Health risk assessment of heavy metal toxicity in the aquatic environment of the Persian Gulf

This study aims to explore the potential health risks linked to four heavy metals/metalloids (Pb, Cd, As, Hg) present in four commercially important fish species (Scombromorus commerson, Pseudorhombus elevatus, Thunnus tonggol and Otolithes ruber) in the Persian Gulf. Metals in fish muscle tissue were analyzed via ICP-MS. The analysis revealed that Scombromorus commerson (except for Pb) and Thunnus tonggol (except for As) exhibited the highest and lowest contamination levels, respectively. The Hazard Index findings highlighted arsenic and mercury as the most hazardous elements. However, the Target Hazard Quotient values for each metal and fish species remained within safe thresholds. The highest and lowest Total Carcinogenic Risk was concerning Pseudorhombus elevates (As: 7.41-E05), and Thunnus thonggol (Pb: 3.21-E07), respectively. TCR analysis suggests that the cancer risk of studied metals was below the negligible level (TCR < 10-6) or within the acceptable level (10-6 < TCR < 10-4), potentially not posing carcinogenic risks through extended consumption.

Detection of SARS-CoV-2 in the indoor air of intensive care unit (ICU) for severe COVID-19 patients and its surroundings: considering the role of environmental conditions

There is ambiguity about the airborne transmission of the SARS-CoV-2. While a distance of 6 feet is considered a safe physical distance, new findings show that the virus can be transmitted more than that distance and cause infection. In hospitals, this may cause the virus to be transmitted from the treatment wards of COVID-19 patients to adjacent wards and infect medical staff, non-COVID-19 patients, and patient companions. The aim of this study was to investigate the presence of coronavirus in the air of ICU and adjacent wards. The low volume sampler (LVS) with two separate inlets for PM2.5 and PM10 was applied to collect indoor air of intensive care unit (ICU) with confirmed COVID- 19 patients and its surroundings. The samples were collected on 0.3μ PTFE filter fitted to the holder. Sampling was done at flow rate of 16.7 l/min for 24 h. The SRAS-CoV-2 virus was isolated using a SinaPure™ Virus Extraction Kit (SINACLON, Iran). The presence of SARS-CoV-2 genome was assessed using a commercially available SARS-CoV-2 Test Kit (Pishtaz-Iran), according to the manufacturer's instructions using One Step plus Real-Time PCR system tool (Applied Biosystems, USA). A total of sixteen samples were taken, and the positive test rate for SRAS-CoV-2 was 12.5 % (2/16). All samples from surrounding (rest room and hallway) were negative, but two air samples from indoor of ICU (next to the patient bed and nursing station) were found to be positive. The results support the possibility of transmitting the SRAS-CoV-2 through the air at a greater distance than what is known as a safe physical distance. Therefore, in addition to maintaining a safe physical distance, other precautions including wearing a face mask, preventing air recirculation, and maximizing the use of natural ventilation should be considered, especially in crowded and enclosed environments.

Urinary concentrations of BTEX in waterpipe smokers and nonsmokers: Investigating the influence of conventional activities and multiple factors

The aim of this study was to compare the concentrations of the benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in the urine of smokers and the control group considering the role of age, weight, job, history of waterpipe and cigarette smoking, and driving time. The chemicals in the urine of 99 smokers and 31 nonsmokers were extracted by liquid-liquid extraction method and their concentrations were measured by liquid injection GC/MS. The mean concentration of benzene, toluene, ethylbenzene, m-xylene, o-xylene, p-xylene, and total BTEX in waterpipe smokers were found to be 471.40, 670.90, 127.91, 167.64, 90.62, 46.04, and 1574.50 ng/g. creatinine, respectively. For the waterpipe&cigarette smokers, the concentration of the compounds were 708.00, 959.00, 146.40, 192.50, 93.30, 53.07, and 2152.00 ng/g.creatinine, respectively. For nonsmokers the concentrations of these compounds were 88.12, 140.40, 36.68, 57.29, 31.53, 26.21, and 380.30 ng/g.creatinine, respectively. Driving time, waterpipe smoking and cigarette smoking were positively associated with BTEX concentration (p < 0.05). Fruity tobacco showed higher concentrations of BTEX compared to the regular tobacco, and athlete persons had les urinary BTEX than the non-athletes. There was not significant correlation between the BTEX and age, height, weight, and BMI. High concentrations of BTEX compounds in the urine of waterpipe and cigarette smokers compared to nonsmokers indicate that waterpipe and cigarette can be an important source of exposure to these compounds and the known adverse effects of these compounds, especially carcinogenicity, threaten the health of smokers.

