Dynamics of antimicrobial resistance and susceptibility profile in full-scale hospital wastewater treatment plants.

Drug resistance has become a matter of great concern, with many bacteria now resist multiple antibiotics. This study depicts the occurrence of antibiotic-resistant bacteria (ARB) and resistance patterns in five full-scale hospital wastewater treatment plants (WWTPs). Samples of raw influent wastewater, as well as pre- and post-disinfected effluents, were monitored for targeted ARB and resistance genes in September 2022 and February 2023. Shifts in resistance profiles of Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii antimicrobial-resistant indicators in the treated effluent compared to that in the raw wastewater were also worked out. Ceftazidime (6.78 × 105 CFU/mL) and cefotaxime (6.14 × 105 CFU/mL) resistant species showed the highest concentrations followed by ciprofloxacin (6.29 × 104 CFU/mL), and gentamicin (4.88 × 104 CFU/mL), in raw influent respectively. WWTP-D employing a combination of biological treatment and coagulation/clarification for wastewater decontamination showed promising results for reducing ARB emissions from wastewater. Relationships between treated effluent quality parameters and ARB loadings showed that high BOD5 and nitrate levels were possibly contributing to the persistence and/or selection of ARBs in WWTPs. Furthermore, antimicrobial susceptibility tests of targeted species revealed dynamic shifts in resistance profiles through treatment processes, highlighting the potential for ARB and ARGs in hospital wastewater to persist or amplify during treatment.

The effect of interventional program underpinned by health belief model on awareness, attitude, and performance of nurses in preventing nosocomial infections: A randomized controlled trial study / Efecto de un programa de intervención basado en el modelo de creencias en salud sobre el conocimiento, la actitud y el desempeño del personal de enfermería en la prevención de las infecciones intrahospitalarias. Ensayo controlado aleatorizado / Efeito de um programa de intervenção baseado no modelo de crenças em saúde no conhecimento, atitude e atuação da equipe de enfermagem na prevenção de infecções hospitalares. Teste controlado e aleatório

Objective. The present study examined the effect of an interventional program underpinned by the Health Belief Model (HBM) on nurses' awareness, attitude, and performance in preventing nosocomialinfections.Methods. This randomized controlled trial study was performed on 60 clinical nurses in lar, Iran. Nurses were selected using the simple random sampling method and assigned to two experimental (n=30) and control (n=30) groups. Data collection tool included the valid and reliable questionnaire was developed by Soleimani et al. The research intervention consisted of five 90-min sessions based on the health belief model in preventing hospital infection for experimental group. Before the intervention, immediately and two months after the intervention, the two groups completed the questionnaire. The control group received no intervention. Results. Data analysis showed that the differences between the two groups was statistically significant immediately and two months after the intervention (p<0.05). In experimental group the changes in the mean score of knowledge, attitude and performance of nurses before, immediately and two months after the intervention were significant (p<0.05), but in the control group, only the changes in the mean score of performance were significant (p<0.05). Conclusion. The results showed that the HBM-based intervention is effective in promoting nurses' knowledge, attitude, and performance in preventing nosocomialinfections. hence, periodical and in-service HBM-based training programs on preventing nosocomialinfections are recommended to be held for nurses.

Objetivo. El presente estudio examinó el efecto de un programa de intervención basado en el modelo de creencias en salud (Health Belief Model -HBM-, en inglés sobre el conocimiento, la actitud y el desempeño de las enfermeras en la prevención de las infecciones intrahospitalarias. Métodos. Este ensayo controlado aleatorizado se realizó en 60 enfermeras clínicas de lar, Irán. Las enfermeras fueron seleccionadas mediante el método de muestreo aleatorio simple y asignadas a dos grupos experimental (n=30) y de control (n=30). La herramienta para la recogida de datos incluyó el cuestionario válido y fiable desarrollado por Soleimani et al.La intervención consistió en cinco sesiones de 90 minutos basadas en el modelo de creencias de salud para prevenir la infección intrahospitalaria en el grupo experimental. Antes de la intervención, inmediatamente y dos meses después de la intervención, los dos grupos completaron el cuestionario. El grupo de control no recibió ninguna intervención. Resultados. El análisis de los datos mostró diferencias estadísticamente significativas entre los dos grupos en los momentos inmediatamente y dos meses después de la intervención (p<0.05). En el grupo experimental, los cambios en la puntuación media de conocimientos, actitudes y rendimiento de las enfermeras se observaron en los momentos de antes, inmediatamente y dos meses después de la intervención (p<0.05); mientras que en el grupo de control solamente los cambios en la puntuación media de desempeño fueron significativos (p<0.05). Conclusión. Los resultados mostraron que la intervención basada en HBM fue eficaz para promover el conocimiento, la actitud y el rendimiento de las enfermeras en la prevención de las infecciones intrahospitalaria, por lo que se recomienda impartir a las enfermeras programas de formación periódicos y en servicio basados en HBM sobre la prevención de las infecciones intrahospitalarias.

