Assessing the carcinogenic and non-carcinogenic health risks of metals in the drinking water of Isfahan, Iran.

Metals are significant contributors to water pollution, posing serious threats to human health. This study aims to assess the carcinogenic and non-carcinogenic health risks associated with metals in Isfahan drinking water. Eighty water samples were randomly collected from the city's distribution network between January and March 2020-2021. Inductively coupled plasma Optical Emission Spectrometry was used to measure toxic metals, namely Pb, Cr, Cd, Ni, and As concentrations. Results revealed that the mean concentration of Ni (70.03 µg/L) exceeded the WHO reference value (70 µg/L), while the other metals were below the standard values. The average chronic daily intake order of toxic metals was Ni > Cr > Pb > As > Cd. Non-carcinogenic risk assessment through hazard quotient (HQ) and hazard index (HI) demonstrated that both THI for adults (HQingestion + HQdermal = 4.02E-03) and THI for children (HIingestion + HIdermal = 3.83E-03) were below the acceptable limit (less than 1). This indicated no non-carcinogenic risk to residents through water ingestion or dermal exposure. However, findings indicated that the ingestion route was the primary exposure pathway, with HQ values for ingestion exceeding HQ values for dermal adsorption. Carcinogenic risk assessment showed that the risk associated with As metal exceeded the acceptable limit (1 × 10-6). Therefore, implementing treatment improvement programs and appropriate control measures is essential to safeguard the health of Isfahan City residents.

Prediction of atmospheric PM2.5 level by machine learning techniques in Isfahan, Iran.

With increasing levels of air pollution, air quality prediction has attracted more attention. Mathematical models are being developed by researchers to achieve precise predictions. Monitoring and prediction of atmospheric PM2.5 levels, as a predominant pollutant, is essential in emission mitigation programs. In this study, meteorological datasets from 9 years in Isfahan city, a large metropolis of Iran, were applied to predict the PM2.5 levels, using four machine learning algorithms including Artificial Neural |Networks (ANNs), K-Nearest-Neighbors (KNN), Support Vector |Machines (SVMs) and ensembles of classification trees Random Forest (RF). The data from 7 air quality monitoring stations located in Isfahan City were taken into consideration. The Confusion Matrix and Cross-Entropy Loss were used to analyze the performance of classification models. Several parameters, including sensitivity, specificity, accuracy, F1 score, precision, and the area under the curve (AUC), are computed to assess model performance. Finally, by introducing the predicted data for 2020 into ArcGIS software and using the IDW (Inverse Distance Weighting) method, interpolation was conducted for the area of Isfahan city and the pollution map was illustrated for each month of the year. The results showed that, based on the accuracy percentage, the ANN model has a better performance (90.1%) in predicting PM2.5 grades compared to the other models for the applied meteorological dataset, followed by RF (86.1%), SVM (84.6%) and KNN (82.2%) models, respectively. Therefore, ANN modelling provides a feasible procedure for the managerial planning of air pollution control.

Maternal exposure to benzophenone derivatives and their impacts on offspring's birth outcomes in a Middle Eastern population.

Widespread use of benzophenones (BPs), a group of environmental phenolic compounds, is suspected of interfering with human health. The association of prenatal exposure to benzophenone derivatives with birth outcomes including birth weight and length, head, arm and thoracic circumference, abnormalities, corpulence index and anterior fontanelle diameter (AFD) was investigated. Mother-infant pairs of 166 within PERSIAN cohort population in Isfahan, Iran, in the 1st and 3rd trimesters of pregnancy were assessed. Four common benzophenone metabolites including 2,4-dihydroxy benzophenone (BP-1), 2-hydroxy-4-methoxy benzophenone (BP-3), 4-hydroxy benzophenone (4-OH-BP) and 2,2'-dihydroxy-4-methoxy benzophenone (BP-8) were measured in maternal urine samples. The median concentration of 4-OH-BP, BP-3, BP-1 and BP-8 were 3.15, 16.98, 9.95 and 1.04 µg/g Cr, respectively. In the 1st trimester, 4-OH-BP showed a significant correlation with AFD in total infants, decreasing 0.034 cm AFD per a log unit increase of 4-OH-BP. Within the male neonates, 4-OH-BP in the 1st and BP-8 in the 3rd trimester were significantly associated with head circumference and AFD increase, respectively. Among female neonates in the 3rd trimester, increasing 4-OH-BP and BP-3 concentration was correlated with a decrease in birth weight and AFD, respectively. This study demonstrated that all the target BP derivatives can influence normal fetal growth at any age of the pregnancy, nevertheless, to support these findings further studies are needed in a large and different group population.

