Effects of condensed organic matter on PCBs bioavailability in juvenile swine, an animal model for young children

• We performed an exposure assessment of NDL-PCBs from contaminated soils to piglets.
• We analyzed the impact of soil organic matter on NDL-PCBs bioavailability.
• Two organic matters with opposite degrees of condensation were tested.
• The condensed one strongly reduced bioavailability of NDL-PCBs.
• No retention of NDL-PCBs was seen with the less condensed one.

The 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 (ASs) were prepared according to OECD guideline 207. One standard soil (SS), devoid of OM, 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 digestive physiology model of young children. Animals were randomly distributed into 4 contaminated groups (3 replicates) and a control one (2 replicates). During 10 d, the piglets were fed AS or a corn oil spiked with 19 200 ng of Aroclor 1254 per g of dry matter (6000 ng g−1 of NDL-PCBs) to achieve an exposure dose of 1200 ng NDL-PCBs kg−1 of body weight per day. After 10 d of oral exposure, NDL-PCBs in adipose tissue, liver and muscles were analyzed by GC–MS, after extraction and purification. Two distinct groups of treatments were found: on the one hand oil, SS and FA, on the other hand C 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 major step for further relative bioavailability studies involving mixture of different humic substances.