Lead, Cadmium and Arsenic contamination levels

In Kinshasa, market gardening is observed along roadways with intense motorized traffic. The objective of this study is to evaluate their level of contamination in toxic metallic trace elements in order to deduce the safe cultivation distance (useful zone). The results obtained reveal that:- Notwithstanding, the combined effects of rainfall, runoff and watering, it is attested that these vegetables were contaminated up to a distance as one moves away from the roadside.- Lead levels are inversely proportional to the distance of the vegetable crops from the Kasavubu and Saïo roadways. Lead concentrations in soil are higher than in vegetables and irrigation water. Non-renewal of the soil after harvest may account for the accumulation of lead in the soil. - Cadmium is only detected in soil samples taken within 3m of the road. Tire wear could be the cause- The differential of Cadmium and Arsenic kinetics is null whereas an inverse correlation was observed between physicochemical parameters (pH, OM and TOC) and metals under study.