Modeling and optimization approach for phytoremediation of formaldehyde from polluted indoor air by Nephrolepis obliterata plant.

This study aimed to model the removal of formaldehyde as an indoor air pollutant by Nephrolepis obliterata (R.Br.) J.Sm. plant using response surface methodology (RSM) and artificial neural network (ANN) models, and optimization of the models by particle swarm optimization algorithm (PSO). The data obtained in pilot-scale experiments under a controlled environment were used in this study. The effects of parameters on the removal efficiency such as formaldehyde concentration, relative humidity, light intensity, and leaf surface area were empirically investigated and considered as model parameters. The results of the RSM model, with power transformation, were in meaningful compromise with the experiments. A multilayer perceptron (MLP) neural network was also designed, and the mean of squared error (MSE), mean absolute error (MAE), and R2 were used to evaluate the network. Several training algorithms were assessed and the best one, the Levenberg Marquardt (LM), was selected. The PSO algorithm proved that the highest removal efficiency of formaldehyde was obtained in the presence of light, maximum leaf surface area and relative humidity, and at the lowest inlet concentration. The empirical system breakthrough occurred at 15 mg/m3 of formaldehyde, and the maximum elimination capacity was about 0.96 mg per m2 of leaves. The findings indicated that the ANN model predicted the removal efficiency more accurately compared to the RSM model.

The association of personal care products uses and dietary habits with the urinary concentration of parabens in Iranian adults.

We evaluated the relationships between the use of individual personal care products (PCPs) and food items with the urinary Methylparaben (MP), Ethylparaben (EP), Propylparaben (PP) and Butylparaben (BP) among 178 Iranian adults. The urinary concentrations of parabens were found to be significantly different between low, medium, and high users of PCPs (P < 0.05). The frequency of PCP use was associated with higher urinary MP, PPand BP concentrations. Significant positive association was found between the frequency of food products use and urinary MP and EP concentrations. The urinary concentration of parabens was higher in individuals who used body wash, makeup base, shaving cream and, lotion in the past 24 h compared to non-users. Consumers of cookies and dairy products had significantly higher urinary MP and jelly consumers had higher urinary MP and PP concentrations than non-consumers. Our findings indicated that certain types of foods and PCPs could be important sources of exposure to parabens.

The association of prenatal exposure to benzophenones with gestational age and offspring size at birth.

