The dominant Zn fractionwas residual in both sampling periods, indicating that Zn was associated, and immobilized, within the sediment matrix (66.3% in October 2009 and 65.7% in July 2010). However, more mobile forms of Zn were also identified in both sampling periods. The oxidizable fraction (18.8%) was the dominant mobile fraction in June 2010 while the reducible fraction (12.4%) was dominant in October 2009. The acid soluble fraction ranged from 1% to 15.4% with a mean of 5.5%. Except for Mn among the metals studied, Zn demonstrated a greater tendency to mobility, especially in the sediments of S-3 and S-4 in October 2009 and S-4 and S-6 in June 2010.