Dengue virus and the 2024 Paris Olympics.

The 2024 Paris Olympics and Paralympics face concerns over dengue virus transmission, despite Paris's lower mosquito activity. Preventive measures include eliminating breeding sites, insecticide spraying, and public awareness. Health systems will monitor and respond to cases. Large gatherings like the Olympics can amplify disease spread, as seen with Zika in Rio 2016. Recent reports confirm dengue presence in Europe, highlighting global risks. While Paris's overall dengue risk is low, even a few cases could impact global health. Collaboration among health authorities, researchers, and event organizers is crucial to ensure participant and public safety during the games.

From the Rio 2016 Olympics to the Paris 2024 Olympics: Is there a risk of Dengue disease?

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How Complete Are Tobacco Sales Data? Assessing The Comprehensiveness Of US Tobacco Product Retail Sales Data Through Comparisons To Excise Tax Collections.

INTRODUCTION: Sales data analyses are increasingly used to guide tobacco regulatory science. However, such data do not cover specialist retailers like vape shops or tobacconists. Understanding the extent of the cigarette and electronic nicotine delivery system (ENDS) markets covered by sales data is critical to establishing such analyses' generalizability and potential biases. METHODS: Using retail sales data from Information Resources Incorporated (IRI) and Nielsen, we conduct tax gap analyses comparing states' cigarette and ENDS tax revenue to tax collection estimates based on retail sales data. For the 23 US states in both retail sales datasets, cigarette tax gap analyses were conducted for each year from 2018-2020. Four (Louisiana, North Carolina, Ohio, and Washington) of those 23 states levied per unit ENDS taxes and provided monthly tax revenue data covering January 2018 - October 2021, where we conducted monthly tax gap analyses for both cigarettes and ENDS. RESULTS: Across states covered by both sales datasets, annual mean cigarette sales in IRI and Nielsen account for 92.3% (95% CI 88.3-96.2%) and 84.0% (95% CI 79.3-88.7%) of state cigarette tax revenue, respectively. Monthly average coverage rates for ENDS sales were lower, ranging from 42.3% to 86.1% for IRI and 43.6% to 88.5% for Nielsen, but remained stable over time. CONCLUSIONS: IRI and Nielsen sales data capture almost the entire US cigarette market and a substantial but lower portion of the US ENDS market. With proper care to address shortcomings, sales data analyses can capture changes in the US market for these tobacco products. IMPLICATIONS: Policy evaluations and analyses using e-cigarette and cigarette sales data are often criticized because these data do not cover online sales or sales by specialty retailers like tobacconists.Cigarette sales data consistently cover nearly 90% of taxed sales, while e-cigarette sales data cover around 50% of taxed volumes.Retail sales data capture nearly all cigarette sales and a substantial portion of ENDS sales with relatively stable rates of coverage over time, supporting their continued use in tobacco surveillance and policy evaluation work.

BTEX in Ambient Air of Zarand, the Industrial City in Southeast of Iran: Concentration, Spatio-temporal Variation and Health Risk Assessment.

The existence of several industries in Zarand, a city in Southeastern Iran, caused challenges for the residents about air pollutants and associated health effects. In the present study, the concentration of benzene, toluene, ethylbenzene, and xylene (BTEX), spatio-temporal distribution and related health risks were evaluated. Passive samplers were used to collect 30 samples in the over the hot and cold periods in 2020. The ordinary Kriging method was used to predict the spatio-temporal distribution of BTEXs. Also, the Monte Carlo simulation was used to evaluate the related carcinogenic and non-carcinogenic risks of BTEX for adults. The ranking of mean concentration of overall toluene, xylene, ethylbenzene, and benzene followed as 82.49 ± 26.86, 30.91 ± 14.04, 4.75 ± 3.28, and 0.91 ± 0.18 µg/m3, respectively. The mean value of lifetime carcinogenic risk (LTCR) for residents related to benzene was 7.52 × 10- 6, indicating a negligible carcinogenic risk for them. Furthermore, the ranking of non-carcinogenic risk calculated through hazard quotient (HQ) for investigated BTEX compounds followed as xylene > benzene > toluene > ethylbenzene over the hot period and xylene > toluene > ethylbenzene over the cold period which all points had HQ < 1. Additionally, according to the findings of the sensitivity analysis, the concentration of benzene was the main contributor in increasing the carcinogenic risk. According to our results, it can be stated that the existence of several industries in the study area could not possibly occur the significant carcinogenic and non-carcinogenic risks to the adults residents in the study period. Human studies are recommended to determine definite results.

