batch system. A 120 W UV lamp with irradiation 247 nm wave lenght inside a quartz jacket was submerged in the reactor to provide better irradiation of water samples in the presence of TiO2 nanoparticles. The optimum dosage of TiO2 was obtained equal to 1 g/L, with variation TiO2 dosage at constant pH and initial concentrations of arsenic. The effect of pH, contact time and initial concentration of arsenic was studied at the constant amount of TiO2(1g/L). The results showed that photocatalytic removal efficiency increased with increasing reaction time and TiO2 dosage. In addition, it was found that removal efficiency of arsenic decreased by increasing initial arsenic concentration and pH. In conclusion the results showed that UV/TiO2was an effective method in removal of arsenic from aqueous solutions

Investigating the selected sub-goals of sustainable development indicators in the health, environment and sanitation sectors in Iran and their comparison with the world situation during the years 2013 to 2018

زمینه و اهداف: توسعه پایدار، توسعه‌ای انسان محور است که به مثابه یکی از مهمترین قالب‌های فکری توسعه در قرن بیست و یکم، تمامی عرصه‌های زندگی آدمی را در کنار هم با محوریت سلامت انسان و جامعه مورد توجه قرار می‌دهد. هدف از انجام مطالعه حاضر، بررسی وضعیت ایران از لحاظ برخی شاخص‌های توسعه پایدار است. مواد و روش­ ها: روش مطالعه روش استنادی بوده و برخی زیر اهداف شاخص‌های گزارش شده مرتبط با بخش‌های محیط زیست، بهسازی محیط و سلامت، انتخاب و ضمن مقایسه وضعیت کشور با متوسط جهانی در برخی موارد در صورت دسترسی به داده‌های خاورمیانه و یا کشورهای با در آمد متوسط رو به بالا مورد تجزیه و تحلیل قرار گرفته است. تمامی مراحل مطالعه حاضر طبق موازین اخلاقی اجرا گردید یافته‌ها: ایران در مقایسه با کشورهای جهان و کشورهای با درآمد متوسط رو به بالا از نظر شاخص‌های مرتبط با دسترسی به آب آشامیدنی و تاسیسات دفع بهداشتی وضعیت مناسبی دارد. همچنین در برخی شاخص‌ها مانندکاهش شیوع سل و مالاریا و ابتلا به ایدز پیشرفت چشمگیری داشته است. تماس جامعه با ذرات معلق کوچکتر از 5/2 میکرون طی سال‌های اخیر افزایش یافته است. 36 درصد از سکته‌ها و بیماری ایسکمیک قلبی و 14 درصد از سرطان ریه به آلودگی هوا نسبت داده شده است. نتیجه‌گیری: هرچند ایران در مقایسه با سایر کشورهای جهان در بیشتر زیر شاخص‌های بهداشتی توسعه پایدار، وضعیتی بهتر از میانگین جهانی و کشورهای با درآمد متوسط رو به بالا دارد؛ اما شاخص‌های مرتبط با مسائل زیست محیطی (آلودگی هوا)، چالش‌های اساسی آتی خواهند بود.Background and objectives: Sustainable development based on human being is considered as one of the most important criteria in 21st century. It covers a wide range of human lives with individuals and community health as the main pillar. Materials and methods: A documentary methodology was adopted in the present study. Indicators related to the environment and health targets were selected and analyzed by comparing the country with international average, the Middle East and in some cases with upper middle income countries. All stages of the study were conducted according to moral standards. Results: Iran has a good status in indices related to the safety managed drinking water and basic sanitation services. Population exposure to fine particulate matter (less than 2.5 Micron) has increased in recent years. Almost 36 percent of stroke and ischemic heart diseases, 14 percent of lung cancers, 8 percent of chronic obstructive pulmonary diseases and 6 percent of acute lower respiratory diseases are attributed to air pollution. Considerable progress have been achieved in some indices such as reduction in tuberculosis and malaria outbreaks and newly incidence of HIV cases. Conclusion: Although Iran shows a better status than the world average and upper middle income countries in most of the health related indicators of sustainable development, the country's environmental issues (e.g. air pollution) is still a major challenge, which call for rapid and effective management measures in this area

