DEBtox information
Making sense of ecotoxicity test results

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DEBtox information

DEBtox information


Welcome to the DEBtox information site

Welcome to the DEBtox information page, the site for people that want to make sense of ecotoxicity data. This site contains information on mechanistic models for the analysis of stressor effects on the life-history traits of individual organisms (and from there to higher and lower levels of biological organisation). Specifically, this site is about models based on animal energy budgets (DEBtox and DEBkiss) and survival models from the GUTS framework.

This website constitutes a node in the international DEBnet network, together with the associated site of DEBtox Research.

The mission of  is to simplify biology to get to the essence of what toxicants (and other stresses) are doing to organisms. Simplification is necessary if we need to gain understanding. Furthermore, we cannot expect to test even a small fraction of all possible (combinations of) toxicants, species and environmental conditions. Once we get to the essence, it is possible to make educated predictions of toxicant effects for untested chemicals, untested species, and under untested conditions.

Here, you can find information, lists of relevant publications, (links to) free e-books, and freely downloadable Matlab packages to analyse your data. Use the major categories on the top left of the screen to navigate through this site; the corresponding sub-categories will appear right next to it in the sub-menu.

Messages and warnings

The free and open-source software openGUTS v1.1 is now available for download! It is available as a standalone Windows executable or as Matlab package. It supports the use of GUTS for regulatory purposes, but will also prove useful for scientific studies. The dedicated website provides more information. Version 1.1 repairs a
calculation error that was spotted in openGUTS, which may affect IT calibrations/predictions for specific types of exposure scenarios. The Matlab version has also been updated to v1.1 to repair this. For more information, see the openGUTS website.

For users of BYOM versions before v. 4.3, see the notes and warnings on the BYOM page (bottom of page).
But, really, you should update to a newer version ... If you are working with BYOM, and would like to be notified immediately in case of errors, new versions, etc., email me and I will include you in a mailing list. I may also use this mailing list for other important developments such as new (versions) of the e-books, and new papers. This saves you the hassle of checking this website every week ;-).

Error in BYOM version 4.5-6.2!
I found an error in calc_parspace, in the 'extra sampling' code block. This section is run when the profiling step indicates a poor coverage of the sample: it should resample in the problem areas. Due to the error, it just duplicated the sample sets that were selected as starting points, so this step is useless. This error thus only influences the results for data sets where the initial sampling rounds lead to poor results: the additional step does not improve coverage of the sample. I don't expect this error to cause serious problems in optimisation or error propagation. Only in cases where the sampling is really bad, and in those cases, it should be clear from the parameter-space plot that the sample should not be used! So always check your plots carefully.
This error has been corrected in version 6.3!
   Note that this error is NOT present in openGUTS, even though the same algorithm is used there (the error was made in the translation to BYOM).

Changes at Leanpub (keeping my e-books free). Things changed a bit at Leanpub. My free e-books, from some point onward, required a paid membership to Leanpub for free download. While I do want to support Leanpub, I want several of my e-books to be really free (and free of access hurdles). And, I am not sure whether people interested in my books would also have an interest in the other books offered at Leanpub. I just noticed this change at Leanpub on 19 Sept. 2022, and immediately changed the settings so my free e-books are again totally free.

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The Duck of Vaucanson

Upcoming courses and events

  • Roman Ashauer and Tjalling Jager gave an on-line short course on openGUTS at the 2020 SETAC SciCon. This course is now available for everyone via Leanpub: Although you don't get the interaction with the instructors, this is still a nice way to educate yourself in quarantine.
  • The next DEB school and symposium is planned for the first half of 2023. Excellent to get you started on standard DEB and add-my-pet (not specifically focussing on TKTD). More info available here.
  • The next TKTD Autumn School on dynamic modelling of toxic effects is provisionally planned for October 2023. More info will become available here.
  • The Preditox winter school, 30 January-3 February 2023 in Lyon (France), spends one day on TKTD modelling (GUTS), among other data analysis tools. More information.

Job opportunities for TKTD/DEB modellers

  • Syngenta is looking for a technical expert on TKTD modelling. (offer seems to be closed)
  • Leiden University (the Netherlands) is looking for an assistant professor in process-based ecotoxicology (incl. DEB-based and TKTD). More information. (offer is closed per 7 Sept.)
  • The System Science group at Osnabrück University (Andreas Focks) is looking for a research associate (30 months). The researcher will participate in the EFSA project "AMPHIDEB: Development of biologically-based models in environmental risk assessment to assess the effects of chemicals and pathogenic fungi on amphibian and reptile populations." More information. (closing 30 Sept.)
  • Wageningen Environmental Research (WENR) is looking for a (senior) ecological modeller. The job advertisement is pretty vague, but it seems that TKTD modelling is (or could be) part of the job. More information. (closing 26 Sept.)
  • ...

Latest news

  • 19 September 2022: released a new version of the DEBkiss e-book. Especially the section on toxicant TK and effects has been thoroughly reworked. See book info page.
  • 16 September 2022: added a new BYOM package DEBkiss_tox. This contains the models formulated in primary parameters, which were split out of the DEBtox2019 package (to make that one specific for the compound-parameter version, which is most commonly used). See BYOM downloads page.
  • 22 August 2022: BYOM update to version 6.3, fixing the error found a few days ago. See BYOM downloads page.
  • 19 August 2022: Spotted an error in BYOM for the parameter-sapce explorer. See warning message above (also placed on the BYOM page).
  • 4 July 2022: Take a look at the DeEP tool for EPx predictions with DEBtox2019. Note that this tool does not perform calibrations or validations on data sets, but rather makes EPx predictions for exposure profiles, such as those from FOCUS.
  • 27 June 2022: Small update of BYOM to version 6.2. Correcting a few errors when calculating ECx/EPx with multiple parameter sets. See BYOM downloads page.
  • 22 June 2022: version 1.0 of the stdDEB-TKTD package is uploaded. See BYOM downloads page. Also today, an MS for this model was submitted for publication.
  • 17 June 2022: There will be another TKTD Autumn school in 2023. Tjalling Jager and Roman Ashauer have decided to step out of the teaching team, but a strong team remains. More information will be presented or linked on the course page.
  • 5 May 2022: Paper published on applying DEBkiss to early-life stages of cleaner fish ( Open Access). Part of the StartRens project.
  • 21 April 2022: Small update of the stdDEB-TKTD package to version Beta 4. See BYOM downloads page.
Older news over here.

The DEBtox information site,, since July 2011