Accumulation and translocation of toxic elements from contaminated soils to plants, Nigeria: Implications for metal potential hazards to humans.

Soil pollution by heavy metals, their health effect on humans via the food chain are pressing issues of the environment caused by human activities. Plant’s accumulation and translocation potentials were investigated to determine their suitability for phytoremedial purposes, and the potential of the edibles/vegetables to cause harm to humans when consumed. Plant and soil samples were collected, prepared, digested in acid mixture of H 2 O 2 and HNO 3 for plants and Li 2 B 4 O 7 − LiBO 2 for soils and were analysed. These analyses were carried out to determine the concentration of these metals in soil, their accumulation and translocation in plant parts. The data acquired were evaluated using bioconcentration (BCF), translocation factor (TF), bioaccumulation coefficient (BAC), metal uptake efficiency (ME%) and hierarchical cluster analysis to determine hyperaccumulators, phytoextractors, phytostabilizers, metal source plants and metals that could be toxic to humans through intake of roots, grains/seeds, fruits and leaves as vegetables. ANOVA analysis revealed that the data were significant at p < 0.05. Correlation and cluster analyses were employed to understand the relationships between variables determined. From this study, Colocasia asculenta (CA), Corchorus aestuans (COA) and Laportea aestuans (LA) were hyperaccumulators of Co at various points. Arsenic has phytostabilizer plants from the study. COA and LA were phytostabilizers of Cd while Sida acuta was the only phytoextractor. The concentration of metals in the vegetables/edibles in roots, shoots and leaves were above permissible levels for Cr, Co and Cd. The metal uptake efficacy (%) were in this order Co (28.99 to 89.08) > Cd (21.74 to 50.96) > Cr (22.90 to 49.06) > and As (9.65 to 39.19).