Analytical Evaluation of Water Quality of Swimming Pools in The Southern Regions of Tehran in 2019

The water used in swimming pools, like drinking water, must comply with the required quality. Failure to comply with the physical, chemical and biological criteria of the pools will lead to health hurt to swimmers. In this cross-sectional paper carried out with a descriptive-analytical approach in the summer of 2019, 23 public and private pools located in the south of Tehran (districts 18 and 19) were selected. Pool water sampling was performed to determine microbial indices including thermophilic coliforms, heterotrophic plate count (HPC), and physicochemical parameters including turbidity, pH and residual chlorine. Then, each of the studied parameters was assigned a weight based on their importance and their status was analyzed by water quality index. Based on the findings, the microbial indices of thermophilic coliforms and HPC in the water of the sampled pools were at the desired level in 74 and 26.1% of samples, respectively. Regarding turbidity, pH and residual chlorine content in 13.1, 60.9 and 47.9% of the samples, were at the acceptable values, respectively. The results also showed that none of the sampled water was in excellent condition and 68% of the samples were in fair condition in terms of water quality. According to the obtained results, the necessity of continuous sampling of pool water to check their quality and effective interventions and finally the imposition of fines is suggested for those which their quality is not in accordance with the standards

MODELING AND ANALYSIS OF ALGAL BLOOMS IN ARAS DAM BY ARTIFICIAL NEURAL NETWORK

Man made practices have contributed to large-scale algal blooms that have caused serious ecological, aesthetic, water purification and water distribution problems. Aras Dam, which provides Arasful city with drinking water, has chronic algal blooms since 1990. This study addresses the use of artificial neural network (ANN) model to anticipate the chlorophyll-a concentration in water of dam reservoir. Operation tests carried out by collecting water samples from 5 stations and examined for physical quality parameters namely: water temperature, total suspended solids (TSS), biochemical oxygen demands (BOD), ortophosphate, total phosphorous and nitrate concentrations using standard methods. Chlorophyll-a was also checked separately in order to investigate the accuracy of the predicted results by ANN. The results showed that a network was highly accurate in predicting the Chl-a concentration. A good agreement between actual data and the ANN outputs for training was observed, indicating the validation of testing data sets. The initial results of the research indicate that the dam is enriched with nutrients (phosphorus and nitrogen). The Chl-a concentration that were predicted by the model were beyond the standard levels; indicating the possibility of eutrophication especially during fall season

Artificial Neural Network Approaches to the Prediction of Eutrophication and Algal Blooms in Aras Dam, Iran

Abstract Background and purpose: Eutrophication is one of the major environmental problems in waterways causing substantial adverse impact on domestic, livestock and recreational use of water resources. Aras Dam, Iran which provides Arasful city with drinking water, has chronic algal blooms since 1990. Levels of up to 900,000 cells/mL of toxic cyanobacteria (mainly Anabaena and Microcystis) have been recorded in the dam. Materials and Methods: In this study, artificial neural network (ANN) model was investigated to predict the chlorophyll-a (Chl-a) concentration in water of dam reservoir. Water samples were collected from 5 stations and analyzed for physical quality parameters including water temperature, total suspended solids, biochemical oxygen demands, orthophosphate, total phosphorous and nitrate concentrations using standard methods. Chl-a was also measured separately in order to investigate the accuracy of the predicted results by ANN. Results: The results showed that a network was highly accurate in predicting the Chl-a concentration. The mean squared error and coefficient of correlation (R2) between experimental data and model outputs were calculated. A good agreement between actual data and the ANN outputs for training was observed, indicating the validation of testing data sets. The initial results of the research indicate that the dam is enriched with nutrients (phosphorus and nitrogen) and is on the verge of being eutrophic. Conclusion: The Chl-a concentration that was predicted by the model was beyond the standard levels indication the possibility of eutrophication especially during fall season

