Abstract

In order to maintain environmental quality and ensures food security, this study evaluated baseline heavy metal contents in agricultural fields in the Eastern Flank of Mt Cameroon. It specifically (a) determined the physicochemical properties of soils and the heavy metal concentrations; (b) produce geochemical maps for the heavy metals; (c) determined the major factors controlling the distributions of the metals. Twenty composite soil samples were collected and analyzed for their cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn) and zinc (Zn) using the atomic absorption spectrophotometer. Soil texture, pH, and organic matter contents were also assessed. Geochemical maps were produced using the krigging. The concentrations of the metals did not exceed the guideline values for agricultural land but higher concentrations of Cd and Pb were obtained in soils where human activities are denser. From geochemical mapping, noticeable hot-spots of heavy metals were marked at the central (for Mn) and eastern (for Cu) sides. Pearson’s correlation coefficient showed a significant (p<0.05) negative relationship between clay and Cd (r=-0.47) and a non-significant (p>0.05) negative relationship between clay and Pb (r=-0.17. Four principal factors were extracted in the study, explaining 79.86% of the total variance. Most heavy metals concentrations did not exceed threshold values, but there is concern of environmental quality and human security due to continuous anthropogenic inputs. There is the need for proper monitoring of waste disposal and agrochemicals use.

Key words: Heavy metals, geochemical maps, environmental quality, human security.