Objetivo. Examinar o efeito de um programa de intervenção baseado no Modelo de Crenças em Saúde (MBH) no conhecimento, atitude e desempenho dos enfermeiros na prevenção de infecções hospitalares. Métodos. Este ensaio clínico randomizado foi conduzido em 60 enfermeiras clínicas de lar, Irã. Os enfermeiros foram selecionados pelo método de amostragem aleatória simples e distribuídos em dois grupos experimental (n=30) e controle (n=30). O instrumento de coleta de dados incluiu o questionário válido e confiável desenvolvido por Soleimani et al. A intervenção consistiu em cinco sessões de 90 minutos baseadas no modelo de crenças em saúde para prevenir infecção hospitalar no grupo experimental. Antes, imediatamente e dois meses após a intervenção, ambos os grupos responderam ao questionário. O grupo controle não recebeu nenhuma intervenção. Resultados.A análise dos dados mostrou diferenças estatisticamente significativas entre os dois grupos imediatamente e dois meses após a intervenção (p<0.05). No grupo experimental foram observadas alterações na pontuação média de conhecimentos, atitudes e desempenho dos enfermeiros antes, imediatamente e dois meses após a intervenção (p<0.05); enquanto no grupo controle apenas as alterações na pontuação média de desempenho foram significativas (p<0.05). Conclusão.Os resultados demonstraram que a intervenção baseada no HBM foi eficaz na promoção do conhecimento, atitude e desempenho dos enfermeiros na prevenção de infecções hospitalares, pelo que se recomenda proporcionar aos enfermeiros este tipo de programas de formação em serviço baseados no HBM.

Enhanced adsorption and recyclability of surface modified hydrophobic silica aerogel with triethoxysilane: removal of cefixime by batch and column mode techniques.

Amine modified pumice-derived silica aerogel (AMPDSA) was synthesized and grafted up to 6.52 [Formula: see text] with (3-aminopropyl) triethoxysilane for cefixime antibiotic adsorption. Using Response surface methodology, at the pH of 3, the maximum removal of cefixime of 80.42% for an initial concentration of 3.56 mg L-1 was achieved at an equilibrium time of 150 min. The compliance of various kinetic and isotherm models for the batch sorption system was corroborated from the correlation coefficient (R2) values. The maximum adsorption capacity of 19.76 mg g-1 and 49.63 mg g-1 was calculated for Langmuir and Khan isotherm models, respectively. The removal by fixed-bed column as a function of flow rate, initial cefixime concentration, and bed height was also performed. The maximum adsorption capacity of column with the bed height of 15 cm was found to be 31 mg g-1 at the flow rate of 10 mL min-1 for the initial concentration of 20 mg L-1. The compliance of Thomas model with the column sorption was observed. The characterization using SEM, BET, and XRD was carried out for the virgin and regenerated AMPDSAs. The regeneration experiments confirmed the ability of AMPDSA for its cefixime removal efficiency of 80% up to eight cycles.

Adverse effects of polystyrene nanoplastic and its binary mixtures with nonylphenol on zebrafish nervous system: From oxidative stress to impaired neurotransmitter system.

