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Evaluation of hydroxyapatite as a metal immobilizing soil additive for the remediation of polluted soils. Part 1. Influence of hydroxyapatite on metal exchangeability in soil, plant growth and plant metal accumulation

Evaluation of hydroxyapatite as a metal immobilizing soil additive for the remediation of polluted soils. Part 1. Influence of hydroxyapatite on metal exchangeability in soil, plant growth and plant metal accumulation

Authors :
Vangronsveld, J.
Mench, M.
Ruttens, A.
Boisson, J.
Source :
Environmental Pollution; Feb1999, Vol. 104 Issue 2, p225, 0p
Publication Year :
1999

Abstract

In order to evaluate the possible use of hydroxyapatite (HA) as a soil additive for the in situ remediation of metal contaminated soils, the immobilizing capacity of this product was investigated. Three different concentrations of HA (0.5%, 1%, and 5% by weight (w/w)) were applied to a metal (Zn, Pb, Cu, Cd) and As contaminated soil originating from an old zinc smelter site in Belgium. After a three weeks equilibration period, exchangeable metal concentrations of the soils weredetermined using 0.1 M Ca(NO<subscript>3</subscript>)<subscript>2</subscript> extraction. Test plants (Zea mays cv. Volga and Phaseolus vulgaris cv. Limburgse vroege) were grown on all soils. Growth parameters were determined and mineral analysis (Cu, Zn, Pb, Cd, Ni, Mn, Mg, Ca, K, As and P) of plants was performed. Exchangeable metal contents in soil decreased withincreasing HA application. Plant growth was partly restored on the 0.5% and 1% HA treated soils. However, at the 5% HA application rate growth was inhibited again. Plant mineral analysis showed that concentrations of 'toxic' metals in the leaves of the test plants decreased after HA application. However, the uptake of essential trace elementsalso decreased and probably led to Mn-deficiency in maize. In bean, addition of 0.5% and 1% HA resulted in a gradual decrease of metal uptake. At the 5% application level an increase of Zn, Cu, and Ni uptake was observed compared to the 0.5% and 1% application rate. In contrast to metal uptake, As uptake was found to increase after HA treatment. The increased PO<subscript>4</subscript><superscript>2-</superscript> concentration in the soil may be responsible for this. These results illustrate that HA application for the remediation of metal contaminated soils can be effective, but is not self evident. Strong immobilization of essential nutrients may lead to deficiency problems and mobilization of As may leadto an increased transfer to plants and animals and to an increased percolation of this element to the ground water. (c) 1999 Elsevier Science [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02697491
Volume :
104
Issue :
2
Database :
Supplemental Index
Journal :
Environmental Pollution
Publication Type :
Academic Journal
Accession number :
8290488