Diagnosis of anomalies based on hybrid features extraction in thyroid images

Diagnosing benign and malignant glands in thyroid ultrasound images is considered a challenging issue. Recently, deep learning techniques have significantly resulted in extracting features from medical images and classifying them. Convolutional neural networks ignore the hierarchical structure of entities within images and do not pay attention to spatial information as well as the need for a large number of training samples. Capsule networks consist of different hierarchical capsules equivalent to the same layers in the convolutional neural networks. We propose a feature extraction method for ultrasound images based on the capsule network. Then, we combine those deep features with conventional features such as Histogram of Oriented Gradients and Local Binary Pattern together to form a hybrid feature space. We increase the accuracy percentage of a support vector machine (SVM) by balancing and reducing the data dimensions of samples. Since the SVM provides different training kernels according to the sample distribution method, the extracted textural features were categorized using each of these kernels to obtain the result. The parameters of classification evaluation using the researcher-made model have outperformed the other methods in this field. Experimental results showed that the combination of HOG, LBP, and CapsNet methods outperformed the others, with 83.95% accuracy in the SVM with a linear kernel.

The concentration of potentially hazardous elements (PHEs) in drinking water and non-carcinogenic risk assessment: A case study in Bandar Abbas, Iran

In this study, concentration of potentially hazardous elements (PHEs) including slice (Si), strontium (Sr), aluminum (Al), Fluoride (F), Iron (Fe), Zinc (Zn), Barium (Ba), Lead (Pb), Lithium (Li), Vanadium (V), selenium (Se), Chrome (Cr), Arsenic (As) and Uranium (U) in tap drinking water (n = 40) and filtration plant (n = 22) in Bandar Abbas city between March to July 2020 were analyzed. Analysis of PHEs ions was conducted by inductively coupled plasma mass spectrometry (ICP-MS). Also, concentration of F was measured by SPADNS Method. The non-carcinogenic risk in the exposed population (adult and children) were estimated. Concentration of PHEs between tap drinking water and filtration plant was compared using T statistical test. In addition, association among PHEs in tap drinking water and water filtration plant using Pearson correlation coefficient. The rank order of PHEs in tap drinking water was Si (6356.25 μg/l) > Sr (3980 μg/l) > Al (115.42 μg/l) > Fe (30.00 μg/l) > Zn (14.59 μg/l) > Ba (13.91 μg/l) > Pb (13.01 μg/l) > Li (11.60 μg/l) > V (4.43 μg/l) > Se (4.17 μg/l) > Cr (2.51 μg/l) > As (2.00 μg/l) > U (0.65 μg/l) > F (0.31 μg/l) and also in filtration plant was Si (1825.00 μg/l) > Sr (539.00 μg/l) > Fe (45.00 μg/l) > Al (26.00 μg/l) > Zn (8.08 μg/l) > Ba (2.24 μg/l) > Se (1.36 μg/l)> Pb(1.28 μg/l) > Li (1.26 μg/l) > Cr (1.17 μg/l) > F (0.66 μg/l) > V (0.61 μg/l) > As (LOD < ) ~ U (LOD <). The most of PHEs in tap drinking water was considerable different with filtration plant (p value < 0.05) therefore the chemical quality of tap drinking water should be more attention. The results of non-carcinogenic risk assessment revealed that TTHQ in the adults and children due to drinking tap water content of PHEs was 2.59E-3 and 6.05E-3 and filtration plant was 8.88E-04 and 2.07E-03, respectively. Therefore, TTHQ in adults and children was lower than 1; therefore, consumers are in the safe range due to drinking tap water and water filtration plant content of PHEs.

Level of air BTEX in urban, rural and industrial regions of Bandar Abbas, Iran; indoor-outdoor relationships and probabilistic health risk assessment

This study focused on the measurement of BTEX (benzene, toluene, ethylbenzene and xylene) concentrations in the air of various regions and indoor-outdoor environments in Bandar Abbas, Iran. Air samples were taken actively and analyzed by gas chromatography-mass spectrometry (GC-MS) during two one-month periods i.e., Feb 2020 (period I) and Sep/Oct 2020 (period II). The mean air temperature and the levels of all BTEX compounds were higher in period II. The highest total BTEX (t-BTEX) levels (median [min-max]) were found in the urban region (18.00 [5.21-67.24] μg m^-3), followed by industrial region (7.00 [2.05-14.76] μg m^-3) and rural region (2.81 [ND-7.38] μg m^-3). The significant positive correlations between all BTEX compounds and T/B ratio >1 indicated the vehicular traffic as the main source of emission. At 95th percentile probability, the non-cancer risk of t-BTEX in urban region was only less than one order of magnitude below the threshold level of unity (1.91E-01) and the cancer risk of benzene exceeded the recommended level of 1.0E-06 by U.S. EPA in urban (7.69E-06) and industrial (2.97E-06) regions. It was found that the indoor/outdoor ratio of BTEX concentration in beauty salon and hospital was greater than 1. Overall, the current levels of BTEX in the ambient air of study area, especially near urban roadside and in some indoor environments, should not be overlooked and appropriate mitigation actions should be undertaken.

