نشریه مهندسی بهداشت محیط
سال ششم شماره 2 (پیاپی 22، زمستان 1397)

Isocyanate Compounds NCO groups react easy with biological molecules & considered to be a powerful respiratory irritant and major cause of asthma, bronchitis chemical. Studies /investigations have shown that the risk of death from lung cancer is spreading among car painters. This study aimed to identify amount of worker with Physical contact on reduction of this contaminant in the work places produces isocyanates are about 3 million tons annually and 280000 workers are in contact with it in America. Extensive research on the 57000 of Painter are shown that the risk of death from lung cancer is very high among workers of painter. toluene diisocyanate (TDI) have used as the most important industrial intermediates in industry. The purpose of epidemiological studies of isocyanate compounds is appointment occupational exposure of workers. In order to reduce this pollutants in the workplace, the employers must be know the safety rules and use effectively controls. The purpose of performance of this project is survey impact of control on reducing the amount of isocyanate in air of workplace. 10%of car painters were selected in Karaj city, then 58 air samples were collected by using standard methods. Analysis of samples was performed by HPLC with niosh 5522 method. statistical analysis was analysis by SPSS software. Average of age, work history and work history with pain, in a sequence were 36.8, 18.25, 16.65.35.5% were smokers.63.8% of workshop had industrial ventilation. The Pollutant concentration average MDI, TDI was 7.9 mg/m3 and 1.05 that the highest concentration was related to No 9. Between smoking and respiratory problem among workers significant relations were found (p<0./002). In statistical analysis correlation coefficient (0.5) was observed between the temperature factor and increase HDI concentration pollutant concentration is significant between groups, where as it is not the same inside groups. This is correlation between workshop temperature & amount of pollutants and it increase at the end of the shift. Most of the samples had more concentration then standard. High concentration of pollutants. Lack of ventilation system in 36% of the workshops & and smoking in the 35.5% of workers could increase diseases related to compounds isocyanate in future.

Aniline is a toxic compound characterized by high solubility in water (3.5 percent; 35000 mg/l) leading to increased presence risk of aniline in wastewater. The presence of this compound in the blood causes the formation of met hemoglobin and prevent oxygen uptake and plays a key role in chemical asphyxiation, moreover, it has been thought as a carcinogenic risk factor to humans. Therefore, this study aims to synthesizes chitosan graphene oxide and determine the usefulness of using this absorbent to remove aniline from aqueous solutions. Chitosan Graphene Oxide (CGO) which was prepared from graphite powder by adapting the procedure used by Hummer, doped with chitosan and the characterization of CGO were determined by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Powder Diffraction (XRD). To optimize the conditions, parameters including adsorbent dosage (g / L 0/2, 0/4, 0/6, 0/8, 1, 1/25,1/5), pH (2, 4, 6, 8, 10), contact time (5, 15, 30, 45, 60, 90, 120 min) and aniline concentrations (mg/L 50, 100, 150, 200, 300) were evaluated in a total of 126 tests. Finally Chitosan Graphene Oxide was used for aniline removal from aqueous solutions. The results of present study showed that with increase in contact time and absorbent dosage and with decrease in aniline concentration, removal efficiency tend to increase. PH=6, time=30min, absorbent dose=1 g/l and concentration of aniline=50 mg/l were obtained as optimum conditions. Under optimum condition (pH=6, time=30min, absorbent dose=1 g/l and concentration of aniline=50 mg/l) the highest efficiency of aniline removal is %93.14. The adsorption isotherm showed that absorption process correlates well with Langmuir adsorption isotherm (R2>0.9996). Reaction kinetics complies with Pseudo-second order model with correlation coefficient of (R2=0.9799). In the study of thermodynamics, negative values of ΔH0 and ΔG0 respectively illustrate that reactions are exothermic and spontaneous. chitosan graphene oxide composite has the ability to remove aniline effectively from aqueous solutions. And also it can be used as an efficient adsorbent for related aqueous solutions.

