marzieh farhadkhani 1. dept. of environmental health engineering, school of health, isfahan university of medical sciences , isfahan, iran. mahnaz nikaeen 1. dept. of environmental health engineering, school of health, isfahan university of medical sciences , isfahan, iran. behrouz akbari adergani 2. water safety research center, food and drug organization, ministry of health and medical education , tehran, iran. maryam hatamzadeh 1. dept. of environmental health engineering, school of health, isfahan university of medical sciences , isfahan, iran. bibi fatemeh nabavi 1. dept. of environmental health engineering, school of health, isfahan university of medical sciences , isfahan, iran. akbar hassanzadeh 3. dept. of statistics and epidemiology, school of health, isfahan university of medical sciences , isfahan, iran.