Environmental Health Engineering and Management Journal

157-163

Authors: Sana Abedini , Vali Alipour

Background: Cadmium (Cd) is a heavy metal that is widely utilized in industries and contaminates soil and groundwater. There are several environmental problems related to cadmium, therefore, the technical and economic methods of removing Cd are of great importance. So this study was conducted to evaluate the efficiency of a type of plant to remove the Cd from aqueous environments. Methods: In this cross-sectional study, the adsorption of Cd examined from synthetic aqueous solutions was evaluated using the seed powder of Miracle tree (Moringa oleifera). In this order, 70 samples were prepared and tested. To determine the absorption of metals by this sorbent, different pH (5, 7 and 9), sorbent dose (1.5, 3 and 5 g), temperature (20, 30 and 45°C), concentrations of Cd (2, 5, 10 and 20 ppm) and exposure time (0, 30, 60, 120, 180 and 210, 240 minutes until reaching equilibrium) were experimented upon, using atomic absorption spectrometer (Varian-AA240FS), and the residual concentration of Cd was read. Results: The highest removal efficiency of Cd under optimum condition (180 minutes and pH of 5) was 70%. The optimum sorbent dose was 1.5 g, which achieved a removal efficiency of 75%. The removal trend was an inverse of Cd concentration. The adsorption of Cd using M. oleifera fitted into both models (Freundlich and Langmuir), but was somewhat better fitted with the Freundlich model and followed pseudo second order kinetics. Conclusion: The results indicated that under optimized absorption conditions (pH: 5, sorbent: 1.5 g, temperature of 45°C, Cd concentration of 2 ppm and exposure time of 180 minutes), the removal rate of Cd was 80% and thus the nature of the adsorption reaction was endothermic. Based on the results obtained, the studied sorbent could be introduced as a practical sorbent to the Industrial society. In some sorbents, for M. oleifera, the adsorption capacity was determined based on the results obtained, and the adsorption capacity was found to be 0.1 mgg. This means that, in order to remove any pollutant (in this case Cd), 10 times of the sorbent weight need to be added.

173-178

Authors: Saeed Motesaddi, Parviz Nowrouz , Behrouz Alizadeh, Fariba Khalili , Reza Nemati

Background: Air pollution and concerns about health impacts have been raised in metropolitan cities like Tehran. Trend and prediction of air pollutants can show the effectiveness of strategies for the management and control of air pollution. Artificial neural network (ANN) technique is widely used as a reliable method for modeling of air pollutants in urban areas. Therefore, the aim of current study was to evaluate the trend of sulfur dioxide (SO2) air quality index (AQI) in Tehran using ANN. Methods: The dataset of SO2 concentration and AQI in Tehran between 2007 and 2013 for 2550 days were obtained from air quality monitoring fix stations belonging to the Department of Environment (DOE). These data were used as input for the ANN and nonlinear autoregressive (NAR) model using Matlab (R2014a) software. Results: Daily and annual mean concentration of SO2 except 2008 (0.037 ppm) was less than the EPA standard (0.14 and 0.03 ppm, respectively). Trend of SO2 AQI showed the variation of SO2 during different days, but the study declined overtime and the predicted trend is higher than the actual trend. Conclusion: The trend of SO2 AQI in this study, despite daily fluctuations in ambient air of Tehran over the period of the study have decreased and the difference between the predicted and actual trends can be related to various factors, such as change in management and control of SO2 emissions strategy and lack of effective parameters in SO2 emissions in predicting model.

187-192

Authors: Mojtaba Pourakbar, Mohammad Mosaferi , Saeed Lak

Background: Continuous expansion of potable water pollution sources is one of the main concerns of water suppliers, therefore measures such as water safety plan (WSP), have been taken into account to control these sources of pollution. The aim of this study was to identify probable risks and threatening hazards to drinking water quality in Lighvan village along with assessment of bank filtration of the village.Methods: In the present study all risks and probable hazards were identified and ranked. For each of these cases, practical suggestions for removing or controlling them were given. To assess potable water quality in Lighvan village, sampling was done from different parts of the village and physicochemical parameters were measured. To assess the efficiency of bank filtration system of the village, independent t test was used to compare average values of parameters in river and treated water. Results: One of the probable sources of pollution in this study was domestic wastewater which threatens water quality. The results of this study show that bank filtration efficiency in water supply of the village is acceptable.Conclusion: Although Bank filtration imposes fewer expenses on governments, it provides suitable water for drinking and other uses. However, it should be noted that application of these systems should be done after a thorough study of water pollution level, types of water pollutants, soil properties of the area, soil percolation and system distance from pollutant sources.

199-202

Authors: Yaser Sharifi, Azadeh Abedzadeh, Atieh Salighe, Naser Kalhor, Mohammad Khodadad Motlagh , Ali Javadi

Background: Enterococci have emerged as a major cause of nosocomial infections and within this group, Enterococcus faecalis and Enterococcus faecium cause the majority of human and livestock enterococcal infections. In this article, we tried to determine antibiotics and metals resistance patterns of E. faecalis and E. faecium strains. Methods: One hundred sixty different strains of E. faecalis and E. faecium were collected from livestock sewage and the human fecal waste during 15 months. Then bacterial antibiotics sensitivity tests were carried out using the Agar disc diffusion method. Results: Generally, 100% of E. faecalis strains separated from human and livestock sources (i.e. sheep) showed penicillin (P)/ kanamycin (K)/ nitrofurantoin (N)/ loracarbef (L)/ Ciprofloxacin (Cc)/ ampicillin (AN)/ nalidixic acid (NA)/ sulfamethoxazole (S) antibiotics resistance patterns. In addition, 55% of isolated E. faecium showed P/S/AN/NA antibiotics resistance patterns. Each strain showed a resistance to at least two aminoglycoside antibiotics. However, E. faecalis strains from human and the livestock sources showed 94% and 100% of resistance to nitrofurantoin, respectively. The effects of different metal concentrations was evaluated in both strains. The agar dilution method was applied in this stage. Hg at 0.05 mmol/L of minimum inhibitory concentration (MIC) showed toxicity to both the human and livestock Enterococcus strains. Cadmium at 1 mmol/L and 0.5 mmol/L concentrations had the most toxicity to E. faecalis and E. faecium strains, respectively. Obviously, toxicity to bacteria is less than other metals. As a result, Zn/Ni/Cu/Co resistance pattern is suggested for both strains. Finally, antibiotics and heavy metals resistance patterns were monitored simultaneously. Conclusion: Almost all E. faecalis strains isolated from humans and livestock showed antibiotics and heavy metals resistance patterns of P/K/L/Cc/S/AN/NA/Zn/Cu/Co simultaneously. Moreover, 55% of E. faecium strains showed similar antibiotics and heavy metals resistance patterns of P/S/AN/NA/Zn/Ni/Cu/Co.