Do Current Standards of Practice in Canada Measure What is Relevant to Human Exposure at Contaminated Sites? II: Oral Bioaccessibility of Contaminants in Soil

ABSTRACT

Human health risk estimates for sites with contaminated soils are often based on the assumption that the outdoor soil sieved to < 250 μm is a reasonable surrogate for predicting exposures via incidental soil ingestion. In vitro bioaccessibility tests are also increasingly used to “improve” ingestion exposure predictions of contaminants at different sites. However, when considered in terms of factors that influence desorption of contaminants from particles and uptake into humans, available studies indicate that current “standards of practice” with respect to assays of oral bioaccessibility have a number of significant shortcomings, at least in Canada. These shortcomings are discussed and various factors that influence the assessment of bioaccessibility of contaminants in soils are examined. We finish with proposing some minimum data submission requirements to support the application and relevance of bioaccessibility assays at contaminated sites.

Key Words:

• soil
• contaminant
• exposure
• risk assessment
• bioavailability
• bioaccessibility
• contaminated sites.

Notes

¹As reported by USEPA IRIS, accessed November 16, 2004.