Bioaccessibility and speciation of As and Pb in soils contaminated by two distinct anthropic activities
Abstract
Man exposure to the soils can occur via a number of different ways, including dust inhalation, adsorption and subsequent permeation through the skin and soil ingestion, and the soil ingestion. In human health risk assessment for sites contaminated with heavy metals, this later the major exposure route and is used to calculated the remediation thresholds. Currently, it is assumed that the fraction of the pollutant which reaches the systemic circulation (i.e. the bioavailable fraction) is equal to the bioavailability of the same pollutant in the matrix used for the establishment of the toxicological reference value. The measurement of the bioavaiiable fraction needs in vivo experiment which might be cost and time consuming and ethically problematic. Thèse last years chemical tests were developed to approach the bioavailability by the bioaccessibility which is the fraction of pollutant solubilized in the digestive tract. As shown by the literature, both bioaccessibility and bioavailability are dépendent on the soil pollutant speciation (Davids et al., 1993; Ruby et al., 1999). Objective of this work was to study the possibility to use speciation as a tool to estimate As and Pb bioaccessibility.