Partitioning Characteristics of Heavy Metals in a Non-Tidal Freshwater Ecosystem

Trace metals in the aquatic environment have to date come essentially from naturally occurring geochemical resources. However, this has been enhanced by anthropogenic activities resulting in pollution. Consequently, correlations and partitioning of trace metals in the dissolved phase, suspended particulate matter (SPM) and sediments were investigated in five selected sites along the Taylor Creek, southern Nigeria. The degree of correlations between the various metals was different in each of the investigated matrices. In the matrices studied, not many significant correlations (P < 0.05) were recognized. Only Ni-Cd (r=0.95), Mn-Cd (r=0.63), Mn-Ni (r=0.64) are correlated in the sediments and in SPM, Fe-Cr (r=0.54) and Zn-Ni (r=0.72), which suggests that the sources are not common for both matrices. In the dissolved phase, no strong correlations (P < 0.05) between the trace metals are obvious. The best correlations are observed for Ni-Zn (r=0.72) and Cd-Pb (r=0.65). Partitioning coefficients (Kd) of trace metals between dissolved phase and SPM are generally low, which is typical for fresh water ecosystems and fairly stable over the creek all through the seasons. Thus, the state of the aquatic ecosystem indicates that the trace metals, which are bio-accumulatable, could contribute to inferior biodiversity and shifts in community composition from sensitive to tolerant taxa.