Preparation of Folic acid@Arsenic nanoparticles and evaluation of their antioxidant properties and cytotoxic effects.

In this study, arsenic nanoparticles containing folic acid (FA@As NPs) were synthesized by microwave irradiating a mixture of As2O3 and sodium borohydride solution in the presence of folic acid. The physicochemical characteristics of the prepared NPs were studied by UV-visible spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. Antioxidant activities, hemocompatibility, and cytotoxic effects of the prepared NPs were then evaluated. The attained results showed that the hexagonal FA@As NPs have a size range between 12.8 nm and 19.5 nm. The DPPH scavenging activity of FA@As NPs was found to be significantly greater than that of As NPs at concentrations ranging from 40 µg/mL to 2560 µg/mL (p<0.05). The hemolytic test confirmed that the measured hemolysis percentage (HP) for FA@As NPs and As NPs was 0% at concentrations between 20 to160 µg/mL, and for FA@As NPs, the measured HP was not significantly higher than As NPs at concentrations higher than 320 µg/mL (p>0.05). The necessary concentration for the death of half of the cells (IC50) for MDA-MB-231, MCF-7, and HUVEC cells treated (24 h) with FA@As NPs was measured to be 19.1±1.3 µg/mL, 15.4±1.1 µg/mL, and 16.8±1.2 µg/mL, respectively. However, further investigations are necessary to clarify the mechanisms behind the biological activities of FA@As NPs.

Human exposure to pesticides and thyroid cancer: a worldwide systematic review of the literatures.

Thyroid cancer is considered as one of the most prevalent cancers in the world. Some pesticides can play a role as a potentially important risk factor in thyroid cancer by affecting thyroid morphology and thyroid hormone homeostasis. The aim of present study was to systematically review the available epidemiological evidence for human exposure to pesticides and thyroid cancer. Articles were searched in PubMed, Scopus and Web of Science by suitable keywords from January 2000 to May 2021. Standard techniques for systematic reviews were followed in the current study and results reported according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Based on the inclusion and exclusion criteria, finally seven studies including four cohort studies and three case-control studies were reviewed. Organochlorines (OCPs) in more cases, Organophosphates (OPs) and Carbamates insecticides, herbicides and fungicides were the studied pesticides. Inconsistent results were reported in the surveyed articles on the OCPs. Two articles on the Carbamates (Carbaryl and Mancozeb) showed consistently an inverse association between exposure and thyroid cancer. Increased risk of thyroid cancer due to the exposure to the Malathion was reported in one article on the OPs. Due to the limited current knowledge about the effect of pesticides on thyroid cancer in humans, human health policies must be implemented to control individual's exposure to chemicals through using of botanical pesticides in agricultural. Also, more studies must be done to fill this gap of knowledge.

HOW COMPLETE ARE TOBACCO SALES DATA? ASSESSING THE COMPREHENSIVENESS OF TOBACCO PRODUCT RETAIL SALES DATA THROUGH COMPARISONS TO EXCISE TAX COLLECTIONS.

