نشریه مهندسی بهداشت محیط
سال سوم شماره 3 (پیاپی 11، بهار 1395)

Background and Fluoride is one of the common anion in water that its concentration varies in different water supplies. Most of the body's requirement for fluoride is supplied through drinking water. Fluoride in low concentration is essential for human health but in high concentration is very hazardous for human health. The efficiency of modified-clay and lime-marl were investigated in this research as an adsorbent for the elimination of fluoride from aqueou solution.
In this study, the capability of modified-clay and lime-marl to adsorb fluoride ions was conducted using a series of batch tests in a shaker-incubator instrument. The effect of experimental parameters such as pH (4,7,10), adsorbent dosage (1,5,10 g/L), initial fluoride concentration (5,10,15 mg/L) andcontact time (15-120 min) were evaluated. The morphological and micro-structural character of modified-clay and lime-marl have performed by using X-ray diffraction (XRD). The formation of the carboxylic functional groups was verified by Fourier transform infrared spectra (FT-IR).
Findings: results well demonstrate higher removal efficiency of fluoride was 95.23% and 28.71 by clay-modified and lime-marl, respectively; at 10 mg/L of fluoride concentration and 60 min contact time. The adsorption kinetics fitted well using the pseudo second-order kinetic model; however, equlibrium data were best fitted onto Langmiur isotherm model. The maximum adsorption capacities of modified-clay and lime-marl for fluoride were found to be 4.43 mg/g and 1.32 mg/g, respectively.
According to our finding, it proposed that adsorption process by using modified clay is very efficient and economic process for fluoride removal from aqueous solution.

Exposure to air pollutants can cause many problems, including the health effects in humans and animals. The aim of this study was to assay the air quality in the Shiraz city during 2011-2013.
In this descriptive-analytical study, the air pollutant data during the study period were taken from Air Quality Co. for two main stations i.e. Darvazeh Kazeroun and Imam Hossein and then were analysed to determine air quality index.
The maximum (0.018 ppm) and minimum (0.015 ppm) annual concentration of SO2 were determined in 2011 and 2013, respectively. The maximum NO2 concentration was measured in summer 2011 with a value of 0.025 ppm. Regarding ozone, the highest average concentration was measured in the summer season of 2013 with the concentration of 0.068 ppm. In terms of air quality, the worst situation was experienced in 2011, which about 31 percent of the days have been marked as unhealthy, but during the last years of the study, the air quality get better.
In general, the results of the study showed that SO2 concentration has been decreased during recent years due to strengthen of air pollution regulation but NO2 concentration was increased because the number of gas fuel automobile was also increased. With regard to air quality, it has an improving trend during the study period.

Fluoride is one of the essential elements of water that introduce to water resources through several natural and human activities ways. The benefits and risks of fluoride depend on concentration of this anion on drinking waters. In this research, defluoridation of aqueous solution with graphene nanoparticles was studied.
In the present study, effects of pH, contact time, fluoride initial concentration, adsorbent dosage, temperature as well as presence of sulfate anion in performance of graphene nanoparticles in removal of fluoride from aqueous solution were investigated. Langmuir and Freundlich isotherms also were evaluated.
Maximum adsorption capacity occurred in first 15 minutes in pH=3 and initial fluoride concentration of 10 mg/L. The results also show that adsorption of fluoride on graphene well fitted with Freundlich isotherms. In presence of the sulfate anion, the adsorption capacity decreased. Furthermore, Increasing of temperature led to reducing the adsorption capacity that indicative of exothermic adsorption reaction.
According to results of this research, graphene have good adsorption capacity in removal of fluoride from aqueous solution.

Background and Phenol is an aromatic hydrocarbon and one of the banzan derivatives which have a higher dissolution rate in water and common methods cannot completely remove it. The main objective of this research was to study removal of phenol using UV/ZnO.
This study was conducted in a batch system. the experiments was conducted in a reactor with a capacity of 1 liter using zinc oxide nanoparticles that fixed on glass with the thermal fixing method and UVc radiation were used. The effects of initial concentration of phenol, solution pH, and contact time on the photocatalytic removal of phenol were studied. [MP2D1]
The results showed that the best conditions for the removal of phenol were achieved at pH 3, 5 mg/L initial phenol concentration, 3950 μw/cm2 radiation intensity and 120 min contact time (100% removal efficiency). The pH, initial phenol concentration, and contact time have an effect on phenol removal efficiency; the phenol removal efficiency increases with the decrease of initial phenol concentration and pH.
Results of the present study showed that the photocatalytic degradation process (UV/ZnO) is an effective method in removal of phenol from aqueous solutions.

Polychlorinated biphenyls (PCBs) are toxic xenobiotic compounds that are extremely persistent in the environment. Use of plants for the treatment of polluted sites, has been used successfully to removal of variety of organic compounds, including PCBs. In this study the effects of polychlorinated biphenyls evaluated on bacterial populations of two plants onobrychis.s and sorghum single and mixed plants cultivation.
The soil samples were collected from ranges (0–20cm Depth) of Yasuj city, province of Kohqiluyeh & Buyerahmad and then polluted with different concentrations of PCBs (0, 100, 200,400,800 ppm). Soil bacterial population was measure than dilution series (Serial method), and, expressed as cfug-1 dry soil. At the end of the study (120 days after planting), plants were separated from the soil.
According to the results, average bacterial population in the soil with plant in compare by soil without the plant had a significant difference (p sorghum> onobrychis. S. root/shoot ratios have the greatest amount in mix culture (90%) and after onobrychis.s (72%) and sorghum (63 percent)
According to the results of mix culture to single it caused more stimulate of bacteria and increase their numbers in the rhizosphere zone. In generally mix culture surfactant (Tween80) were as the best mod.

Antibiotic resistance Genies causes many problems in hospitals. Dissemination of these agents to the environment is a great concern worldwide. The aim of this study was to investigate the concentration of antibiotic resistant bacteria (ARB) and presence of antibiotic resistance genes(ARGs) in hospital wastewaters.
in present work, 33 sample from raw hospital wastewater were taken from three hospitals. Heterotrophic plate counts (HPC) method was used to assess the concentration of ARB in hospital wastewater samples. Six conventional antibiotics were selected. Presence of six resistance genes regarding to the selected antibiotics were surveyed in wastewater samples and isolated ARB by PCR method.
Average concentration of ARB in raw hospital wastewater was 3.81 ×107 CFU/100mL. Frequency pattern of ARB in raw hospital wastewater was as follows: ceftazidim(CAZ)> tetracycline(TE)> sulfomethoxazol (STX)> chloramphenicol (CHL)> erythromycin (ER)> and gentamicin(GM), respectively. ARGs in raw wastewater samples were detected more than isolated bacteria. ARGs frequency pattern in wastewater samples were as follows: sul1>cmlA1>ermB>tetW>aac3-1>ctx-m-32.
The results of this study revealed that there are high concentration of ARB and ARGs in hospital wastewaters. Therefore, hospital wastewaters could play an important role in dissemination of ARB and ARGs into the natural environment and therefore, may pose serious public health risks.