Micro(nano)plastics generally co-exist with other chemicals in the environment, resulting in inevitable interaction and combined toxic effects on biota. Nevertheless, little is known regarding the interaction of nanoplastics (NPs) with other co-occurring insults. Hereby, we investigated single and combined effects of chronic exposure (45 days) to polystyrene nanoplastic particulates (PS-NPs) and nonylphenol (4-NP) on zebrafish nervous system. Multiple biomarkers concerning with oxidative-stress [catalase (CAT) activity and reduced glutathione (GSH) level], cholinergic system [Acetylcholinesterase (AchE) activity], glutamatergic system [glutamine synthetase (GS) and glutamate dehydrogenase (GDH) activities], energy metabolism [a-ketoglutarate dehydrogenase (a-KGDH) activity], and histological alterations were assessed. Both single and binary exposure to PS-NPs and 4-NP induced oxidative stress through reducing CAT activity and GSH level, in which a more sever effect was noticed in combined exposure. The AchE activity was significantly inhibited only in single treatment groups demonstrating antagonistic interaction between PS-NPs and 4-NP. Effects on GS activity was also alleviated in binary exposure as compared with single exposure to each contaminant. In addition, an increase in GDH activity was noticed in PS-NPs at 10 and 100 µg/L, and simultaneous presence of PS-NPs and 4-NP with a greater response were observed in combined treatments. PS-NPs and 4-NP either in separate or binary mixtures disrupted energy metabolism by deficiency of α-KGDH activity; however, co-exposure to PS-NPs and 4-NP induced more intense adverse impacts on this parameter. Furthermore, histological analysis revealed that 4-NP and PS-NPs, alone or in combination, reduced neural cells. These findings provide new insight into the neurotoxic effects of binary exposure to PS-NPs and 4-NP at environmentally relevant concentrations. Overall, our findings raise concerns about the presence and toxicity of nano-scale plastic particulates and highlight the importance of investigating the interaction of Micro(nano)plastics with other environmental irritants.

The effect of interventional program underpinned by health belief model on awareness, attitude, and performance of nurses in preventing nosocomial infections: A randomized controlled trial study.

Objective: The present study examined the effect of an interventional program underpinned by the Health Belief Model (HBM) on nurses' awareness, attitude, and performance in preventing nosocomial infections. Methods: This randomized controlled trial study was performed on 60 clinical nurses in lar, Iran. Nurses were selected using the simple random sampling method and assigned to two experimental (n=30) and control (n=30) groups. Data collection tool included the valid and reliable questionnaire was developed by Soleimani et al. The research intervention consisted of five 90-min sessions based on the health belief model in preventing hospital infection for experimental group. Before the intervention, immediately and two months after the intervention, the two groups completed the questionnaire. The control group received no intervention. Results: Data analysis showed that the differences between the two groups was statistically significant immediately and two months after the intervention (p<0.05). In experimental group the changes in the mean score of knowledge, attitude and performance of nurses before, immediately and two months after the intervention were significant (p<0.05), but in the control group, only the changes in the mean score of performance were significant (p<0.05). Conclusion: The results showed that the HBM-based intervention is effective in promoting nurses' knowledge, attitude, and performance in preventing nosocomial infections. hence, periodical and in-service HBM-based training programs on preventing nosocomial infections are recommended to be held for nurses.

Placental plastics in young women from general population correlate with reduced foetal growth in IUGR pregnancies.

Constant exposure to plastics particulates has raised concerns against human health, particularly when it comes to birth outcomes. The present study explores the first appraisal of plastic particles in fresh human placenta and its association with foetal growth in neonates. Specifically, 43 pregnant women from general population were selected and their placentas were analyzed by digital microscopy and Raman microspectroscopy for microplastics (MPs <5 mm). We used regression analysis to estimate associations between MPs count in placenta and neonatal anthropometric measurements. MPs were found in all (13 out of 13) intrauterine growth restriction (IUGR) pregnancies and their average abundance ranged from 2 to 38 particles per placenta, but were less than limit of detection (LOD) in normal pregnancies except three out of 30 subjects. This study is one of very few that detected MPs in human placenta in which particles <10 µm were the most abundant in both IUGR and normal pregnancies, accounting for up to 64%. Fragments clearly prevailed at normal pregnancies and fragments together with fibers predominated at IUGR placentas. Despite four different polymers forming the MPs being identified, the majority of MPs comprised of PE (polyethylene) and PS (polystyrene). Inverse associations between MPs exposure and birth outcomes were observed in terms of birth weight (r = - 0.82, p < 0.001), length (r = - 0.56, p < 0.001), head circumference (r = - 0.50, p = 0.001), and 1-min Apgar score (r = - 0.75, p < 0.001) among those with IUGR, compared to those that were nominated as normal pregnancies. While it seems plastic particles may affect placental-foetal interrelationship, the pattern of associations between their content in placenta and birth outcomes, however, shows evidence of a nonlinear or nonmonotonic dose response possibly through perturbation of gas and nutrients exchange which is worth future investigation.

