Effects of the Municipal Solid Waste Landfill on the Quality of Water Resources in Khalkhal: A Case Study

Transmission of leachate from municipal solid waste landfills can potentially threaten ecosystems and human societies when the landfill has no system for collecting and treating leachate. Leachate produced from landfills finds its way through the soil to groundwater and surrounding surface waters, leading to pollution of water resources. This study aimed to investigate the effects of leachate from Khalkhal landfill (a city in Ardabil province, northwestern Iran) on the quality of groundwater and surrounding surface water. During 2019-2020, 4 wells (one control well located upstream of the landfill and three wells located downstream of the landfill) and two stations of the surface water resource of the Herochai river were spots for sampling. First, we did sampling during high and low rainfall seasons in accordance with the standards. Second, we analyzed the values of some physical, chemical, and biological quality parameters according to standard methods. The sampling of the soil texture was conducted following ASTM D 422 standards. Then, the soil was analyzed at Reference Laboratory of Water, Soil, and Plant in Ardabil province. The value of most parameters measured in the water of downstream wells was lower than the limit recommended by the Iranian and World Health Organization, indicating no limitation for drinking and agricultural uses. The quality of the Herochai river water was also relatively undesirable in terms of turbidity and total coliform in some samples. Additionally, consistent with the study results, no difference was observed between high and low rainfall seasons. According to the results obtained from different parameters, Schuler and Wilcox diagrams, and landfill water pollution index (LWPI), the quality of upstream and downstream water resources of Khalkhal municipal solid waste landfill was not much different. In other words, the landfill did not affect water

Occupational and Environmental exposure to mercury in Iran: a systematic review

Introduction: Mercury is one of the three heavy metals which are listed on top of the US EPA,s list for toxic and hazardous material with priority for human health. The aim of this study was to evaluate the situation of environmental and occupational human contamination with mercury in Iran. Method: All studies conducted in Iran which had measured mercury levels in humans in Iran, were searched by electronic databases including Iranmedex, SID, Magiran, Google Scholar, Web of Knowledge, Science Direct and PubMed. Due to the heterogeneity of the study results, meta analysis was not performed on the results. Results: After searching the databases, fourty seven articles were found. From these, 44 were chosen and evaluated. Although contamination with mercury is not high in Iran, but occupational exposure is considerable and contamination in specific groups such as dentists is high. Conclusion: Considering the high exposure to mercury in some occupational groups, using personal protective equipment and proper ventilation at workplaces should be emphasized. Also periodic monitoring of mercury exposure and medical examination of related workers is necessary. In order to decrease environmental exposure, it is suggested that legislations for routine monitoring of mercury in food and using composites without mercury be practiced. Key­words: Mercury, Iran, Environmental exposure, Occupational exposur

Method development of di-(2-ethylhexyl) phthalate metabolites detection by dispersive liquid–liquid microextraction gas chromatography–mass spectrometry from urine

Aims: Phthalates (e.g., diethylhexyl phthalate) act as one of the endocrine disruptive compounds and can have adverse effects on different biological pathways including hormonal receptors, affecting the synthesis, secretion, or metabolism of hormones. The aim of this study was, method development of the dispersive liquid-liquid microextraction (DLLME), to determine the monoesters of diethylhexyl phthalate in children and adolescents in Isfahan city, Iran. Materials and Methods: This study was conducted in 2016 (during a year) on 242 children and adolescents, aged 6–18 years, living in Isfahan, Iran. In this method, acetonitrile and chlorobenzene were used as disperser and extractant, respectively, to extract the investigated monoesters. The analytes were determined by gas chromatography–mass spectrometry. Results: Acetonitrile (as disperser) and chlorobenzene (as extractant) were used for monoester phthalates extraction (750 μl of acetonitrile and 80 μl of chlorobenzene). The results indicated that the recovery and relative standard deviation (RSD) of the utilized method were 55–109 and 6.3%–13.2%, respectively. The limit of detection and limit of quantification (LOQ) of the method were 0.024–0.088 and 0.05–0.48 μg/L, respectively. Monoethylhexyl phthalate (MEHP), monoethyl oxo-hexyl-phthalate (MEOHP), and monoethyl hydroxyl-hexyl-phthalate (MEHHP) were observed in 99.6%, 95.87%, and 96.28% of the studied samples, respectively. The mean concentration of MEHP, MEOHP, and MEHHP in the study population was 151.7 ± 143.8, 258.26 ± 143.07, and 194.17 ± 147.3 μg/L, respectively. Conclusion: Acetonitrile (as disperser) and chlorobenzene (as extractant) were suitable solvents for phthalate monoesters extraction in method development of DLLME. On the other hand, the mean concentrations were very high values in comparison with other similar studies that require the attention and legislation regarding limitation of the application of phthalate compounds

