Source Apportionment of Heavy Metals in Utility Water Sources
No Thumbnail Available
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Terrestrial and Aquatic Environmental Toxicology
Abstract
Description
Heavy metals cause cancer and non-cancer health effects in humans when consumed via drinking water. Therefore, the importance of
assessing the levels and sources of heavy metals in utility water sources, with a view to proffering mitigation measures, cannot be
overemphasized as not all toxic metals can be removed by conventional water treatment processes. A total of 40 composite water samples
were randomly collected from utility dams and their feeding rivers from January, 2010 to December, 2011. The concentrations of metals
were determined by atomic absorption spectrometry and were found to vary with season. The concentrations of Cd, Co, Cr, Cu, Fe, Mn,
Ni, Pb and Zn (mg L-1) in the water sources ranged from 0.02 to 0.49, 0.01 to 0.17, 0.03 to 0.38, 0.09 to 0.48, 0.17 to 3.25, 0.05 to 0.34,
0.02 to 0.33, 0.13 to 0.61 and 0.09 to 1.07, respectively, in the dry season, and from 0.08 to 0.68, 0.02 to 0.58, 0.13 to 0.87, 0.02 to 0.69,
0.28 to 5.62, 0.31 to 1.28, 0.09 to 1.08, 0.23 to 1.98 and 0.26 to 1.59, respectively, in the wet season, indicating that the concentrations of
Cd, Cr, Fe, Ni, and Pb exceed regulatory limits in both seasons. Furthermore, the result of principal component analysis on absolute
principal component scores (PCA/APCS) used to apportion sources to the metals in the dams and rivers revealed two major
anthropogenic sources accounting for over 90% of the metals. Source 1 represents anthropogenic release from small-scale entrepreneurial
enterprises, such as automobile-mechanic, panel beaters, vehicle sprayers and battery recharger workshops generating and spilling wastes
such as lubricating oil, grease, petrol, diesel, battery electrolytes, contributing 96.2, 99.2, 95.9, 100, 99.4, 99.9, 100 and 95.2%, of Cd, Cr,
Cu, Fe, Mn, Ni, Pb and Zn, respectively, while source 2 represents the release from agricultural activities, such as from fertilizers and
fungicides and contributes 63.2, 100 and 51.6% of Cd, Co and Cr, respectively.
Keywords
QD Chemistry