Assessing Arsenic Oral (Bio)Availability In Soil and Human Health Risk by Using In Vitro Gastrointestinal Methods

Human health risk assessment science continues to mature with bioavailability-based risk assessment frameworks being developed and/or considered for implementation in the U.S., Canada, the European Union, Australia and other countries. Incidental ingestion is an important exposure pathway in these frameworks for assessing human health exposure and risk associated with contaminated soils. The oral bioavailability of arsenic and other soil contaminants can be determined by conducting dosing trials using acceptable surrogate animal models. To overcome the difficulty and expense associated with in vivo dosing trials, in vitro gastrointestinal (IVG) methods have been developed that simulate human gastrointestinal conditions. Bioaccessible arsenic determined by several IVG methods have been shown to be correlated with in vivo bioavailability data. Soil chemistry, mineralogy, and other geomedia properties influence contaminant bioavailability in urban contaminated soils. The influence of soil chemistry and arsenic source on arsenic bioaccessibility will be presented. Soil and contaminant chemistry requirements necessary for accurate application of IVG methods to access contaminant (bio)availability in urban soils will be presented.