Risk Assessment of Contamination by Heavy Metals in Zanjan of Iran using SAW methodA. Khodadadi, M. Hayaty, M. R. Tavakoli Mohammadi, S. Partani, M. Marzban and H. HashemiE3S Web of Conferences, 1 (2013) 41013DOI: https://doi.org/10.1051/e3sconf/20130141013