Issues in consumer exposure modeling: towards harmonization on a global scale.

Understanding where and how chemicals are used throughout their life cycle is becoming increasingly important. In 2003, within the context of REACH and GPSD legislation, the European Commission started developing a European and global infrastructure of exposure methods and tools. The infrastructure aims (1) to link modeling tools and exposure-related data and scenarios in a single framework so that harmonized exposure assessment procedures can be developed for consumer products in the EU and (2) to make this framework flexible enough to allow global application. A number of issues are raised by a global infrastructure of consumer exposure modeling that answers to multi-legislative mandates. These include transparency, consistency, usability, and defensibility of the models, including the relevant degree of complexity for priority setting versus assessment. As part of the initiative to set up a harmonized global infrastructure on consumer exposure assessment, these issues were presented, discussed, and further developed in a series of European Commission-sponsored workshops organized in October 2004 and June 2005 as part of the "Harmonization of Consumer Exposure Models on a Global Scale" project. The project focused on development, harmonization, and validation of consumer exposure modeling approaches. The workshops included experts from the EU, USA, Japan, and Canada. The conclusions and recommendations made on the basis of this work are described. To help achieve harmonization of approaches, the European Commission's Joint Research Centre is proposing a framework (1) to compare information on elements of chemical risk assessment to understand exposure regulations in different countries, (2) to save time and expense by sharing information and models, and (3) to promote credible science through better communication among organizations and by peer review of assessments and assessment procedures.