Introduction: Sales data analyses are increasingly used to guide tobacco regulatory science. However, such data do not cover specialist retailers like vape shops or tobacconists. Understanding the extent of the cigarette and electronic nicotine delivery system (ENDS) markets covered by sales data is critical to establishing such analyses' generalizability and potential biases. Methods: Sales data from Information Resources Incorporated (IRI) and Nielsen Retail Scanner data are used to conduct a tax gap analysis, comparing state tax collections based on cigarette and ENDS sales data to states' annual 2018-2020 cigarette tax collections and monthly ENDS and cigarette tax revenue data for January 2018 to October 2021. Cigarette analyses consider the 23 US states covered by both IRI and Nielsen. ENDS analyses consider the subset of those states with per unit ENDS taxes: Louisiana, North Carolina, Ohio, and Washington. Results: Across states covered by both sales datasets, IRI's mean cigarette sales coverage was 92.3% (95% CI 88.3-96.2%), while Nielsen's was 84.0% (95% CI 79.3-88.7%). Coverage rates for average ENDS sales were lower, ranging from 42.3% to 86.1% for IRI and 43.6% to 88.5% for Nielsen, but remained stable over time. Conclusions: IRI and Nielsen sales data capture almost the entire US cigarette market and, while coverage rates are lower, a substantial portion of the US market for ENDS as well. Coverage rates are relatively stable over time. Thus, with proper care to address shortcomings, sales data analyses can capture changes in the US market for these tobacco products.

Erectile dysfunction from mechanisms to medicines with a focus on the application of topical Minoxidil.

INTRODUCTION: Erectile dysfunction (ED), for multifactorial reasons, is one of the biggest current quandaries among men worldwide and results in other complications such as reduced quality of life of the patient and his sexual partner, impotence, and psychiatric problems. OBJECTIVES: Understanding of disease etiology, penile anatomy, erectile physiology, therapeutic mechanisms, and effective molecular pathways all play key roles in determining a therapeutic approach. This project is based on the study of topical minoxidil's effectiveness in treating ED. METHODS: To perform a comprehensive overview of the subject, we performed a triple-keyword combination search to assess recent studies of ED. RESULTS: The most common formulation used in these studies was 2% minoxidil solution. Except for cases studied in paralytic patients, topical treatment with minoxidil appears to elicit a mild erectile response; however, this finding is insufficient to confirm the effectiveness of this topical treatment. CONCLUSIONS: Although evidence to confirm the therapeutic properties of minoxidil in ED is limited, combination therapy and the use of modern formulations of minoxidil are promising options for treating ED in the future.

Investigation of health and ecological risk attributed to the soil heavy metals in Iran: Systematic review and meta-analysis.

The presence of heavy metals (HMs) in the soil can pose risks to human health via ingestion and dermal absorption. This systematic review and meta-analysis study focused on both of health and ecological risks attributed to the six HMs (As, Cd, Cr, Cu, Pb, Zn) in the soil of different Provinces of Iran. Articles were selected in the Web of Science and Scopus from 2000 to August 2021. The study was carried out according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline. Based on the inclusion and exclusion criteria, finally 32 studies were reviewed which the ranking of mean concentrations of the studied metals followed as: As > Zn > Cr > Pb > Cu > Cd. Mean concentration of Cd and As calculated via meta-analysis in the studied Provinces was found to be more than Iran's environment protection agency (EPA) guideline values. Other HMs met guideline values. A significant non-carcinogenic risk attributed to the As found in Kurdistan Province (hazard index, HI > 1). Furthermore, a significant carcinogenic health risk was found in Kurdistan and West Azerbaijan associated to As and in Fars, Khozestan and Khorasan-e-Razavi Provinces associated to Cd (ELCR >10-4). Concerning the impact on the ecosystem, Cd, As and Pb caused ecological risks in some areas of Iran (ecological risk, ER > 40 and potential ecological risk, PER >150). Hence, we can conclude that Cd and As are important heavy metals from the health aspect. Moreover, Cd, As and Pb must be considered from an ecological point of view. Therefore, control of the Cd, As and Pb release in the environment and remediation of polluted sites through novel approaches is recommended.