A global systematic review, meta-analysis and health risk assessment on the quantity of Malathion, Diazinon and Chlorpyrifos in Vegetables

It is widely believed that an increasing trend in the production and consumption of vegetables has led to a dramatic rise in the use of pesticides potentially threatening the health of consumers around the world. This systematic study along with meta-analysis has mainly centered on the evaluation of the quantity of three well-known pesticides namely, Malathion (MLT), Diazinon (DZN) and Chlorpyrifos (CPF) in vegetables. In this regard, a comprehensive literature search has been performed over the last decade (January 1, 2011 to June 21, 2020) within the scientific databases including PubMed, Web of Science, and Scopus. Of 1239 articles identified through the database screening, 22 plus 37 data report were retained and included in the meta-analysis phase. Additionally, the probabilistic human health risks for the consumers due to the intake of CPF, DZN and MLT from eating vegetables were estimated by the Monte Carlo Simulated (MCS) method. According to the findings, the maximum quantities of MLT, DZN and CPF in the vegetables were observed in Pakistan (222 μg/kg, 95%CI = 214.94-229.08), Thailand (245.00, 95% CI = 235.2-254.8) and South Korea (440 μg/kg, 95% CI = 437.19-442.81), while the lowest concentration levels were reported in China (1.7 μg/kg, 95% CI = 1.56-1.84), Poland (0.57, 95% CI = 0.46-0.68) and Poland (5.78 μg/kg, 95% CI = 4.40-7.12), respectively. The results of the Egger's and the Begg's tests revealed that no bias with regard to the potential publication was observed. Finally, non-carcinogenic risk assessment results demonstrated that the exposure to the studied pesticides thorough vegetables consumption could not threaten the health of consumers.

Knowledge, attitude, and preventive behaviors of Hormozgan residents toward COVID-19, one month after the epidemic in Iran

Aim

COVID-19 has become prevalent in the world since December 2019. The further prevalence of the disease can be prevented by correct management of society and increasing knowledge, practices, and attitudes of the people. The present research aimed to evaluate the knowledge, attitudes, and preventive behaviors of people in Hormozgan in the south of Iran toward COVID-19.

Subject and methods

The present cross-sectional research was conducted over 2 months (March 2020–April 2020). The online questionnaire comprised four sections: demographic information, knowledge, attitude, and behavior toward COVID-19. Knowledge included 36 items, attitude eight items, and behavior ten items. The collected data were analyzed statistically using SPSS ver. 22. The split-half method was used to test the reliability of knowledge and the estimated value was 0.84. That of attitude and behavior was estimated via Cronbach’s alpha and was found to be 0.81 and 0.75, respectively.

Results

A total number of 2024 participants with an average age of 33.94 years took part in this research. Of all participants, 64.4% were female. According to the results, 65.8% enjoyed a good level of knowledge and 34.2% enjoyed an average level. In addition, 63.2% demonstrated a good attitude and 36.8% an average level. A large percentage of participants (90.6%) had good practices and only 9.4% had an average level of practices.

Conclusion

The present findings show that participants had a relatively good level of knowledge, positive attitude, and good behavior concerning COVID-19.

Pattern of disinfectants use and their adverse effects on the consumers after COVID-19 outbreak

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the pattern of disinfectants use within outbreak of COVID-19 and estimate their adverse effects on the consumer's health.

METHODS

In this descriptive-analytical study, 1090 participants were entered into the study without age and gender limitations. A researcher-made electronic checklist containing 43 questions was applied to collect data. The checklist included three sections: demographic characteristics (8 questions), disinfection of body and non-living surfaces (21 questions), and adverse effects of disinfectants on health (15 questions).

