摘要：As part of assessment Ase river, in dry and wet season of 2006, sediment samples were collected at five locations to determine spatial variation of anthropogenic pollutants. Heavy metal levels (mg kg-1) in the sediment were Cd 2.89±2.97, Pb 7.00±10.04, Cr 2.34±2.53, Cu 3.32±2.37, Mn 24.27±9.92, Ni 7.04±7.49, Fe 110.53±101.54 and Zn 12.46±4.56 for dry reason and Cd 2.35±2.71, Pb 6.42±9.03, Cr 21.16±2.19, Cu 3.38±1.72, Mn 21.58±14.93, Ni 5.62±4.22, Fe 86.93±88.36 and Zn 5.63±4.22 for wet season. The results (p≥0.05) revealed significant spatial and temporal variation in the characteristic levels of heavy metals in the sediments. The variance results from changes in contaminants supply, rate of deposition and erosion as well as seasonal variability in physicochemical conditions. The accumulation pattern of heavy metals in the sediment follows the order Fe> Mn >Zn >Ni >Pb >Cu >Cd >Cr. The levels of heavy metals were similar to levels found in unpolluted sediments and continental crust except for Cd. Such sediment system is at risk of cadmium pollution.
