| dc.description.abstract | Heavy metals are metalloids of environmental concern, especially in urban and peri-urban small
scale farming systems. Plants are contaminated with heavy metals through different pathways,
including uptake from soil and from the atmosphere. These pathways need to be distinguished from
each other in order to understand where massive contamination comes from and the one suitable
for a particular metal. The uptake is affected by various factors, among them are environmental
conditions (climatic conditions, soil characteristics, and root system), plant species/morphology and
chelating agents. Most vegetables are known to be contaminated by heavy metal like cadmium
(Cd), chromium (Cr), lead (Pb), arsenic (As), iron (Fe), zinc (Zn), copper (Cu), with leafy vegetables
mostly affected. The contamination levels of these metals have largely exceeded the recommended
consumption levels by the world health organization (WHO), thus likely to cause adverse health
effects to human beings if regulation measures are not put in place. Research on heavy metal
contamination mostly focuses on other vegetables and less has been done with respect to African
Indigenous Vegetables (AIVs). On the other hand, plant species, especially AIVs, have different
physical, morphological and physiological traits that may affect the movement and accumulation of
various heavy metals and thus the extent of contamination and metal affiliation may vary from one
vegetable to the other. Since contamination occurs along the value chain, this calls for research that
guides farmers to choose the best farming practices, package and transportation measures for
reduced heavy metals contamination of vegetables will be vital. | en_US |
