Abstract

For substances used in consumer products, human exposure via dust is often suggested to be a potentially important exposure pathway. In the DustEx project the relative contribution of the dust ingestion pathway was systematically evaluated by using a model framework consisting of a combination of published models, which describe the transfer of substances from consumer products into the indoor environment (DustEx model). On the basis of the calculated indoor air and dust concentrations and further conservative parameters the exposure of consumers via the dust pathway was calculated and compared to other exposure pathways. This inter-pathway comparison was performed (1) in a generic way by exploring the chemical property space and (2) by selecting realistic case studies for different types of consumer products.

The development of the DustEx model for substance transfer was supported by a small-scale field study under controlled conditions. In this study the transfer of deuterium-labelled semi-volatile organic compounds from artificial consumer products to indoor air and settled dust was analysed. Altogether two measurement campaigns were conducted. The first field study had enrolled five apartments for twelve weeks. During the second field study three apartments selected from the previous five were investigated for eight weeks. The field study results were used to validate the model.

The results of the inter pathway comparison were summarised in a conservative decision tree that gives guidance on when to consider the dust pathway in a risk assessment of a substance released by a single consumer product. In the case studies it was shown that compared to conservative, lower Tier calculations of direct exposure to a product, the dust pathway was always negligible (lower by more than 1 order of magnitude). Only in higher Tier assessments with refined parameters for other pathways, the pathway of dust ingestion may be important.