Investigation of SARS-CoV-2 Genome in the Indoor Air and High-Touch Surfaces.

This study aimed to investigate the presence/absence of SARS-CoV-2 genome in the air and high-touch surfaces. This cross-sectional study was conducted from late-2020 to mid-2021 in the sections of Intensive Care Unit (ICU), emergency, infectious disease ward, and nursing station of the COVID-19 patient reception center in Kerman, Iran. The presence/absence of SARS-CoV-2 genome in the 60 samples of high-touch surfaces and 23 air samples was analyzed by reverse transcription polymerase chain reaction (RT-PCR). Fisher's exact test was used to compare the number of positive samples in different sampling sites. The genome of SARS-CoV-2 was found in the eight samples (13.32%) taken from the high-touch surfaces (two samples in COVID-19 ICU, two samples in general ICU, two samples in emergency ward, and two samples in nursing station) and two air samples (8.70%) (one sample in the general ICU and one sample in the emergency ward). Statistical analysis showed that there was no significant difference between the type of sampling site and the positive cases of SARS-CoV-2 in the surface samples (p value = 0.80) and air samples (p value = 0.22). According to the results, the SARS-CoV-2 can find in the high-touch surfaces and indoor air of the COVID-19 patient reception centers. Therefore, suitable safety and health measures should be taken, including regular and accurate disinfection of surfaces and equipment and proper ventilation to protect healthcare workers and prevent disease transmission. More studies are recommended to investigate the SARS-CoV-2 concentration in the high-touch surfaces and air samples in the similar researches, efficacy of different disinfectants used on the high-touch surfaces and compare the effect of type of ventilation (natural or mechanical) on the viral load.

Status of TNF-α and IL-6 as pro-inflammatory cytokines in exhaled breath condensate of late adolescents with asthma and healthy in the dust storm and non-dust storm conditions.

Exposure to airborne particulate matter (PM) can be considered as an important risk factor for human health. Some cytokines have been recognized as the biomarkers of exposure to air pollution. Experimental studies indicate that PM exposure could be associated with inflammation. Thus, the purpose of this study was to evaluate whether the exposure to air PM is associated with biomarkers of inflammation. The specific aim of this study was to determine the correlation between airborne PM levels and IL-6 and TNF-α as airway inflammation biomarkers among two groups of late adolescents in northwest of Iran. This study included 46 subjects, comprising 23 asthmatic subjects and 23 non-asthmatic persons. Environmental PM (PM10, PM2.5 and PM1) levels were measured in dust storm and non-dust storm days during both cold and warm seasons. Following the sampling of PM, Two pro-inflammatory cytokines of IL-6 and TNF-α in exhaled breath condensate (EBC) were also determined in the EBC samples via commercial ELISA kits. Daily mean ambient air PM10, PM2.5 and PM1 concentrations during the dust storm days was 221.79, 93.13 and 25.52 µg m-3 and in non-dusty days 48.37, 18.54 and 6.1 µg m-3, respectively. Biomarkers levels were significantly (p < 0.001) higher in asthmatic students compared to the non-asthmatic subjects. EBC cytokines levels were increased in dust storm days compared to the non-dusty days (p < 0.001) and were positively correlated with different size of ambient PM concentration. Dust storm conditions can increase the pro-inflammatory cytokines and cause adverse effects on pulmonary health and lung tissue damage.

Ecological and Probabilistic Health Risk Assessment of Heavy Metals in Topsoils, Southeast of Iran.

This study aimed to assess ecological and health risk of heavy metals (HMs) in the 35 topsoils in southeastern Iran. Ecological and health risks were assessed based on the EPA method. The order of the HMs followed as: Zn > Cr>Cu>Pb>As>Cd. All samples, except As and Cu, had the moderate enrichment and low to moderate pollution, respectively. The As in both regions and Cu in the city was classified in the lack to minimal enrichment and no pollution category. The studied HMs in both regions were shown a low ecological risk. There was minimal possibility of adverse non-carcinogenic effects. The Cr and As had an acceptable or tolerable carcinogenic risk from ingestion route (ELCRing) in both regions. According to the important role of As, Cd and Cr from the aspect of ecological and health risk, control of their sources must be considered to attenuate ecological and human adverse effets in the studied areas.