In recent decades, emerging environmental pollutants such as endocrine-disrupting chemicals (EDCs) have become a particular concern. This study examined the association of maternal exposure to benzophenones as one of the EDCs with gestational age and evaluated their effects on birth outcomes including birth weight, birth length, head circumference, and Ponderal Index. We assessed 166 pregnant mothers of the PERSIAN cohort population of Isfahan, Iran, in the 1st and 3rd trimesters of pregnancy and their infants at birth. Four common benzophenones (BPs) including 2,4-dihydroxy benzophenone (BP-1), 2-hydroxy-4-methoxy benzophenone (BP-3), 4-hydroxy benzophenone (4-OH-BP), and 2,2'-dihydroxy-4-methoxy benzophenone (BP-8) were measured in maternal urine samples. The median urinary concentrations of 4-OH-BP, BP-3, BP-1, and BP-8 in the 1st trimester were 6.62, 7.5, 4.39, and 1.32 µg/g creatinine and those in the 3rd trimester were 3.15, 16.98, 9.95, and 1.04 µg/g creatinine, respectively. BP-3 was the predominant metabolite in both trimesters. There was a significant correlation between BP-3, BP-1, and 4-OH-BP levels (p < 0.05) but not BP-8. BP-1 showed a significant positive association with gestational age (GA) in all infants in the 1st trimester, but a negative association was observed between BP-3 and BP-1 levels and GA in girls. Classification of infants' birth weight for different GAs represented that the majority of them were appropriate for GA. However, boys' weights were heavier than girls. Also, birth outcomes of preterm (< 37 weeks) infants were noticeably lower than term infants (37-42 weeks). This study demonstrated that benzophenone derivatives especially BP-3 can affect the duration of pregnancy and consequently fetal growth in the early and late stages of pregnancy. This is more pronounced in girls; however, more investigations in a different population are needed to prove the results. Therefore, the application of these compounds as a UV protector requires precise regulation to reduce exposure, especially in pregnant women.

Indoor radon measurement in buildings of a university campus in central Iran and estimation of its effective dose and health risk assessment.

Indoor radon is a serious health concern and contributes about 10% of deaths from lung cancer in the USA and Europe. In this study, radon and thoron levels of 20 multi-floor buildings on the campus of Isfahan University of Medical Sciences were measured in cold and hot seasons of a year. SARAD- RTM1688 radon and thoron monitor was used for measurement. The annual effective dose of radon exposure was also estimated for residences on the campus. The results showed that radon concentration was below the WHO guideline (100 Bq m- 3) in most of the buildings. The ranges of radon were from 3 ± 10% to 322 ± 15% Bq m- 3 in winter and from below the detectable level to 145 ± 8% Bq m- 3 in summer. Mostly, the radon concentration in the basement or ground floors was higher than upper floors, however, exceptions were observed in some locations. For thoron, no special trends were observed, and in the majority of buildings, its concentration was below the detectable level. However, in a few locations besides radon, thoron was also measured at a high level during both seasons. The average annual effective dose via radon exposure was estimated to be 0.261 ± 0.339 mSv y- 1. The mean excess lung cancer risk (ELCR) was estimated to be 0.10%. It was concluded that indoor air ventilation, buildings' flooring and construction materials, along with the geological structure of the ground could be the factors influencing the radon concentration inside the buildings. Thus, some applicable radon prevention and mitigation techniques were suggested.

Spatial patterns and temporal variations of traffic-related air pollutants and estimating its health effects in Isfahan city, Iran.

Isfahan as an important industrial city has faced with air pollution recently. Thus, we assessed the spatial and temporal trends of ambient PM2.5, CO, SO2, and O3 and for estimating their health effect on Isfahan citizens between March 2018 and March 2019 through the AirQ+ software. Our results showed that citizens of Isfahan in almost 240, 167, and 134 of the days in the year has exposure to PM2.5, SO2, and O3 higher than the WHO daily guideline, respectively. Daily variations of PM2.5, CO, and SO2 concentration showed the increasing trend of pollutants in the morning to evening. The maximum concentrations of O3 were observed in the noonday. Also, the concentrations of these pollutants on Friday due to the holiday effect were higher than the weekdays. Except for O3, the PM2.5, CO, and SO2 concentrations in the cold months and cold seasons was higher compared with the hot months and hot seasons. The total number of deaths because of lung cancer, natural mortality, ischemic heart disease, chronic obstructive pulmonary disease,, stroke associated with ambient PM2.5 with the attributable proportion (AP) 11.43%, 11.63%, 15.96%, 15.15%, and 13.1% (95% CI) were 683, 19, 2, 202, and 55 cases, respectively. Therefore, the present study provides additional data for the provincial managers and politicians useful in planning proper strategies of air pollution control to decrease exposure and attributable mortalities.

