This study aimed to review the impact of climate change around the world on the incidence of emerging and noncommunicable diseases in sensitive and vulnerable individuals, such as pregnant women and newborns. The combination of keywords such as climate change, ambient temperature, pregnancy outcomes, spontaneous abortion, preterm birth, stillbirth, autism, orofacial cleft, cleft palate, heart disorders, and diabetes was used for comprehensive search on reputable citation databases such as Scopus, PubMed, Web of Science, and Google Scholar, throughout research conducted previously with a focus on the years from 2018 to 2020. The results of the literature cited showed that long-term exposure to high temperatures reduced birth weight. Heat has been reported to have serious adverse effect than cool weather for preterm birth. A significant association has been reported between seasonal changes and diabetes and gestational hypertension. Climate changes, by increasing infant mortality and miscarriage, have made a difference in sex ratios. Further, the development of neonatal abnormalities such as hypospadias, autism, cleft palate, and heart disorders has been significantly associated with climate change. Seasonal changes, rising temperatures, sunlight, increased ultraviolet rays, and ozone concentration have been suggested to involve in the prevalence of cleft palate. Changes in relative humidity, temperature, sunlight, oxygen pressure, and elevated environments have also contributed to the development of heart disorders. This review showed that climate change has played an important role in the incidence and prevalence of emerging diseases. Hence, climate change has adverse effects on pregnant women and neonates. This study confirms critical importance of climate change and its negative effect on susceptible people and next generation.

Aim: In this study, the presence of four phthalate esters, including diethyl phthalate (DEP), Dibutyl phthalate, benzyl butyl phthalate (BBP), and diethylhexyl phthalate (DEHP) in pasteurized milk with plastic packages was investigated during the time allowed for consumption. Materials and Methods: The pasteurized milk samples, including 7 high-consumed brands, were purchased from reputable stores and two factories in Isfahan in 2019. The concentration of phthalate esters was measured by gas chromatography-mass spectroscopy paired with dispersive liquid-liquid microextraction. Results: According to the results of this study, among the analyzed samples of stores, DEHP (0.25 μg/l) and BBP (0.25 μg/l) had the highest mean concentrations in pasteurized milk, respectively. The analyzed results of the factories showed a high BBP of 0.1 μg/l. Among the studied brands, the highest concentration of phthalate esters was 0.42 μg/l. The mean concentrations obtained in this study were lower than the international standards set. Conclusion: Due to the low average concentration of phthalate esters in pasteurized milk, consumption of these products has no serious risk for humans and the share of pasteurized milk in terms of the presence of phthalate esters is negligible.

Aim: Low-frequency sounds are generated from many sources in both the occupational and nonoccupational environments. Hence, the aim of this study was to investigate the effect of low-frequency noise (LFN) on the working speed and the rate of annoyance of the subjects under study. Materials and Methods: This cross-sectional/interventional study was performed in the sound and vibration laboratory of Isfahan University of Medical Sciences in 2019. Simple random sampling was used to select the subjects. In this study, the working speed of the subjects was evaluated using mental arithmetic test and the rate of the perceived annoyance was measured using ISO 15666 in Likert format (0–11) due to exposure to noise sources. Mann–Whitney U-test was used to analyze the data. Results: There was a significant statistical difference in the rate of the individuals' working speed Between 0 and 90 min at the frequency of 125 Hz and the sound level of 95 dB (P = 0.029). There was a statistically significant difference between the frequencies of 125 and 1000 Hz at the sound pressure level of 85 dB and the 45 min time (P = 0.001) and 90 min (P = 0.001) as well as at the 95 dB sound pressure level at 45 min (P = 001) and 90 min (P = 0.001). Conclusion: The results of the present study showed that increasing sound pressure levels and the exposure time in both LFN and high-frequency noises, increased the working speed and the amount of perceived annoyance in individuals.

