In this study, the total concentrations of As, Cd, Cr, Ni, Hg, Cu, Se, Pb and Zn in top layer and C horizon of soils of Hamedan province were measured. In the next step, the health risk associated with these metals for residents of the studied regain was assessed using the total non-cancer hazard quotient and cancer risk assessment equations presented by USEPA. Then, continuous maps of human health risk related to Ni and Hg were prepared using multi factor method and S- shaped fuzzy memberships in MATLAB software. Accumulation rates of the metals in agricultural soils of the studied region were also modeled using Mass Flux Analysis (MFA) model after some modifications to add weathering input and distinguishing different animal manures effect in total uncertainties of the model. A total of 286 soil samples from surface layer (0- 30 cm) and C horizon, 145 samples from edible parts of wheat, potato, barley and maize, 11 irrigation and drinking water samples, and 3-5 samples from different kinds of animal manures commonly used in the region were taken. According to the results obtained, the total non-cancer hazard of Ni and Hg were greater than 1. The total cancer risk of As and Pb was greater than 1 × 10 ?6 . Food consumption was identified as the major route of human exposure to metals although soil ingestion was found as an important exposure route for children. Through the studied region, manure was the most important flux of all metals. Crop removal was the next important flux of Zn, Cu and Se. The main sources of uncertainties related to animal manures were cattle native and fat poultry. Key Words: heavy metals, risk assessment, Hamedan Province, risk maps, mass balance modeling.
