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RP2E INRA Université de Lorraine

Assessment of the impact of organic mater in NDL-PCBs sequestration in industrially contaminated soils : comparison of an in vitro bioaccessibility and an in vivo relative bioavailability assays

24th Annual Meeting of the Society of Environmental Toxicology and Chemistry (SETAC Europe), 11-15 mai, Bâle, Suisse

Delannoy, M., Fournier, A., Rychen, G., Cave, M., Feidt, C.

2014

Quantitative health risk assessments are critical issues in management of contaminated soils and involuntary ingestion is one of the exposure pathway studied. Currently, as a margin of safety, 100% of the pollutants from the ingested soil is considered to reach the target organ and to exert toxic effects. However, it is established that only a fraction of the total ingested quantity really enters the bloodstream and reaches the target organs. In recent years, in vitro bioaccessibility tests aiming at estimating organic pollutant bioavailability and less expensive and easier to carry out than in vivo bioavailability tests, have been developed. Bioaccessibility is the fraction of an ingested compound that could be solubilized in the gastrointestinal tract before being absorbed. Few data are currently available concerning such approaches for organic pollutant contaminated soils. This study was carried out in order to compare bioaccessibility data with relative in vivo bioavailable ones in juvenile swine, a physically close model of young children. It concerned 8 "PCBs contaminated soils" which were collected at five different sites. Soil were freeze-dried and sieved to 500µm and homogenised. Characterization of soils were performed and were notably focused on organic matter (Black carbon amount, carbon organic content). This study involved five juvenile male swine per soil. During 10 days, the piglets were fed one of five doses chosen for one soil to achieve an exposure dose between of 200 and 3 600 ng NDL-PCBs.Kg-1 of BW per day in order to assess linearity of dose-response. This soil-fed group was compared to one fed increasing doses of spiked corn oil by Aroclor 1254. After 10 days of oral exposure, NDL-PCBs concentrations in adipose tissue, liver and muscles were determined by GC-MS, after extraction and purification. Linearity assessment were performed on NDL-PCBs levels in tissues using GLM procedure of SAS software. Bioaccessibility of each soil were assessed using the FOREhST procedure. Preliminary results highlight that condensed organic matter is a critical parameter affecting bioavailability or bioaccessibility of PCBs. 

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