Geosciences-Scholarly Publications

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Browsing Geosciences-Scholarly Publications by Subject "Anthropogenic"

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  • Item
    Open Access
    Contamination assessment of surface and groundwater within and around two dumpsites
    (International Journal of Environmental Science & Technology, 2010) Odukoya, A.M; Abimbola, A.F
    Geochemical analyses of groundwater and streams flowing around abandoned and active dumpsites in Lagos, Southwestern Nigeria were carried out. Results show that water samples have generally low total dissolved solids with average values of 163.75 and 153.4 for abandoned and active dumpsites, respectively. pH ranges from 3.96- 8.34 while total hardness varies from 10-220 mg/L calcium carbonate (soft to slightly hard). Average concentrations of the dominant ions for abandoned and active dumpsites were 57.8 and 25.86 mg/L (Na) representing 40.7 and 46.3 % of the total cations respectively and Nitrate (av. 96.89 and 61.51 mg/L) representing 49.1 % and 40 %, respectively of the total anions. The pH, coliform count and concentrations of nitrate iron, manganese and sodium in most of the water samples were above the national drinking water standards proposed by the United States Environmental Protection Agency. Trace elements like silver, arsenic, beryllium, bismuth, cerium, cobalt, chromium, lithium selenium, tellurium, titanium, uranium, vanadium, tin and yttrium were below detection level for all the water samples while tungsten, thallium, molybdenum and lead were only present in surface and groundwater close to the dumpsites and also display values higher than recommended standards while cupper, zinc, aluminum, barium and strontium were present in most of the samples. The pollution index among all sites varied from 0.009 to 1.26 and 0.106 to 6.25 for abandoned and active dumpsites, respectively while the water around most of the dumpsite areas exceeded the acute and chronic effect levels proposed by the United States Environmental Protection Agency in 2007.
  • Item
    Open Access
    Metal contamination assessment in the urban stream sediments and tributaries of coastal area southwest Nigeria.
    (Chinese Journal of Geochemistry, 2015) Odukoya, A.M; Akande, O
    A geochemical assessment of the fifty surface stream sediments from Ikorodu Southwest Nigeria was carried out to determine the level of contamination. The sediments were dried, disaggregated and sieved to\75 lm fraction for geochemical analysis, using the aqua-regia digestion technique and inductively coupled plasma mass spectrometry. Major elements showed the following trend Fe [Al [Ca [Na [Mg [K[P[Ti and were below the average shale concentration, except for Na in one sample. Results from factor and correlation analyses showed two groups of trace elements Ni, Co, Mn, U, Th, Sr, V, La, Cr, Ba, Sc, Ga, Cs, Nb, Rb, Y,Ce and Mo, Pb, Zn, As, Cd, Sb, Sn, Zr, which were from geogenic and anthropogenic sources, respectively. The enrichment factor showed that Cd, Bi, Pt, Mo and Ag were, for all samples, within background concentrations, except those of the Ogun River and the Owode Onirin, which showed significant enrichment of Cd, Zn, Cu, Pb and Ag, depletion to minimal enrichment for Bi, Mo and moderate enrichment for Pt. The contamination degree ranged between 1.25 and 143.79. The highest value was found at Owode Onirin and the lowest, at Igbonla 7. The geoaccumulation index showed that all the stream sediments ranged between practically uncontaminated to moderately to highly contaminated—with Pb, Sn, Zn, Cd, Cu, Cr, Zr and Ba. The potential ecological risk factor and environmental risk index (IER) showed that all of the samples were within the class of low to medium contamination risk, except samples from the Owode Onirin, which fell within the class of very high risk to extremely high risk respectively.