SEASONAL EVALUATION OF THE EFFECTS OF CHEMICAL EFFLUENTS ON SELECTED WATER BODIES IN RIVERS STATE, NIGERIA

Abstract

Abstract This study evaluated the effects of chemical effluents discharge on selected water bodies (Okulu and Chokocho Rivers) in Rivers State, Nigeria. The sampling was conducted in the rainy and dry seasons. The water samples collected were analyzed for physicochemical parameters and heavy metal content. The results revealed that the rivers were neither acidic nor too alkaline in nature, with no significant seasonal variation in pH and dissolved oxygen levels of the rivers. Rainy season mean electrical conductivity levels were 61.90 and 1548.63 µs/cm for Chokocho and Okulu rivers respectively; dry season mean conductivity levels were 62.47 and 1933.49 µs/cm for Chokocho and Okulu rivers respectively. Rainy season mean chloride levels were 48.51 and 438.85 mg/l for Chokocho and Okulu rivers respectively; dry season mean chloride levels were 50.46 and 491.87 mg/l for Chokocho and Okulu rivers respectively. Rainy season mean Total PAHs were 3.55 and 601.57 mg/l for Chokocho and Okulu rivers respectively; dry season mean Total PAHs were 4.07 and 385.95mg/l for Chokocho and Okulu rivers respectively. Rainy season mean NO3- levels were 10.53 and 74.06 mg/l for Chokocho and Okulu rivers respectively; dry season mean NO3- were 10.64 and 69.27 mg/l for Chokocho and Okulu rivers respectively. Rainy season mean TDS levels were 52.11 and 618.88 mg/l for Chokocho and Okulu rivers respectively; dry season mean TDS were 50.52 and 1160.09mg/l for Chokocho and Okulu rivers respectively. Rainy season mean Oil and Grease levels were 5.10 and 288.01mg/l for Chokocho and Okulu rivers respectively; dry season mean Oil and Grease were 5.10 and 288.01mg/l for Chokocho and Okulu rivers respectively. Rainy season mean BOD levels were 4.05 and 9.25mg/l for Chokocho and Okulu rivers respectively; dry season mean BOD were 4.10 and 9.3mg/l for Chokocho and Okulu rivers respectively. Rainy season mean COD levels were 78.35 and 678.44 mg/l for Chokocho and Okulu rivers respectively; dry season mean COD were 77.74 and 616.62mg/l for Chokocho and Okulu rivers respectively. It was observed that approximately 85% of physicochemical components of Okulu River exceeded limits; 100% of heavy metals in Okulu River surpassed limit. About 20% of physicochemical components of Chokocho River exceeded limits; about 30% of heavy metals in Chokocho River surpassed limit. The study showed that the Okulu River is more polluted than Chokocho River which underscored the need for urgent government interventions to safeguard waterbodies in Rivers State from further deterioration. Keywords: Chemical Effluents, physicochemical components, heavy metals, rainy season, dry season