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پیاپی 3 (پاییز 1392)

Water disinfection by electrochemical methods is widely used in the recent years. The goal of this research is to investigate of Pseudomonas aeruginosa, as a source of nosocomial infection caused by waterborne bacteria, removal from drinking water by batch photoelectrochemical reactor using zinc-copper electrode and lamp emitting dynode UV-A lamp. In this study, the contaminated water sample was prepared through adding 102 and 103 P. aeruginosa per ml of drinking water. Different conditions were studied, including pH (6-8), number of bacteria (102-103 per milliliter), radiation time (7.5-45 min), lamp intensity (360-600 mW / cm2), distance between lamp and electrode (1.5 cm), and current density (3-9 mW / cm2). In electrochemical reactor, percentage of 103 bacterium / ml removal in distance 1.5 cm, current density 6 mW / cm2 and electrolysis time 7.5 min in pHs 6, 7, and 8 were obtained 95%, 96.5%, and 95.9%, respectively. In electrochemical reactor, percentage of 102 bacteria / ml removal in distance 1.5 cm, current density 6 mW / cm2 and electrolysis time 7.5 min in pHs 6, 7, and 8 were obtained 95.2%, 100%, and 100%, respectively. In photoelectrochemical reactor, percentage of 103 bacterium / ml removal in distance between lamp and electrode 1.5 cm, radiation intensity 600 mW/cm2, current density 6 mW / cm, and radiation time 7.5 min in pHs 6, 7, and 8 were obtained 96%, 100%, and 100%, respectively. In photoelectrochemical reactor, percentage of 102 bacteria / ml removal in distance between lamp and electrode 1.5 cm, radiation intensity 600 mW/cm2, current density 6 mW / cm2 and radiation time 7.5 min in pHs 6, 7, and 8 were obtained 100%, 100%, and 100%, respectively. The findings indicated that bacterium removal efficiency was increased with increasing current density, increasing radiation time, increasing lamp intensity, and decreasing number of bacteria.

Corrosion and scaling are among the problems that despite science advancement, water facilities are still faced it. Corrosion lead to financial and health losses on water supply system and consumer, scaling also causes clogging and head loss in water supply network. Therefore, the aim of this study is to determine the corrosion and scaling potential of Qom villages water supply sources. In cross-sectional study 100 samples in 12 months from 2011 to 2012 were collected to verify the water quality according to 1053 standard of Institute of Standards and Industrial Research of Iran (ISIRI). Then water corrosion and scaling were studied using Langelier, Ryznar, Aggressive and Puckorius indexes. The results showed that the Langelier index, Reynar index, aggressive or corrosion index and index Puckorius were -1.62 (±0.11), 10.5 (±0.17), 12.03 (±0.14) and 9.92 (±0.13) respectively. Physical and chemical parameters of the water showed that the mean pH, TDS, total hardness, turbidity, calcium, magnesium, fluoride, sodium, ammonia, phosphate, and chloride were 7.27, 1205.29 mg/L, 435.661 mg/L CaCO3, 0.747 NTU, 132.29 mg/L, 25.58 mg/L, 0.68 mg/L, 245.50 mg/L, 0.015 mg/L, 0.17 mg/L and 231.22 mg/L respectively. The amounts of color, TDS, turbidity, pH, calcium, magnesium, fluoride andammonia in the study areas are in satisfactory and acceptable status compared to the internal standard but the amount of phosphate, hardness and chloride in this area were exceeded from permissible limit. Comparison of four stability index also showed that water conditions in all parts of this study are located in corrosive range.

Health care personnel are at occupational risk of blood-transmitted pathogens such as; HBV, HCV, and HIV. Educational interventions must be designed for this vulnerable group before entering workplaces. Medical sciences universities are the best places for designing such interventions, and also, academic duration is the best time for that. Assessing current situation is considered as a primary phase of designing programs. This study has been carried out for assessing knowledge and health beliefs of Isfahan medical students toward HIV/AIDS in 2009. The present study is a cross-sectional research. All the 1st year students of Isfahan medical school (disciplines of medicine, anesthesia, and laboratory sciences) in 2009-2010 (n=175) participate in this study. Data gathering instrument were demographic questionnaire and scales (knowledge, perceived susceptibility, and perceived severity) that designed by the authors. For validity of the designed tools, two methods of face and content validity were applied using expert panel. The tools reliability was done by two methods (test-retest & internal consistency, Cronbach’s Alpha). Participation of students in research was voluntary and with informed consent. SPSS 16.0 software was used for data analysis in this research. Based on findings, 99.4% of all students have high level of knowledge about HIV/AIDS. Also, results showed 50.6% and 64.6% of samples have respectively high levels of perceived susceptibility and perceived severity. There was no significant correlation between demographic variables and main factors of research (knowledge, perceived susceptibility, and perceived severity). Although, knowledge of medical students was desired and acceptable, but this result dose not means that these students do not need HIV/AIDS education. Perceived susceptibility and perceived severity of students is not acceptable, and thus educational interventions are seriously needed.

