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Risks of chemicals on human health and the environment are assessed by combining the chemical-specific hazard data (toxicity or other potential to cause harm) and the estimation of the extent to which man and other organisms are exposed to chemicals. Environmental exposure is usually expressed in terms of environmental concentration in air, water, sediment or soil.
OECD activities on environmental exposure assessment focuses on the following four areas.
1. Release estimation
For improving the estimation of releases of chemicals, the Task Force is developing emission scenario documents that describe the conditions and parameters for release estimation in specific industry and use categories. Information on existing emission scenario documents and other technical tools is available from the Database on Use and Releases of Industrial Chemicals.
Estimation of releases of chemicals related to the use of products and articles is becoming increasingly important in risk assessment of chemicals of concern. Although these releases are covered in some of the emission scenario documents, further activities to address this issue is under consideration.
This work is undertaken in close co-operation with the PRTR Programme.
2. Exposure models
Many kinds of computer models are used in exposure assessment. Harmonised approach in the use of exposure models were discussed in the Workshop on the Application of Simple Models for Environmental Exposure Assessment (Berlin, December 1991), and the outcome of this workshop was incorporated into the Interim Manual for Investigation of High Production Volume Chemicals.
More recent activities on exposure models include the development of a database of exposure models, and development of a guidance document on the use of multimedia models in the assessment of overall persistence and long-range transport. The latter is a follow-up on the OECD/UNEP Workshop in October 2001.
3. Use of monitoring data
The Workshop on Improving the Use of Monitoring Data in the Exposure Assessment of Industrial Chemicals (Berlin, May 1998) delivered a number of recommendations on improving the availability of monitoring data, better design of monitoring programmes, and enhanced dialogue between monitoring and risk assessment communities. Specific projects to follow up on these recommendations are currently under consideration.
4. Reporting of exposure information
OECD published a Guidance Document on Reporting Summary Information on Environmental Occupational Exposure in December 2003. This includes a set of formats for reporting information including monitoring and modelling studies.
Project oversight
These activities are directed by the Task Force on Environmental Exposure Assessment, composed of experts nominated by OECD Member governments and observer organisations. This Task Force was established in 1995, following a recommendation from the OECD Workshop on Environmental Hazard/Risk Assessment in 1994. The Task Force meets once a year. The activities are supported by the OECD Secretariat in Paris.
Also see the list of Publications
Useful links
EU Risk Assessment (European Chemical Bureau)
USEPA Exposure Assessment
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