Improvement of Floxin photocatalytic degradability in the presence of sulfite: Performance, kinetic, degradation pathway, energy consumption and total cost of system.

In this study, photocatalytic degradability of Floxin antibiotic by UV/ZnO/sulfite (UZS) advanced oxidation process was evaluated. The degradation rate of Floxin antibiotic by UV/ZnO (UZ) and UV alone processes were 30% and 15%, respectively, within 5 min. It was observed sulfite has a synergistic effect on the performance of UZ, as the complete destruction of Floxin was achieved when sulfite was introduced into the photocatalytic medium. The complete degradation of Floxin by UZS was obtained at pH of 12.0, sulfite/ZnO molar ratio of 1:3 after 5 min of reaction. According to kinetic studies, the observed rate of Floxin degradation (robs (mg L-1 min)) by UZS was 63 and 25 times that of UV alone and UZS, respectively. The values of energy consumption and the total cost for UV alone, UZ and UZS processes were estimated to be (50 kWh m-3 and 1.4 $ m-3), (20 kWh m-3 and 0.98 $ m-3) and (0.78 kWh m-3 and 0.82 $ m-3), respectively.

Synthesis of modified ZnO nanorods and investigation of its application for removal of phthalate from landfill leachate: A case study in Aradkouh landfill site.

In this study, zinc oxide nanorods, co-doped with iron and silver, were synthesized in a co-precipitation method. Its properties were determined using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), Dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS) analysis. The results of FE-SEM and TEM showed that zinc oxide nanoparticles synthesized and co-doped with iron and silver were formed as separate nanorods. Also, the average values of DBP and DEHP amount of phthalates in the leachate from the landfill site of Aradkouh were obtained 52.5 and 94.69 mg/L, respectively. The highest removal efficiency in real samples for phthalates was found to be 52%. The highest removal efficiency of TOC were was 61%. The synthesized nanostructure could have proper efficiency in removal of phthalates from water sources under the visible light of LED lamp.

Health risk assessment of nitrate in groundwater resources of Iranshahr using Monte Carlo simulation and geographic information system (GIS).

Because of exposure to a wide range of chemical contaminants such as nitrate via potable water resources, the use of the approaches to set standards for drinking water quality and also to do a risk assessment is necessary for maintaining the public health. High levels of nitrate in drinking water can have adverse health effects; primarily for infants and pregnant women. So, the present study aimed to the assessment of nitrate health risk in drinking water resources of the Iranshahr city, Sistan and Baluchistan province and also, evaluation of the uncertainty of nitrate and the probability of contamination occurrence by Monte-Carlo Simulation (MCS) technique. Besides, the geographic information system (Arc GIS, Ver 10.3) was applied to mapping the nitrate concentration in groundwater resources of the studied area. For these aims, the numbers of 66 samples were collected from rural groundwater resources, and nitrate concentration was measured using a Spectrophotometer in wavelength of 220 nm. According to the results, the nitrate concentration was in the range of 6.49 mg/L, and its average level was 6.15 mg/L. Also, the simulation results with 90% confidence showed that the hazard equitant (HQ) in the infant groups, children-teenagers and adults was less than 0.331, 0.311, 0.312, and 0.3, respectively.

Carcinogenic and non-carcinogenic health risk assessment of heavy metals in drinking water of Khorramabad, Iran.

The continuous urbanization and industrialization in many parts of the world and Iran has led to high levels of heavy metal contamination in the soil and then on the surface and groundwater. In this study, the concentrations of 8 heavy metals were determined in forty water samples along distribution drinking water of Khorramabad, Iran. The ranges of heavy metals in this study were lower than EPA and WHO drinking water recommendations and guidelines and so were acceptable. The mean values of CDItotal of heavy metals concentrations in adults were found in the order of Zn > Ba > Pb > Ni > Cr > Cu > Cd > Mo. The health-risk estimation indicated that total hazard quotient (HQing + HQderm) and hazard index values were below the acceptable limit, representing no non-carcinogenic risk to the residents via oral intake and dermal adsorption of water. Moreover, the results of total risk via ingestion and dermal contact showed that the ingestion was the predominant pathway. This study also presents that the carcinogenic risk for Pb, Cr, Cd and Ni were observed higher than the acceptable limit (1 × 10-6). The present study will be quite helpful for both inhabitants in taking protective measures and government officials in reducing heavy metals contamination of urban drinking water. •The data analyzed in this study show a clear situation regarding the quality of drinking water in Khorramabad.•The results of this study can be used to improve and develop the quality of drinking water that directly affects the health of consumers.•The present study will be quite helpful for both inhabitants in taking protective measures and government officials in reducing heavy metals contamination of urban drinking water.