Occurrence, identification, and discharge of microplastics from effluent and sludge of the largest WWTP in Iran-South of Tehran.

Microplastic pollution is a serious threat to the biota and humans, and wastewater treatment plants act as a pathway for entering microplastics into the environment. This study discusses the identification and quantification of microplastics in the south of Tehran municipal WWTP. The sampling was repeated three times in a month, overall, nine times for water samples and once a month in total, three times for digested sludge samples by steel bucket with the WPO method. The microplastics from water and digested sludge samples were identified using the micro-Raman microscope. According to this study, 98.9% of microplastic particles in effluent and 99.2% of microplastics particles in the sludge were fibers. The influent contained an average of 180 ± 4.3 MP/L and was reduced to 5.3 ± 0.31 MP/L in the final effluent. Despite this significant reduction, we calculate that this WWTP releases 2.3 × 109 microplastics per day through final effluent and 1.61 × 1010 particles per day through dried sludge into the environment. We performed micro-Raman analyses and ICP mass to measure the amount of heavy metal absorption of MPs. In addition, SEM analyses were used to study the surface morphology of microplastic particles. PRACTITIONER POINTS: Fourteen different polymers were identified in the influent, effluent, and digested sludge. The main collected shapes obtained were fiber, film, and fragment, which fiber was the predominant polymer in this WWTP. The plant releases 2.3 * 109 MPs per day to its downstream environment. This WWTP has average removal with an efficiency of 99.06%.

Enhancement of MBBR reactor efficiency using effective microorganism for treatment of wastewater containing diazinon by engineered Pseudomonas putida KT2440 with manganese peroxidase 2 gene.

Pesticides not only are harmful to humans but they are noxious for water reservoirs, soil, and air quality as well. In this research, diazinon was removed from aqueous solutions by Moving Bed Biofilm Reactor (MBBR). The MBBR was spiked with transgenic Pseudomonas putida KT2440 with Pleurotus ostreatus fungus manganese peroxidase 2 gene to enhance the capabilities of Pseudomonas putida KT2440 in the degradation of diazinon. Although the amount of diazinon and COD and diazinon removal in the reactor including transgenic P. putida KT2440 was 95.46% and 97.47% and they were greater than the control and wild type (non-modified) P. putida KT2440 reactors, the surprising result was related to the adaptation pace of transgenic P. putida KT2440. The produced metabolites and the quantity of diazinon were assessed by HPLC and LC/MS. The metabolite hydroxyisopropyl diazinon was not found in the transgenic P. putida KT2440 reactor. Furthermore, a new sequence of cloned manganese peroxidase 2 gene has been recorded in GenBank with the accession number MT185558. According to bacterial identification of provided sludge the most frequent genus belonged to Aeromonas. Therefore, it seems that the MBBR in the presence of transgenic P. putida KT2440 with manganese peroxidase 2 gene can effectively remove the diazinon.

Association of SARS-CoV-2 presence in sewage with public adherence to precautionary measures and reported COVID-19 prevalence in Tehran.

Compared to the growing body of literature on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection and quantification in sewage, there are limited studies reporting on correlations between the viral loads in sewage and the prevalence of infected patients. The present work is a part of the regular monitoring effort for SARS-CoV-2 in wastewater influents from seven wastewater treatment plants (WWTPs) in Tehran, Iran, starting from late September 2020 until early April 2021. These facilities cover ~64% of the metropolis serving >5000,000 M individuals. The study set out to track the trends in the prevalence of COVID-19 in the community using wastewater based epidemiology (WBE) and to investigate whether these measurements correlate with officially reported infections in the population. Composite sewage samples collected over 16 h were enriched by polyethylene glycol precipitation and the corresponding threshold cycle (Ct) profiles for CDC 'N' and 'ORF1ab' assays were derived through real time RT-qPCR. Monte Carlo simulation model was employed to provide estimates of the disease prevalence in the study area. RNA from SARS-CoV-2 was detectable in 100% ('N' assay) and 81% ('ORF1ab' assay) of totally 91 sewage samples, with viral loads ranging from 40 to 45,000 gene copies/L. The outbreak of COVID-19 positively correlated (R2 = 0.80) with the measured viral load in sewage samples. Furthermore, sewage SARS-CoV-2 RNA loads preceded infections in the population by 1 to 2 days, which were in line with public adherence with and support for government instructions to contain the pandemic. Given the transient presence of human host-restricted infections such as SARS-CoV-2, these results provide evidence for assessment of the effectiveness of coordinated efforts that specifically address public health responses based on wastewater-based disease surveillance against not only COVID-19 but also for future infectious outbreaks.

