title: Assessing the bioavailability and bioaccessibility of metals and metalloids.
abstract: Bioavailability (BA) determines the potential harm of a contaminant that exerts on the receptor. However, environmental guidelines for site contamination assessment are often set assuming the contaminant is 100 % bioavailable. This conservative approach to assessing site risk may result in the unnecessary and expensive remediation of a contaminated site. The National Environmental Protection Measures in Australia has undergone a statutory 5-year review that recommended that contaminant bioavailability and bioaccessibility (BAC) measures be adopted as part of the contaminated site risk assessment process by the National Environment Protection Council. We undertook a critical review of the current bioavailability and bioaccessibility approaches, methods and their respective limitations. The 'gold' standard to estimate the portion of a contaminant that reaches the system circulatory system (BA) of its receptor is to determine BA in an in vivo system. Various animal models have been utilised for this purpose. Because of animal ethics issues, and the expenses associated with performing in vivo studies, several in vitro methods have been developed to determine BAC as a surrogate model for the estimation of BA. However, few in vitro BAC studies have been calibrated against a reliable animal model, such as immature swine. In this review, we have identified suitable methods for assessing arsenic and lead BAC and proposed a decision tree for the determination of contaminant bioavailability and bioaccessibility for health risk assessment.
authors.affiliation: The University of Queensland, National Research Centre for Environmental Toxicology (Entox), Brisbane, Queensland, 4108, Australia, j.ng@uq.edu.au.
authors.forename: Jack C
authors.initials: JC
authors.lastname: Ng
authors.forename: Albert
authors.initials: A
authors.lastname: Juhasz
authors.forename: Euan
authors.initials: E
authors.lastname: Smith
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D000818:Animals; D001682:Biological Availability; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000493:pharmacokinetics*; D006801:Humans; D058955:Metalloids / Q000493:pharmacokinetics*; D008670:Metals / Q000493:pharmacokinetics*; D023421:Models, Animal; D018570:Risk Assessment / Q000379:methods*
chemical_list: D004785:Environmental Pollutants; D058955:Metalloids; D008670:Metals