Lack of adequate supervision on the quality of disposal effluent and sludge from wastewater treatment plants (WWTPS) caused to their discharge by many pollutants into the environment. This study aimed to assess the microbial quality of disposal effluent and waste sludge from decentralized WWTPS in Tehran. This cross-sectional study was performed in 12 months on disposal effluent and sludge from 4 decentralized WWTPS in Tehran city. Random sampling was conducted at a monthly period. The microbial quality of disposal effluent and waste sludge were compared with the guidelines of Iranian, and United States Environmental Protection Agency (USEPA), respectively. Effluent and sludge output from these plants typically were used for agricultural purposes. None of the samples of effluent meet Iranian environmental standards. Microbial quality of waste sludge from Shahrak Gharb and Ekbatan WWTPS were higher than class B of USEPA guidelines but, waste sludge from Gheitarieh and Shoosh WWTPS meet this index. At the present time, reuse of effluent and waste sludge from decentralized WWTPS in Tehran city were performed without any health considerations. This is a serious threat to public health; hence, executive and regulatory agencies must take action corrective measures and controls necessary in this regard as soon as possible.

Phenol and chlorophenol are among the serious pollutants in industrial effluents. These pollutants in drinking water have a medicinal taste and are quite pronounced and objectionable. The aim of this research was investigation the feasibility potential of nano particle zero valent iron for phenol and chlorophenol removal from aqueous solutions. nZVI was synthesized by reduction of ferric chloride by sodium borohydrid. Finally, the chemical and physical characterization of sorbents carried out with SEM analysis. The Batch experiment was conducted to evaluate the effect of pH, chlorophenol and phenol concentration, sorbent dosage, contact time and temperature. Then for experiments the central composite design (CCD) was applied to appraisal the effect of these variables. Results showed that the adequate initial concentration for phenol removal, pH, contact time, and dosage of nZVI were at 5 mg/L, 2, 54.75 min, and 1.40 g, respectively. Also results showed that the adequate initial concentration for chlorophenol removal, pH, contact time, and dosage of nZVI were at 5 mg/L, 4, 70 min and, 1.33g, respectively. According to the results of this study and high resistance in degradation by biological processes, iron nano particles can be used for phenol removal and its compound. Also, the results of the CCD showed that the fundamental parameters resulted from pH and phenol concentration having an intense effect on the efficiency.

Chlorophenols are a group of pesticides contaminated with dioxin compounds during their manufacturing. The International Agency for Research on Cancer (IARC) demonstrated an association between dioxin exposure and lung cancer, non-Hodgkin lymphoma, and soft-tissue sarcoma but the risk of kidney cancer and dioxin exposure has not been clearly defined. This study was proposed a meta-analysis of published researches to evaluate relationship between chronic chlorophenols exposure in pesticide production workplace and the mortality risk of kidney cancer. ″chlorophenol″, ″Phenoxyacetic acid″, ″cancer″ and ″dioxin″ keywords were used in PubMed, Embase, Science Direct, Ovid, Google Scholar, and Medline until 2012 and all publications that investigated the association between chroniccholophenols exposure in the production workplace and kidney cancer were identified. Publication bias was evaluated based on Egger test and funnel plot. We evaluated the heterogeneity of the studies with Q test. Random-effects model of DerSimonian Laird method was conducted in heterogenic studies, otherwise fixed-effects model based on Mentel-Henzel random effects model was used. Our search yielded 27 papers which investigated the association between chronic cholophenols exposure in the production workplace and cancer. After reviewing these papers 7 publications without overlapping represented standardized mortality rate (SMR) of kidney cancer. Results of metaanalysis showed that SMR for kidney cancer in workers with cholophenols exposure was increased (SMR: 1.25, 95% CI: 0.9- 1.63, p = 0.09). The results of this study strengthen the evidence of cancer in occupational exposure to cholophenols contaminated with TCDD. Moreover, these compounds increased the risk of death from kidney cancer which was related to the type of cholophenols compound and dioxine contamination.

Wastewater treatment and color removal is always one of the most important measures to control pollution from industrial effluents especially in the textile and dyeing industry. This industry is one of the largest producers of organic compounds and color. For this reason, their treatment conditions are complicated and difficult. This study investigates the efficacy of ash produced from walnut shell as a natural adsorbent in color removal of methylene blue (MB) from aqueous solutions in the experimental condition. At present study, effect of various operating parameters such as pH (2-13), reaction time (30-250 min), amount of adsorbent dosage (0.2-5 g/l) and initial concentration of dye (25-250 mg/l) on color removal from synthetic wastewater were studied. Also the adsorption behavior of dyes by isotherms of Freundlich and Langmuir and synthetic of adsorption were conducted using excel program and regression coefficient. Maximum removal efficiency of methylene blue (93.25%) were achieved at optimal pH 10, reaction time 150 min, adsorbent dosage 3 g/l and initial dye concentration 100 mg/l. Data of this study was fitted with Langmuir and Freundlich isotherms and more fitted with Freundlich (R=0.8500). Also, kinetic adsorption study showed that for initial dye concentrations 100, 150 and 200 mg/l, pseudo-second order kinetic is more favorable (R2=0.9900). More than 90% removal efficiency for MB dye showed that this adsorbent is an effective natural compound and also inexpensive for treatment processes. Hence, using this technique and process was recommended for dye pollutants removal from aqueous environments.