Seasonal and Spatial Variations in Water Quality and Its Ecological Implications on Challawa River, Nigeria

Abstract

The water quality of Challawa River, Kano, Nigeria at three sites was investigated for a period of eighteen months (January, 2005 - June, 2006). Results obtained showed some degree of variations along the river course. The pH, colour, temperature, bicarbonate and turbidity values
increased from sample site I (upstream), through site III (downstream) of the river. Levels of dissolved oxygen and phosphate decreased down the stream while biochemical oxygen demand, chemical oxygen demand, electrolytic conductivity, nitrate and sulphate fluctuated between sites. Significant differences (P < 0.05) between both sites and seasons for colour, pH, temperature, electrolytic conductivity, bicarbonate and sulphate exist while no significant difference (P > 0.05) was observed on both sites and seasons for turbidity, nitrate and phosphate. However, dissolved oxygen, biochemical oxygen demand and chemical oxygen demand were significantly different (P < 0.05) only between seasons. The implications of the results were discussed.

Keywords: Physico-chemical quality, seasonal, spatial, variation, Challawa River, Kano.