Exposure to Parabens Through The Use of Personal Care Products Among Iranian Men.

Despite the widespread use of parabens as antimicrobial preservatives in personal care products (PCP) and foodstuffs, recent studies have shown that exposure to parabens can play a role in the endocrine disruption process. In the present study, the urinary concentrations of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were measured among 125 men, and their relationship with the use of 13 distinct PCPs was examined. MP, EP, PP, and BP were detected with a median concentration of 60.12, 8.40, 9.74, and 7.19 µg/L, respectively. The difference of urinary MP and PP between three groups of users of PCPs (low, medium, and high users) was significant (p < 0.05), and the higher levels were found in the high-users' group. The total number of PCP applications was associated with higher urinary MP and PP. Furthermore, the urinary concentration of parabens was found to be dependent of the types of products used. Participants who reported the use of sunscreen, lotions, and deodorant had significantly higher urinary MP (76-185%) than nonusers. Bodywash users had higher levels of urinary MP and PP (112-160%). The use of mouthwash, perfume/cologne, and toothpaste also had urinary PP concentration (73-412%) higher than nonusers. The use of handwashing products remarkably increased the urinary levels of parabens (158-520%). Our findings showed that the use of certain types of PCP is an important source of paraben exposure among Iranian men. These findings can serve as a basis for more extensive studies to investigate the extent of exposure to parabens and to apply appropriate strategies for reduction of their exposure.

The sex-specific association between maternal urinary paraben levels and offspring size at birth.

Parabens are a group of antimicrobial preservatives applied in an extensive range of products and are suspected to impair fetal growth because of their disrupting effect on the endocrine system. We aimed to examine maternal urinary paraben concentrations and their neonates' outcome indexes. Methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) concentrations were measured in 105 maternal urine samples collected before delivery. Length, weight, and head circumference at birth were extracted from the mothers' delivery files. A multivariable linear regression analysis was performed to evaluate the association between paraben levels and neonatal anthropometric indices. The median levels of urinary parabens, especially BP, were higher than those in other countries. Prenatal urinary concentration of MP and BP showed a significantly positive association with birth weight in all neonates (ß = 0.79, 95% CI: 0.16, 1.41, and ß = 8.56, 95% CI: 3.95, 13.17, respectively), while these chemicals showed a significant negative association with head circumference (ß = - 0.002, 95% CI: - 0.004, - 0.000, and ß = - 0.016, 95% CI: - 0.030, - 0.002, respectively). A significant positive association between MP and birth length was also found (ß = 0.004, 95% CI: 0.00, 0.00) in all the neonates. In sex-stratified adjusted models, MP and BP were found to be associated, respectively, with higher birth length and weight in male neonates (ß = 0.008, 95% CI: - 0.001, 0.017, and ß = 7.948, 95% CI: 1.045, 14.851). In girls, maternal urinary MP, PP, and BP were associated with increased birth weight (ß = 0.831, 95% CI: 0.043, 1.620; ß = 4.178, 95% CI: 0.877, 7.480; and ß = 10.821, 95% CI: 3.545, 18.097, respectively), and MP and BP were associated with reduced head circumference at birth (ß = - 0.003, 95% CI: - 0.005, - 0.001, and ß = - 0.035, 95% CI: - 0.055, - 0.016). These results revealed potential impacts between neonatal growth and maternal exposure to parabens. However, these findings should be interpreted while considering the limitations of the present study.

PM2.5-associated bacteria in ambient air: Is PM2.5 exposure associated with the acquisition of community-acquired staphylococcal infections?