RESULTS

87% of participants used the incorrect proportions of water and alcohol to make this disinfectant available at home. The percentage of people with wrong proportion of sodium hypochlorite was 74.2%. Approximately 42% of participants experienced at least one disorder on their hands, feet, eyes, respiratory or gastrointestinal systems after sequential uses of disinfectants. The most common disorders among the participants were found to be skin dryness (76.3%), obsession (42.2%), skin itching (41.2%), coughing (41.1%), and eyes irritation (39.5%). The mean frequency of hand washing and hand disinfecting were 15.28 and 10.74 times per a day, respectively, and the clean-up in case of surfaces was 2.99 times a day. The frequency of hand washing and disinfecting in women group (16.4 and 11.2 times a day) were higher than in men (14.0 and 10.3 times a day) group. In addition, these self-care actions in married people (15.6 and 11.0 times a day) were higher compared to those in single people (14.0 and 10.6 times a day).

CONCLUSION

Being unaware of participants with instruction for preparation and use disinfectants may harm their health. Therefore, it is suggested that the authorities provide the necessary training program for public through official media.

Pattern of disinfectants use and their adverse effects on the consumers after COVID-19 outbreak

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the pattern of disinfectants use within outbreak of COVID-19 and estimate their adverse effects on the consumer's health.

METHODS

In this descriptive-analytical study, 1090 participants were entered into the study without age and gender limitations. A researcher-made electronic checklist containing 43 questions was applied to collect data. The checklist included three sections: demographic characteristics (8 questions), disinfection of body and non-living surfaces (21 questions), and adverse effects of disinfectants on health (15 questions).

RESULTS

87% of participants used the incorrect proportions of water and alcohol to make this disinfectant available at home. The percentage of people with wrong proportion of sodium hypochlorite was 74.2%. Approximately 42% of participants experienced at least one disorder on their hands, feet, eyes, respiratory or gastrointestinal systems after sequential uses of disinfectants. The most common disorders among the participants were found to be skin dryness (76.3%), obsession (42.2%), skin itching (41.2%), coughing (41.1%), and eyes irritation (39.5%). The mean frequency of hand washing and hand disinfecting were 15.28 and 10.74 times per a day, respectively, and the clean-up in case of surfaces was 2.99 times a day. The frequency of hand washing and disinfecting in women group (16.4 and 11.2 times a day) were higher than in men (14.0 and 10.3 times a day) group. In addition, these self-care actions in married people (15.6 and 11.0 times a day) were higher compared to those in single people (14.0 and 10.6 times a day).

CONCLUSION

Being unaware of participants with instruction for preparation and use disinfectants may harm their health. Therefore, it is suggested that the authorities provide the necessary training program for public through official media.

Coagulating potential of Iranian oak (Quercus Branti) extract as a natural coagulant in turbidity removal from water

Because of the presence of tannin in the molecular structure of oak extract, this substance is used as a natural coagulant to remove turbidity from water. The aim of this study was to determine the efficiency of this coagulant alone and in combination with polyaluminium chloride (PACl) in turbidity removal from water under optimal conditions. In this experimental study, Iranian oak extract was prepared by maceration method using ethanol 96% as an extractor. Kaolin was used to prepare synthetic turbid water samples. Using the jar test, the optimum concentrations of oak extract and PACl were determined in various concentrations of initial turbidity and pH. Moreover, the central composite design (CCD) method was utilized to design experiments and RSM was applied for analyzing the obtained results. Optimum concentrations of oak extract and PACl were 62.6 mg/L and 52.6 mg/L, respectively. An increase in initial turbidity and pH led to an increase in turbidity removal by the two coagulants. The efficiency of turbidity removal by oak extract and PACl was 63.5% and 66.5%, respectively. The simultaneous application of oak extract and polyaluminium chloride increased removal efficiency (85%) and reduced the total organic carbon concentration (TOC) in water (42.3%). The results showed that the simultaneous application of Iranian oak extract and polyaluminium chloride had an acceptable performance in removing turbidity from water.

Assessment of hydrogeochemical characteristics and quality of groundwater resources in relation to risk of gastric cancer: comparative analysis of high- and low-risk areas in Iran