Chemical Oxidation Demand (COD) is an important parameter in treatment of leachate. Leachate from solid waste has a high pollutants that must be treatment before discharge to environment. The aim of this study was optimization of US-Electro/persulfate process, predicate of optimum conditions by RSM for landfill leachate treatment. In this experimental study used to sonochemical-reactor with one liter volume that equipped with 40 KHz and two Iron electrodes as an anode and two Copper electrodes as a cathode that connected to direct current supply source. In final step of study pH (2-4), S2O82- (1- 2gr/L), direct electrical current (1/5-3 A) and reaction time parameters as an independent parameters were studied. In optimum condition, corrosion of the electrodes in anode and energy consumption were measured. Sludge properties before and after the process were analyzed by SEM / EDAX and FT-IR spectroscopy. By using this software (design Expert), the optimum condition was done at PH=3/41, S2O82- dose=1.2 gr, current density=2/41 A, and reaction time were 70 min. In this condition the efficiency of COD removal was 75 %. The R-squared and Adj R-squared process is 0/78 and 0/88 respectively. The electrodes corrosion in optimum condition were 0.77 gr and energy consumption was 9/23 KW/kg COD. The results of analysis indicate that change in sludge during the process happened and elements structure in leachate has observed, the most obvious oxygen and iron increase in sludge after the process. The US-Electro/persulfate has a good efficiency in COD removal and with this model can be tested with a few run and high accuracy to optimize the process.

Environmental pollution from waste is one of the main problems of municipal waste management. Since evaluation of the recycling and recovery process is one of the most important stages in municipal waste management, this study aimed to determine the optimal strategies for recycling and recycling Ardabil municipal waste by SWOT analysis and QSPM matrix in 2017. In this descriptive-analytic study, basic information was obtained through library studies and review of texts, observations, field visits, specialized interviews, and completion of a questionnaire from 80 experts in this field. Finally, was used analytical method SWOT and QSPM Matrix. The final score of the internal factors 2.03 and the external factors were 3.05. According to the IE matrix, the current status of the process was located in the WO status. In the QSPM matrix, among strategies based on the charm score, the option of supporting recycling capabilities (composting, extracting energy, producing quality products), and recovery waste for the construction of related factories and the creation of a job market for unemployed youth proportional to The conditions of the status with a score of 11.57 were introduced as the first priority. Considering the current status of Ardabil municipal waste recycling and recycling process, which is in accordance with the IE matrix in the region of change, it is necessary to take advantage of opportunities in order to compensate for the weaknesses of the process.

Industrial wastewaters containing high amounts of compounds such as sulfate can cause serious risks to human health and environment. Therefore, proposing practical solutions with the lowest cost and the highest efficiency for pollutants removal is of special importance. The purpose of this study is to find a suitable method for treatment wastewater containing very high amounts of sulfate. This research is an experimental-research study in which four different practical methods have been investigated for treatment of sulfate containing wastewater including chemical precipitation with lime, electrocoagulation, biological degradation and thermal distillation. After examining the performance of different methods and considering the special characteristics of wastewater, the results showed that the methods of chemical precipitation (removal efficiency of 5%) and electrocoagulation (removal efficiency of 7%) were less efficient. The distillation process also showed an acceptable performance in removing TDS and sulfate from this wastewater (removal efficiency of 98.7%) and the biological method could function well after wastewater dilution (the removal percentage of sulfate in the first 24 hours for wastewater with dilutions of 10, 25 and 50%, are about 55, 40 and 17%, respectively). According to the results obtained from this study, methods of chemical precipitation and electrocoagulation are proposed only as a pre-treatment method and biological treatment can be used as a supplementary treatment after pre-treatment. Distillation is also not recommended as a practical method due to high cost and energy consumption.

