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Changes in the Rhizosphere of Metal‐Accumulating Plants Evidenced by Chemical Extractants
Author(s) -
Hammer D.,
Keller C.
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.1561
Subject(s) - rhizosphere , chemistry , phytoremediation , cadmium , environmental chemistry , soil water , extraction (chemistry) , salix viminalis , calcareous , hyperaccumulator , organic matter , bioavailability , botany , soil ph , soil contamination , bulk soil , metal , soil organic matter , heavy metals , biology , ecology , willow , chromatography , organic chemistry , genetics , bacteria , bioinformatics
The plants Salix viminalis L. (common osier) and Thlaspi caerulescens J. Presl & C. Presl have been studied often because of their high potential to extract heavy metals from soils. The soil properties favoring this phytoextraction are not yet fully known. In this study we compared three frequently used single‐extracting agents (NaNO 3 , diethylenetriaminepentaacetic acid [DTPA], and ethylenediaminetetraacetic acid [EDTA]) with a sequential extraction procedure to describe changes in the different Cd, Cu, and Zn pools in the rhizosphere of S. viminalis and T. caerulescens grown on calcareous and acidic Swiss soils in a pot experiment. The sequential extraction was used to assess the chemical affinities of these heavy metals (HM) in the soil whereas the single extractants were used for estimating the bioavailable HM pools in the soils. Cadmium depletion in several pools was most apparent in the acidic soil, with a significant decrease observed in the NaNO 3 ‐, DTPA‐, and EDTA‐extractable fractions following T. caerulescens growth compared with control pots. The sequential extraction showed that most Cd extracted by the plant from the acidic soil originated from the organic pool, which implies that heavy metals bound to organic matter may constitute a significant part of the bioavailable Cd pool in soils. In the calcareous soil only a small amount of Cd was taken up by T. caerulescens , and this came mainly from the carbonate‐bound fraction. This study shows that T. caerulescens , and to a lesser extent S. viminalis , can alter the heavy metal distribution in different soil pools within 90 d.