Dust ingestion rates for guideline development and human health risk assessment

Importance of the Work and Objectives: Dust ingestion rate is a key input parameter in the development of indoor dust guidelines and human health risk assessment of substances in indoor dust; however, dust ingestion rates have... [ view full abstract ]

Importance of the Work and Objectives: Dust ingestion rate is a key input parameter in the development of indoor dust guidelines and human health risk assessment of substances in indoor dust; however, dust ingestion rates have received relatively little attention in the scientific literature. Consequently, there was a need to develop estimates of dust ingestion rates.
Methodologies: A mechanistic method was developed that incorporates the concept of hand-to-mouth transfer to estimate indoor dust ingestion rates. The approach provides indoor dust ingestion rates as “mg/day” and “m2/day” such that these results can be applied to measurements provided as either bulk dust (where contaminant concentrations are presented in units of “µg/g”) or surface loadings (where contaminant concentrations are presented in units of “µg/m2”). The methods incorporated both deterministic and probabilistic techniques.
Main Results and Conclusions: For residences that are comprised of similar proportions of hard and soft surfaces, mean indoor dust ingestion rates were estimated to range from 2.2 mg/day for teenagers to 41 mg/day for toddlers. For consideration of surface loadings, the analysis resulted in estimated mean dust intakes that range from 0.0032 m2/day (for teenagers) to 0.061 m2/day (for toddlers). Ingestion rates assuming 100% hard surfaces and 100% soft surfaces were also estimated. The values provided are intended to assist the interpretation of indoor dust investigations where substance content is presented as either surface loadings or bulk dust concentrations.