title: Association between Aluminum and Silicon Concentrations in Isfahan Drinking Water and Their Health Risk Assessments.
abstract: BACKGROUND
  High concentrations of elements such as aluminum (Al) and silicon (Si) in drinking water can affect human health. It is suggested that high daily intake of Al is associated with increased risk of neurodegenerative disorders. Si, as an antidote of Al, may decrease Al bioavailability. The study was conducted to estimate Al and Si concentration and correlation in water and evaluate their health risk.
  
  
  METHODS
  In this cross-sectional study, water samples were collected from 20 points of water distribution system and the water treatment plant of Isfahan in spring and summer. Samples were analyzed using DR-5000. The health risk was evaluated via calculating chronic daily intake (CDI) and hazard index (HI).
  
  
  RESULTS
  Significant negative correlation was documented between Al and Si (R = -0.482, P = 0.037 in spring, and R = -0.452, P = 0.049 in summer). These values were approximately similar in all types of Al and Si. The amounts of CDI for Al in spring and summer were 6.67E-04 and 0.002 mg/kg/day, respectively. The Al HI values were below 1 in both seasons.
  
  
  CONCLUSIONS
  The significant correlation between Al and Si concentrations suggests that Si can eliminate Al in water, and probably it might do the same in the body. The health risk of Al intake from tap water was negligible, it was assessed in an acceptable range with an HI value of less than the standard levels. The health risk of Si remained unknown due to lack of information regarding its toxicity and adverse health effects.
authors.affiliation: Department of Environmental Health Engineering, Student Research Center, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hajar
authors.initials: H
authors.lastname: Pourgheysari
authors.affiliation: Department of Environmental Health Engineering, Environment Research Center, Research Institute for Primordial Prevention of Non Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Yaghoub
authors.initials: Y
authors.lastname: Hajizadeh
authors.affiliation: Department of Epidemiology and Biostatistics, Lorestan University of Medical Sciences, Khorramabad, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Tarrahi
authors.affiliation: Department of Environmental Health Engineering, Environment Research Center, Research Institute for Primordial Prevention of Non Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Afshin
authors.initials: A
authors.lastname: Ebrahimi
keywords: Aluminum; chronic daily intake; correlation; hazard index; silicon