12The relative bioavailability of arsenic, antimony, cadmium and lead for the ingestion pathway was 22Using benchmark criteria for assessing the 'fitness for purpose' of the UBM bioaccessibility data to 23 act as an analogue for bioavailability in risk assessment, the study shows that the UBM met criteria

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Human activities produce polluting compounds such as persistent organic pollutants (POPs), which may interact with agriculture. These molecules have raised concern about the risk of transfer through the food chain via the animal product. POPs are characterised by a strong persistence in the environment, a high volatility and a lipophilicity, which lead to their accumulation in fat tissues. These compounds are listed in international conventions to organise the information about their potential toxicity for humans and the environment. The aim of this paper is to synthesise current information on dairy ruminant exposure to POPs and the risk of their transfer to milk. Three major groups of POPs have been considered: the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), the polychlorobiphenyls (PCBs) and the polycyclic aromatic hydrocarbons (PAHs). The results show that contamination of fodder and soil by these compounds is observed when they are exposed to emission sources (steelworks, cementworks, waste incinerators or motorways) compared with remote areas. In general, soil contamination is considered higher than plant contamination. Highest concentrations of POPs in soil may be close to 1000 ng/kg dry matter (DM) for PCDD/Fs, to 10 000 mg/kg DM for PAHs and 100 μg/kg DM for PCBs. The contamination of milk by POPs depends on environmental factors, factors related to the rearing system (fodder and potentially contaminated soil, stage of lactation, medical state of the herd) and of the characteristics of the contaminants. Transfer rates to milk have been established: for PCBs the rate of transfer varies from 5% to 90%, for PCDD/Fs from 1% to 40% and for PAHs from 0.5% to 8%. The differential transfer of the compounds towards milk is related to the hydrophobicity of the pollutants as well as to the metabolic susceptibility of the compounds.

A fast and efficient multiresidue extraction-purification procedure was developed for low levels (ppb range) of phenanthrene and hydroxyphenanthrene in biological matrices, in order to quantify phenanthrene and metabolites in blood, milk, urine, and biological tissues of lactating goats. Detection and identification of the analytes (phenanthrene and 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrene) were achieved using gas chromatography coupled to mass spectrometry. Deuterium-labeled phenanthrene was used as internal standard for phenanthrene and 2-OHfluorene for metabolites. The developed method includes enzymatic hydrolysis, liquid-liquid extraction, and Envi-Chrom P SPE column purification. Analyses were performed in the selected ion monitoring mode to achieve ad hoc sensitivity in accordance with analyte concentrations in food samples. Detection limits were between 2.3 and 5.1 ng/mL (ppb) for milk samples, 0.5 and 2.5 ng/mL for urine and blood samples, and 1.9 and 8.0 ng/g for tissue samples. This original multiresidue and multimatrix analytical methodology was applied to metabolism studies and polycyclic aromatic hydrocarbon (PAH) risk assessment. We demonstrated, for the first time, that metabolites were present in milk. These results suggested that usual PAHs analysis methods based on the detection of native molecule are not representative of the real contamination of biological matrices.