Project Details Humic-metal binding constants database

Project No.:
Start Date:
01 November 2008
End Date:
19 March 2020


Systematic compilation of data on complexation of trace metals by humic substances and construction of a database to facilitate its access.


BACKGROUND – The significance of natural organic matter (NOM) in determining trace metal speciation in aquatic systems has long been recognized. The polyfunctional and polyelectrolytic nature of these ligands provides an effective buffer for metal ion concentrations and as such is essential for the maintenance of life. However, despite an enormous number of studies, many unresolved aspects remain, e.g. the relative contribution of different types of NOM (e.g. humic-type substances versus biota exudates) to overall metal binding, or the relative degree to which different trace metals are bound by a given NOM type. Furthermore, no systematic compilation of published data exists, thus making any quantitative appraisal difficult.

AIM – We have undertaken the compilation of all data published. It includes the collection of data on trace metal binding by fulvic and humic compounds. Our long-term aim is of providing a robust framework for the understanding of the complexation of trace metals by NOM in natural environmental systems. The references compiled are stored in a web-based database.


Project announcement published in Chem. Int. May-June 2009

A key methodological paper was published in 2011 (M. Filella and W. Hummel, Trace element complexation by humic substances: issues related to quality assurance. Accreditation and Quality Assurance, 16, 215-223 (2011); This article can be read for free at: (Springer SharedIt).

The database is available at: This database will be continuously updated by Montserrat Filella (University of Geneva, Switzerland) and Wolfgang Hummel (PSI, Switzerland). New capabilities will be also added. Researchers are kindly invited to contribute by sending new data.

An article presenting the database is in preparation.

Project completed

Page last updated 20 March 2020