Aim: In this study, the levels of indoor and outdoor (I/O) airborne particles and bioaerosols were assessed in two primary schools. Simultaneously, I/O microbial airborne and particle matter (PM) concentrations were analyzed during the autumn of 2018. Materials and Methods: A total of 96 I/O air samples were taken by using a single-stage Andersen sampler from two selected primary schools located in Arak, Iran. Simultaneous with sampling, PM₁₀ and PM_2.5 concentrations, temperature, and relative humidity were also measured. Results: The results indicated that the mean levels of indoor airborne bacteria and fungi were 448 and 94 CFU/m³, respectively. The I/O ratios of bacteria and fungi were 2.1 and 0.7, respectively. The airborne bacteria levels showed a weak-positive and moderate-positive association with PM_2.5 (r = 0.28, P < 0.05) and PM₁₀ (r = 0.32, P < 0.05), respectively. Further, a moderate-positive association was observed between indoor fungi and the PM_2.5 (r = 0.46, P < 0.05) and PM₁₀ (r = 0.30, P < 0.05). In our study, the most fungal species identified were Penicillium, Cladosporium, and Aspergillus, and Staphylococcus spp., Micrococcus spp., and Bacillus spp. were the most frequently founded indoor bacteria. Conclusion: Comparative analysis of classrooms in two schools showed that indoor sources and building conditions have a key role in indoor air quality.

Aims: This study aimed to comparatively investigate the efficiency of removal of formaldehyde using advanced oxidation process ultraviolet (UV)/S₂O₈^2-/Fe²⁺ and UV/S₂O₈^2- from aqueous solutions. Materials and Methods: In this experimental-laboratory study, the UV/S₂O₈² and UV/S₂O₈^2-/Fe²⁺ processes were used to remove formaldehyde. UV radiation was provided by a low pressure (6 W) UV lamp. Effects of various factors including pH, different irradiation durations, different concentrations of iron ions, initial concentration formaldehyde, and persulfate concentration were evaluated. The remaining formaldehyde concentration in the samples was measured by spectrophotometer at 412 nm wavelength. Results: The results showed that in the UV/S₂O₈^2- method, the formaldehyde removal efficiency decreased with increasing pH from 3 to 9, while in the UV/S₂O₈^2-/Fe²⁺ method, the formaldehyde removal efficiency increased with increasing pH and concentrations of iron ion. In both methods, as the initial concentration of formaldehyde was increased, its removal efficiency decreased, and the highest formaldehyde removal rate was obtained in UV/S₂O₈^2- method at persulfate concentration of 100 mM. However, in the UV/S₂O₈^2-/Fe²⁺ method, the removal efficiency decreased with increasing concentration of persulfate to 100 mM. Conclusion: The results showed that the UV/S₂O8^2-/Fe²⁺ process was more efficient (87.57%) to remove formaldehyde at high concentrations. Therefore, it is recommended to study the efficiency of this process as one of the clean and environmentally friendly methods at full scale for real wastewater.

Aims: This study was aimed to discriminate ion aflatoxin B₁(AFB₁) contamination of pistachio kernels after/E-beam irradiation. Materials and Methods: Pistachios were inoculated with known concentrations of Aspergillus flavus. Then pistachio samples were exposed to E-beam at five different doses (0, 1, 3, 5, and 7 kGy) and in various storage times (0, 30, 60, 90, and 180 days) at ambient temperature. Then, sensorial characteristics, fungal, and AFB₁ contamination of pistachio kernels were investigated. Statistical analysis was performed using the SPSS software version 22. by using descriptive statistics, Kolmogorov-Smirnov, and Kruskal–Wallis tests. Results: The mean percentage reduction of aflatoxin in the treated samples at doses of 1, 3, 5, and 7 kGy on different days of storage with two replicates was 38.84%, 48.79%, 53.50%, and 77.17%, respectively. The dose of 1 kGy was found to be appropriate in reducing the number of mold in pistachios without having any change in their organoleptic properties. The organoleptic properties, including color, texture, and overall palatability of pistachios, significantly changed after a dose of 5 kGy. Conclusion: Electron-beam (E-beam) efficiency against A. flavus and aflatoxin degradation increased with increasing radiation dose. Due to the sensitivity of A. flavus to radiation, this method can be used to improve the quality of pistachio products.

