Immobilization of Copper and Fluoride in Soils: Uptake by Chinese Cabbage

Elevated concentrations of fluoride (F) and copper (Cu) in food substances cause healthproblems. Effects of Wood ash, Cattle manure and CAN+NPK on mobility and uptake of Cuand F by Chinese cabbage were explored. The soils in this study were collected from Arusha,Tanzania. The experiment was completely randomized design with four treatments, eachreplicated four times. Four Chinese cabbage seeds were sown in the sieved soil samples (1 kg)and sown in 1 L containers. The Chinese cabbage were irrigated daily and allowed to grow forsix weeks, and harvested. Organic amendments decreased the soluble fractions of Cu and F inthe soils and reduced their uptake by Chinese cabbage. For fluoride, although significantreductions were observed, the concentrations were still above the allowed concentrations forhuman consumption. The Wood ash treatment was generally the most effective treatment of all.It was revealed that log10 of Cu concentrations in Chinese cabbage was positively related withlog10 concentration of F in the plants, elucidating that the presence of one contaminant willgenerally enhance the uptake of the other. It was concluded that the amendments reduced thepossibility of contaminating the food chain by the two pollutants in the soils.