The effect of job stress management training on observance of professional ethics by nurses.

The present study was conducted to investigate the effect of job stress management training on observance of professional ethics by nurses. This quasi-experimental study was performed on 50 clinical nurses in Shiraz, Iran. Data collection tools included a questionnaire. The research intervention consisted of six two-hour sessions of stress management training. SPSS 21 were used to analyze the data. Data analysis showed that before intervention, the level of professional ethics of 64% of nurses was relatively good, but after intervention, the level of professional ethics of the majority of nurses (94%) was at the desired level. The results showed that the levels of professional ethics after job stress management training has increased significantly compared to before. The results showed that stress management training has led to improving the level of professional ethics of nurses.

Synthesis of modified ZnO nanorods and investigation of its application for removal of phthalate from landfill leachate: A case study in Aradkouh landfill site.

In this study, zinc oxide nanorods, co-doped with iron and silver, were synthesized in a co-precipitation method. Its properties were determined using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), Dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS) analysis. The results of FE-SEM and TEM showed that zinc oxide nanoparticles synthesized and co-doped with iron and silver were formed as separate nanorods. Also, the average values of DBP and DEHP amount of phthalates in the leachate from the landfill site of Aradkouh were obtained 52.5 and 94.69 mg/L, respectively. The highest removal efficiency in real samples for phthalates was found to be 52%. The highest removal efficiency of TOC were was 61%. The synthesized nanostructure could have proper efficiency in removal of phthalates from water sources under the visible light of LED lamp.

Moore swab performs equal to composite and outperforms grab sampling for SARS-CoV-2 monitoring in wastewater.

Wastewater-based epidemiology (WBE) approaches to detect SARS-CoV-2 in municipal wastewater can provide unique information on the incidence or prevalence of COVID-19 in community. However, there are several technical challenges coupled with sewage sampling for SARS-CoV-2, including intermittent shedding of viruses, sampling time, volume, and frequency. Sampling schemes thus may need to be tailored to reach out highly sensitive, accurate, and reliable results. Herein, we compared the accuracy and threshold cycle (Ct) profiles of SARS-CoV-2 in Moore swabs, composite (16-h), and grab samples taken from sewage manholes (n = 17) at the Middle Eastern city of Tehran, Iran, on two occasions (November 2020 and May 2021). Samples were concentrated by polyethylene glycol precipitation and the corresponding Ct values for CDC 'N' and 'ORF1ab' assays were derived by means of real time RT-qPCR. Overall, the Moore swabs performed equal to samples composited over 16 h for qualitative monitoring, and 34/34 (100%) were positive for SARS-CoV-2. The 'N' assay showed the highest detection frequency as compared to 'ORF1ab'. The mean Moore swab Ct profiles were more consistent with 16 h composite sampling as compared with corresponding grab samples, providing hints as to the best sampling protocol to adopt when planning a sewage monitoring campaign particularly under WBE. Furthermore, our analyses on local differences showed somewhat higher virus copy numbers in the southern areas. The experimental design of this study revealed that the Moore swab and composite samples are more sensitive than grab samples, suggesting that the collection of grab samples may be inappropriate for characterizing total number of viral RNA copies in sewage samples. Given the transiently presence of human host-restricted infections such as SARS-CoV-2 and the simplicity and affordability of Moore swab, the method is well suited for disease surveillance in resource poor regions struggling with limited capacity for clinical testing.

Data on the microplastics contamination in water and sediments along the Haraz River estuary, Iran.

The type and extent of microplastic contamination in water and sediment of Haraz River were evaluated. Water and sediment samples were collected using a planktonic trawl with a mesh size of 300 µ and a Van Veen grab, from February to May 2017. The morphology and elemental compounds of microplastic particles were analysed using SEM/EDX. Moreover, differential scanning calorimetry (DSC) was done for polymers identification; so that the data could be used for comparative analyses. The number of pieces per kg dry weight in sediments and per cubic meter sampled water was determined. Last but not least, plastic types were also distinguished.