The chemical quality of groundwater supplies in two high-risk area (HRA) and low-risk area (LRA) for gastric cancer in Iran was assessed through hydrogeochemical analysis and water quality indices. For this aim, Piper and Schoeller diagrams and water quality index (WQI) were applied. In addition, exposure to nitrate via drinking water and its corresponding risk were also assessed using Monte Carlo simulation technique. Data on physicochemical properties of groundwater resources were obtained from Iran Water Resources Management Company. Sampling and analysis of tap water for nitrate concentration were conducted in two cities of Shiraz (as a representative of LRA) and Ardabil (as a representative of HRA). According to Piper diagrams, the dominant hydrogeochemical facies of groundwater supplies in HRA and LRA were Na-HCO₃ (43.75%) and Ca-HCO₃ (41.77%), respectively. The predominant cations in groundwater resources of HRA were found to be Na⁺ (68.06%) and Ca²⁺ (31.94%). For LRA, the typical cations were in decreasing trend: Ca²⁺ (39.64%) > Mg²⁺ (18.35%) > Na⁺ (17.26%). For two areas, HCO₃^-, SO₄^2- and Cl^- were, respectively, the most frequent anions. Two-sample Wilcoxon test showed that there were statistically significant difference between two areas in terms of anions and cations concentrations (p value < 0.05). The mean of total hardness (Ca²⁺ + Mg²⁺) concentration of water supplies in LRA (528.1 mg/L) was higher than HRA (263.1 mg/L), whereas the mean of Na⁺ concentration was found to be lower in LRA (90.6 mg/L) compared with HRA (108.1 mg/L). The sum of nitrate intake and its risk in LRA was higher than HRA. WQI results showed that drinking water quality in HRA and LRA ranged from excellent to poor and most water resources were of a good quality class. Further studies are suggested to investigate the role of drinking water in the etiology of gastric cancer in Iran.

Modeling and optimizing parameters affecting hexavalent chromium adsorption from aqueous solutions using Ti-XAD7 nanocomposite: RSM-CCD approach, kinetic, and isotherm studies

BACKGROUND

Due to the high toxicity of chromium, particularly as Hexavalent chromium Cr (VI), it is removed from industrial effluents before their discharge into the environment by a variety of methods, including loading catalysts onto the polymeric supports. This study focused on the removal of Cr(VI) from aqueous solutions using Amberlite XAD7 resin loaded titanium dioxide (Ti-XAD7).

METHODS

Ti-XAD7 was synthesized using Amberlite XAD-7 impregnated with titanium tetraethoxide. The prepared Ti-XAD7 was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Isotherms and kinetic studies were carried out to describe the adsorption behavior of adsorbent for the removal of Cr(VI) ions. Quadratic models considering independent variables, i.e. the initial Cr(VI) concentration, adsorbent dosage, time, and pH, were evaluated and optimized to describe the behavior of Cr(VI) adsorption onto the Ti-XAD7 using RSM based on a Five-level-four-factor CCD approach.

RESULTS

The accuracy and the fitting of the model were evaluated by ANOVA with R² > 0.725 and P value = 5.221 × 10^-5. The optimum conditions for the adsorption process were an initial Cr(VI) concentration 2750 ppb, contact time of 51.53 min, pH of 8.7, and Ti-XAD7 dosage of 5.05 g/L. The results revealed that the Langmuir and Sips isotherm models with R² = 0.998 and 0.999 were the best models fitting the experimental data. The adsorption capacity of Ti-XAD7 and R_L constant were 2.73 mg/g and 0.063-0.076 based on the Langmuir isotherm, respectively. Kinetic studies also indicated that the adsorption behavior of Cr(VI) was acceptably explained by the Elovich kinetic model with a good fitting (R² = 0.97).

CONCLUSIONS

Comparison of the Ti-XAD7 and XAD7 yield in chromium adsorption showed that modified XAD7 had higher removal efficiency (about 98%) compared to XAD7 alone.

Monitoring and exposure assessment of nitrate intake via fruits and vegetables in high and low risk areas for gastric cancer

BACKGROUND

Gastric cancer (GC) is the first leading cause of cancer-related deaths in Iran. GC is a multifactorial disease and is caused by the interaction of genetic and environmental factors. The aim of this study was to assess the exposure and risk of nitrate intake through fruits and vegetables (F&V) in high-risk area (HRA) and low-risk area (LRA) of GC in Iran.

METHODS

Twenty nine species of F&V were examined for nitrate by reverse-phase HPLC (RP-HPLC) method. Food frequency questionnaire (FFQ) data of 2000 adults participating in Persian cohort were applied to determine consumption patterns of F&V in those areas. A point-estimate daily intake was applied to compare two areas in terms of nitrate intake. Monte-Carlo simulation technique was applied to estimate chronic daily intake (CDI) of nitrate.

RESULTS

The results showed that point-estimate daily intake of nitrate for subjects participated in the study was 2.02 ± 1.02 mg kg-1 day-1 in HRA and 1.98 ± 1.05 mg kg-1 day-1 in LRA. 6.53% of the participants in the HRA, and 5.9% of the participants in the LRA had an unacceptable point-estimate daily intake compared with an acceptable limit of 3.7 mg kg-1 day-1 established by FAO/WHO. CDI of nitrate in HRA was 1.94 ± 0.95 mg kg-1 day-1 and in the LRA was 1.93 ± 1.06 mg kg-1 day-1.

