Assessment of In-Situ Natural Dendroremediation Capability of Rhizophora racemosa in a Heavy Metal Polluted Mangrove Forest, Rivers State, Nigeria

Journal of Applied Sciences and Environmental Management

ERAKHRUMEN, A.A.¹ 

关键词: Mangrove forest;    Coastal pollution;    Noxious substances;    Toxic metals;    Phytoremediation;   

DOI  :  

学科分类：环境科学（综合）

来源: University of Port Harcourt * Department of Pure and Industrial Chemistry

【 摘 要 】

Environmental pollution is assuming frightening dimensions in many parts ofthe world. This is not excluding Niger-Delta region of Nigeria where most of the country’s oiland gas are sourced with attendant production of noxious substances as byproducts/residues/waste. Many of these noxious substances have been noted to be removablefrom polluted environment through proper application of phytoremediation techniques,particularly using native plant species. Consequently, this research was conceived to evaluatepotentials for phytomediation by native red mangrove tree ( Rhizophora racemosaG.F.W.Meyer). This was carried out by evaluating the presence of heavy metals ions and their bioconcentrationlevels in the samples of root and wood tissues axially along the stem of thistree. The sorrounding soil and water were also sampled and evaluated for presence andconcentration of these metal ions in comparison with those for the sampled plant tissues. Allthe samples were sourced from a mangrove forest in Okrika, Rivers State, Nigeria. Thesamples from the root, butt, 50% and 90% bole length were oven-dried at 60±5°C to constantweight, pulverised and heated with trioxonitrate (v) acid to achieve total dissolution beforesubjecting them to atomic absorption spectroscopy (AAS). Similarly, samples fromsorrouding soil were dried at 35±2°C to constant weight, crushed and sieved using a ≤ 2mmmesh before performing metal extraction and detection using AAS while water samples werealso subjected to AAS for heavy metal analyses, in line with appropriate standard methods.The data obtained were statistically analysed using basic descriptive tools, Analyses ofVariance and Fishers’ Least Significant Difference (P < 0.05). Outcomes of these statisticalanalyses showed that, in terms of bio-concentration values, the evaluated metal ions thatinclude Fe, Cu, Mn, Cd, Pb, Ni and Cr were more in the root than the surrounding soil andwater. The bio-concentration trends, for the metal ions, also progressively declined from theroot towards the crown of the trees. The bio-concentration distribution in all the tree sectionsshowed an inconsistent pattern with Fe ions having higher bio-concentration. In addition, Cr,Ni, Pd and Cu also inconsistently followed Fe in terms of bio-concentration level.

【 授权许可】

Unknown