The emerging risk of exposure to nano(micro)plastics on endocrine disturbance and reproductive toxicity: From a hypothetical scenario to a global public health challenge.

Humans are potentially exposed to nano(micro)plastics, however their interaction with tissues and cells in humans remains largely unknown. This premise is particularly notable with nano-sized plastic particulates, a potentially most pernicious form of plastic pollution. In this study, even in a hypothetical scenario in terms of dose (1, 3, 6 and 10 mg/kg-day) and exposure time (five weeks), the potential endocrine disturbances with particular reference to reproductive toxicity of polystyrene nanoplastics (PS NPs, average size = 38.92 nm) was studied in male rats considering biomarkers of semen quality, changes in hormonal milieu and molecular signatures of endocrine disruption. Sperm DNA integrity and its chromatin structure were also analyzed. There observed significant inverse associations between exposure to PS NPs and serum concentrations of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Tissue and cell impairments were also noticed even at the lowest tested dosage, though the severity of lesions followed a clear dose-response pattern. DNA damage as well as alterations in sperm morphology and viability were evident, again proportionally with the amount of exposure dosage. RT-qPCR data were in accordance with the results of physio-histological alterations and fluorescence imaging, as significant down-regulation of PLZF, DAZL, FSH and LH gene expressions were noticed in the testis of exposed animals, suggesting that exposure interferes with spermatogenesis and also with HPT-axis. However, among those with highest exposure dosage, expressions of FSH and LH were significantly increased. ABP modulation further revealed evidence of a nonlinear dose response. The association between PS NPs exposure and GnRH was indeed in an unexpected positive direction, though these end-points were less sensitive at higher doses. Although additional evidence is warranted, the present work provides new insights into the possible risks of plastic nanoparticles exposure in humans, especially since the problem is growing and will persist for a long time.

Exposure to BTEX in beauty salons: biomonitoring, urinary excretion, clinical symptoms, and health risk assessments.

Benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations were measured in beauty salons (BS) and in the urine of the beauty practitioners and a control group. Indoor and outdoor concentrations of BTEX were measured in 36 randomly selected salons. Before- and after-shift urinary BTEX were measured from one female non-smoker employee in each salon, and repeated three times. Clinical symptoms in that beautician were assessed by a physician. Thirty-six unexposed women were included as the control group. Cancer and non-cancer risks of exposure were assessed using deterministic and stochastic methods. Average indoor concentrations of BTEX were higher than those in the ambient air. Urinary BTEX concentrations in the beauty practitioners were significantly higher than in the control group. Linear regression showed that 77% of urinary benzene and toluene variations can be explained by their airborne concentrations. A positive significant relationship was found between age and urinary BTEX concentrations. Although the BTEX cancer and non-cancer risks were not significant, BTEX led to irritation of the eyes, throat, lung, and nose. In addition, toluene caused menstrual disorders among beauty practitioners. These results suggest that it is essential to decrease the exposure of beauty practitioners to BTEX compounds.

ASSESSMENT OF INDOOR GAMMA RADIATION AND DETERMINATION OF EXCESS LIFETIME CANCER RISK IN TEHRAN IN WINTER AND SPRING 2017.

Natural radiation is a feature of the environment in which we live. One of the contributions of human exposure to ionizing radiation due to natural sources arises from gamma radiation. Therefore, present study was aimed to evaluate and map indoor gamma dose rate in Tehran. The corresponding annual effective dose (AED) and excess lifetime cancer risk (ELCR) were also calculated. All measurements were performed by a Geiger Muller detector in 43 dwellings in Tehran. The average indoor gamma dose rate in Tehran was appointed as 343.2 nGy/h. AED and ELCR were calculated as 2.4 mSv and 10.3 × 10-3, respectively. The evaluated indoor gamma dose rate and calculated AEDs and lifetime cancer risk were found higher than the world average value.

Thyroid endocrine status and biochemical stress responses in adult male Wistar rats chronically exposed to pristine polystyrene nanoplastics.