Aim: The aim of this study was to reduce the amount of diazinon from aqueous media using chemical–thermal-activated watermelon rind. Materials and Methods: This experimental study was carried out in a laboratory. First, watermelon rind was activated by chemical–thermal method. Then, the effective parameters of the diazinon adsorption process, including the initial concentration of diazinon (0.17–1 μg/L), pH (3–10), adsorbent amount (0.05–1 g/l), and contact time (30–100 min), were investigated and optimized. The amount of residual diazinon was measured by high-performance liquid chromatography. In this study, Taguchi method was used to determine the sample size and statistical analysis. Furthermore, in this study, to describe the adsorption equilibrium, Freundlich and Langmuir isotherm models were used. Results: The results showed that under an optimal pH of 6, the equilibrium time of 30 min, the amount of adsorbent 1 g/L, and the initial concentration 0.17 μg/L, the elimination efficiency of diazinon was 95.1%. Furthermore, the results of isothermic studies have shown that the removal of diazinon follows the Freundlich model (R² = 0.921). Conclusion: Chemical–thermal-activated watermelon rind can effectively be used to remove low concentrations of diazinon from aqueous solutions.

Aim: This study is aimed to determine the disinfectant activity of Derdevice plus Y^® and I&D Sept^® against carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates. Materials and Methods: The bactericidal activity of Derdevice plus Y^® and I&D Sept^® were tested in vitro under clean and dirty conditions by a quantitative suspension test according to EN 13727. The effectiveness of the disinfectants was compared with 10% sodium hypochlorite (NaOCl), 7% benzalkonium chloride (BC), 2% chlorhexidine digluconate (CHX), and 70% ethyl alcohol (EtOH). After 1, 5, and 60 min of contact with the biocides, the colony-forming units were counted, and the logarithmic reduction factor was determined. Results: A dilution of 1/300 of Derdevice plus Y^® disinfectant showed bactericidal activity against clinical isolates and standard strains (growth reduction was =5 log₁₀) after 5 and 60 min contact times and under clean and dirty conditions. A 100% concentration of I&D Sept^® showed a bactericidal effect within the contact time (60 min) under clean and dirty conditions with the reductions of =5 log₁₀ and =3 log₁₀, respectively. Standard biocides such as BC, CHX, NaOCl, and EtOH showed marked effects after various contact times and the conditions onto tested strains. Conclusions: The results of our study confirm that the biocides of Derdevice plus Y® and I&D Sept^® used in our hospital were found to be effective against K. pneumoniae isolates.

Aims: Nitrate can enter water bodies through using chemical fertilizers and discharging the effluents from municipal and industrial sewage treatment plants. As a superiority to the conventional statistical models, Grey models (GMs) require only a limited amount of representative data to estimate the behavior of unknown systems. In the current study, the nitrate concentration of the year 2023 in Babol groundwater resources was forecasted by using GM, namely GM (1, 1). Materials and Methods: This descriptive-cross-sectional study was performed in the city of Babol. The data of 63 wells in urban and rural areas during the warm and cold seasons between 2007 and 2017 were supplied from the Health Center and Babol Rural Water and Sewage Company. In data set, the observed values between 2007 and 2015 were used to fit models, and the observed values between 2016 and 2017 were used to evaluate the accuracy of the model's predictions. To assess the efficiency of the model fitted and precision of the predicted values, we used indexes of forecast absolute error, small error probability, and the proportion of variance statistical metrics. Results: Simulated results showed that the accuracy of the model GM (1, 1) to predict and forecast both data sets is entirely appropriate and reliable. The forecasting values of nitrate concentration of the year 2023 and 8 years later, for urban and rural areas in warm and cold seasons, are 21.30 and 7.30 and 15.63 and 5.34 mg/L, respectively. Conclusion: Although the predicted concentration of nitrate in the studied area is lower than that the standard concentration suggested by the World Health Organization, all water resources should be protected effectively.

