ISO 7303:2025

This document deals with the assessment of human exposure to metals and metalloids from ingestion of soil. It specifies a simplified method for the prediction of the oral bioaccessibility of metals and metalloids from contaminated soils. The method is a chemical extraction using hydrochloric acid (HCl) and can be used at least for first-tier screening for prediction of the oral bioaccessibility of arsenic (As), cadmium (Cd) and lead (Pb) in soil samples. It produces extracts that are representative of the bioaccessible concentrations measured by using the validated unified bioaccessibility method (UBM) (ISO 17924). More specifically, from the extractable concentrations of metals and metalloids by HCl, the predicted bioaccessibility in both the gastric and gastrointestinal phases is calculated using the equations and the prediction intervals provided in this document, and which have been derived from simple linear regressions of data obtained during validation studies.[2] NOTE The simplified method is applicable to prediction of the metals and metalloids bioaccessibility in soil with total concentrations range from 2 mg/kg to 2 600 mg/kg for As, from 0,2 mg/kg to 480 mg/kg for Cd, and from 4 mg/kg to 50 000 mg/kg for Pb.