Influence of combined use of iodide and compost on Hg accumulation by Lepidium sativum L.

This study focuses on the influence of adding iodide (KI) and compost in different soil/compost ratios on the efficiency of Hg phytoextraction by Lepidium sativum L. Plant growth and non-enzymatic antioxidants are studied to understand metabolic plant adaptations to Hg stress during soil reclamation and their relations to Hg accumulation. Due to the use of relatively high chelant dosages in current plant-based soil remediation techniques and associated environmental risks, it is necessary to explore alternative approaches to the phytoextraction of Hg from contaminated soils. The results show a coordinated increase in non-enzymatic antioxidants in plants cultivated in growing media containing polluted soil, compost and KI. This indicates that the non-enzymatic antioxidative defence system of L sativum L is involved in its strategy to survive conditions of mercury-induced stress. Adding compost and iodide to Hg polluted soil also increases the total accumulation of Hg by L. sativum L and the translocation of pollutants to aerial plant tissues. Simultaneous application of compost and KI promoted the Hg accumulation by L. sativum L. in a pot experiment. (C) 2014 Elsevier Ltd. All rights reserved.