Aim: This study was conducted on the microbial contamination of water of Bandar Abbas beaches in order to achieve comprehensive information for determining the quality of swimming coasts. Materials and Methods: After initial examination of the number and location of swimming coasts in terms of appearance and areas with the highest number of swimmers, 5 coastal swimming areas were selected as sampling sites. Sampling was done for 6 months and 10 samples per month. Physicochemical (water temperature, pH, turbidity, electrical conductivity, and salinity) and microbial indicators including total and fecal coliforms, Escherichia coli, fecal streptococci, Clostridium perfringens as well as Salmonella as a pathogenic microorganism were measured in each sampling period. Results: Results of this study showed that the mean number of streptococci, total coliforms, fecal coliforms, and E. coli was 930, 24,000, 9300, and 9300 most probable number (MPN)/100 ml, respectively. It was also found that the mean concentration of C. perfringens in the sampling stations was 250 CFU/100 ml. The frequency of detection of Salmonella in stations 2 and 3 was 16.7% and in station 5 was 8.3% and was not observed in other stations. According to the results, in most sampling stations, the concentration of the microbial indicators was higher than the standard. A significant relationship between different species of bacteria was observed. The results also showed a significant relationship between the amount of turbidity and microbial (P < 0.05). Conclusion: According to the results of the present study, it was observed that most of the swimming coasts of Bandar Abbas were not in a favorable microbial condition, due to the discharge of industrial and municipal sewage and waste disposal. The results highlight the potential risk of microbial pathogens for swimmers and the necessity of sanitation practices of coastal area to protect public health.

Aims: This study was aimed at the evaluation of heavy metals in the drinking water of the rural area of Divandarreh city and the assessment of carcinogenic and non-carcinogenic health risks. Materials and Methods: In the present work, concentration of four heavy metals in drinking water resource in the rural area of Divandarreh County were evaluated. For these aim, the numbers of 29 samples were collected from rural drinking water resources, and the concentration of heavy metals was determined. In addition, carcinogenic and noncarcinogenic risk assessment was conducted in children and adults as target groups. Results: The level of Cd was higher than the WHO drinking water Standard. The average amount of target hazard quotient for heavy metals through ingestion in children and adults were in the order of Cd > Cr > Pb > Ni. The total hazard quotient hazard quotients (HQ ing + HQ derm) in children group was higher than the limit set by the USEPA (hazard index = 1.68), indicating probable noncarcinogenic risk to this group through consumption of water. Conclusion: Based on the obtained data, the carcinogenic risk for all of the heavy metals were higher than the permissible standard. The obtained data can be useful for managers and the water and wastewater department regarding the improvement of drinking water quality.

Aims: Over 5.5 trillion cigarettes are produced annually. Based on the observations, 76% of these consumed cigarettes are littered in public areas instead of discarding in suitable bins. Rainwater drain system carries the water and other wastes such as cigarette butts from the ground and transfers them to the bigger aquatic media without any treatment in which hundreds of chemicals leach into animal's habitats and our water supply origin. The key purpose of this article was to measure the concentration of Arsenic (As) released into water from cigarette butts and to compare their levels among the different brands. Materials and Methods: Ten cigarette butts (comprising cigarette filter and remaining tobacco) of five cigarette brands named Winston, Bahman, Kent, Montana, and Magna were soaked into individual 100 ml of distilled water for 10 days. Five solutions were prepared for each brand, as was detected in all leachate of brands but with different quantities. Results: Arsenic levels were 53.51, 32.78, 55.33, 42.4, and 59.24 μg/l for Kent, Winston, Montana, Bahman, and Magna, respectively. Conclusion: As concentrations were placed in the following order: Winston < Bahman < Kent, Montana, Magna. Based on the present study, cigarette butt plays an important role in environmental pollution and its importance should not be ignored in terms of arsenic potential.