Particulate matter (PM), a major component of air pollution, is an important carrier medium of various chemical and microbial compounds. Air pollution due to PM could increase the level of bacteria and associated adverse health effects. Staphylococci as important opportunistic pathogens that cause hospital- and community-acquired infections may transmit through air. This study aimed to obtain knowledge about the concentration of airborne bacteria as well as staphylococci associated with particulate matter with a diameter of less than 2.5 micrometers (PM2.5) in ambient air. The impact of meteorological factors including ultraviolet (UV) index, wind speed, temperature, and moisture on microbial concentrations was also investigated. Quartz filters were used to collect PM2.5 and associated bacteria in ambient air of a semiarid area. Airborne bacteria were quantified by culture method and Staphylococcus species identified by molecular methods. The mean (SD) concentration of PM2.5 and airborne bacteria was 64.83 (24.87) µg/m3 and 38 (36) colony forming unit (CFU)/m3, respectively. The results showed no significant correlation between the levels of PM2.5 and concentrations of bacteria (p < 0.05). Staphylococcus species were detected in 8 of 37 (22%) samples in a concentration from 3 to 213 CFU/m3. S. epidermidis was detected with the highest frequency followed by S. gallinarum and S. hominis, but S. aureus and methicillin-resistant Staphylococcus aureus (MRSA) were not detected. No significant correlation between the concentrations of bacteria with meteorological parameters was observed (p < 0.05). Our finding showed that, although the study area is sometimes subject to air pollution from PM2.5, the concentration of PM2.5- associated bacteria is relatively low. According to the results, PM2.5 may not be a source of community-associated staphylococcal infections.

Urinary concentrations of parabens amongst Iranian adults and their associations with socio-demographic factors.

BACKGROUND: Parabens are widely used to prevent organism growth and increase the shelf life of foods, medicines and personal care products (PCPs). Recent studies indicate their potentially harmful effects on human health. There is no information on the extent of exposure to parabens among Iranians. METHODS: We measured the concentration of urinary methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) among Iranian adults and calculated their estimated daily intake (EDI). Also, association between the level of urinary parabens with socio-demographic and lifestyle variables were investigated. RESULTS: Detection frequencies of MP, EP, PP, and BP were 98.9, 91, 94.3, and 88.2%, and their median urinary concentrations were 69.06, 9.10, 12.4, and 9.87 µg/l, respectively. Urinary parabens were higher in females, and the difference in the concentration of MP and PP was significant. A significantly positive correlation between MP and PP (r = 0.638) and a moderate to a weak correlation between other parabens were observed. There was a significantly negative weak correlation between age and MP, BP and PP. There was also a significant association between different age groups and MP, BP and PP as well as different BMI values and MP. The highest EDI value belonged to MP in the female group. Despite being lower than the acceptable daily intake (ADI), its value was higher than that reported in other countries (except the US). CONCLUSIONS: Our findings indicated that Iranians are widely exposed to the parabens and the range of exposure was associated with socio-demographic factors. These results could serve as a basis for assessing the risk of exposure to parabens amongst Iranians.

Dietary Habits and Personal Care Product Use as Predictors of Urinary Concentrations of Parabens in Iranian Adolescents.

Despite the widespread use of parabens as antimicrobial preservatives in personal care products (PCPs) and foodstuffs, recent studies show that exposure to parabens could result in endocrine disruption. The urinary methylparaben, ethylparaben, propylparaben, and butylparaben among 100 adolescents and their relationships with using 19 personal care and 18 food products were evaluated. Urinary paraben concentrations were significantly higher in the high-user group (8-19 products) compared to both low (0-3 products) and middle (4-7 products) user groups. The frequency of PCP use was associated with higher urinary levels of 4 parabens, and the frequency of food product use was associated with higher urinary methylparaben and ethylparaben. The use of mouthwash was associated with higher levels of methylparaben, ethylparaben, and propylparaben. Users of makeup base had higher methylparaben and propylparaben, users of eye makeup had higher propylparaben, and users of body wash, sunscreen, and lotion had higher urinary propylparaben than nonusers. Consumers of dairy products had significantly higher urinary methylparaben, propylparaben, and butylparaben, and cookie consumers had higher urinary methylparaben and ethylparaben, than nonusers. Consumers of canned foods and chips/snacks had higher methylparaben, and consumers of sauces and jams had higher ethylparaben than nonconsumers. The findings show that certain types of foods and personal care products could be important sources of paraben exposure. Environ Toxicol Chem 2020;39:2378-2388. © 2020 SETAC.

