EcoIsoMix – Stable Isotope Mixing Models for Estimating Source Proportions in Ecological Applications

Donald L. Phillips, Ph.D., Consultant

I worked as a Research Biologist and then Special Government Employee at the U.S. Environmental Protection Agency until 2016. During that time I developed several stable isotope mixing models that have been adopted worldwide in ecological applications for estimating source proportions in a mixture. These models (IsoError, IsoConc, and IsoSource) have always been freely available at an EPA web site, and now here. While I no longer work for EPA, I am continuing to provide consultation on applications of these models at no charge. The purpose of this web site is: (a) to provide description and downloads of these models, as well as links to related ongoing developments; and (b) to provide my current contact information for users who have further questions about their application. This web site is still under construction and more information will be added to it in the near future.

Google Scholar profile:



Stable isotope analysis can be used in ecological studies to trace chemical movement through the environment.  A common application is to use the isotopic composition of a mixture to determine the proportions of various sources in the mixture, using mathematical mixing models.  Examples include quantifying the importance of various pollutant sources to contaminated water, or the importance of various prey species in a predator’s diet.

The links below provide information and download files for three stable isotope analysis tools: IsoError, IsoConc, and IsoSource.

Further Information:

Publications: Publications describing these methods and related applications


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