Aims: This survey aimed to investigate the impact of common storage conditions on the migration of phthalate esters (PEs) including di-2-(ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), terephthalic acid (TPA), and phthalic anhydride from polyethylene terephthalate (PET) bottle into the water and to assess the potential human health risk using Monte Carlo simulation (MCS). Materials and Methods: Three different PET-bottled water brands were stored for 7 and 90 days at three temperatures: 5, 25, and >45°C. PEs were extracted from samples using the solid-phase extraction method with gas chromatography–mass spectrometry. Results: The highest concentrations were found for TPA in samples immediately after purchasing. DEHP and DBP were identified at 90 days in all of the samples. Based on the health risk assessment, the hazard quotient of four compounds in the MCS method was <1; therefore, it should not be considered as a matter of concern. However, excess lifetime cancer risk for DEHP (3.09 × 10⁻⁵) based on the maximum concentration was found to be more than 10⁻⁶. Furthermore, the adverse estrogenic effects of DEHP and DBP appeared to be significant. Conclusion: The probabilistic risk assessment revealed that high estrogen equivalence (DEHP and DBP) seemed to have adverse estrogenic effects on adults. Furthermore, adults were in carcinogenic risk of DEHP. The quality of water bottled in PET may change during the long period, and further research is recommended for the monitoring of phthalates in bottled water to ensure human health.

Aims: This study designed to investigate the concentration of some heavy metals (HM) in the soil of agricultural land of Gonbad-e Kavus in Golestan province and relationship of these metals with esophageal cancer disease. Materials and Methods: For the investigation of pollution, especially HM in the soil, 5 points were randomly selected from each village (3 villages). The samples dried and screened by 200 mesh sieve.Then, the samples were analyzed for HM using ICP/MS. Results: The mean of Cadmium (Cd), Zinc, Cobalt, Chromium, Manganese, Nickel, Arsenic, Copper (Cu), Lead (Pb), and Iron (Fe) in soil was 0.5938 ± 1.7, 74.06 ± 18.9, 12.06 ± 1.28, 68.68 ± 5.85, 627.37 ± 53.3, 38.43 ± 4.4, 6.51 ± 1.21, 29.37 ± 4.3, 17.25 ± 3.5, and 27766.06 ± 2200 mg/kg, respectively. Conclusion: The concentration of metals except Cd and iron was less than the global standards. The concentration of some metals in the soil is almost high due to the high consumption of urea, phosphate, and nitrogen fertilizers. Therefore, it is recommended to educate farmers and use less chemical fertilizers.

Aim: Nosocomial infections have become increasingly a major health concern in many hospitals. Gram-negative bacteria (GNB), including Acinetobacter baumannii, Pseudomonas aeruginosa and Legionella have emerged among the most problematic microorganisms in hospital settings, which can cause a variety of nosocomial infections, especially in susceptible individuals. Biofilm formation allows these waterborne agents to persist in hospital water systems for extended periods. Since the transmission is the initial step in disease occurrence, effective prevention of nosocomial infections requires a better knowledge about waterborne bacteria. The aim of this study was to investigate the frequency of presence of GNB in hospital water systems by a rapid and reliable assay. Materials and Methods: A total of 33 water samples were collected from 11 hospitals of Isfahan University of Medical Sciences, Iran and analyzed for the presence of GNB by a polymerase chain reaction (PCR) assay with the application of specific primer sets. Results: From the 11 hospitals surveyed, 91% (10 of 11) were positive for at least one of the types of GNB. GNB were detected in 58% (19 of 33) of water samples. 45% (15 of 33) of samples were positive for legionella. A. baumannii and P. aeruginosa were detected in 18% (6 of 33) of water samples. The mean concentration of heterotrophic bacteria was 36 CFU/ml. Conclusion: Detection of GNB in hospital water systems with a relatively high frequency revealed that hospital water may act as an important route for transmission of nosocomial infections. The results emphasize the importance of rapid microbiological monitoring and the implementation of strict control measures in hospital water systems.