Effect of photocatalytic pretreatment on the biodegradation of n-hexane vapours in a biofilter.

Hydrophobic volatile organic compounds (VOCs) such as n-hexane are not completely biodegradable by a single biofilter. So, in the present study, a photoreactor system packed with scoria granules coated with TiO2, as a pretreatment unit, was used for increasing the removal efficiency of n-hexane by a biofilter during an operation period of 191 days. The inlet and outlet concentration of n-hexane was analyzed with a gas chromatography coupled with a flame ionization detector (GC/FID). The results indicated that the removal efficiency of the single biofilter with input concentrations of 0.18 - 1 g/m3 at empty bed residence times (EBRTs) of 30, 60, and 120 s was 10.06%, 21.45%, and 46.8%, respectively. When the photoreactor was used as a pretreatment system, the removal efficiency of the combined system in corresponding EBRTs was improved to 39.79%, 63.08%, and 92.60%, respectively. The results proved that the combined system provided higher removal efficiencies than the single biofilter. Thus, the application of the photoreactor as a pretreatment step was much effective in increasing the removal efficiency of n-hexane from the polluted air by the biofilter.

Concentrations and mortality due to short- and long-term exposure to PM2.5 in a megacity of Iran (2014-2019).

The present study aimed to survey the spatial and temporal trends of ambient concentration of PM2.5 and to estimate mortality attributed to short- and long-term exposure to PM2.5 in Isfahan from March 2014 to March 2019 using the AirQ+ software. The hourly concentrations of PM2.5 were obtained from the Isfahan Department of Environment and Isfahan Air Quality Monitoring Center. Then, the 24-h mean concentration of PM2.5 for each station was calculated using the Excel software. According to the results, the annual mean concentration of PM2.5 in 2014-2019 was 29.9-50.9 µg/m3, approximately 3-5 times higher than the WHO guideline (10 µg/m3). The data showed that people of Isfahan in almost 58% to 96% of the days of a year were exposed to PM2.5 higher than the WHO daily guideline. The concentrations of PM2.5 in cold months such as October, November, December and January were higher than those in the other months. The zoning of the annual concentrations of PM2.5 in urban areas showed that the highest PM2.5 concentrations were related to the northern, northwestern, southern and central areas of the city. On average, from 2014 to 2019, the number of deaths due to natural mortality, lung cancer (LC), chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD) and stroke associated with ambient PM2.5 were 948, 16, 18, 281 and 60, respectively. The present study estimated that on average, 14.29% of the total mortality, 17.2% of lung cancer (LC), 15.54% of chronic obstructive pulmonary disease (COPD), 17.12% of ischemic heart disease (IHD) and 14.94% of stroke mortalities were related to long-term exposure to ambient PM2.5. So provincial managers and politicians must adopt appropriate strategies to control air pollution and reduce the attributable health effects and economic losses.

Urinary Concentrations of Parabens in a Population of Iranian Adolescent and Their Association with Sociodemographic Indicators.

Parabens are widely used as preservatives in personal care products, foodstuffs, and pharmaceuticals. Concerns have been raised regarding the potential endocrine disruption effects of parabens. In the present study, the urinary concentration of four common parabens, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), in 100 Iranian adolescents randomly referring to health services centres were analyzed using GC/MS. The association of sociodemographic and lifestyle variables, collected through questionnaire, with the concentration of parabens also were studied. Median concentrations of MP, EP, PP, and BP were 92.21, 8.46, 12.26, and 8.42 µg/g creatinine, respectively. There was a strong positive significant correlation between MP and PP (r = 0.694) and moderate to a weak correlation between the other parabens. The concentration of urinary MP in females was significantly higher than those in male (p = 0.021). There was a significant negative association between different BMI groups and MP and EP. There also was a positive significant association between the MP and age, and between MP, EP, and PP, and tobacco use. Although the estimated daily intake of the parabens was lower than the Acceptable Daily Intake, it was higher than those reported in other countries. This confirms the widespread exposure of Iranian adolescents to the paraben compounds and their association with sociodemographic factors. This was the first study reporting the urinary parabens level in Iranian adolescents, and the data can be used as a basis for assessing the risk of exposure to parabens in the Iranian population in future studies.

