Pages: (1-12 )
Abstract
Thermal water effluents discharge from power stations has been a major source of pollution of some parts of the Lagos lagoon. Water chemistry and benthos around Egbin Power Plant located in the North Eastern axis of Lagos lagoon, South West Nigeria was investigated for five days during the periods of the study. Water and benthic samples were collected daily between 1000 and 1200 hours during the period of study. Highest water temperature (38.83 0C) was recorded at station 2 which correspond with the lowest dissolved oxygen (5.20mg/l) while the lowest water temperature (33.230C) correspond with the highest dissolved oxygen (8.00mg/l) in station 6. Apart from turbidity, other parameters of the water shows no significant differences (P>0.05) among the sampling stations. A total of 3 phyla comprising of 4 classes, 14 genera, 15 species and 946 individuals were recorded in the period of the study for all the sampling stations. The gastropods recorded the highest number (642) constituting about 67.9% of the total individuals sampled during the period of study. The polychaetes recorded the lowest number of individual (2) constituting only 0.2% of the total number of individual sampled. Station 6 recorded the highest number of individual (261) constituting of (27.6%) of individuals sampled in all the stations. All the four classes of benthic macro-invertebrates were represented in Station 3. The thermal pollution by the power plant might be responsible for the general low biodiversity of the study area.
Keywords: Water chemistry, thermal pollution, benthos, biodiversity,