Total and Available Copper and Zinc in Soils Affected by Palm Oil Mill Effluent in Oghareki, Oghara Kingdom, Delta State, Nigeria

Abstract

This study evaluates the physicochemical characteristics, total and available copper and zinc in soils affected by four palm oil mills effluent (POME) of Oghareki in Oghara Kingdom, Delta State, Nigeria using standard methods. The results showed generally increased pH, organic matter, electrical conductivity, available phosphorus, exchangeable bases and cation exchange capacity (CEC), compared to the non-POME-contaminated soils. Concentrations of the exchangeable bases increased in the order, Na < Mg < K <Ca, in both the POME- and non-POME-soils. Data of total copper and zinc also revealed higher amounts in the POME soils. Total copper in POME- and non-POME-soils gave means of 0.232 and 0.212 mmol/kg, and 0.237 and 0.219 mmol/kg in respect of zinc, respectively, with no significant difference (P<0.05). The increased amounts of the different soil physicochemical parameters recorded in the POME-affected soils may be accounted for by their enhancement with every discharge of the effluent on one hand, and perhaps, the greater level of biodegradation and mineralization of the constituent organic matter, on the other. The study lends support to the view that raw palm oil mill effluent (POME) could alter the physicochemical properties of the receiving environment.