Correction to: Improved degradation of n-hexane vapours using a hybrid system, a photoreactor packed with TiO2 coated-scoria granules and a multilayer biofilter.

[This corrects the article DOI: 10.1007/s40201-019-00416-4.].

Urinary paraben concentrations and their implications for human exposure in Iranian pregnant women.

Parabens are widely used as preservatives in cosmetics, medicines, and foods due to its antimicrobial properties. Concerns have been raised regarding the estrogenic activity and potential endocrine disruption effects of parabens. Studies on monitoring of paraben exposure in the Iranian population are very scarce. This study was carried out to measure urinary concentrations of parabens, to estimate their daily intake, and to identify some of the sociodemographic factors affecting exposure to these compounds. The concentrations of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were measured in urine samples collected from 95 Iranian pregnant women by gas chromatography mass spectrometry. The highest median concentration was 87.0 µg/L for MP, followed by PP, EP, and BP with median concentrations of 15.6, 9.64, and 8.57 µg/L, respectively. Except BP, the urinary concentrations of other parabens were comparable to those in other countries. Also, the highest daily intake was related to MP (median = 16.5 µg/kg-BW/day), which is less than the acceptable daily intake (ADI). A significant positive correlation was observed between the measured parabens. Significant negative associations were observed between age and BP, BMI and EP as well as parity and PP. On the other hand, income and smoking were significantly positively associated with MP, BP and EP, BP, respectively. The urinary MP and BP concentrations were higher among the subjects with diploma education (P = 0.003 and P = 0.006, respectively), and during the spring, urinary MP concentration was higher than other seasons. The results showed that Iranian pregnant women are more prone to parabens and their urinary paraben concentrations are associated with sociodemographic factors. This result could serve as a basis for evaluating the rate of exposure of the Iranian population to parabens in future studies.

Improved biodegradation of hydrophobic volatile organic compounds from the air stream in a multilayer biofilter.

Biofiltration of n-hexane as a representative of hydrophobic volatile organic compounds (VOCs) at presence and absence of rhamnolipid biosurfactant was studied using a multilayer biofilter packed with scoria, compost, poplar tree skin and sugar beet pulp, for 131 days. The concentration of n-hexane was measured by a gas chromatograph coupled with a flame ionization detector (GC/FID). The results showed that the mean removal efficiency (RE) of n-hexane at the presence of the biosurfactant was two times higher than that at absence of the biosurfactant. According to the results, rhamnolipid can enhance the efficiency of biofiltration of VOCs from polluted air streams.

Protocol for identification of airborne asbestos fibres in the urban areas and spatio-temporal trend.

Asbestos is classified as a hazardous pollutants between the airborne particles that cause diseases such as lung fibrosis (asbestosis). This protocol describes an integrated method for determination of asbestos fibres concentration and its temporal-spatial trends in the air of urban areas. To do this, 60 samples were gathered from various areas of Yazd city with low, moderate and high traffic. For analysis of asbestos fibres in the samples scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) were utilized. The spatial and temporal variation of asbestos fibres concentration was carried out by ArcGIS 10 analysis. The Inverse Distance Weighting (IDW) method was used to draw asbestos fibres distribution maps. The interpolation of asbestos fibre by IDW method indicated that the distribution of the fibres in summer and winter were followed almost the similar pattern. However, the distribution of asbestos fibre concentrations in the direction of southeast to the northwest of the city was higher than that in the other areas due to high vehicular traffic.