Geochemical media such as water, soil, blackshales and plants were collected around Akwuke community in Awkanawnaw in Enugu area of southwestern Nigeria, and analysed for physicochemical parameters, inorganic ions /salts and heavy metal abundance. The ultimate goal was to investigate the geochemical environment and ascertain if the abandoned Okpara coal mine has any contamination effect on geoenvironment. The measured pH range of 3.98-4.42 renders the water as acidic to moderately acidic and consequently unsuitable drinking purposes, vegetation and aquatic life and wild life. Other physical and inorganic /organic parameters in water such as TDS, EC, Turbidity, TOC, total harness, Cl-, NO3, PO4, F, CN, Ca, Mg, Na and K all fall below recommended standard for potable water guidelines by WHO and EU and they do not portend any health threat to the end-users. Heavy metals results indicated that Fe comprise the most abundant metal in all the media except in plants where Zinc top the list. This is evidence that Fe is of main interest in all the media. It is only in soil sample s that the elements: Fe, Zn, Cr, Cd, Pb, Mn, Cu and Ni exceed standards by US EPA for agricultural soils. This high concentration of potentially toxic metals in soils and acidic water condition constitute a threat to the ecosystem. Specifically, acidic and Fe polluted waters are not benign for fish growth and survival of aquatic biota. Also, acidic and ferruginous waters corrode borehole installation materials and produce iron stained water with characteristic reddish colour and offensive odour. Assessment of the comparative heavy metal abundance in water plants, soil and black shale revealed that there is more heavy metal enrichment loading in soil than other media. The hazard potential is that soils serve as a source that can release heavy metals into other media by various processes of remobilization.Therefore, phytoremediation can be adopted in the for heavy metal attenuation in soils.
Keywords: Ecosystem, Phytoremediation, geoenvironment, potentially toxic
