The application of in vitro gastrointestinal extraction to assess oral bioaccessibility of potentially toxic elements from an urban recreational site

The use of in vitro gastrointestinal extraction to assess the oral bioaccessibility of 7 potentially toxic elements (PTEs) from soil derived from an urban recreational site, has been assessed. The pseudo-total concentration of the 7 PTEs was determined using microwave digestion followed by inductively coupled plasma mass spectrometry. The bioaccessible fraction was determined and the data compared to the pseudo-total concentrations to determine % bioaccessibility. A generic quantitative risk assessment (GQRA) was undertaken on the pseudo-total PTE concentration of the site by comparing the values with soil guideline (SGV) or generic assessment criteria (GAC) using the residential land use scenario. Based on the GQRA, concentrations of 3 of the PTEs investigated within the soils could present a potential risk to site users. Consideration of receptor exposure and bioaccessibility data allowed a more considered approach to human-health risk assessment at this site. Although the bioaccessibility data did not significantly alter the sites preliminary designation as contaminated (As and Pb concentrations exceeded the GAC even in the in vitro extracts) bioaccessibility data are clearly an additional tool towards furthering our understanding of human-health risk at contaminated sites and have the potential to act as a pragmatic decision-support tool.