Water Quality and Trophic State of Two Rivers in Edo State

Ekikhalo Catherine Osimen, Glory Omontese Ogbagha, Cyril Oziegbe Onogbosele

Abstract: The water quality and trophic state of Ovbioti and Owan Rivers in Owan West, Edo State, Nigeria was studied to determine their suitability for drinking and aquaculture. Water samples were collected from two sites in each river monthly from March to June 2015. Water level, air temperature, water temperature, pH, total dissolved solids (TDS), conductivity, total alkalinity, chloride, free carbon dioxide, dissolved oxygen, biochemical oxygen demand, total hardness, calcium, magnesium and phosphate were determined using standard methods. Chlorophyll a was extracted with acetone and determined with spectrophotometry. Carlsons trophic state index (CTSI) model for productivity was employed in the assessment of trophic state of the rivers. With the exception of magnesium, values of the physicochemical parameters did not exceed permissible limits for drinking water quality and tropical aquaculture. There was significant difference (p

Keywords: Physicochemical parameters, Oligotrophic, Carlsons index