Rhizosphere Concentrations of Zinc and Cadmium in a Metal Contaminated Soil After Repeated Phytoextraction BySedum Plumbizincicola

Repeated phytoextraction of four metal-contaminated soils using the cadmium/zinc hyperaccumulator Sedum plumbizincicola

“…During phytoextraction soil available metal fractions will decrease and this may lower plant metal uptake by the next crop in the phytoextraction sequence (Dessureault-Rompre et al, 2010;Liu et al, 2011). Many extractants have been used to estimate soil metal availability and the metals extracted by neutral salts and DGT have shown, in some circumstances, good relationships with metals in conventional crops and hyperaccumulators (Tandy et al, 2011;Menzies et al, 2007;Liu et al, 2011).…”

“…Short-term remediation is not adequate for predicting the dynamics of plant metal uptake and changes in soil metals during the phytoextraction process. Some repeated cropping experiments have been conducted using hyperaccumulator species to extract metals from soils (Keller and Hammer, 2004;Liu et al, 2011) but most studies have focused on a limited range of soils or short remediation periods. It is therefore desirable to study metal changes during plant metal uptake in a wide range of soils over relatively long time periods of phytoextraction.…”

Changes in metal availability, desorption kinetics and speciation in contaminated soils during repeated phytoextraction with the Zn/Cd hyperaccumulator Sedum plumbizincicola

“…This indicates that the metal declines in the soil solution are controlled mainly by the decreases in the available metal pool sizes in acid soils during phytoextraction. Previous studies show that hyperaccumulators can significantly decrease soil metal availability (Keller and Hammer, 2004;Dessureault-Rompre et al, 2010;Liu et al, 2011), but if just short-term phytoextraction is conducted the decreased available metal can be offset as the soil metals rebalance when phytoextraction ceases (Keller and Hammer, 2004). In the longterm repeated phytoextraction of the present study, metal extracted by CaCl 2 and EDTA showed clear decreasing trends during phytoextraction of the acid soils.…”

“…During the process of phytoextraction soil metal availability will change as prolonging the remediation time increases interactions between soil and plant. Both short-term phytoextraction and rhizosphere experiments on hyperaccumulators show clear decreases in soil metal availability in contaminated soils after phytoextraction and in rhizosphere soils as compared to bulk soils (Keller and Hammer, 2004;Liu et al, 2011). However, after short-term phytoextraction the decreased available metal may be replenished through soil metal re-equilibration (Keller and Hammer, 2004).…”

Copper changes the yield and cadmium/zinc accumulation and cellular distribution in the cadmium/zinc hyperaccumulator Sedum plumbizincicola

“…As metal distribution in different cell parts and different metal chemical forms have different toxicity to plant, metal in cellular distribution and chemical forms can be used to investigate plant detoxification mechanisms [15]. Sedum plumbizincicola, a Cd/Zn hyperaccumulator with large biomass and high accumulation of Cd/Zn in the shoots [16,17], is a promising species for the remediation Cd/Zn polluted soils. However, this species was found to have a very high Cu concentration (254 mg kg −1 ) in shoots and its growth was significantly inhibited when plant grow in acid soil (pH, 4.56; total Cu in soil, 369 mg kg −1 ) [18].…”