Correlation between heavy metal concentration and oxidative potential of street dust.

The current study aimed to consider oxidative potential (OP), its spatial distribution, and correlations with heavy metals (HMs) in street dust in Kerman city, Iran. The concentration of HMs in 35 street dust samples was detected by ICP-AES. The OP in samples was measured through dithiothreitol (DTT). The mean concentration of elements followed Zn > Cu > Pb > Cr > As > Cd. The OP value was found to be 7.17 ± 2.98 nmol/min. µg dust in the current study. A strong correlation was observed among the concentrations of As and Cr and OP values in dust samples. More values of OP were observed in the center and west of the Kerman city. According to results of the current study, it could be concluded that OP can be applied as metrics of pollution originated from different sources and human health effects. The amount of OP in the street dust in the Kerman city can be reduced through the use of clean fuels.

Exposure to road noise and asthma prevalence in adults.

Noise has been reported as one of the most important risk factors for asthma, but there are some disagreements. This study aimed to investigate the effect of road noise on asthma prevalence in adults. In the current study, 3172 adults were interviewed through the ECRHS standardized questionnaire in Tehran, the capital of Iran. Exposure to road noise was assessed considering distance of individual participants from the noise monitoring stations via the spatial analysis in GIS software. Logistic regression was used to assess the effect of noise on the symptoms of asthma. Findings showed a significant positive association between wheezing with dyspnea as the best marker for asthma and noise levels at daytime (OR 1.03; 0.98-1.05) and nighttime (OR 1.05; 0.84-1.09). Also, a significant positive association was obtained between daytime and nighttime noise levels and other asthma symptoms including wheezing, nocturnal chest tightness, nocturnal dyspnea, wheezing without cold, nocturnal cough, and asthma medication. Association between current asthma and noise level was not significant. There was a significant association between population age and current asthma prevalence (P = 0.001). Therefore, chronic exposure to road noise especially in the nighttime could increase asthma prevalence. So, control of noise sources can be suggested to diminish asthma in adults.

Probabilistic risk assessment of soil contamination related to agricultural and industrial activities.

Soil contamination related to industrial and agricultural activities were associated with many adverse health effects and climate change could exacerbate this effect. However, the evidence on this topic in low and middle-income countries (LMICs) is still scarce. We, therefore, aimed to investigate the heavy metals (HMs) concentrations in topsoil around Lake Urmia (which dried about 50 % of it in recent years). Accordingly, 96 surface soil samples were collected from an area of about 4000 km2 in 2019. An inductively coupled plasma-atomic emission spectrometry (ICP-AES) was used to measure the HMs concentrations, including cadmium (Cd), arsenic (As), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb) and zinc (Zn). Health risk assessment of exposure to HMs was performed using Monte Carlo simulations technique. The mean concentrations of Zn, Cu, Ni, Co, Pb, Cr, As and Cd were 68.66, 35, 31.66, 15, 14.4, 11.2, 7.04, and 0.26 mg/kg, respectively, which was in the allowable range of USEPA guideline. The mean enrichment factor (EF) values for Zn, Cd, Cu, Cr, Ni, Pb, Co and As were1.3, 1.9, 1, 1.2, 1.7, 2.8, 1.8 and 2, respectively. Carcinogenic risks of exposure to HMs for inhalation, dermal and ingestion exposure pathways were at safe level. Similarly, the hazard index (HI) was at safe level (HI < 1). The sensitivity analysis indicated that the exposure duration (ED) for As, exposure frequency (EF) for Cd and Ni, concentration (Csoi) for Cr and Pb had the highest impact on ELCR values. Our finding confirmed that HMs concentrations around Lake Urmia had no health risk for inhabitants.

