Speciation of Heavy Metals in Soils and Sediments. An Account of the Improvement and Harmonization of Extraction Techniques Undertaken Under the Auspices of the BCR of the Commission of the European Communities

TLDR

BCR initiated investigations into current chemical extraction methods for metal speciation in soils and sediments. The studies aim to prepare reference soils and sediments for certification of heavy‑metal extractable contents using agreed EDTA, acetic acid, and sequential extraction procedures. Collaborative interlaboratory trials of single‑extractant and sequential extraction procedures were conducted to evaluate and refine these methods. The trials demonstrated that diverse procedures could be harmonized into agreed methods and that reference materials with certified extractable contents could be feasibly produced.

Abstract

Abstract An account is presented of a series of investigations and collaborative studies, initiated by BCR, on current methods of metal speciation by extraction of soils and sediments with chemical reagents. It was established by extensive consultation with European experts that the diverse procedures used could be harmonized into agreed methods. These methods, including both single extractant and sequential extraction procedures were subjected to collaborative, interlaboratory trials and the results, presented briefly here, showed that it was both possible and desirable that reference soils and sediments, characterised by certified values for extractable contents, be prepared. As a consequence of these studies two soils have been prepared and will shortly be the subject of interlaboratory analysis with a view to certification of their EDTA and acetic acid extractable contents of some heavy metals. Following this workshop a feasibility study of the agreed sequential extraction procedure will, it is believed, shortly lead to certification of sediments for contents extractable by a defined sequential extraction procedure.