Heavy Metal Concentration and Bioaccumulation Potential of Plants Within Dumpsite Soil In Ozoro, South-South, Nigeria

Abstract

This study investigated the concentration and bioaccumulation of Heavy metals of plants within waste dumpsites in Ozoro, South_South Nigeria. The soil and plants parts (Root and shoot) were obtained from the dumpsite and at farm land far away from the dumpsite (Control site).The soil and plant parts were digested using aqua regia and analysed for heavy metals using Atomic Absorption Spectrophotometer (Buck 200A model). Musa paradisiacal (Plantain), Manihot esculenta, (Cassava), Colocasia esculenta (Cocoyam) and Carica papaya (Pawpaw) were studied. The heavy metals cadmium, copper, Iron, lead, Manganese and zinc were analyzed. The metal concentration in mg/kg ranged thus; Cd (0.01 – 0.06); Cu (0.01 – 0.08); Fe (0.01 – 0.08); Pb (0.01 – 0.07); Mn (0.01 – 0.06) and Zn (0.01 – 0.05). The metal concentration in the dumpsite soil and plants were relatively higher than those from the control site. Musa paradisiacal and Manihotesculenta had their heavy metals concentrations accumulated more in the roots than in the shoots while Colocasia esculenta and Carica papaya had heavy metal concentration more in the shoot than in the root. Bioaccumulation Factor of the studied plants showed that Musa paradisiacal is a bioaccumulator for Manganese, Manihot esculenta and Colocasia esculenta are bioaccumulators for cadmium while Carica papaya is a bioaccumulator for Cadmium, copper and Iron. Translocation Factor (TF_{Root to Shoot}) of the heavy metals in Musa paradisiacal and Manihot esculenta were all less than 1 while the (TF_{Root to Shoot}) for Colocasia esculenta and Carica papaya were all greater than 1 indicating easy translocation of the metals to the shoot by Colocasia esculenta and Carica. The Translocation Factor (TF_{Soil to Root}) for cadmium was greater than 1 for all the plants except Carica papaya. Copper and Iron had TF_{Soil to root} greater than 1 in Manihot esculenta while manganese had TF_{Soil to root} greater than 1 in Musa paradisiacal implying easy translocation of the metals from soil to root. The Enrichment Factor of the heavy metals were all greater than 1 which implies that the metals are all readily available for absorption by the plants. The metal concentrations were less than FAO/WHO guidelines except lead. The ease at which cadmium and lead were translocated from the root to the shoot calls for concern. Therefore planting of crops around dumpsite soils should be discontinued with in order to safeguard our health.