Aims: Urban expansion has caused lots of problems such as air pollution, which endanger the health of residents. In this research, the spatiotemporal trend of atmospheric fine particulate matter (PM_2.5) of Isfahan was studied and modeled using distributed space–time expectation–maximization (D-STEM) software in 2017. Materials and Methods: This software uses a flexible hierarchical space–time model that can deal with multiple variables and massive loads of missing data. Model estimation is based on the expectation–maximization algorithm. The effects of confounder variables such as holidays, altitude, average temperature and relative humidity, rainfall, wind speed, and direction were considered in the modeling. The hourly measured ambient PM_2.5concentration data were obtained from seven air pollution monitoring stations installed in different zones of Isfahan and operated by the department of environment. Results: The distribution map of the pollutant demonstrated two polluted areas located in southwest and southeast regions of the city that are high traffic and densely populated area. PM_2.5concentration was significantly increased (P < 0.05) with an increase in land elevation by a coefficient of 0.93; conversely, it decreased significantly (P < 0.05) with every increase in wind speed by a coefficient of −0.226. Conclusion: Given the spatiotemporal correlations between air pollutant data, it is necessary to incorporate these correlations into model to obtain more accurate estimates. Using the statistical models and methods to manage the data, time, and volume of calculations in spatiotemporal estimations, the D-STEM program gives more accurate estimates of the desired parameters. Presenting models and maps for every desired time period are another feature of this software that can be useful in health programming and environmental management. Vehicular traffic had a significant effect on the increasing trend of the pollutant level in urban areas; however, the effects of atmospheric phenomena such as dust storms and thermal inversion cannot be ignored.

Aim: This study was conducted to evaluate the effects of ambient concentrations of PM_2.5 and PM₁₀ on the health-related aspects including the total mortality, respiratory and cardiovascular diseases, and hospital admissions due to respiratory and cardiovascular diseases in Karaj, Alborz Province, Iran, during 2012–2016 using the AirQ2.2.3 software. The effects of meteorological parameters on the PM_2.5 and PM₁₀ levels were also investigated. Materials and Methods: Meteorological parameters, population, and the pollutant data were obtained from the Department of Environmental Protection, Karaj (Alborz, Iran). Statistical analysis was performed using the SPSS 24 software to study the relationship between the PM_2.5 and PM₁₀ concentrations and the meteorological parameters. Results: Our results showed a direct relationship between the PM₁₀ concentration and the temperature (r = 0.34, P < 0.018) and relative humidity (r = 0.37, P < 0.5). However, there was a negative relationship between the PM₁₀ concentration with wind speed (r < −0.328, P < 0.014) and precipitation (r < −0.179, P < 0.327). Similarly, there was a direct relationship between the PM_2.5 concentration and the temperature (r = 0.41, P < 0.014) and relative humidity (r = 0.37, P < 0.05). On the other hand, a negative relationship was observed between the PM_2.5 concentration with wind speed (r < −0.138, P < 0.010) and precipitation (r < −0.12, P < 0.201). The total number of death, death due to cardiovascular and respiratory diseases, and hospital admissions due to cardiovascular and respiratory diseases were equal to 1619, 1096, 306, and 4822, respectively. Conclusions: The results of this study showed that the concentrations of PM_2.5 and PM₁₀ should be reduced through applying the management strategies to improve the health of the residents in Karaj city.

Aim: In developing countries, pesticide poisoning, regardless of occupational exposure or deliberate actions, is one of the major public health problems. To determine the impact of occupational exposure to pesticides on workers' health status, this study evaluated the consequences of pesticide exposure and its effects on hematological indices.Materials and Methods: Eighty workers of pesticide production factories were studied in two experimental and control groups during 2018–2020. Data were collected using demographic, occupational, health questionnaires, and blood analysis. The collected data were analyzed using SPSS software (ver. 23), Chi-square, and U Mann–Whitney test considering a significance level of 0.05. Results: The age range of subjects was 23–56 years (mean = 36.21 ± 6.744). A significant difference was observed between studied groups in terms of marital status, education level, and work shift. In addition, levels of erythrocyte sedimentation rate (ESR) (P = 0.036), white blood cell (WBC) (P = 0.009), uric acid (P = 0.033), and alkaline phosphates (P < 0.001) were significantly different between the two studied groups. The results showed a significant difference between the hematology Index level of toxin production workers and workers in administrative and service units. Conclusion: As expected given the type of their job, a significant difference was observed between studied groups in terms of marital status, education level, and work shift, use of safety equipment, as well as residency. Furthermore, levels of ESR, WBC, uric acid, and alkaline phosphates were significantly different. It seems that pesticide toxins exposure in the poison-production industry causes hematological changes, which may be dangerous in a long time.