Effect of titanium dioxide nanoparticles on DNA methylation of human peripheral blood mononuclear cells.

The aim of the current study was to investigate the effect of well-characterized TiO2 nanoparticles on DNA methylation of peripheral blood mononuclear cells (PBMCs) in vitro. Maximum non-toxic concentration of nanoparticles for PBMCs was determined by MTT assay. The effect of TiO2 nanoparticles at concentrations of 25-100 µg/ml on DNA methylation of PBMCs was investigated by measuring the %5-mC alterations through an ELISA assay. The physicochemical analysis showed that the TiO2 nanoparticles were crystalline, pure and in the anatase phase. Peaks related to Ti-O tensile vibrations were observed in the range of 1510 cm-1. The size of nanoparticles was in the range of 39-74 nm with an average hydrodynamic diameter of 43.82 nm. According to the results of the MTT test, 100 µg/ml was found to be maximum non-toxic concentration. The %5-mC in treated PBMCs revealed that TiO2 nanoparticles could lead to DNA hypomethylation in PBMCs. The %5-mC difference compared with the negative control was found to be 2.07 ± 1.02% (P = 0.03). The difference of %5-mC between the 25 and 100 µg/ml concentration of nanoparticles was statistically significant (P = 0.02). The results of the current study show that the TiO2 nanoparticles cause DNA hypomethylation in PBMCs in a dose-response manner. Therefore, it is recommended to evaluate the effects of cytotoxicity and epigenotoxicity of commonly used nanoparticles before their use.

Estimating greenhouse emissions from sanitary landfills using Land-GEM and IPCC model based on realistic scenarios of different urban areas: a case study of Iran.

This study examined the emission of greenhouse gases from municipal solid waste disposal centers in different regions of Iran based on different scenarios. Assuming landfill site opening in 2012 and considering the 20-year plan period for its usage, the amount of wastes entering the landfill site was calculated for 2012-2032. For calculating the production of methane (CH4) and other gases during different years of the project, Land-GEM and IPCC model were used. We defined 9 scenarios for these two models based on the growth rate of population and waste generation. The results revealed that the lowest amount of gas emission in nine scenarios by Land- GEM model was related to non-methane organic compounds (NMOCs). According to the results obtained, the total emissions of greenhouse gases from sanitary landfills for Iran in 2032 were 3,844,000 Mg/year, the largest and lowest amounts of gas emission were related to Tehran region, 860,400 Mg/year, and the South Coast area of the country,138,200 Mg/year, respectively. The major section of the gas production in both landfills was related to greenhouse gas and carbon dioxide emissions. The difference in gas production in the studied regions was due to differences in the percentage of moisture and organic compounds.

Spatial distribution and correlations among elements in smaller than 75 µm street dust: ecological and probabilistic health risk assessment.

This study aimed to investigate spatial distribution, correlations among elements and ecological and probabilistic health risk assessment in smaller than 75 µm street dust in Kerman city, Iran. Street dust samples were collected from 35 different points. Elements were detected by ICP-AES. Pollution degree was characterized through Enrichment Factor (EF), Contamination Factor (CF), Geo-accumulation Index (Igeo) and Potential Ecological Risk (PER). The health risk was assessed using the Monte Carlo simulation method. The mean values of elements were in the order of Al > Mn > Zn > Cu > V > Pb > Cr > Ni > Li > As > Co > Mo > Sb > Cd > Ag. The results of Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) showed that Al, As, Co, Li, Mn and V were possibly derived from natural sources (local soil), while traffic and mining activities were proposed as the main source of Cd, Cr, Cu, Mo, Ni, Pb, Sb and Zn. The order of EF and CF mean values decreased as follows: Mn > Ag > Cu > Zn > Pb > Sb > Mo > Li > Co > V > Cd > As > Cr > Ni. In addition, 73% of Cu and 35% of Zn, Ag and Mn had significant enrichment in the street dust samples. Also, Ag and Mn were categorized in the significant and very significant pollution category. In terms of the PER index, all samples could be classified at low-risk category. Ingestion of street dust was the significant route for exposure of residents of Kerman to the elements studied. No significant ecological hazards and health risks were observed from street dust in the study area in the period of the study. The improvement in the fuels quality and development of green spaces can be suggested to control natural and anthropogenic street dust pollution sources in the Kerman city.

