ARCHIVE OF HYGIENE SCIENCES
Year:2019 | Volume:8 | Issue:1|Papers Count:8

Background & Aims of the Study: In this study, 4-(2-pyridylazo) resorcinol (PAR) as model azo dye was used. In spectroscopic measurements and studies of PAR reagent as a ligand are used to formation a complex with toxic metals. So, removal and degradation these compounds of wastewaters are necessary. The aim of this study is the degradation of PAR from aqueous solutions in circulating fludized bed photo reactor (CFBPR) using ZnO powder. The UV/O2 system was used for dye degradation. Materials & Methods: ZnO powder used a catalyst for the degradation of dye in aqueous solution. ZnO powder has been characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The effect of operational parameters such as: pH, catalyst dosage and temperature were studied. The effect of UV irradiation, UV/O2 and UV/O2/ZnO on photocatalytic degradation of PAR were studied. The reaction kinetic was studied. The optimum conditions were determined using design of experimental based one factor at the time (OFAT) method. Results: The optimum conditions for this reaction were obtained at pH=10, catalyst dosage=20 mg/L, and temperature=40° C. The pseudo first order reaction with rate constant (k=0. 0105 min− 1) in T=40° C was observed for the photocatalytic degradation of PAR. Activation energy (Ea) for the degradation of PAR was obtained as 48. 12 (kJ/mol). These experiments demonstrated that UV/O2 and ZnO catalyst were needed for the effective degradation of dye. Conclusions: The results showed that the photocatalytic process can be suitable to degradation PAR dye from aqueous solutions using ZnO catalyst.

Background & Aims of the Study: Exposure to formaldehyde in ambient air has attracted a great attention, due to harmful health effects. This study was aimed to determine formaldehyde concentration in winter and spring seasons, in Azadi square region, Tehran, and the relation of variations of CO, NO2, O3, temperature and humidity with formaldehyde concentration was modeled based on Response Surface Methodology. Materials & Methods: This cross-sectional study was conducted in 2014– 2015 in Tehran, Iran. For measuring the formaldehyde concentration, NIOSH3500 method was employed. The concentration of formaldehyde was detected at 580 nm wavelengths by PerkinElmer LAMBDA spectrophotometer model of 25UV/Vis. Data of CO, NO2 and O3 concentration were attained from Tehran Air Quality Control Company. SPSS 16 and Design Expert (version 7) were used for analyzing data. Results: Results showed the concentration of formaldehyde in the spring was on average 4. 7 ppb more compared to winter season. The Model fitted for the prediction of formaldehyde showed a significant p-value (<0. 001). Moreover, the R2 and Adj-R2 values were obtained about 0. 8237 and 0. 7607. In this model, it is observed the parameters of CO, NO2, O3 and temperature has a direct relation with the variations of formaldehyde, and humidity has an indirect relation. Conclusions: Results indicated formaldehyde concentration in spring season is on overage higher than winter spring. The fitted model showed the CO, NO2, O3 and temperature is in a direct correlation with formaldehyde changes in ambient air, and humidity is in an indirect correlation.

Background & Aims of the Study: In this study three types of starch such as wheat, corn and potato were used as natural coagulants for turbidity removal of wastewater in stone cutting industry using jar test and their performance was compared with that of alum. Materials & Methods: This study is an analytical-applied. Natural wastewater from stone industry was used. The conventional jar test apparatus was utilized in all the coagulation-flocculation experiments. To evaluate the effect of gelatinized starch, the solution was prepared in both autoclaved and non-autoclaved forms. The effect of pH and coagulant doses were investigated in this study. Results: It was found that with regard to the effect of control sample from autoclaved starches, potato starch with a pH of 6 had the highest removal rate with 4. 78% and among non-autoclaved starches, wheat starch with a pH of 7 had the maximum turbidity removal rate with 9. 53%. Conclusions: The results showed that the non-autoclaved wheat starch has more efficiency in turbidity removal from wastewater in stone cutting industry than other starches.

Background & Aims of the Study: Household Hazardous Waste (HHW) are the wastes can potentially increase the hazardous properties of municipal solid waste in the landfill, incineration, or composting. The lack of information about their generation and composition hinders the creation of special programs for their collection and treatment, making these wastes a potential threat to human health and the environment. Therefore the aim of this study was to determine the quantity, quality and to be able to compare the results of four seasons, regarding consumption patterns and solid waste generation rates. Materials & Methods: A cross-sectional study was done in 2015-2016 years in Isfahan compost plant (waste receipt place) and the analyses were performed on household hazardous waste in four seasons of the year. The Shapiro– Wilk test was used to evaluate the normality of the quantitative data. Results: HHW comprised 0. 6% of municipal solid waste (MSW). The largest percentage of HHW in total HHW were home cleaners in spring (37. 53%), summer (26. 82%), and fall (39. 78%), because home cleaners are the daily necessities of residential households but in winter medical products (34. 70%) were more than others. Probably cause of the high percentage of medical products is disease outbreaks in winter. Generally, the most hazardous materials in MSW included home cleaning (0. 2%), medical products (0. 19%) and self-care equipment (0. 11%) and the lowest were biological infection materials. Conclusions: This study demonstrated that the production of HHW in Isfahan is independent of different seasons of the year. Household cleaners and personal protective equipment and medicine had formed the highest percentage of household hazardous waste.

