Selected trace elements evaluation in soil from an urban farming area
Abstract
BACKGROUND AND OBJECTIVES: Urban farming makes a substantial influence on
the household economy of the urban poor especially in developing countries. Urban
soil the hot spot of urban farming is a natural sink for contaminants especially the
trace elements derived mainly from anthropogenic activities. This study’s aim was
to quantify the concentrations of selected trace elements (Cr, Mn, Cu, Ni, and Zn) in
topsoil (0-20 cm) and subsoil (21-50 cm) and to evaluate whether their concentration
vary during dry and rainy season.
METHODS: Grid soil sampling method was used to collect soil samples and their total
concentration was determined using a portable X-ray Fluorescence Spectrometer.
FINDINGS: The study revealed that the topsoil had higher concentration than sub soil.
The topsoil concentration in mg/kg were 61.62, 4042.58, 30.82, 43.90 and 456.43 for
Cr, Mn, Ni, Cu and Zn respectively. The subsoil concentration in mg/kg were 54.67,
3791.38, 30.32, 27.83 and 370.32 for Cr, Mn, Ni, Cu and Zn respectively. It also noted
that concentration of the trace elements was higher during dry season than wet
season but not significantly different (P ≥ .05) for all the elements.
CONCLUSION: The study recommends that there is need to monitor levels of trace
elements investigated in soil to ensure they do not reach detrimental levels.