Explore the vast range of titles available.

Ensuring a healthy indoor environment for children is crucial, as they are particularly vulnerable to environmental hazards. Indoor radon exposure is a significant concern due to its carcinogenic effects. This study assessed radon concentrations in primary schools and kindergartens in Kermanshah, Iran, estimated the annual effective dose, and evaluated potential health risks. This cross-sectional study randomly selected 24 primary schools and kindergartens across Kermanshah. Radon concentrations were measured seasonally using a radon meter (SARAD, RTM1688). Air samples were collected at breathing height and at least 40 cm from walls. Building characteristics were recorded using a checklist, and meteorological parameters were measured during sampling. Statistical analysis was conducted using SPSS version 25. The average annual radon concentration was 37.1 ± 6.1 Bq/m 2 in kindergartens and 30.9 ± 6.5 Bq/m 2 in primary schools. The highest concentration was recorded in winter (39.4 ± 4.9 Bq/m 2 ) and the lowest in summer (30.6 ± 6.1 Bq/m 2 ). Radon concentrations correlated significantly with classroom size and relative humidity ( p  ≤ 0.01) but not with building age. Ground-floor rooms had higher concentrations, particularly in winter. Rooms with granite walls exhibited the highest radon concentrations (39.15 Bq/m 2 ), while those with plaster and paint had the lowest (28.5 Bq/m 2 ). The estimated annual effective lung dose was 0.28 mSv/y in kindergartens and 0.23 mSv/y in primary schools, both below the UNSCEAR recommended limit of 1.15 mSv/y. Indoor radon concentrations in Kermanshah’s primary schools and kindergartens were below WHO and ICRP safety thresholds. However, as radon’s effects build up over time, even low levels can contribute to a higher lifetime dose of radiation, increasing health risks over decades and the World Health Organization (WHO) recommend mitigation even at relatively low levels. Therefore, efforts should be made to increase public awareness, and policymakers must implement radon-resistant building codes while maintaining adequate ventilation systems. Further research is needed to identify influencing factors and develop mitigation strategies.

There is an increasing concern about the health effects of exposure to a mixture of pollutants. This study aimed to evaluate the associations between serum levels of heavy/essential metals ([Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Nickel (Ni), Chromium (Cr), Copper (Cu), Iron (Fe), and Zinc (Zn)]) and the risk of developing cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2D). Data were collected from 450 participants (150 with CVDs, 150 with T2D, and 150 healthy subjects) randomly selected from the Ravansar Non-Communicable Disease (RaNCD) cohort in Western Iran, covering the years 2018–2023. Trace element levels in the serum samples were assayed using ICP-MS. Logistic regression was performed to estimate the adjusted risk of exposure to single and multi-metals and CVD/T2D. Odds ratios were adjusted for age, sex, education, residential areas, hypertension, and BMI. The mixture effect of exposure to multi-metals and CVD/T2D was obtained using Quantile G-computation (QGC). In the logistic regression model, chromium, nickel, and zinc levels were associated with CVD, and significant trends were observed for these chemical quartiles ( P  < 0.001). Arsenic, chromium, and copper levels were also associated with T2D. The weight quartile sum (WQS) index was significantly associated with both CVD ( OR  4.17, 95% CI 2.16–7.69) and T2D ( OR  11.96, 95% CI 5.65–18.26). Cd, Pb, and Ni were the most heavily weighed chemicals in these models.The Cd had the highest weight among the metals in the CVD model (weighted at 0.78), followed by Hg weighted at 0.197. For T2D, the serum Pb (weighted at 0.32), Ni (weighted at 0.19), Cr (weighted at 0.17), and Cd (weighted at 0.14) were the most weighted in the G-computation model. The results showed the significant role of toxic and essential elements in CVDs and T2D risk. This association may be driven primarily by cadmium and mercury for CVDs and Pb, Ni, Cr, and Cd for T2D, respectively. Prospective studies with higher sample sizes are necessary to confirm or refute our preliminary results as well as to determine other important elements.