Aim: Zayandehrood River is an important drinking water source in Isfahan Province which has been exposed to contamination. The high variation of physical and chemical properties of water is an important factor influencing on the consumers' health and the recipient environment. This study aims to access the health and ecological hazards related to water quality-determining parameters. Materials and Methods: In present work, all the existing data on the physical and chemical quality of Zayandehrood water for two years (March 2013 to March 2015) were collected from Isfahan Province Regional Water Company. The collected data are including dissolved oxygen, turbidity, conductivity, nitrate, phosphate, ammonia, and heavy metals such as arsenic and cadmium. The environmental hazard were determined using the contamination indices such as heavy metal pollution index, positive index, and organic pollution index, and health hazards arising from the absorption of chemical parameters were assessed based on the Environmental Protection Agency model and the use of Rural Access Index. Results: The highest noncarcinogenic hazard due to the absorption of chemical parameters was for the children group, and the ratio of health hazard and the probability of exposure to each of the chemical compounds lies in the permissible limit. The hazard higher than 1 revealing the medium hazard was, however, found in the children age group. Assessment of environmental hazards accordingly shows that the quality of the water environment has low contamination. Conclusion: The contamination of Zayandehrood water with chemical compounds can play an important role in diseases due to the exposure of low-quality water. It is thus advised to properly treat water before drinking it, and in order to decrease the concentration of poisonous chemicals in Zayandehrood Lake water, appropriate actions should be taken to conserve it.

Aim: Welding is one of the most common occupations associated with occupational lung disease and is often associated with respiratory symptoms because inhalation is a common way of exposure with welding fume in welders. The aim of this study was to investigate the efficiency and Total Internal Leakage (TIL) valve fabric respiration protection mask made in Iran against different metals in the welding fume. Methods: To determine the efficiency of the mask, the concentration of pollutants in the air outside the mask and the concentration of pollutants in the air inside the mask were measured simultaneously. NIOSH 7302 method was used to sample the air inside and outside of the masks. The elements Al, Cu, Fe, Mn, Ti, and Zn in the welding fume were analyzed. Results: The efficiency of the mask against titanium and iron metals is higher than other metals. The average efficiency of the respiratory mask is 75.46% and the TIL rate is 23.42%. Conclusion: The mask absorbs different metals of welding fumes with different efficiencies. Improving the efficiency of the mask body to create a suitable fit that eliminates or minimizes the leakage caused by the seal is a priority.

Aim: The present study aimed to investigate the effect of meteorological parameters on particulate matter concentration (PM_2.5) in ambient air of Karaj metropolitan. Materials and Methods: In this cross-sectional descriptive study, 17 sampling points in Karaj city were chosen using GIS software. Sampling of PM_2.5 was carried out for 24 h using the sampling pilot during the four seasons in the air of Karaj city. Sampling of PM_2.5 was performed using PTFE filters, peripheral pump, and personal modular impactor. The concentration of particles collected on the filter was calculated by gravimetric method. Meteorological parameters including temperature, humidity, pressure, cloud coverage rate, ultraviolet (UV), and dew point were recorded during sampling through portable devices. Finally, the relationship between PM_2.5 concentration and meteorological parameters was assessed by SPSS24 and Excel software. Results: Seasonal variation trends of PM_2.5 particles showed that maximum and minimum annual concentrations have happened in autumn and spring seasons with a value of 67.48 and 19.85 μg/m³, respectively. Furthermore, the citizens of Karaj are exposed to PM_2.5 pollutants four times more than the Environmental Protection Agency-recommended standard (10 μg/m³). The findings of this study also show that there is a positive correlation between PM_2.5 particle concentration and temperature, relative humidity, and pressure (P < 0.05). Moreover, a weak and negative correlation was found between UV radiation, cloud cover, and dew point with PM_2.5 particle concentration (P > 0.05). Conclusion: The highest concentrations of particles were observed in autumn season. Furthermore, the particle concentration scatter map shows that the central and eastern regions and north of Karaj are more polluted than other areas. Therefore, to protect the health of citizens of Karaj, appropriate policies and strategies should be adopted to reduce the concentration of particulate matter and other pollutants in the ambient air of this city.

