The Bioavailability of Contaminants in Soil: Considerations for Human Health Risk Assessment (BCS-1, 2017) guidance explains how bioavailability information can be integrated into human health risk assessments to improve decision-making. It focuses on how much of a chemical in soil is actually absorbed by the body, since contaminants in soil may be less available for uptake than the forms used in toxicity testing. When risk assessments assume full absorption from soil, they can overestimate exposure and risk. Accounting for bioavailability can improve accuracy and reduce uncertainty in exposure estimates.
The document helps regulators, practitioners, and stakeholders select and interpret site-specific bioavailability testing, understand the strengths and limitations of in vivo and in vitro methods, and choose appropriate approaches for evaluating site conditions while maintaining human health protection. It also explains how to apply tools to develop site-specific bioavailability values in risk assessments, with a focus on lead, arsenic, and polycyclic aromatic hydrocarbons (PAHs), where the science is more developed. In addition, the guidance describes general bioavailability concepts, reviews current science, and includes information on dermal exposure to polycyclic aromatic hydrocarbons from soil as part of the risk assessment process.
Topic(s): Bioavailability, Human Health, Risk Assessment, Risk Communication, Risk Management, Sediments, Soils
