In vitro assessment of arsenic bioaccessibility in contaminated (anthropogenic and geogenic) soils Albert L. Juhasz a, * , Euan Smith a , John Weber a , Matthew Rees b , Allan Rofe b , Tim Kuchel b , Lloyd Sansom c , Ravi Naidu a,1 a Centre for Environmental Risk Assessment and Remediation, Division of Information Technology, Engineering and the Environment, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095, Australia b Institute for Medical and Veterinary Science, Frome Road, SA 5000, Australia c Sansom Institute, School of Pharmacy and Medical Sciences, Division of Health Science, University of South Australia, City East Campus, SA 5001, Australia Received 8 February 2007; received in revised form 11 April 2007; accepted 13 April 2007 Abstract Arsenic (As) bioaccessibility in contaminated soils (n = 50) was assessed using the simplified bioaccessibility extraction test (SBET). Soils used in the study were collected from sites where As was used as an herbicide (railway corridor) or pesticide (cattle dip sites), from former gold mines and from highly mineralised locations containing geogenic As sources (gossans). In all but three soils, As bioacces- sibility was less than 50% indicating that a significant proportion of the total As concentration may not be available for absorption in the gastrointestinal tract following incidental soil ingestion. When regression models were developed based on soil properties, the descriptive variables best able to describe As bioaccessibility in railway corridor, dip site and mine site soils were total As and total or dithionite- citrate extractable (free) iron (Fe). While As bioaccessibility could be predicted (r 2 = 0.955, n = 50) in these contaminated soils, As bio- accessibility for gossan soils was a poor fit using linear or multivariate regression analysis. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Arsenic; Bioaccessibility; SBET; Model 1. Introduction The assessment, management and remediation of haz- ardous wastes, including arsenic (As) containing wastes, is a worldwide environmental concern. Exposure to As has been shown to result in human carcinogenesis and the development of numerous health disorders (Lien et al., 2001; Mandal and Suzuki, 2002). In Australia, As soil con- tamination has resulted from the use of As-based herbi- cides, pesticides, timber preservatives as well as through mining and smelting processes (Smith et al., 1998). It has been reported that As contamination at these sites may range up to 15 000 mg As kg 1 soil (Ellice et al., 2001). In addition, elevated concentrations of As have also been detected in naturally occurring mineralised zones of arseno- pyrite (gossans) (Scott et al., 2001). Owing to the increase in urbanisation, many of these sites are being developed as residential areas and as such, has raised concerns about the potential risk of soil-borne As to animal, human and environmental health. Bioavailability refers to the ability of a chemical in the environment to interact with human or ecological receptors (Peijnenburg et al., 1997). When defining bioavailability in terms of human receptors, the bioavailable fraction is the fraction of a compound that is absorbed into systemic cir- culation (Ruby et al., 1996, 1999; Rodriguez et al., 1999). 0045-6535/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2007.04.046 * Corresponding author. Tel.: +61 8 8302 5045; fax: +61 8 8302 3057. E-mail address: Albert.Juhasz@unisa.edu.au (A.L. Juhasz). 1 Present address: Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Mawson Lakes, SA 5095, Australia. www.elsevier.com/locate/chemosphere Chemosphere xxx (2007) xxx–xxx ARTICLE IN PRESS Please cite this article in press as: Juhasz, A.L. et al., In vitro assessment of arsenic bioaccessibility in ..., Chemosphere (2007), doi:10.1016/j.chemosphere.2007.04.046