Microplastics (MPs) as an emerging pollutant can affect aquatic organisms through physical ingestion, chemical problems and possible creation of biological layers on their surfaces in the environment. One of the significant ways for MPs to enter the aquatic environment is through the effluent discharge of wastewater treatment plants (WWTPs). In this study, first, the concentration and characteristics of MPs in secondary wastewater effluent, and the influential variables related to the coagulation process, for MPs removal were identified using systematic reviews of previous studies. Then, the most proper MPs characterization and coagulation variables were chosen by experts’ opinions using a fuzzy Delphi method. Therefore, the experiment tested in conditions close to the full-scale wastewater treatments. Finally, in the laboratory removal of MPs by coagulation of polyamide (PA), polystyrene (PS), and polyethylene (PE), < 125 and 300–600 μm in size, was tested by a jar test applying Al 2 (SO 4 ) 3 in doses of 5 to 100 mg/L plus 15 mg/L polyacrylamide as a coagulant aid. Using R and Excel software, the results were analyzed statistically. It was concluded that the maximum and minimum removal efficiency was 74.7 and 1.39% for small PA and large PE, respectively. Smaller MPs were found to have higher removal efficiency. The MPs type PA achieved greater removal efficiency than PS, while PE had the least removal efficiency.

This research was conducted to study the adsorption of ammonium ions onto pumice as a natural and low-cost adsorbent. The physico-chemical properties of the pumice granular were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Modeling and optimization of a NH₄⁺ sorption process was accomplished by varying four independent parameters (pumice dosage, initial ammonium ion concentration, mixing rate and contact time) using a central composite design (CCD) under response surface methodology (RSM). The optimum conditions for maximum removal of NH₄⁺ (70.3%) were found to be 100 g, 20 mg/l, 300 rpm and 180 min, for pumice dosage, initial NH₄⁺ ion concentration, mixing rate and contact time. It was found that the NH₄⁺ adsorption on the pumice granular was dependent on adsorbent dosage and initial ammonium ion concentration. NH₄⁺ was increased due to decrease the initial concentration of NH₄ and increase the contact time, mixing rate and amount of adsorbent.

The present study aimed at synthesizing chromium doped zinc oxide nanoparticles (Cr:ZnO NPs) under mild hydrothermal conditions (temperature ~100 °C, p = autogenous and time ~12 hr). Chromium oxide and n -butylamine were used as dopant and surface modifier, respectively. The characteristics of the synthesized nanoparticles were determined through conducting specialized experiments including powder XRD, FTIR, SEM, EDX, and UV-VIS spectroscopy. Then, the Cr:ZnO NPs were immobilized on a sandblasted glass through thermal method. The photocatalytic degradation of aniline was conducted in a continuous reactor with a volume of 1.5 liters. Before and after photocatalytic degradation, the immobilized Cr:ZnO NPs were characterized for SEM and EDX to determine the degree of stability of immobilized nanoparticles as well as the influence of the current applied on them. The photodegradation operational parameters investigated were aniline initial concentration (150, 200, and 250 mg/L), pH (5, 7, 6, and 12), and reaction time (2, 4, and 6 hours) under sunlight illumination. The characterization results indicated high purity of the Cr:ZnO NPs and no change in morphology or composition even after the immobilization and photo-oxidation process. Finally, it was found that the optimum conditions for 93% removal of aniline under sunlight illumination was about 6 hours retention time at pH 9.

In this study, the photocatalytic efficiency of scoria-Ni/TiO 2 nanoparticles is evaluated for methyl orange removal under both the ultraviolet (UV) and sunlight irradiations. The synthesized catalysts are characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectra (DRS), scanning electron microscope (SEM), and energy dispersive X-ray analysis (EDAX) analysis. According to the results, the absorption edge of TiO 2 alternated to visible light successfully, and the SEM and EDAX analysis approved that the particles, which are in nano-size, doped on the scoria. The effect of pH, catalyst dosage, methyl orange concentration, and contact time on efficiency was assessed. The initial experiment revealed that 0.05% and 0.1% of nickel have more efficiency while using the sun and UV light sources, respectively. In a 50-ml lab-scale reactor, methyl orange removal efficiency by scoria-Ni/TiO 2 was 95.89 and 93.97% under UV and sunlight irradiation, respectively, within 45 min contact time while it was 26.7 and 45.9% under the sun and UV light irradiation, respectively, for commercial TiO 2 . In addition, the reaction kinetics followed the Langmuir–Hinshelwood model. Finally, radical production and catalytic activity of Ni/TiO 2 verified by significant decrease in removal efficiency due to surface and solution radical scavengers addition. Graphic abstract