Estimate the effective dose of gamma radiation in Iran cities: lifetime cancer risk by Monte Carlo simulation model.

Background radiation can be different in both indoor and outdoor places. Background radiation is always in the environment, and all people in the community are constantly exposed to it. The most important source of exposure to gamma ray is natural radionuclides. Gamma rays can have harmful effects on the human body. The purpose of this study was to evaluate the health risk of gamma-ray exposure and to simulate using the Monte Carlo simulation. In this study, gamma-ray data were extracted from the studies carried out at intervals January 1, 2000, to December 31, 2018. Iranian and international databases were used to search for the articles. A total of 11 studies were found. To determine the health effects of gamma-ray radiation, the annual effective dose and excess lifetime cancer risk were calculated. To determine the uncertainty, a health risk assessment was conducted via Monte Carlo simulation. In outdoor, the mean, highest, and lowest absorbed dose of gamma ray were 117.82 nSv/h, 295.17 nSv/h, and 49 nSv/h, respectively. Ardabil Province and Chaharmahal and Bakhtiari Province have the highest and lowest gamma ray concentrations, respectively. In indoor, the mean, highest, and lowest absorbed dose of gamma ray were 118.22 nSv/h, 141 nSv/h, and 60.2 nSv/h, respectively. The last column, the mean, maximum, and minimum of excess lifetime cancer risk values for gamma-ray radiation were 2.45E-3, 4.17E-3, and 4.61E-4, respectively.

Catalytic ozonation process using a MgO nano-catalyst to degrade methotrexate from aqueous solutions and cytotoxicity studies in human lung epithelial cells (A549) after treatment.

Pharmaceutical compounds which enter the environment are classified as emerging pollutants. Among different drug compounds, anti-cancer drugs like methotrexate are of more concern due to their mutagenic, carcinogenic, and genotoxic properties. Therefore, the main objective of this study was to use catalytic ozonation processes (COPs) as novel advanced oxidation processes to degrade methotrexate from aqueous solutions. The calcination method was used to obtain a nitrate magnesium oxide nano-catalyst. The main variables considering the effect of single ozonation processes (SOPs) and COPs on the target pollutant were initial methotrexate concentration, contact time, solution pH, and MgO dosage. The BET results indicated that the surface area of the MgO nano-catalyst was 140.031 m2 g-1. Based on the BJH plot, the size of the MgO nano-catalyst and average pore volume were 44.5 nm and 0.4454 cm3 g-1, respectively. The weight percent of Mg and O was 61.09% and 38.91%, respectively. In acidic and alkaline pH, the degradation rate of methotrexate showed a higher increase in SOPs and COPs than at neutral pH. The degradation rate of methotrexate decreased with increasing concentration. By increasing the contact time, the degradation rate of methotrexate of both SOPs and COPs increased. Actually, the methotrexate degradation in COPs was faster than in SOPs. When using tert-butanol as a scavenger, the reduced removal efficiency in SOPs and COPs was 32% and 31%, respectively.

Health risk assessment of heavy metals on PM2.5 in Tehran air, Iran.

The general goal of this study was to measure the concentration of heavy metals on suspended particles and evaluate the health-risk assessment of these metals on human health. In this study, the concentration of heavy metals adsorbed on suspended particles less than 2.5 µm was determined. For determining of health-risk assessment, the developed method of USEPA was used. The health-risk assessment of carcinogen and non- carcinogen of suspended particles were evaluated in three main paths include oral ingestion, inhalation, and dermal contact. The average annual concentrations of Al, Fe, As, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn were 1.77, 1.14, 0.03, 0.02, 0.07, 0.15, 0.06, 0.03, 0.1, 0.04, and 0.14 µg/m3, respectively. Between different stations, the order for the heavy metals was followed as urban>traffic>suburban. The average risk of carcinogenic at urban stations in the spring for As, Cd, and Cr was 2.25*10-9, 2.09*10-12, and 2.05*10-11, respectively.

Systematic review and health risk assessment of arsenic and lead in the fished shrimps from the Persian gulf.

