Determination of Some Heavy Metals in Selected Edible Vegetables Grown Along River Owade in Oyugis Area, Homa Bay County, Kenya

Abstract

Harmful materials such as heavy metals, which may be itoxic are sometimes found in vegetables. The levels of some of these heavy metals were investigated in selected vegetables, kale and cabbage, which are grown in Oyugis along Owade River in Homa Bay County, Kenya. All samples were randomly collected from two gardens along the river. The levels of the selected heavy metals (Copper, Iron, Cadmium, Chromium, and Zinc) were analysed using an Atomic Absorption Spectrophotometer. In the samples analysed, Cd and Cr were not detected. In kale, iron was found to be the highest in farm A, with an average of 46.68, and copper in farm B (32.73). Zinc was the lowest in both farms, with an average of 12.00 and 7.70, respectively. In cabbage, iron was highest in farm A (43.00) while copper was highest in farm B (37.00). Lowest in both farms was zinc (10.53 and 11.50, respectively). The data were analysed with t-test and analysis of variance (ANOVA). There were significant differences (p < 0.05) between the levels of the heavy metals in the vegetables obtained from Farms A and B. The concentration levels of metals in vegetables in the two gardens could be attributed to excessive usage of fertilisers and other agro-chemicals. The results were, however, lower than the values considered toxic, except for Fe, with higher values, which may be due to soil composition. From the results of this study, the consumption of these vegetables as food may not pose health hazards to humans.