Evaluation of the impact of untreated cassava mill effluent on the physicochemical properties of the soil in Aba, Abia State, Nigeria.

Abstract

Samples of fresh cassava effluent, cassava effluent polluted soil and unpolluted soil were collected during the rainy season to evaluate the effect on the physicochemical characteristics of the soil in Aba, Abia State. The physical and chemical parameters of the untreated cassava mill effluent, untreated cassava mill effluent-polluted soil and unpolluted soil were determined using standard laboratory methods. It was observed that addition of cassava mill effluent to the soil resulted to changes in the physicochemical parameters. The cyanide content, conductivity, turbidity, moisture content, TDS, TSS, TS, total acidity, total alkalinity, total chloride, and magnesium were higher in the contaminated soil samples than the unpolluted soil. The values of pH, Total hardness, calcium hardness, phosphorus, organic carbon, COD and BOD of the contaminated soil samples were lower than those of the unpolluted soil due to high content of hydrogen cyanide present in the contaminated soil. The high cynogenic potential had been attributed to the high cyanogenic glucoside (linamarin and lotaustralin) contained in cassava. The pH range of the untreated cassava mill effluent and the untreated cassava mill effluent polluted soil were completely acidic while the unpolluted soil was neutral indicating that the effluent impacted acidic properties to the soil. Phosphorus buildup in the unpolluted soil can be caused by excessive use of inorganic fertilizer or use of composts and manures high in phosphorus. The effluent from cassava plant when discharged on soil causes physicochemical changes in the soil, which calls for serious concern if the soil will be used for agricultural and other purposes. Therefore, cassava mills must be owned and managed by individuals who have basic knowledge of environmental protection.