Removal of lead from enriched sewage sludge- amended soil by canola (Brassica napus L.) through phytoremediation technology

Lead (Pb) in sewage sludge, used as a soil additive, is a major problem for soil quality. A field experiment was conducted during the two successive growth seasons (2011-12) at the experimental station of King Abdulaziz University. The objective of this study was to investigate the capability of canola (Brassica napus L.) plants to uptake lead (Pb) from soil contaminated with lead-enriched sewage sludge. The translocation of lead from root to shoot system then to seed and its effects on studied agronomic traits (plant root length, plant height and seed yield/plant besides seed yield/ha were evaluated. The study outcomes showed that Pb had significant effects (at p≤0.01) on all evaluated traits. As Pb concentration in the sewage sludge amended soil increased, Pb in each plant part significantly increased. Pb concentrations in root system were more than in shoot system and in shoot system were more than in seeds. Moreover, canola removal of Pb ranged between 44 to 67% from the Pb content of the polluted soil before phytoremediation, without toxic effects on plants during growth. Canola plants could be used as phytoremediators to eliminate or reduce heavy metal concentrations of polluted soils for environmental and human health.