Photocatalytic Reduction of Nitrate in Aqueous Solutions using Ag-doped TiO2/UV Process

Background and Objectives: Pollution of water resources to nitrate is an environmental problem in many parts of the world. This problem possibly causes diseases such as methemoglobinemia, lymphatic system cancer and Leukemia. Hence, nitrate control and removal from water resources is necessary. Considering that application of nanomaterials in treatment of environmental pollutants has become an interesting method, in this research use of Ag-doped TiO2 nanoparticles synthesized through photodeposition produced under UV irradiation was studied for removal of nitrate from aqueous solutions.Materials and Methods: Three nitrate concentrations of 20, 50, and 100 mg/L were considered. In order to determine the effect of Ag-doped TiO2 nanoparticles on  nitrate removal, dosages of  0.1, 0.4, 0.8 and 1.2 g/L nanoparticles were used; pH range of 5-9 was also considered. The effect of Ag-doped TiO2 nanoparticles both in darkness and under UV irradiation was studied. Moreover, the presence of chloride and sulfate anions on the system removal efficiency was investigated.Results: The optimum performance of nitrate removal (95.5%) was obtained using nitrate concentration of 100 mg/L, in acidic pH and 0.8 g/L Ag-TiO2. Increase of nanoparticle dosage up to 0.8 g/L, increased the removal efficiency, but for 1.2 g/L dosage of nanoparticles, the removal efficiency decreased. Maximum reduction performance without nanoparticles, under UV irradiation and under darkness conditions were 32% and 23.3% , respectively. In addition, we found that presence of sulfate and chloride anions in aqueous solution reduced efficiency of nitrate removal.Conclusion: Results of this study showed that Ag-doped TiO2 nanoparticles may be efficiently used for nitrate removal from aqueous solutions

Removal of BPA from Aqueous Solutions by Electrocoagulation Using iron Electrodes and Optimization

  Background and Objectives: Bisphenol A (BPA) is one of the toxic environmental pollutants that can be entered into aquatic ecosystems by raw wastewaters. In the current study, electrocoagulation used in the treatment of water and wastewater in a wide range was investigated for the removal of BPA. Materials and Methods: All the experiments were conducted in a batch system. The effect of operating parameters such as pH, BPA concentration, electrolyte concentration, distance between electrodes, current intensity, and reaction time were evaluated. Experiments were carried out at laboratory temperature (25 °C), potential difference 30 V. Results: According to the results, the optimal condition were follows: BPA concentration 10 mg/L, current intensity 1500 mA, pH=7, and distance between electrodes 0.5 cm. The removal efficiency was ranged 60 to 90 percent. Conclusion: It can be concluded that the electrocoagulation process using iron electrodes in the optimal condition can acceptably remove BPA from aqueous solutions. &nbsp

Comparing the efficiency of UV/ZrO2 and UV/H2O2/ZrO2 photocatalytic processes in furfural removal from aqueous solution

Abstract Furfural is a toxic chemical compound that is widely applied as a solvent in a great many of industries, and it can cause many problems to the human beings and environment. Various methods of removing furfural from the wastewaters have been studied. AOPs methods are utilized for the elimination of a vast majority of the pollutants due to their high efficiency as well as for their lack of creating secondary contamination. Therefore, the present study aims at comparing the efficiency of UV/ZrO2 and UV/H2O2/ZrO2 photocatalytic processes in removing furfural from aqueous solutions. The solution’s initial pH, furfural’s concentration, zirconium catalyst dosage and time were investigated as the parameters influencing the removal efficiency by the two foresaid processes, and the effect of H2O2 addition in various concentrations into UV/H2O2/ZrO2 process was also evaluated. Spectrophotometer device was employed to assay the concentration of the residual furfural. The results indicated that the pH of the environment, the amount of the nanoparticle and H2O2 input concentration largely influence the furfural omission. The optimal condition for the removal of furfural in UV/ZrO2 process in an initial concentration of 20 mg/L, a pH equal to 3, a catalyst dose of 0.25 g/L during a period of 60-min time was 81.6%, and it was 99% for UV/H2O2/ZrO2 process in a pH equal to 7 with the addition of H2O2 for a concentration of 0.75 mL/L under the same conditions. Generally, it can be concluded that UV/H2O2/ZrO2 and UV/ZrO2 photocatalytic processes can effectively be applied to remove furfural from the aqueous solutions, especially in lower concentrations