Accumulation and Translocation of Toxic Elements From Contaminated Soils, Nigeria: Implications for Phytomining and Hazards to Humans
Abstract Soil pollution by heavy metals and their health effect on human 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, their ability to serve as reservoir for recovery of additional economic amount of metals and the potential of the edibles/vegetables to cause harm to humans when consumed. The plant and soil samples were collected, prepared, digested in acid mixture of H2O2 and HNO3 for plants and Li2B4O7 - LiBO2 for soils and were analysed. The 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, CA, COA and LA were hyperaccumulators of Co at various points. Arsenic has only phytostabilizers. COA and LA were phytostabilizers of Cd while Sida acuta was the only phytoextractor. Chromium, Co and Cd have prospect of being phytomined from some of the plants. Vegetables/edibles values in 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).