Assessment of chemicals

OECD Pov and LRTP Screening Tool


What's new? 

The OECD releases Review of the OECD POV and LRTP Screening Tool 15 years after its release. This report assesses the continued relevance of the Tool and identifies possible updates to improve the simulation accuracy and usability of the Tool following a citation review, a user survey, simulation accuracy evaluations, and expert discussion. As a result, possible elements for updating the Tool to increase usability, avoid misuse and misinterpretation of the results, and improve simulation accuracy were identified. The final decision on whether/how to adopt each of the elements will be made through further discussion at the Working Party on Exposure Assessment in designing the new version of the Tool.



  • A software in a spreadsheet format containing multimedia chemical fate models;
  • A tool for estimating overall persistence (POV) and long-range transport potential (LRTP) of organic chemicals at a screening level,
  • A tool for comparative assessment of environmental hazard properties of different chemicals. Specifically designed to help identify potential POPs (Persistent Organic Pollutants) according to persistence and long-range transport metrics.


Features of the Tool

1. Simple and easy to use

The Tool has a “Main menu” for entering data and results are shown in easy to read graphical mode, which allows even beginners to utilise it easily.

2. Flexible Data Management and Model Setting

Users can chose chemicals from a database installed in the Tool, or enter data for chemicals of interest, i.e. physical-chemical properties and degradation half-lives. It is possible to transport users’ own databases, and store them within the Tool. It is also possible to change model settings.

3. Representative of several models

The model in the Tool was developed as a “consensus model” reflecting features of several existing multimedia fate and transport models.

4. Graphical and Numerical Output

The result of model calculation is shown in both numerical and graphical outputs, such as:

  • Plots of LRTP metric (CTD and TE) vs. Pov. (See Example A below)
  • Numerical values of Pov, CTD (Characteristic Travel Distance) and TE (Transfer Efficiency) in three emission scenarios to soil, water and air.
  • Pie charts showing the fraction of chemicals that are contained in soil, water and air for each scenario. (Example B)


How was the Tool developed?

The Tool has its origin at the OECD/UNEP Workshop on the Use of Multimedia Models held in Ottawa, Canada in 2001. After the workshop, an OECD Expert Group for the Follow-up to the OECD/UNEP Workshop was established. Between 2002 and 2005, the Expert Group developed a consensus model based on existing predictive approaches to environmental persistence and long-range transport.

The software has been developed by Switzerland in co-operation with Germany, under the supervision of the OECD Task Force on Environmental Exposure Assessment (TFEEA), and in co-operation with the participants of the OECD/UNEP Training Workshops on Application of Multimedia Models for Identification of POPs held in 2005 and 2006.

The software (Version 2.1) was endorsed by the TFEEA in late 2007, and published in April 2008. The updated Version 2.2 was released in April 2009.


Download the Tool and related materials

The OECD Pov and LRTP Screening Tool (Version 2.2)

Requirements for the software: MS Excel 2002 or higher on MS Windows MS Excel 2004 for Macintosh on Mac OS X (The Tool will not work with MS Excel 2008 for Macintosh.)

Manual for the Tool


The software is described in detail in the journal article by F. Wegmann et al(2009), Environmental Modeling & Software 24, 228-237. 


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