Evaluation of Heavy Metals in some selected Waste Dumpsites in Gboko Metropolis, Benue State, Nigeria

Journal of Chemical, Biological and Physical Sciences (Impact Factor: 0.72). 01/2013; 3(1):575-580.
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    ABSTRACT: The objectives of this study was to investigate the chemical fractionation, mobility and bioavailability of Cd, Cu, Mn, Pb and Zn in refuse waste soils of some dumpsites in Zaria metropolis. The heavy metals in the waste soils samples were sequentially extracted and measured using atomic absorption spectrometry. Mean of total extractable metals in the samples analysed for Cd, Cu, Mn, Pb and Zn ranged from 25.86 - 95.71, 1.70 - 446.43, 141.92 - 423.22, 39.9 - 739.10, and 122.45 - 511.57 mgKg-1 dry weight, respectively. Cd and Pb were mostly found to be in the mobile phase of the samples indicating that the metals are potentially more bioavailable to the environment than the other metals studied. Overall, the order of mobility and bioavailability of the metals is Cd > Pb > Zn > Mn > Cu.
    African Journal of Biotechnology (ISSN: 1684-5315) Vol 7 Num 2.
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    ABSTRACT: Speciation of heavy metals in soils determines the availability for metals for plant uptake and potential for contamination of groundwater following application of composts to agricultural lands. Methods used to characterize heavy metals in solid phase of composts and compost amended soils include physical fractionation and chemical extraction. Chemical extraction schemes are most frequently used approach to fractionate trace metals in soils, sewage sludge and composts. Several variations exist in the sequential extraction procedures. These variations include reagent types, strength, volume and extraction time. A main drawback shared by all sequential extraction schemes is that the procedures themselves are complex and time consuming. This setback has been overcome by the use of ultrasound accelerated extraction which reduce the extraction time for the entire extraction steps to about 90 minutes allowing composting process to be monitored more frequently which help to provide detailed understanding of the partitioning behaviour of heavy metals. Inspite of the variability the sequential extraction schemes, they all aimed at correlating each fraction with the mobility and plant availability of each metal. Several studies have shown that phase association of heavy metal in composts include water-soluble, exchangeable, precipitated as discrete phases, co-precipitate in metal oxides and adsorbed or complexed by organic ligands and residual forms. The phase association and solubility of metals changes over composting time thereby altering metal availability. It is apparent that the positive effects of resulting from compost application far outweigh the negative effect, but more research is needed on a wide range of municipal solid waste compost with more precise determination of the fate of municipal solid waste compost applied trace metals in the environment.
    ChemInform 11/2007; 38(48).
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    ABSTRACT: The modified BCR three-step sequential extraction procedure was used to examine the temporal dynamics of trace elements in soils contaminated by an accidental spill from an opencast mine in south-west Spain. Soils were mainly contaminated with pyritic sludge and acidic wastewater, whereas some soils were affected only by acidic wastewater. The distributions obtained for both some major (Ca, Fe and Mn) and trace elements (As, Cd, Cu, Pb and Zn) in the sludge and soil samples taken at different times after the accident, 1-3 months and 21 months, were compared. Sequential extractions were useful in identifying different sources of contamination, and in obtaining additional information on the solubility of secondary minerals formed by pyrite oxidation. Thus, the effectiveness of the BCR procedure has proved to be a useful tool for predicting short- and long-term mobility of trace elements, even in complex environmental scenarios.
    Environmental Pollution 04/2008; 152(2):330-41. · 3.90 Impact Factor


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May 29, 2014