Selective chemical extraction and grainsize normalisation for environmental assessment of anoxic sediments: validation of an integrated procedure.

An integrated selective extraction and size normalisation procedure for use in metal partitioning and diagenetic studies of anoxic sediments and soils is presented. Data obtained by this procedure can readily be combined with other primary data (e.g. sulfur concentrations, carbonate concentrations, cation exchange capacity, etc.) and derived parameters (e.g. degrees of pyritisation and sulfidisation) that enhance interpretation of the behaviour of trace metals in anoxic sediments. Achieving size normalisation during extraction, allows direct comparison of sediments from dissimilar sedimentary environments, and simplifies assessment of the processes that determine whether a sediment is a source of or a sink for trace metals. Aspects of a study of trace metals in sediments from the Brisbane River estuary, Australia, are used to illustrate applications of the integrated procedure.