Characterizing the availability of metals in contaminated soils. I. The solid phase: sequential extraction and isotopic dilution

• Published in: Soil use and management Vol. 21; no. s2; pp. 450 - 458
• Main Authors: Young, S.D., Zhang, H., Tye, A.M., Maxted, A., Thums, C., Thornton, I.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2005
• Subjects: Contaminated soils; isotopic dilution; metal fractionation; sequential extraction
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1079/SUM2005348

. The two approaches most commonly applied to characterizing the chemical form and ‘reactivity’ of metals in the soil solid phase are sequential extraction procedures (SEPs) and isotopic dilution (ID). The development and limitations of both approaches are described and their application to contaminated soils discussed. It may be argued that ID offers a better means of discriminating between ‘reactive’ and ‘inert’ forms of metal. However, the literature on SEPs is considerably larger, providing greater scope for comparative analysis of new data. Although ID methods are subject to operational constraints, the procedural dependency of SEPs is probably much greater. Thus greater effort has been expended to standardize and verify methodologies for SEPs. However, despite achieving a level of ‘political ratification’ at the procedural level, the use of SEPs within risk assessments for planning or development purposes is currently almost absent. The future for ID methods in this context may lie in site‐specific risk assessments that include improved methods for the prediction of metal solubility and bioavailability.