Investigation of the use of Mangrove and Nypa palm Parts as Tools for Remediating Polluted Soils in the Niger Delta, Nigeria

Abstract

This study is based on the theory that mangrove parts can be used to remediate polluted soils. Using chemicals to clean oil spill sites can cause negative feedback by increasing the heavy metal load of the soil and river. However, ground mangrove parts are harmless and can biodegrade faster when introduced on polluted soils. We thus postulate that mangrove parts can be used to remediate polluted sites by conducting an experiment with some parts of mangrove (leaves, root, stem seed, and branch) and nypa palm (leave, root, and seed) that were collected in situ, ground into fine powder applied to polluted soil. We also decided that reduced reduced hydrocarbon content (THC) and heavy metal concentration (Cadmium, Cd, Iron Fe, Zinc, Zn, and Lead Pb) over time means remediation. Soil samples were collected monthly for six months from the treated and control soils. The results show that THC and heavy metal concentrations reduced in the soil over time because of the remediating effect of the plant parts applied. The ANOVA result showed that there was significant difference in heavy metal concentration between treated and control soils (P< 0.05) where mangrove-treated soils had lower concentration of total hydrocarbon content and heavy metals from control (i.e., non-treated soils) for three of the five heavy metals analyzed (Cd, Fe and Zn) compared to the low concentration of two metals for nypa palm-treated soils (THC and Pb). Season has little or no effect on THC and heavy metal concentration apart from Fe that has low concentration during the wet season (P<0.05). There is more correlation in chemical concentration between the roots and soils of both plant species (R=0.95). More experiment is needed with mangrove and nypa palm parts to determine their effectiveness in remediation so that they can be used in a large-scale clean-up of polluted sites globally.