Use of Festuca ovina L. in Chelate Assisted Phytoextraction of Copper Contaminated Soils

Abstract

Festuca ovina L. is a hyperaccumulating plant which has aroused considerable<br />interest with respect to its possible use for phytoremediation of contaminated soils. This<br />study has been conducted to evaluate the potentials of F. ovina L. to serve as a<br />phytoremediation plant in the cleaning up of Cu in the polluted soils and to identify<br />extraction efficiency of Ethylene Diamine Tetraacetic Acid (EDTA) for desorbing copper<br />in relation to chelator dosage. Seeds have been sown in control and Cu contaminated pots<br />(artificially contaminated with 150 mg kg-1 Cu). Results revealed that Cu negatively<br />affected growth and tolerance indices of F. ovina and the root length was the most<br />sensitive parameter among all measured parameters. The treatments used for assessing<br />EDTA efficiency were 1.5, 3, 6, 15+1.5, 3+3 mmolkg-1, control (C: uncontaminated soil<br />without EDTA) and W (contaminated soil without EDTA). Results showed that the<br />application of 1.5 mmolkg-1 of EDTA did not significantly improve the phytoextraction of<br />Cu and statistically, there was no significant difference in Cu uptake between single and<br />split applications of 1.5 mmolkg-1 of EDTA. A sharp increase in root Cu concentration was<br />observed when 3 mmolkg-1 of EDTA was applied. The highest amount of Cu extracted for<br />the plant tissues was achieved at the doses of 6 mmolkg-1 and 3+3 mmolkg-1 EDTA,<br />respectively. Higher Remediation Factors (RF) were obtained for the plants grown in<br />contaminated soil and the highest RFs (0.08% and 0.07%) were recorded after the addition<br />of 6 and 3+3 mmolkg-1, respectively. Application of EDTA showed a relatively decrease in<br />TI (Tolerance Index) value and the lowest value of TI was recorded in 6 mmolkg-1 EDTA<br />treatment. According to the experiment, EDTA has appeared to be an efficient amendment<br />when Cu phyto-extraction with F.ovina was addressed. But further studies would be<br />needed on investigating the reduction of percolation risk by the amount and process of<br />chelate application.