标题：Some Aspects of the Limnology and Heavy Metal Content of Water, Sediment and Oreochromis niloticus (Linnaeus, 1758) from Ologe Lagoon, Lagos, Nigeria
摘要：This study examined some limnological properties of Ologe Lagoon and the levels of six heavy metals (Cu, Zn, Cd, Pb, Fe and Cr) were also assessed in water, sediment and a commercially important fish, Oreochromis niloticus from the lagoon. The study lasted between July, 2010 and April, 2011 spanning both dry and wet season. Some of the physicochemical parameters (temperature, pH, salinity, dissolved oxygen and alkalinity) did not show significant (p>0.05) monthly variation. However, others (turbidity, total hardness, conductivity, total dissolved solids, total suspended solids, chemical oxygen demand and biological oxygen demand) showed significant (p<0.05) monthly variation. All the water quality variables investigated in this study did not show seasonal variation except turbidity, chemical oxygen demand and biological oxygen demand. The concentrations of five of the heavy metals (Cu, Zn, Cd, Pb and Fe) showed significant monthly variation in water and sediment. The range of concentrations of Cu, Zn, Cd, Pb and Fe in this study is 26.68±2.65-44.79±6.11, 29.41±2.52-94.40±12.08, 4.67±1.45-16.48±1.18, 6.43±1.03-21.60±2.08 and 60±15-290±32 μg L-1, respectively. The concentrations of Zn and Fe in Oreochromis niloticus showed significant monthly variation and their range of values are Zn, 0.19±0.15-1.69±0.33 mg kg-1 and Fe, 5.08±1.50-12.56±3.12 mg kg-1. This study has shown that these heavy metals are present in Ologe Lagoon, though, their levels are still within the tolerable limits.
