Bioconcentration and Translocation Factors of Heavy Metals in Rhizophora racemosa and Sediments from Egbokodo Mangrove Swamp, Delta State, Nigeria

Abstract

The mangrove ecosystem is well known to be impacted by anthropogenic activities such as oil spillage, agricultural run-off, industrial effluents, and mining in coastal areas. These activities increase heavy metals accumulated by mangroves, which are eventually released back into the environment via decomposition. This study aimed to analyze the concentration of heavy metals including cadmium (Cd), Zinc (Zn), lead (Pb), and copper (Cu) in the roots and leaves of Rhizophora racemosa and mangrove sediments obtained from Egbokodo mangrove swamp in Delta State, Nigeria. The results showed that the concentrations of Cu, Cd, Pb, and Zn ranged between 0.048 – 1.343 mg/g in the sediments and was higher than the concentration in the roots (0.023- 0.667 mg/g) and leaves (0.026- 0.530 mg/g) of the plant. Bioconcentration factor (BCF) was in the order of Cd> Zn> Pb> Cu with values greater than one (>1) except for Cu and Pb with less than 50% accumulation. Translocation factor (TF) was in the order of Cu> Pb> Cd> Zn. TF for Pb, Cd, and Zn were less than one (<1) except for Cu with a value of 1.14. This result suggests that the uptake and accumulation of heavy metals were higher in the roots of R. racemosa than in its leaves and that the plant may be a suitable extractor for Cu