Heavy metal contaminations in soil and cassava harvested near a cement processing facility in the Volta Region, Ghana: Implications of health risk for the population living in the vicinity

Abstract

Heavy metals concentration of Arsenic, Chromium, Nickel and Lead were determined in fresh cassava crops and the corresponding soils, from which they were harvested, collected in the vicinity of the Diamond Cement Factory (DIACEM) in the Volta Region, Ghana. In addition, similar samples (control) were collected 8km South of DIACEM in an area without charge from industrial influence. The average concentrations of the metals in the cassava were: 0.017µg/g for As, 3.04 µg/g for Cr; 6.76 µg/g for Ni; and 0.86 µg/g for Pb. For the corresponding soils the average concentrations for As, Cr, Ni and Pb were, 0.23, 53.22, 78.35 and 1.37 µg/g respectively. With the exception of Ni, all the metal levels in cassava were higher in the subject samples than in the controls. A similar situation occurred in the case of corresponding soils with Cr replacing Ni as the exception. This observation places much responsibility on the cement plant as the culprit of the higher metals in the samples. All the metal levels in the cassava samples with the exception of As were above permissible levels prescribed by the FAO/WHO for vegetables. The results of the estimated daily intake (EDI) for the metals also observe similar situation when compared to the Provisional Tolerable Daily Intake (PTDI) proposed by FAO/WHO. Values of Target Hazard Quotient (THQ) of heavy metals were calculated to estimate the risk to human health. All the metals values exceeded the safe limit of unity indicating a high human health risk for the population who consume cassava from the area