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Aspects of Geo-mathematical Diagnoses and Prognoses from Physiochemical Analyses in Landfills and other Areas of Lagos, Nigeria
IMOUKHUEDE, M. IDEHAI & ADEGBOYEGA, ROSE T.
Abstract
Upon physiochemical analyses of groundwaters samples in active
government operated landfills and other areas of Lagos, geomathematical evaluations
were undertaken to ascertain the roles of the municipal solid wastes (MSW) in the
differentials in concentrations with depth and / or distances away from the suspected
causal mode. Novel transpositions of the correlation tables to produce composite tables
revealed striking interactions amongst the analytes at depth and / or distances. The
correlations between the anions and cations were essentially excellent except for K &
Mn. The likely substitutions of K/Mn in the groundwater are in the sequence: Cd > Cr
>Ni >Hg >Fe >Zn > Pb > As >K/Mn. Using the regression plots in the Olusosun
groundwater, Cd showed that it required the most distance (802m) away from the landfill
for complete attenuation among the cations while chloride required the most distance
(570m) amongst the anions. The results show that attenuation is exponentially higher for
depth relative to distance. Corollary, it takes a factor of 1:55 (depth : surface distance) to
produce a unit change in pH, electrical conductivity- 1:117 , DO- 1:47, chloride- 1:68,
nitrate/phosphate-1:107, sulphate- 1:100; and 1:37,85,64,63,40,64,89,56,37,117 for K,
Zn, Fe, Ni, Cd, Hg, Pb, Cr, Mn, & As respectively. Overall, the sequence indicates
attenuation of pollution away from the landfills with clayey/ lateritic lithology. The
physiochemical results of areas extraneous to MSW operations implicate the landfills as
major contributors to pollution in the Lagos landfill area of Nigeria.
Keywords
Composite correlation tables; coefficient of determination; attenuation; pollution
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