SREL Reprint #2654

 

 

 

Selected bioavailability assays to test the efficacy of amendment-induced immobilization of lead in soils

W. Geebelen 1,2 , D.C. Adriano2 , D. van der Lelie3,4, M. Mench5, R. Carleer 6 , H. Clijsters1,
and J. Vangronsveld 1

1Environmental Biology, Centre for Environmental Sciences, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium
2University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina, 29802, USA
3
Brookhaven National Laboratory, Building 463, 50 Bell Avenue, Upton, NY 11973, USA
4Vlaamse Instelling voor Technologisch Onderzoek, MIT, Boeretang 200, B-2400 Mol, Belgium
5INRA Bordeaux Aquitaine Research Centre, Agronomy Unit, BP 81, F-33883 Villenave d'Ornon, France
6Environmental Chemistry, Centre for Environmental Sciences, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium

Abstract: Lead immobilization in 10 soils contaminated with Pb from different origin was examined using lime (CaCO3), a mix of cyclonic ash and steelshots (CA+ST), and a North Carolina phosphate rock. The immobilization efficacy of the three amendments was evaluated using single (CaCl2solution) and sequential (BCR method) chemical extractions in tandem with a microbiological Pb biosensor (BIOMET), a Pb phytotoxicity test, Pb plant uptake, and a Physiologically Based Extraction Test (PBET) mimicking Pb bioavailability in the human gastrointestinal tract. The results demonstrated the necessity of using a diverse suite of bioavailability methodology when in situ metal immobilization is assessed. Sequential (BCR) extractions and PBET analysis indicated that PR was the most effective amendment. PR however, proved ineffective in totally preventing Pb phytotoxicity and Pb uptake on all soils tested. On the contrary, CA+ST and lime decreased BIOMET Pb, Pb phytotoxicity, and Pb uptake to a far greater extent than did PR. BIOMET detectable Pb and Pb uptake, however, were strongly related to Pb in soluble or exchangeable soil fractions (i.e., CaCl2 extractable). By combining these fractions with the acid-extractable Pb, accomplished by using acetic acid extractant, the recently developed BCR sequential extraction scheme appeared to have lost some valuable information on judging Pb bioavailability. The data show that different amendments do not behave consistently across different soils with different sources of contamination. Different indices for measuring Pb bioavailability are also not necessarily consistent within particular soil and amendment combinations.

Keywords: biosensor, cyclonic ash, lime, phosphate rock, phytotoxicity, steelshots

SREL Reprint #2654

Geebelen, W., D. C. Adriano, D. van der Lelie, M. Mench, R. Carleer, H. Clijsters, and J. Vangronsveld. 2003. Selected bioavailability assays to test the efficacy of amendment-induced immobilization of lead in soils. Plant and Soil 249:217-228.

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