Exposure assessment of sequestrated organic compounds in polluted sites and soils: use of a juvenile animal model to estimate their relative bioavailability

International audience

Inglés. Exposure assessment of Polychlorinated biphenyls (PCBs) contaminated soils is a critical issue in terms of human health, especially since little reliable information on transfer of PCBs to humans via involuntary soil ingestion is available. Indeed, young children with their hand-to-mouth activity may be exposed to contaminated soils. The current study addresses the impact of soil Organic Matter (OM) condensation on bioavailability of sequestrated NDL-PCBs. Three Artificial Soils (AS) were prepared according to OECD guideline 207. One Standard Soil (SS), containing no organic matter, and two amended versions of this SS with Fulvic Acid (FA) or Activated Carbon (AC) were prepared to obtain 1% organic mass. This study involved fourteen juvenile male swine as a physically close model of young children. Animals were randomly distributed into 4 contaminated groups (3 replicates) and a control one (2 replicates). During 10 days, the piglets were fed AS or a corn oil spiked with 19 200 ng of Aroclor 1254 per g of dry matter (6 000 ng/g of NDL-PCBs) to achieve an exposure dose of 1 200 ng NDL-PCBs.Kg-1 of BW per day. After 10 days of oral exposure, NDL-PCBs concentrations in adipose tissue, liver and muscles were determined by GC-MS, after extraction and purification. Variance analyses were performed on NDL-PCBs levels in tissues as repeated measures using MIXED procedure of SAS software. A Significant treatment effect and two distinct groups of treatments were found: on one hand oil, SS and FA, on the other hand control and AC. This study highlights that condensed OM (AC) strongly reduces bioavailability whereas the less condensed one (FA) does not seem to have a significant effect. This result has to be considered as a first step for further relative bioavailability studies involving mixture of different humic substances.