A. The most comprehensive listing of diffusion coefficients of mainly inorganic substances appropriate for DGT measurements can be found in W. Davison and H. Zhang, Diffusion Layer Properties, Chapter 3, in: Diffusive Gradients in Thin-films (DGT) for Environmental Measurements, Editor: William Davison, Cambridge University Press, 2016. A list of consensus values for metal ions at various temperatures is available (Diffusion Coefficients). Simple algorithms are also provided (adapted from the Appendix of the above DGT book) to enable calculation of values at any temperature from 1 to 35oC.

There are no clear consensus values for mercury, as can be seen from the tables of Chapter 3 in the DGT book. However, Suggested values of diffusion coefficients for mercury deduced from available knowledge and information are available.

As new methods for measuring organics using DGT are developed, diffusion coefficients are being determined, as provided in Information for organic analytes. While theses values are expected to be reliable, it is advisable to recognise that generally there are as yet insufficient data to establish them as consensus values.