CONCLUSION

The results showed that there is no difference between HRA and LRA in terms of nitrate intake through F&V.

Environmental etiology of gastric cancer in Iran: a systematic review focusing on drinking water, soil, food, radiation, and geographical conditions

The aim of this systematic review study was to investigate the causal relationship between environmental factors and gastric cancer (GC) in Iran. In a narrow definition, the environment includes water, soil, air, and food. This definition was the main criterion for the inclusion of articles in this study. In addition, exposure to radiation and geographical conditions were considered as less investigated environmental factors in the literatures. International (PubMed, Web of Science, ScienceDirect, Scopus, and Cochran) and national (Scientific Information Database) databases were searched for articles on GC and environmental risk factors in Iran. Twenty-six articles were found to meet the inclusion criteria after title, abstract, and full text review. Risk factors identified for GC include consumption of red meat; high fat, fried, and salted meat; smoked, salted, and fried foods; some dairy products; roasted and fried seeds; strong and hot tea; and un-piped and unchlorinated drinking water, as well as exposure to radiation, loess sediment, soft and grassy soil, soil containing low concentration of molybdenum, and proximity to volcanos. Fresh fruits and vegetable, fresh fish, and honey consumption were recognized as protective agents. Given the risk factors identified, strategies to prevent GC would be educating people to choose a healthy diet and to cook and store food properly, providing access to safe drinking water, taking into account topographical and geographical conditions in choosing a right location to build residential areas, and regulating the use of radiation-emitting devices.

Environmental determinants of polycyclic aromatic hydrocarbons exposure at home, at kindergartens and during a commute

The aim of this study was to assess the potential health risk of exposure to polycyclic aromatic hydrocarbons (PAHs) at home and kindergarten for pre-school children. The urine samples were taken from 200 pre-school children aged 5-7 years and analyzed for 1-OHP as a biomarker of PAHs. Mixed effect models were applied to investigate the association between effective environmental parameters (mode of transport, distance to major roads, traffic density, greenness, tobacco exposure, home ventilation, and grill foods) and urinary 1-OHP levels. A Monte-Carlo simulation technique was applied to calculate the risk of exposure to PAHs and to check the uncertainty of input variables and the sensitivity of the estimated risk. The median and inter quartile range (IQR) of 1-OHP was 257 (188.5) ng L^-1. There was a positive significant association between distance from the kindergartens to the green space with surface area ≥5000 m² and 1-OHP concentration (β = 0.844, 95% CI: 0.223, 1.46, P-value = 0.009). Also, urinary 1-OHP was found to be inversely associated with the time the window was open at the home (β = -12.56, 95% CI: -23.52, -1.596, P-value = 0.025) and normalized difference vegetation index (NDVI) in a 100 m buffer around the homes. The mean (9.76 E-3) and 95th percentile (3.28 E-2) of the hazard quotient (HQ) indicated that the concentration of urinary 1-OHP is at a safe level for the target population (HQ < 1). According to the sensitivity analysis results, the concentration of 1-OHP is the most influential variable in the estimated risk. Our findings indicated that the proximity of homes and kindergartens to green space areas and their remoteness from the main streets and heavy traffic areas are associated with reduced exposure to PAHs.

Asthma disease as cause of admission to hospitals due to exposure to ambient oxidants in Mashhad, Iran

Nowadays, asthma is one of the most common chronic respiratory diseases, worldwide. Many reports have emphasized the correlation between the short-term exposure to the ambient air pollutants and acute respiratory diseases, especially among children with asthmatic symptoms. The aim of this study was to evaluate the relationship between the exposure to three atmospheric antioxidants (NO₂, SO₂, and O₃) and hospital admission due to asthmatic disease (HAAD) in the city of Mashhad, Iran. The concentrations of atmospheric antioxidants were obtained from the real-time monitoring stations located in the city. The collected data were employed for developing predictive models in the AirQ software. In order to investigate the association between short-term exposure to air pollutants and HAAD, the study participants were categorized into two age groups: less than 15 and from 15 to 64 years old. The results indicated that in people less than 15 years increase in NO₂ (attributable proportion (AP) = 3.775%, 95% CI 0.897-6.883%), SO₂ (AP = 3.649%, 95% CI 1.295-5.937%), and O₃ (AP = 0.554%,95% CI 0.00-3.321) results in increase in HAAD. While for those aged between 15 and 64 years, the AP was 4.192% (95% CI 0.450-7.662%) for NO₂; 0.0% (95% CI 0.00-1.687%) for SO₂; and 0.236% (95% CI 0.00-1.216%) for O₃. The number of asthmatic cases who were less than 15 years admitted to the hospitals during the study period was higher than that of those within the age groups between 15 and 64 years as a consequence of exposure to NO₂ (101 vs. 75), SO₂ (98 vs. 0), and O₃ (15 vs. 3), respectively. To the best of our knowledge, the AirQ model has not been applied before to estimate the effect of atmospheric antioxidant exposure on hospital admission because of asthma disease. Eventually, this model is proposed to be applicable for other cities around the world.