Background & Aims of the Study: Discharge of untreated colored wastewater into aquatic environments could cause problems such as cancer. Among the various treatment methods, advanced oxidation processes (AOPs) have attracted much attention in recent years. The aim of this study was the removal of acid orange 7 dye using CoFe2O4@PAC nanocomposite in the presence of peroxymonosulfate (PMS) and hydrogen peroxide (H2O2). Materials & Methods: The various variables effect including pH, catalyst dose, peroxymonosulfate and hydrogen peroxide concentration, reaction time, and initial dye concentration were evaluated. The synthesized nanocomposite was characterized by SEM, EDX, XRD and BET analyses. The residual concentration of AO7 dye was determined using UV– Vis spectrophotometer at wavelength of 485 nm. Results: It was found that decolorization increases by increasing the catalyst dosage and reaction time, and decreasing pH. With increasing the dye initial concentration from 10 mg/L to 250 mg/L, in the presence of H2O2 and PMS dye removal decreased from 99. 5% to 39. 7% and from 99. 9% to 43. 7%, respectively. The adsorption kinetics was found to follow pseudo-first-order kinetic model (R2>0. 99). Conclusions: The results indicated that the prepared composite could be used as an effective and environmental friendly magnetic adsorbent for the removal of AO7 dye from aqueous solutions.

Background & Aims of the Study: There are several methods for determining the water supply system safety, including the WSP program that recommended by the World Health Organization (WHO). So, the aim of this study was assessment the water supply system of Hamadan city based on the Water Safety Plan (WSP) guideline introduced by the world health organization in 2018. Materials & Methods: This investigation employed the WSP-QA Tool and the WSP manual of the WHO and the AWI in 2017. For this purpose, software checklists were prepared and, after confirmation of content and face validity, completed based on Hamadan water and wastewater company records and interview with company’ s experts. Data was analyzed using WSP-QA Tool and then system hazards were identified and risk assessment and prioritized hazards were performed by use of semi-quantitative risk matrix approach presented by the WHO guideline. Results: The results showed that from the total score of 440 complete implementations of WSP and according to the 384 score related investigation different phases of this study, the 220 score was achieved that 50 % was coordinated with WSP. The Results of risk assessment showed that discharge wastewater from a village and agriculture in the catchment, blocked filter and algae in treatment, old pipe and excavation and installation facilities in the distribution and pressure drop and constructing wells at home in point of use are the most important hazards in water supply system of Hamadan. Conclusions: Overall, The results showed that the implementation WSP in Hamadan city is in a moderate situation.

Background & Aims of the Study: In this study, Metal Organic Frameworks (MOFs) were synthesized as an additive for the preparation of mixed-matrix membranes. MOFs were investigated by FTIR, XRD and FE-SEM techniques. Materials & Methods: Synthesized MOFs were prepared via the hydrothermal method. The effect of MOFs on the morphology and property of the polyethersulfone (PES) membranes was examined using scanning electron microscopy (FE-SEM). The membranes were characterized by rejection of salt solutions, removal of heavy metals and dyes rejection. Results: Results show that membrane containing 5 wt% of MOFs provides better hydrophilicity, flux, antifouling and rejection properties and change on the aforementioned characteristic properties was studied for this membrane. The results suggested that the water flux of membrane increased to 190 L. m-2 h-1 which related to 7 wt% membrane as well as the highest rejection for different heavy metals and dyes were related to 5 wt% MOFs in mixed matrix membranes. Conclusion: Based on the results, hydrophilicity, water flux, and antifouling properties were improved by hybrid membranes.

Background & Aims of the Study: Complex surface of vegetables facilitate attachment and transmission of several pathogens. No previous study has been conducted in survey of parasitic contamination of vegetables in Hamedan. This study aimed to detect the parasitic contamination in common raw vegetables in Hamedan markets. Material and Methods: For this cross sectional study, 150 grams of raw vegetables, including (Mentha, Basil, Chives, Garden cress, and Radish) were collected from 12 retail stores in Hamadan, Iran, in 2017. Each sample washed in three ways; washing by potable water (a), saline solution (b) and a commercial routine detergent (Reeka, company, Iran) (c) for five minutes. After that, the washing solutions were separated and centrifuged at 1800 RPM for 5 minutes. Results: The results showed that various parasites including: helminthic parasites (Strongyloides stercoralis eggs, Ascaris lumbricoides, Toxocara. sp, Taenia. sp, Nemadoda, and free-living larvae) and protozoan parasites (Giardia lamblia trophozoite, Giardia lamblia cyst, and Amoeba trophozoite). This study showed the contamination rate of Mentha (27. 08%) and Radish (24. 16%) are more than Garden cress. It was observed that Ascaris eggs and Tennia eggs are at the highest and the least Parasitic contamination in vegetables washed with potable water, respectively. Conclusion: One of the ways to eliminate parasitic contamination of vegetables is to use saline solution and detergent to reduce parasites.