Toxicity evaluations of micro- or nano-sized plastics in rodent species commonly employed for toxicity analyses based on which risk assessment for humans could be performed are still largely lacking. Given this knowledge gap, the present work was aimed at determining the potential impact of chronic exposure to polystyrene nanoplastics (PS NPs) on the thyroid endocrine status and biochemical stress in a rat model. Young adult male rats were orally administered with PS NPs (1, 3, 6 and 10 mg kg-1 day-1) for five weeks. Thyroid hormones (THs) l-thyroxine (T4), l-triiodothyronine (T3), l-free triiodothyronine (FT3), and l-free thyroxine (FT4) as well as thyroid stimulating hormone (TSH) serum levels of normal rats and those exposed to PS NPs were compared. Serum levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, and creatinine, as well as glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) enzymes were also measured. Exposure to PS NPs suppressed the serum levels of T3 and circulating levels of THs, whereas TSH increased significantly. Though exposure to PS NPs did not affect the molar ratios of T3/T4, it induced a slight, but significant, increase in FT3/FT4. In addition, exposure to plastic nanoparticles showed signs of nephrotoxicity induction and kidney injury in exposed organisms as can be inferred from the significantly higher serum levels of creatinine in exposed groups. Our results provide clear evidence of an association between exposure to plastic NPs and thyroid endocrine disruption as well as metabolic deficit, and generate new leads for future research efforts.

Measurement and monitoring of anions, cations and metals in landfill leachate in Iranian metropolises.

Leachate generation is a major problem for municipal solid waste (MSW) landfills and causes significant threat to surface and groundwater. Samples were collected from the landfills of Iranian metropolises (Ahwaz, Mashhad, Tehran (before and after treatment plant), Isfahan, Tabriz, Hamedan, Rasht, Sanandaj and Qazvin) based on the standard sampling methods and transferred to the laboratory. Cr, Cd, Hg, Pb, Ni, As, Ca, Mg, Fe, Mn, Na, K, Zn, Al, Ba, Li, Sr, Ti and V were analyzed. The pH values for the ten leachate samples obtained from 4.57 to 8.95. The results showed the amount of some metals in Iranian landfill sites higher than the DOE standards for agricultural irrigation and surface water.

Health risk assessment of heavy metals on PM2.5 in Tehran air, Iran.

The general goal of this study was to measure the concentration of heavy metals on suspended particles and evaluate the health-risk assessment of these metals on human health. In this study, the concentration of heavy metals adsorbed on suspended particles less than 2.5 µm was determined. For determining of health-risk assessment, the developed method of USEPA was used. The health-risk assessment of carcinogen and non- carcinogen of suspended particles were evaluated in three main paths include oral ingestion, inhalation, and dermal contact. The average annual concentrations of Al, Fe, As, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn were 1.77, 1.14, 0.03, 0.02, 0.07, 0.15, 0.06, 0.03, 0.1, 0.04, and 0.14 µg/m3, respectively. Between different stations, the order for the heavy metals was followed as urban>traffic>suburban. The average risk of carcinogenic at urban stations in the spring for As, Cd, and Cr was 2.25*10-9, 2.09*10-12, and 2.05*10-11, respectively.

Neurobehavioral assessment of rats exposed to pristine polystyrene nanoplastics upon oral exposure.

The increasing use of plastics has raised concerns about pollution of freshwater by these polymeric materials. Knowledge about their potential effects on environmental and public health is limited. Recent publications have suggested that the degradation of plastics will result in the release of nano-sized plastic particles to the environment. Therefore, it is of utmost importance to gain knowledge about whether and how nanoplastics affect living organisms. The present study aimed to analyse potential neurobehavioral effects of polystyrene nanoparticles (PS-NPs) after long-term exposure on rat. Potential effects of PS-NPs were investigated using four test dosages (1, 3, 6, and 10 mg PS-NPs/kg of body weight/day) administrated orally with adult Wistar male rats for five weeks. Neurobehavioral tests were chosen to assess a variety of behavioral domains. Particle diameters in test suspensions were determined through dynamic light scattering and showed an average hydrodynamic diameter of approximately 38.92 nm. No statistically significant behavioral effects were observed in all tests performed (p > 0.05). In the elevated plus maze, PS-NPs-exposed rats showed greater number of entries into open arms compared to controls. Also, PS-NPs had no significant influence on body weight of animals. Taking into account the subtle and transient nature of neurobehavioral consequences, however, these results underline the possibility of even pristine plastic nanoparticles to induce behavioral alteration in the rest of the food web, including for marine biota and humans. Indeed even though studied neurobehavioral effects in our study was not statistically significant, the observed subtle effects may be clinically considerable.