A time series analysis of environmental and metrological factors impact on cutaneous leishmaniasis incidence in an endemic area of Dehloran, Iran

The aim of this study was to investigate the relationship between the environmental and metrological variables and cutaneous leishmaniasis (CL) transmission and its prediction in a region susceptible to this disease prevalence using a time series model. The accurate locations of 4437 CL diagnosed from 2011 to 2015 were obtained to be used in the time series model. Temperature, number of days with temperature over 30 °C, and number of earthquake were related to CL incidence using the Seasonal Auto-correlated Integrated Moving Average (SARIMA) model according to the Box-Jenkins method. In addition, the relationship between land use and surface soil type in 500- and 1000-m radius around the CL patients were investigated. The SARIMA models showed significant associations between environmental and meteorological variables and CL incidence adjusted for seasonality and auto-correlation. The result indicated that there are need more robust preventive programs in earthquake-prone areas with high temperature and inceptisol soil type than other areas. In addition, the region with these characteristics should be considered as high-risk areas for CL prevalence.

A comparative study of anaerobic fixed film baffled reactor and up-flow anaerobic fixed film fixed bed reactor for biological removal of diethyl phthalate from wastewater: a performance, kinetic, biogas, and metabolic pathway study

BACKGROUND

Phthalic acid esters, including diethyl phthalate (DEP), which are considered as top-priority and hazardous pollutants, have received significant attention over the last decades. It is vital for industries to select the best treatment technology, especially when the DEP concentration in wastewater is high. Meanwhile, anaerobic biofilm-based reactors are considered as a promising option. Therefore, in the present study, for the biological removal of DEP from synthetic wastewater, two different anaerobic biofilm-based reactors, including anaerobic fixed film baffled reactor (AnFFBR) and up-flow anaerobic fixed film fixed bed reactor (UAnFFFBR), were compared from kinetic and performance standpoints. As in the previous studies, only the kinetic coefficients have been calculated and the relationship between kinetic coefficients and their interpretation has not been evaluated, the other aim of the present study was to fill this research gap.

RESULTS

In optimum conditions, 90.31 and 86.91% of COD as well as 91.11 and 88.72% of DEP removal were achieved for the AnFFBR and UAnFFFBR, respectively. According to kinetic coefficients (except biomass yield), the AnFFBR had better performance as it provided a more favorable condition for microbial growth. The Grau model was selected as the best mathematical model for designing and predicting the bioreactors' performance due to its high coefficients of determination (0.97 < R²). With regard to the insignificant variations of the calculated Grau kinetic coefficients (K_G) when the organic loading rate (with constant HRT) increased, it can be concluded that both of the bioreactors can tolerate high organic loading rate and their performance is not affected by the applied DEP concentrations.

CONCLUSIONS

Both the bioreactors were capable of treating low-to-high strength DEP wastewater; however, according to the experimental results and obtained kinetic coefficients, the AnFFBR indicated higher performance. Although the AnFFBR can be considered as a safer treatment option than the UAnFFFBR due to its lower DEP concentrations in sludge, the UAnFFFBR had lower VSS/TSS ratio and sludge yield, which could make it more practical for digestion. Finally, both the bioreactors showed considerable methane yield; however, compared to the UAnFFFBR, the AnFFBR had more potential for bioenergy production. Although both the selected bioreactors achieved nearly 90% of DEP removal, they can only be considered as pre-treatment methods according to the standard regulations and should be coupled with further technology.

A comparative study on capability of different tree species in accumulating heavy metals from soil and ambient air

Heavy metals (HMs) in the urban environment can be bio-accumulated by plant tissues. The aim of this study was to compare fourteen different tree species in terms of their capability to accumulate four airborne and soilborne HMs including; zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd). Samplings were performed during spring, summer, and fall seasons. To compare bioaccumulation ability, bio-concentration factor (BCF), comprehensive bio-concentration index (CBCI), and metal accumulation index (MAI) were applied. Species with the highest accumulation for single metal which shown using BCF did not have the highest CBCI and MAI. Based on CBCI and MAI, Pinus eldarica (7.74), Wistaria sinensis (8.82), Morus alba (8.7), and Nigral morus (27.15) had the highest bioaccumulation capacity of HMs, respectively. Therefore, these species can be used for phytoextraction of HMs pollution and green and buffer zone in the urban.

