The distribution and circulation of chromium and Cadmium in Tigris river were
estimated over a period (2001–2002). Significant difference was observed in the
concentration of these metals in any component of the homomorph model in studied
area. Result obtained were in agreement with those reported for heavy metal
concentrations in other polluted ecosystems. All components of the ecosystem were
involved in the circulation of the heavy metals either by accumulation or
concentrations processes.