Wassim Saadaoui¹, K. Mokrani¹, N. Mezghani², and N. Tarchoun¹

1. Vegetable Laboratory, Horticultural Department- Higher Agronomic Institute of Chott Mariem, Sousse, Tunisia

2. National Bank of Genes, Tunis, Tunisia

 

 

Abstract: Some vegetable crops irrigated with wastewater are highly contaminated with heavy metals and are the main source of human exposure to the contaminants.

  In this study accumulation of three heavy metals (Pb, Cu and Cd) in two locale varieties of Vicia faba in vegetative stage, irrigated with two different concentrations of each metal are studied using Atomic Absorption Spectrophotometer. For these heavy metals, the highest concentration was used according to WHO/FAO. For lead, lead nitrate was used at the highest and lowest concentration (6 mg/l and 3 mg/l, respectively), while for copper, we used copper nitrate, the two concentrations were 0.3 and 0.15 mg/l for the highest and the lowest concentration respectively. For cadmium, cadmium acetate was used with 0.03 and 0.01 mg/l for the highest and the lowest concentration respectively. Plants irrigated with tape water are the control.

  The most heavily contaminated parts for these two varieties were roots; the accumulation of Cu was 15.56 mg/kg of dray matter (DM) and 15.35 mg/ kg of DM in shoots respectively in bean and faba bean for lower concentration. Heavy metals concentrations were lower in shoot parts than in roots and lower than permissible limits of WHO/FAO either in bean and faba bean.

  The concentration of Cu in vegetable parts was the highest, where the accumulation was respectively of 14.48 mg/ kg DM and 16.54 mg/kg DM in bean and faba bean for lower and higher concentration respectively. The present study provides the evidence that the local variety of faba bean could accumulate and tolerate higher concentrations of lead and cadmium in vegetative stage better than the locale variety of bean which accumulate and tolerate higher concentration of copper which is less danger than Pb and Cd which can affect human health and environment.

 

Key words: heavy metals, vegetative stage, different concentrations, leguminous, phytoremediation, tolerance, Tunisia