Iron deficiency is the most common nutritional disorder detrimental to the behavior, cognitive performance, immune system, and physical growth of infants and preschool- and school-age children. Iron deficiency anemia (IDA) increases children’s susceptibility to some metals, including the highly toxic lead (Pb), but the character of this relationship is still disputed. Thus, this study aimed to review and meta-analyze the association between the IDA and blood lead levels (BLL) among children, based on papers indexed by international scientific databases and published up to September 2021. A search was performed of the literature in several databases including the ISI Web of Science, PubMed, and Scopus. The final papers were assessed concerning their quality based on the Newcastle–Ottawa Scale (NOS) for cross-sectional studies. Moreover, analyses were performed using R statistical software with the “meta” package. Of the 1528 articles found, only 12 studies met the inclusion criteria and were considered in the meta-analysis. Significantly higher BLL in IDA children (SMD = 2.40; CI 95%, 0.93–3.87 µg/L; p  = 0.0014) was seen when compared to non-IDA children. Moreover, the pooled OR is equal to 2.75 (CI 95%, 1.10–6.85 µg/L; p  = 0.0303) suggesting a higher risk of IDA development among children with BLL > 10 µg/dL. Thus, we recommend systematic monitoring of Fe and Pb levels among children, especially in countries with limited sources of nutritious food. Since only a few studies were available for this meta-analysis, further studies are necessary to examine the association between IDA and BLL in detail.

Recently, we showed that pre-treatment with ultrasound/ozone (US/O3) could remarkably enhance the performance of coagulation in removing natural organic matter (NOM) and turbidity from surface waters. In the present study another of our aims was to investigate whether pretreatment with coagulation combined with post-oxidation (US/O3) can also remove NOM, turbidity and coliform from the same water resources. NOM and turbidity removal were measured by UV absorbance at 254 nm (UV254) and a turbidimeter, respectively. Aluminum sulfate (alum), ferric chloride (FC), and poly aluminum chloride (PACl) were tested as coagulants. The disinfection potential of the US/O3 process was evaluated by measuring coliform counts. The effects of different input variables including ozone dose, power intensity, ultrasound frequency, reaction time, coagulant type, dose of coagulant and coagulant aid were examined on the process performance. Design of experiments (DoE) and surface response methodology (RSM) techniques were employed to optimize the operating parameters. Individual coagulation process with ferric chloride decreased NOM and turbidity up to 33% and 15%, however pre-coagulation with ferric chloride combined with US/O3 decreased NOM and turbidity 75% and 32%, respectively. PACL was the best coagulant in the sole coagulation, but in pre-coagulation combined with US/O3 process, FC exhibited the best performance. Treatment with US/O3 following pre-coagulation decreased the amount of coagulant and coagulant aid needed for the treatment. Pre-coagulation followed by US/O3 improves the NOM, turbidity and coliform removal, and so could be considered as a potential method for removing NOM, turbidity and coliform.

The current study aimed to evaluate the levels of some toxic and essential elements (Pb, Cd, Cu, Ti, Ni, Cr, Co, Fe, Ca, Hg, Mn, Se, and Zn) in the urine of opium-addicted compared to non-addicted cases. In this study, 126 participants were recruited and their fasting urine samples were collected (63 opium-addicted and 63 non-addicted subjects served as the reference group). ICP-MS was utilized to detect the concentration of trace elements. Results exhibited that the concentration of all elements than Ni, Cu, and Zn was markedly different between the addicted and non-addicted groups. Compared to controls, the Cd, Cr, Co, Hg, Mn, Pb, Se, and Ti levels were higher among opium-addicted cases ( p < 0.05) whereas the Fe and Ca concentrations were higher among controls ( p < 0.05). Robust regression analysis showed no statistically significant effect of gender on element levels. It revealed that age was associated with the levels of Ni and Cu only and also the route of administration was related to the urinary levels of Co, Cr, Hg, and Mn. In conclusion, results confirmed that it is opium consumption that affects the concentration levels of most elements.

The aim of the present study is to evaluate the application of high rate integrated anaerobic-aerobic/biogranular activated carbon sequencing batch reactor (IAnA-BioGACSBR) to treat raw strong leachate from open dumping of municipal solid waste. The influence of two important and effective independent variables, COD concentrations and volumetric filling rate with GAC, onto the leachate treatment were investigated. Three responses such as TKN, BOD and COD were considered for evaluating the interaction of parameters. The results showed that maximum BOD 5 removal of 98.9% in anaerobic zone and 99% in aerobic zone was obtained at the highest values of COD (~30000 mg/L) and filling ratio (~50%). The highest values of COD removal efficiency were found to be 98.54% and 98%, at COD rate of 10000 mg/L and GAC of 35%, respectively. The highest removal values of TKN was 77.2% and 78.9% in anaerobic and aerobic zone, respectively. Under optimal conditions, compared with the SBR and the GAC-SBR performances, results reveal that the application of the GAC-SBR has shown better effluent characteristics. Based on the results, it can be asserted that the application of the high rate IAnA-BioGACSBR for the treatment of biodegradable landfill leachate was more effective.