Aluminum (Al) is a widespread environmental contaminant with suspected links to neurodegenerative diseases, particularly Alzheimer's disease (AD). This systematic review and meta-analysis aimed to evaluate the association between environmental Al exposure and the risk of AD by synthesizing evidence from diverse sources and study designs. A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Literature searches were performed in PubMed, Scopus, Web of Science, EMBASE, and the gray literature up to June 2024. After duplicate removal and screening of 6504 records, 54 eligible studies on Al exposure and dementia/AD were included. Data extraction focused on exposure media, Al concentrations, Al and AD/dementia correlation, and geographic context. Screening was independently conducted by two reviewers, with good inter-rater reliability (Kappa = 0.75). Meta-analysis was conducted on the studies that reported sufficient quantitative data, using Hedges' g to estimate the effect size of Al exposure on AD. The included studies demonstrated considerable spatial and temporal variation. Of the 54 studies, 26 reported a positive association between Al exposure and AD or dementia, while 24 found no or negative associations. Major exposure sources included contaminated water, soil, diet, occupational settings, and medical interventions. Although few studies confirmed Al-induced brain pathology as a direct cause of dementia, meta-analysis of four eligible studies revealed a strong association between Al exposure and AD (Hedges' g = 2.451), despite high heterogeneity across data sources and outcome measures. Our findings suggest that environmental Al exposure may contribute to the development of AD, though it is likely one of several interacting risk factors. Environmental conditions appear to influence both Al bioaccumulation and its neurotoxic effects related to cognitive decline.

Background: Organophosphate pesticides are of concern to the drinking water supply and high risks on human health. Methods: An occurrence survey was performed in the spring and summer of 2016 for 6 months to assess the preva­lence of organophosphate pesticides in the Hablehrood River that is located in Semnan Province. Besides, 10 kinds of organophosphate pesticides were sampled in 5 stations. Moreover, were measured by Gas Chromatography (GC) was supported by an electron capture detector (ECD) and Turbochrom software. In all stations, Diazinon was detect­ed in the spring and summer, but Malathion only in the spring. Results: The highest concentration of Diazinon was observed at the Mahmoud Abad station in spring (0.94ppb) and the Bonekooh station in the summer (0.93ppb). The highest and lowest concentrations of Malathion were detected in Mahmoud Abad (0.35ppb), and Gache station, respectively. Conclusion: The concentration of pesticides in BoneKooh and Mahmood Abad was higher than the standard.

Controlling the microbiological quality of water is important for its uses. Microbiological requirements of drinking water ensure the absence of coliforms, but may indicate the potential presence of other potentially pathogenic microorganisms and viruses of fecal origin. A total of 36 water samples, representing the drinking water of the whole city of Aradan, Semnan, Iran, were randomly collected from the old and new distribution systems of Aradan from December 2014 to June 2015.The hetroterophic plate count (HPC), coliform, residual chlorine, and pH of the samples were measured. Heterotrophic bacteria were measure using R2A and nutrients agar culture media, and the spread plate count method was used to determine HPC. Average concentration of total coliform in the old distribution network ( 13⁄84 100 ml ) was more than the new distribution network ( 9⁄42 100 ml ). The results of studying microbial load in the old and new distribution network showed that there is a significant difference between total coliforms in the two networks (P = 0.002). Moreover, the average concentration of heterotrophic bacteria in the old distribution network (1917.33 number/100 ml) was more than that in the new distribution network (14.57 number/100 ml). There was a significant difference between the average concentration of heterotrophic bacteria in the old and new distribution networks (P = 0.003). The effects of seasons and the age of the water network on coliform bacteria and heterotrophic bacteria were also studied. The concentrations of heterotrophic bacteria, total coliform, and fecal coliforms were higher in the old distribution network in comparison to that in the new distribution network.

The majority of diseases caused by air pollution, such as asthma and allergies, are caused by pathogenic bacteria, which are transmitted through bioaerosols. Bacteria and fungi are the main sources of hospital infections causing the majority of diseases and cases of mortality. The aim of this study was to determine the ratio of indoor to outdoor fungi concentration, the effect of population density on fungi concentration, and the relationship between indoor and outdoor environments. In this study, 3 stations were assessed; the outdoor environment, general indoor environment, and intensive care units (ICUs) of a hospital affiliated to Ahvaz University of Medical Sciences, Iran. These stations were used for the sampling of airborne fungi from October to December 2010. The samples were collected over a period of 2 minutes in a flow rate of 28.3 l/minute using a QuickTake 30 air sampling pump. The 3 dominant fungi genera in the sampling stations were Aspergillus, Penicillium, and Cladosporium. The average of total fungi concentration before visiting hours was 365.8 CFU/m which was reduced to 578 CFU/m after visiting hours. The indoor to outdoor ratios in the ICU and internal wards for fungi before visiting hours were 0.36 and 0.68, respectively. However, these ratios in the ICU and internal wards for fungi after visiting hours were 0.78 and 0.99, respectively. Following the visiting hours, the concentration of fungi available indoors was conspicuously higher (even in the wards in which no visitors were allowed (e.g., ICUs). Hence, the amount of indoor fungi was affected by the concentration of outdoor fungi and the number of visitors.

Controlling the microbiological quality of water is important for its uses. Microbiological requirements of drinking water ensure the absence of coliforms, but may indicate the potential presence of other potentially pathogenic microorganisms and viruses of fecal origin. A total of 36 water samples, representing the drinking water of the whole city of Aradan, Semnan, Iran, were randomly collected from the old and new distribution systems of Aradan from December 2014 to June 2015.The hetroterophic plate count (HPC), coliform, residual chlorine, and pH of the samples were measured. Heterotrophic bacteria were measure using R2A and nutrients agar culture media, and the spread plate count method was used to determine HPC. Average concentration of total coliform in the old distribution network ( 13⁄84 100 ml ) was more than the new distribution network ( 9⁄42 100 ml ). The results of studying microbial load in the old and new distribution network showed that there is a significant difference between total coliforms in the two networks (P = 0.002). Moreover, the average concentration of heterotrophic bacteria in the old distribution network (1917.33 number/100 ml) was more than that in the new distribution network (14.57 number/100 ml). There was a significant difference between the average concentration of heterotrophic bacteria in the old and new distribution networks (P = 0.003). The effects of seasons and the age of the water network on coliform bacteria and heterotrophic bacteria were also studied. The concentrations of heterotrophic bacteria, total coliform, and fecal coliforms were higher in the old distribution network in comparison to that in the new distribution network.