Investigation of outdoor BTEX: Concentration, variations, sources, spatial distribution, and risk assessment

The aim of this study was to measure BTEX (benzene, toluene, ethylbenzene, and xylenes) concentrations in the ambient air of Tehran, the capital of Iran, and investigate their seasonal variations, probable sources, spatial mapping, and risk assessment. The concentrations of BTEX were measured using a continuous monitoring device installed in seven stations around the city. Spatial mapping procedure was conducted using the inverse distance weighting (IDW) method. Monte Carlo simulation was used to assess the carcinogenic and noncarcinogenic risks imposed by BTEX. The highest and lowest annual mean concentrations of toluene and ethylbenzene were recorded as 16.25 and 3.63 μg m(-3), respectively. The maximum (6.434) and minimum (3.209) toluene/benzene (T/B) ratio was observed in summer and winter, respectively. The spatial distribution of BTEX pollution indicated that the highest concentrations were found along the major roads because of heavy traffic. Spearman's rank correlation coefficients and concentration ratios showed that BTEX were produced by the multiemission sources. The mean of inhalation lifetime cancer risk (LTCR) for benzene was 3.93 × 10(-7), which is lower than the limits recommended by the United States Environmental Protection Agency (US EPA) and the World Health Organization (WHO). The hazard quotient (HQ), noncarcinogenic risk index, for all BTEX compounds was <1. The obtained results showed no threat of BTEX concentrations to human health. However, as the concentrations of BTEX will increase due to the rapid growth of vehicles and industrial activities, much effort is required to control and manage the levels of these compounds in the future.

Cutaneous leishmaniasis prevalence and morbidity based on environmental factors in Ilam, Iran: Spatial analysis and land use regression models

The aim of this study was to investigate the impact of the environmental factors on cutaneous leishmaniasis (CL) prevalence and morbidity in Ilam province, western Iran, as a known endemic area for this disease. Accurate locations of 3237 CL patients diagnosed from 2013 to 2015, their demographic information, and data of 17 potentially predictive environmental variables (PPEVs) were prepared to be used in Geographic Information System (GIS) and Land-Use Regression (LUR) analysis. The prevalence, risk, and predictive risk maps were provided using Inverse Distance Weighting (IDW) model in GIS software. Regression analysis was used to determine how environmental variables affect on CL prevalence. All maps and regression models were developed based on the annual and three-year average of the CL prevalence. The results showed that there was statistically significant relationship (P value≤0.05) between CL prevalence and 11 (64%) PPEVs which were elevation, population, rainfall, temperature, urban land use, poorland, dry farming, inceptisol and aridisol soils, and forest and irrigated lands. The highest probability of the CL prevalence was predicted in the west of the study area and frontier with Iraq. An inverse relationship was found between CL prevalence and environmental factors, including elevation, covering soil, rainfall, agricultural irrigation, and elevation while this relation was positive for temperature, urban land use, and population density. Environmental factors were found to be an important predictive variables for CL prevalence and should be considered in management strategies for CL control.

Ecological risk assessment of heavy metal (HM) pollution in the ambient air using a new bio-indicator

The aim of this descriptive-analytical study was to measure the concentration of heavy metals (HMs) in the leaf and bark of Ulmus carpinifolia as new biological indicators, and the ecological risk assessment of these metals in the ambient air. To achieve these goals, 48 sampling locations were selected in the city and concentration of four HMs-zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)-was measured in the mentioned indicator using atomic absorption spectroscopy method. After this, ecological risk assessment, source appointment, and spatial distribution were conducted. In this regard, the enrichment factor (EF), potential ecological risk factor (E r), potential ecological risk index (RI), correlation coefficient (r), and other indices were calculated. The results showed that the concentration of HMs in the leaf and bark in ascending order is as Cd<Cu<Pb<Zn and Cd<Pb<Cu<Zn, respectively. The EF results indicated that the main origin of all measured HMs except Zn is anthropogenic sources. Also, the principal component analysis (PCA) and spatial distribution proved that the concentration of HMs is mainly originated from the traffic and other human activities. On the other hand, the results RI presented that the majority of locations sampled in the study area was exposed to serious ecological risk in terms of surveyed HMs. The leaf and bark of U. carpinifolia can be applied as bio-indicators of the presence of heavy metals in the ambient air and ecological risk imposed by them.