PHYSICOCHEMICAL, HEAVY METALS AND HYDROCARBONS STUDYOF SURFACE WATER AND SEDIMENT FROM ALAPE RIVER AND ITS WATERSHED IN IGBOKODA, SOUTH-WEST NIGERIA.

Physicochemical, heavy metals and hydrocarbon parameters of fifteen surface water samples and fourteen sediment samples from the Alape River and its watershed in Igbokoda, South-Western Nigeria have been analysed. APHA and ASTM standard methods were employed in the analysis of the samples while obtained results were compared to DPR, NESREA, NSDWQ and WHO set standards. The mean pH values of the River and its watershed were found to be 6.78 and 7.25 respectively, falling within the recommended limit. In terms of DO, the mean values of 5.25 mg/L and 5.42 mg/L obtained were equally within the acceptable range for supporting aquatic organisms. Mean values of TS and salinity were relatively low, indicating favourable conditions. However, the mean total hardness value was considerably high. The River and its watershed exhibited low levels of O&G, TPH, and Cl-. The presence of organic matter was also observed, as demonstrated from the mean values of BOD and COD, suggesting some level of pollution. Furthermore, the sediments from the River contained detectable concentrations of some heavy metals; Fe, Pb, Cu, Mn, and Zn. The concentration of Fe exceeded the recommended limit set by NESREA. Overall, the research outcomes serve as valuable baseline data for future studies and offer insights to establish effective measures to prevent pollution in the event of industrialization in the area.