Submitted to: US-EPA Applied Phytotechnologies Conference
Publication Type: Abstract Only
Publication Acceptance Date: September 17, 2004
Publication Date: April 19, 2005
Citation: Wang, S., Angle, J.S., Chaney, R.L., Delorme, T.A. 2005. Ph effects on distribution and thlaspi caerulescens uptake of Zn and Cd. International Phytotechnologies Conference, April 20, 2005, Atlanta, Georgia. p. 138.
For phytoextraction to be successful and viable in environmental remediation, the strategies that can optimize plant uptake must be identified. Whether adjusting soil pH is an efficient way to enhance T. caerulescens hyperaccumulation must by clarified. This study used two soils differing in Cd and Zn concentrations and soils were adjusted to 5 or 6 different pH levels ranging from 7.27 to 4.74 and seeded with a hyperaccumulator of Cd and Zn, Thlaspi caerulescens. Plants were harvested after six months. Metals were extracted into 5 sequentially extracted fractions and pH effect on the mobilization of metals from each fraction and T. caerulescens phytoextraction was discussed. Reducing pH significantly redistributed Cd and Zn among five fractions. Soluble metal form (F1) was greatly increased with the decreasing pH. F2, F3, F4, and F5 all had different degree of mobilization under low pH. Most of the “newly” mobile Cd was from F2 and for Zn it was mainly from F2 and F3. Reducing pH significantly influenced plant growth and metal uptake. For high metal soil, plant grown best at the lowest pH treatment and the highest metal concentration was at the second lowest pH treatment. For low metal soil, due to low pH induced Al and Mn toxicity, both plant growth and metal uptake was the best at intermediate pH level. Plant uptake of metal also significantly modified rhizosphere soil metal environment. T. caerulescens was able to reduce the Cd concentration in all 5 fractions, where F1-F3 were most significantly affected. For Zn, T. caerulescens significantly reduced metal concentration in F1 and F2 pools, while caused no significant changes in F3-F5 pools.