MJS15-6

This study assessed the changes in plankton abundance and physicochemical properties in three different rivers (Agba, Oyun, and Asa) in Ilorin, Kwara State, Nigeria. About 250 mL of water samples collected were collected into properly labeled zooplankton and phytoplankton glass containers and preserved in formalin and Lugol’s iodine solution, respectively, and the physicochemical parameters were all measured. About 61 phytoplankton species from three classes were identified. Bacillariophyceae (diatoms and desmids) were found to be the most abundant class, accounting for 63.93%, followed by Cyanophyceae (22.95 %), and finally Chlorophyceae (14.95 %). In the Agba, Asa, and Oyun Rivers, a total of 20 zooplankton species were identified. Protozoa accounted for 15% of the zooplankton found in the three rivers, followed by crustacea (50%). The pH of the water was determined to be between 6.40 and 6.80, with a mean temperature of 25.50°C and 26.90°C. Heavy metals like magnesium had the greatest mean values in the Agba, Oyun, and Asa Rivers. Human activities, particularly those related to agriculture, are a key contributor to the problem. This study will give information on river plankton distribution, potential health problems, and river water treatment strategies. However, more studies on monthly sampling and comparison with other rivers within the states will be necessary.