Title : Oral bioaccessibility of metal(loid)s as a relevant indicator for the health-environment link - Case study on arsenic in contaminated soils
Abstract:
The Haute Autorite de Sante (HAS), a French health agency, recently published a best practice recommendation for healthcare professionals on the screening, management and monitoring of populations living on sites and soils contaminated or at risk of arsenic pollution. More specifically, the focus is on the concentration of bioaccessible arsenic in soil, i.e. the proportion of the metalloid capable of being solubilized in digestive fluids when soil particles are ingested and absorbed by the body. Thus, when the concentration of bioaccessible arsenic in soil exceeds 25 mg/kg, HAS recommends population monitoring. To date, only the map of predicted total arsenic levels in France is available, based on measurements of 2,240 sites from RMQS (the Soil Quality Measurement Network). Approximately 350 soil samples among the 2,240 were collected throughout France, in areas with the highest concentrations. The objective of this study was to determine the oral bioaccessibility of arsenic using two in vitro methods (Unified Bioaccessibility Method ISO 17924 and a simplified method currently undergoing ISO standardization). Currently, ISO 17924 is considered as the reference method in France recommended by French Ministries in the national methodology for managing polluted sites and soils. For the soil samples selected, total arsenic concentrations ranged from 25 to 412 mg/kg, while bioaccessible concentrations ranged from 0.7 to 76 mg/kg. Expressed in relation to total concentrations, percentages of bioaccessible arsenic ranged from 1.6 to 45% (median 7.1%). These results highlight the importance of considering bioaccessibility when assessing population exposure. Indeed, with one exception, predicted bioaccessible concentrations are below the threshold value of 25 mg/kg. Moreover, the percentages of bioaccessible As are relatively low (< 10% on average). The aim of this study is to demonstrate the value of measuring bioaccessibility using in vitro tests to define appropriate management measures and recommend population monitoring.
Audience Take Away Notes:
- Raise awareness on the concept of bioaccessibility
- Promote the use of in vitro method to measure the oral bioaccessibility of metal(loid)s as a relevant indicator for the health-environment link