Aims: In this study, the concentration of particulate matter (PM)_2.5and PM₁₀particles and volatile organic compounds (VOCs) was measured from July of 2016 to June of 2017 in Gorgan City and the values of the air quality index (AQI) for particles were calculated and investigated. Materials and Methods: The concentrations of PM_2.5, PM₁₀, and VOCs were measured at eight stations in the city, and the relationship between different atmospheric conditions and the concentration of pollutants was assessed by statistical tests of variance analysis. Furthermore, the AQI values for the particles were measured, and based on the values of this index, using ArcGIS 10.3 software (ESRI Compony, USA), the zoning maps were prepared. Results: The average concentrations of PM_2.5, PM₁₀, and VOCs in the eight stations were 30.6 μg/m³, 41.3 μg/m³, and 0.82 ppm, respectively. The average concentration of PM_2.5and VOCs is higher than Environmental Protection Agency and clean air standards. Analysis of variance test was showed that the concentration difference of particles in different stations was not significant (P > 0.05), but for VOCs concentration, there was a statistically significant difference between the station of Seyed Masoud restaurant and Terminal square (P < 0.05). Furthermore, the results were showed that the temperature has an inverse relationship with the concentration of pollutants. AQI values for PM_2.5in the cold months of the year and in the central parts of the city were in the range of 101–150. The maximum AQI for PM₁₀was equivalent to 55, which was in December 2016. Conclusion: The air quality of Gorgan City was not in desirable conditions due to the high concentration of pollutants, especially PM_2.5and VOCs, and should be taken control proceedings.

Aims: This study was carried out to investigate the effect of predators' growth on biological excess sludge reduction of adsorption/bio-oxidation process (A/B process) as a modification of activated sludge system. Materials and Methods: The real municipal wastewater after screening and gritting was pumped into A/B pilot plant which consists of two aeration and sedimentation tanks in series. The hydraulic residence time for A and B stages was set at 1 and 4 h, respectively, at an average flow rate of 32 L/h. During operation, the mixed liquor suspended solids (MLSS) in A and B stages was gradually increased. In this period, the operational parameters including dissolved oxygen, pH, volatile suspended solids (VSS), MLSS, alkalinity, biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), phosphorus, nitrogen, and sludge volume index were monitored. Results: The results showed that with increasing solid retention time (SRT) from 0.6 to 56.8 days in Stage A, the biomass yield (Y) decreased from 1.29 to 0.23 g VSS/g COD. Similar results were observed in Stage B and correspondence to 67% reduction of Y as SRT increased from 1.6 to 123.8 days. During the A/B operation, overall tBOD₅and tCOD removal was 70% ± 20% and 57% ± 24%, respectively. Conclusion: Based on the results, A/B process operation with high SRT led to predator growth enhancement and lower biological excess sludge production.

Sustaining optimal health and well-being requires the contribution of multiple sectors and the role of environment sector is indispensable to the attainment of the same. Different types of hazards have been attributed to microplastics, based on the extent and route of exposure. There is an indispensable need to optimize the existing waste-water and drinking-water treatment systems, as this can significantly minimize the concentration of these harmful substances. In conclusion, humans have been exposed to microplastics through a wide range of sources. Acknowledging the fact that plastics in themselves are potential threats for climate deterioration and health hazards, it is high time that adequate focus should be given towards their reduction in production and optimal treatment to eventually minimize the health risks.