Abstract
The chemical speciation of five heavy metals [HMs] in spent sand-filter-media [SFM] waste dumpsite was investigated with a view to ascertain their distribution and chemical availability of the heavy metals in the dumpsite. Samples were collected at the surface, 100cm depth of the dumpsite and 100m away from the dumpsite and analysed using FAAS for total concentration of Cr, Fe, Mn. Ni and Pb. Speciation analysis was carried out usingmodified Tessier’s sequential extraction method. The percentage concentrations showed that Pb occurred more at the exchangeable fraction with 90.6% at the top, 91.34% at 100cm depth. This signifies that Pb is biochemically available for in-take by living organisms. Fe had the highest concentration by mass 12mg/g but its occurrence of between 22- 28% is in the residual/inert fraction. Ni had 40% in the exchangeable and carbonate fractions at the surface and at 100cm depth. Cr had highest exchangeable fraction of 46.29% and 45.59% at the surface and 100cm depth of the SFM. Mn had 37.30% and 42.26% at the surface and at 100cm depth of the SFM. Although Fe had highest concentration by mass, it is least biochemically available occurring more at the residual/inert fraction while the other four metals [Pb, Ni, Cr, Mn] are all biochemically available for intake by organisms and may enhance biochemical accumulation overtime and finally become harmful to living organisms around that dumpsite.
 Keywords: Speciation, Heavy metals, Sand Filter Media, Waste Dumpsite
Highlights
The chemical speciation of five heavy metals [HMs] in spent sand-filter-media [SFM] waste dumpsite was investigated with a view to ascertain their distribution and chemical availability of the heavy metals in the dumpsite
The surface mobility, biochemical redox reactions and underground bioaccumulation of heavy metal contaminants in spent or used sand filter media [SFM] and their related impact in the ecosystem is of considerable concern to chemists and other environmentalists around the world (Leizou et al, 2015)
This paper focuses on the investigation of the distribution and speciation of Cr, Fe, Mn, Ni and Pb in sand-filter-media [SFM] waste dumpsites in Yenagoa, Nigeria and the biochemical availability of the metals for intake by living organisms
Summary
The chemical speciation of five heavy metals [HMs] in spent sand-filter-media [SFM] waste dumpsite was investigated with a view to ascertain their distribution and chemical availability of the heavy metals in the dumpsite. Speciation of Lead: The speciation pattern for Pb at the top of SFM dumpsite as shown in figure 1 revealed that Pb occurred most in the exchangeable fraction with 90.06%, followed by Carbonate fraction with 5.70%, the Organic and Residual fractions has 1.71% respectively while the lowest was Fe/Mn fraction with 0.28%.
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