Comparing THMs level in old and new water distribution systems; seasonal variation and probabilistic risk assessment.

Trihalomethanes (THMs) in drinking water are associated with many chemical parameters in water. However, the available evidence on the relationship between physical parameters of the water distribution system (WDS) and THMs is still scarce; therefore, this study aimed to compare the THMs concentration in the old and new WDS in Yazd, Iran. Moreover, we investigated the seasonal trend and health risk assessment of exposure to THMs through ingestion, dermal, and inhalation pathways. Mann-Whitney test was applied to compare THMs between old and new WDS as well as fall season and winter season. The order of THM concentrations was: chloroform > BDCM > DBCM > bromoform. The maximum levels of THMs in the fall and winter were 31 and 39 ppb, respectively, which were less than the WHO recommended limits for drinking water, i.e., <200 ppb. There was a significant difference between the concentration of BDCM in autumn and winter (P-value = 0.01). There was a marginally significant difference between THM concentration in the autumn and winter (P-value 0.09). The total concentration of THMs and chloroform in the old WDS were significantly higher than the new WDS. The mean values of lifetime cancer risks (LTCR) for oral, dermal, and inhalation exposure pathways to THMs were in the acceptable and low-risk levels. The inhalation exposure pathway had the highest LTCR from among the three mentioned exposure pathways. The hazard index was found to be < 1 through oral and dermal pathways. Moreover, the sensitivity analysis revealed that the ingestion rate for oral exposure, the exposure time for dermal and exposure duration for the inhalation exposure pathway had the highest impact on chronic daily intake (CDI). Our finding confirmed that THM concentration in tap water was associated with the lifespan of WDS and this finding could be useful for urban planners and decision-makers.

Spatial analysis and risk assessment of urban BTEX compounds in Urmia, Iran.

Land Use Regression models (LUR) are the most common tools to estimate intra-urban air pollutant exposure in epidemiological studies. However, number of available and published models in developing and middle up income countries is still scarce. Here, we developed seasonal and overall LUR models for the spatial distribution of benzene, toluene, ethylbenzene and xylene (BTEX) based on 20 monitoring stations and 166 potentially predictive variables (PPVs) in Urmia, Iran. Carcinogenic and non-carcinogenic risks of exposure to BTEX and its sensitivity analysis were assessed using a probabilistic approach. The mean and standard deviation (in brackets) of overall benzene, toluene, ethylbenzene and xylene were 12.83 (16.19), 27.03 (32.00), 4.72 (4.15) and 27.35 (29.36) µg/m3, respectively. In all models the R2 value of LUR models of benzene, toluene, ethylbenzene, xylene and total BTEX ranged from 0.66 to 0.85, 0.61, 0.88, 0.72 to 0.94, 0.75 to 0.84 and 0.67 to 0.93. The root mean square error (RMSE) for leave-one-out cross-validations (LOOCV) for benzene, toluene, ethylbenzene and xylene ranged from 7.48 to 10.31, 23.0 to 30.0, 3.40 to 6.90, 16.27 to 24.49, 36.10-50.0 µg/m3, respectively. The estimated lifetime carcinogenic risk (LTCR) indicated that ambient concentration of benzene is at a risk level for Urmia inhabitants (LTCR >10-6). Sensitivity analysis for LTCR model indicated that concentration of benzene (C) was the most effective variable in increasing the carcinogenic risk (correlation coefficient ranged from 0.97 to 0.98 for all models).