The ingestion of heavy metals through contaminated seafood can causes significant outcomes on human health. In recent years, consume fishes and shrimps has increased in Iran, and several study about heavy metals content in fishes and shrimps from Persian Gulf were carried out to check their food safety. The aims of these systematic reviews and meta-analysis was to summarize the evidence on the relation of the intakes of Arsenic (As) and lead (Pb) levels, based on the origin and sub-groups of shrimp species consumed, Hence that we can estimate the risk of oral cancer induced by Pb and As in these groups of shrimp from the persian gulf. We carried out a search of all suitable studies published between 1995 and 2017 in Scopus, Science Direct, PubMed and Web of Science databases. Since the heterogeneity among studied was significant, we used the random effect model (REM) to perform meta-analysis of data. Data were obtained from 9 articles (14 studies), with 511 samples, and it was reported that pooled levels of As and Pb in the muscle shrimps were 1.37 (95% CI: 0.66-2.08 mg/kg d.w.) and 0.58 (95% CI: 0.33-0.82 mg/kg d.w.), respectively. This pooled levels in muscle shrimps were higher than safe dose reported on Food and Agriculture Organization/World Health Organization guidelines (FAO/WHO). The rank order of shrimps species based on As was Panulirus homarus > Penaeus semisulcatus and for the Pb levels was Litopenaeus vannamei > Panulirus homarus > Fenneropenaeus indicus > Metapenaeus affinis. The lowest and highest risk levels of oral cancer, divided by consumers age groups, were respectively 45-54 (6.94E-04) and 15-24 (8.42E-04) for the Pb, and 45-54 (2.87E-01) and 15-24 (3.51E-01) for arsenic. Incremental Lifetime Cancer Risk (ILCR) of Pb and As was higher than 10-4 and 10-3, respectively. All groups (age) of consumers are subject to the cancer risk of due to the consumption of shrimps contaminated by Pb and As, therefore, should be started a control plan for the reduction of the heavy metal bioaccumulation levels in shrimps of the Persian Gulf coupled to a capillary food safety communication.

Physicochemical characterization of ambient PM2.5 in Tehran air and its potential cytotoxicity in human lung epithelial cells (A549).

As air pollution is a major problem in Tehran, this study aimed to investigate the physicochemical characterization of the water-soluble and organic contents of ambient PM2.5 in Tehran and determine its in vitro toxicological impact on human lung epithelial cells (A549). A total of 11 sampling stations were selected, including three categories: traffic, urban, and suburban. All sampling was carried out in the spring and summer of 2015. Ion chromatography (IC), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and GC-MS were used to analyze ionic compounds, heavy metals, and polycyclic aromatic hydrocarbons (PAHs), respectively, and an ELISA reader was used for cytotoxicity analysis. The most prevalent ionic species found for all three categories was SO42-. PAH concentrations were 43.45±32.71, 50.51±37.27, and 29.13±33.29ng/m3 for traffic, urban, and suburban stations, respectively. For all sampling stations, Al and Fe had the highest values among the investigated heavy metals. Cell viability measurements, carried out using the MTT assay, showed that all three categories of samples cause cytotoxicity, although the urban station samples showed higher cytotoxicity than those from the other stations (p˂0.05). Based on the results of the present study, organic compounds and insoluble particles could be the main causes of cytotoxicity.

Enhanced sonochemical degradation of tetracycline by sulfate radicals.

Tetracyclines (TCs) are widely used antibiotics in human and veterinary medicine and as growth promoters in the world. Sulfate radical-based advanced oxidation processes have been of great interest due to the high oxidizing potential of sulfate radical to degrade refractory organic pollutants in aqueous solution. In this study, the degradation of antibiotic TC in aqueous solution by silver-activated persulfate (Na2S2O8) in the presence of ultrasound irradiation under various conditions has been investigated. The effects of several parameters such as Ag2SO4, Na2S2O8 concentration, temperature, ultrasonic (US) power, initial TC concentration and initial pH on the degradation of TC were investigated. More than 83% of TC removal was achieved within 120 min under optimal conditions. The optimum operational conditions were found to be as follows: Ag2SO4 dosage 3.5 mmol/L, Na2S2O8 concentration 70 mmol/L, reaction temperature 25 °C, US power 120 W, initial TC concentration 50 mg/L, pH 3.0 and contact time 120 min. The degradation of TC in the persulfate/Ag(+)/US process followed the pseudo-first-order kinetics.