INVESTIGATION OF LEGIONELLA SPECIES IN TEHRAN’S HOSPITAL WATER SUPPLIES

The present work was performed to investigate the presence of Legionella spp. and its common species in hospital water supplies. Considering the drawback of culture method, polymerase chain reaction (PCR) assays were developed to detect the gene 16S rRNA regardless of the bacterial serotype. Four well-established DNA extraction protocols (freeze & thaw and phenol-chloroform as two manual protocols and two commercial kits) were examined and critiqued to release DNA from bacterial cells. A total of 45 samples were collected from seven distinct hospitals’ sites during a period of 10 months. The PCR assay was exploited to amplify a 654-bp fragment of the 16S rRNA gene. Legionella were detected in 13 samples (28.9%) by all of the methods applied for DNA extraction. Considerable differences were noted in the yield of extracted nucleic acids. Legionella were not detected in any of the samples when DNA extraction by freeze & thaw was used. Omitting this method and comparing manual protocol with commercial kits, Kappa coefficient was calculated as 0.619 with p < 0.05. Although no meaningful differences were found between the kits, DNA extraction with Bioneer kit displayed a higher sensitivity than classical Qiagen. Showerheads and cold-water taps were the most and least contaminated sources with 55.5 and 9 percent positive samples, respectively. Moreover two positive samples were identified for species by DNA sequencing and submitted to the Gene Bank database with accession Nos. FJ480932 and FJ480933

Community Perspectives on Air Pollution and its Related Health Risks: A Case Study of Tehran (2012-2013)

Abstract Background and purpose:Recent perspectives on public understandings of global environmental risk have emphasized the interpretation, judgment and sense-making “that takes place, modes of perception that are inextricably tied to aspects of and local” context. The main interest of this study is to observe the socio-demographic (gender, age, and education) differences in awareness of pollution and sources of air pollution. Materials and Methods:The target population of this study were adult (>25 years) inhabitants of Tehran city. The information is gathered through a questionnaire conducted in various study areas then compared with demographic variables. Results:Awareness of air pollution was highly found in higher educated of men, while this same result was observed within the women with lower education (under diploma). The results also showed that women in both groups are more concerned with all of the pollution than men. Conclusion:With regard to health impacts, men perceived air pollution to be associated with respiratory disease, whereas women perceive asthma to be associated with air pollution

Bioaccumulation and translocation factors of petroleum hydrocarbons in Aeluropus littoralis

Background: Polycyclic aromatic hydrocarbons (PAHs), which consist of fused conjugated aromatic rings, not only are toxic to humans and other living organisms, but will also pollute groundwater. These compounds can be point source or non-point source and are one of the most widespread organic pollutants. Some of them are suspected carcinogens and are linked to other health problems. This study was carried out to assess the petroleum hydrocarbon phytoremediation potential of the Aeluropus littoralis species. Accumulation of PAHs in roots and upper parts of A. littoralis has been determined. Translocation factor (TF) was also calculated. Methods: In this study, soil samples were taken from the vicinity of Isfahan oil refinery, and the PAHs compounds were analyzed with gas chromatography. One-meter soil columns were prepared from the control and contaminated soil. Unplanted A. littoralis treatments were also prepared to eliminate the effects of environmental factors on the reduction of oil-based contaminants. Seventeen weeks after planting, soil columns were sampled at 25, 50, 75, and 100 cm depths, and the concentration of petroleum hydrocarbons and number of oil-degrading bacteria were counted. Moreover, the roots and shoots of A. littoralis were separated and weighed. Results: Results indicated that A. littoralis reduced the concentration of petroleum hydrocarbons to a significantly higher extent than the control treatment. Increasing depth was associated with improved petroleum hydrocarbon concentrations and decreased number of oil-degrading bacteria. Mostly, the bioaccumulation factor (BAF) of PAHs was <1, which shows A. littoralis could be an excluder of PAHs. The results also showed that the TF of PAHs was less than one, and hence, A. littoralis could be considered as an accumulator of PAHs. Conclusion: It can be concluded that this species is suitable for use in the phytoremediation of PAHS contamination. For further confirmation, an evaluation under field conditions should be undertaken