Heavy metal contamination of cassava (Manihot esculentum) grown on quarry soils in Umunneochi Abia state and its health implications

Abstract

Contamination of agricultural soils by quarry activities is posing serious challenges food security in greater parts of the Sub-Saharan Africa. This study determined the heavy metals in soils and cassava (Manihot esculentum) tubers obtained from three different quarry sites in Umunneochi, Abia State Nigeria. Samples of soil and cassava tubers were collected in replicates following the direction of natural drainage, while control samples were obtained against the direction of natural drainage from the quarry pits. Soil and cassava tuber samples were collected and subjected to standard physicochemical analyses. Heavy metal concentration in the quarry soil and cassava tubers varied significantly from the control except for Cd (mg/kg) at P<0.05. All heavy metals identified in the soil were also present in the cassava tuber samples, with Al concentration in the quarry soils correlating positively (0.977**) with that of cassava tubers. The quarry activities contributed to the heavy metal levels of quarry soils and responsible for the accumulation of heavy metals in cassava tubers that could lead to food insecurity and public health concerns. This further brings to fore the challenges and need to review and update mining and quarry regulations in Nigeria.