Nowadays, the pollution of aquatic ecosystems caused by entry of heavy metals is an issue that makes it essential to check the wholesome of the aquatic animals that are consumed by human. When these metals enter the canvas of aquatic organisms, cause tension due to bioavailability, and their toxicity leads to teratogenic, mutagenic and carcinogenic effects in living organisms Thirty rainbow trout were prepared from each fishing farm pond which are located in Sanandaj (Nanale Village) and Kamyaran (Diwaznaw Village). Then, samples were prepared using acid digestion method in the laboratory and the concentration of these metals was measured using atomic absorption spectrometer (Phonix 986). The achieved data were analyzed using SPSS software.. The average concentration of the copper in liver and muscle tissues was 1. 53 and 0.15, for magnesium 3.7 and 7.57, for iron 0.28 and 0.6, for zinc 4.52 and 1.05, and for Nickel was 0.04 and 0.03 micro grams per a gram of fresh weight. The maximum daily consumption allowance was 888.7 grams for adults and 177.77 for children The average concentration of copper, iron, zinc, nickel and magnesium in muscle tissue of rainbow trout compared to international standards, is slightly lower than that at current consumption rates, long-term health risks to consumers is realized.

Air pollution is one of the most important environmental problems in large cities. Aromatic hydrocarbons as volatile organic compounds (VOCs) have been listed in Hazardous Air Pollutants (HAPs) by Environmental Protection Agencies (EPA). The aim of this study is Passive sampling and determination of aromatic hydrocarbons (AHs) toluene, xylene and ethylbenzene using activated carbon fabric in ambient air of Tehran Activated carbon fabric (ACF) was used as adsorbent for adsorption of aromatic hydrocarbons. The chemical specifications of activated carbon fabric such as specific surface area and pores volume were determined by nitrogen adsorption isotherm (BET method), the microscopic images by scanning electron microscopy (SEM) and surface functional groups by X-ray Photoelectron Spectroscopy (XPS). Air sampling was achieved by passive samplers equipped with activated carbon fabric in cylindrical holders at 8 different stations of Tehran. Gas chromatography mass spectrometry (GC-MS) was used for determination of Toluene, Ethylbenzene, and Xylene after extraction in CH2Cl2. The results showed activated carbon fabric is an efficient adsorbent for passive sampling of aromatic hydrocarbons and at different stations the concentrations of Toluene, Ethylbenzene, and Xylenes were determined. The results indicated that Javadiyeh station (Region 17) and Imam Khomeini station (Region 10) were polluted than other stations, whereas at Chitgar station (Region 22), Sattari station (Region 5) and Tehran pars station (Region 8) had lower concentrations of AHs. The good correlation between carbon monoxide and aromatic hydrocarbons concentrations in each sampling station showed they have similar source of emission (cars). The concentration of these pollutants is influenced by topography, wind direction and speed and the number of car passing through different stations. As the concentrations of aromatic hydrocarbons in ambient air are low using AFC in passive sampler is an efficient method for sampling and adsorption of AHs and then their determination. For this purpose it is necessary to exist special functional groups and especially oxygen containing fuctional groups on the surface of carbon fabric.

Water contamination of heavy metals is one of the major threats to human health and food chain. In this study, concentration of heavy metals of lead, chromium, copper and zinc in sediment was measured in order to assess their ecological effects and their risk. To determine the concentration of metals, 12 stations were selected along the river and 3 samples from the sediment were taken in each station. After the preparation and acid digestion of the samples, the concentration of these metals was determined using atomic absorption device. The average total concentration of lead, copper, chromium and zinc metals in sediments was obtained in mg / kg (22.24±8.08). The results showed that the pollution load and ecological risk of heavy metals in the area are in lower risk category. The environmental hazard of metals was also evaluated (zinc lead). Also, by calculating the geochemical index of molars and contamination coefficient of Balkhloo sediments, the pollution of heavy metals was classified with zero degree of contamination and in non-contaminated area. Based on the results, the contamination and the ecological risk level of metals in the sediments of the region are evaluated at a low level.