Effect of oral exposure to polycyclic aromatic hydrocarbons on goat's milk contaminationNathalie Grovaa, Guido Rychena, Fabrice Monteaub, Bruno Le Bizecb and Cyril Feidta
a URAPA, INRA-INPL-UHP, BP 172, 2 avenue de la Forêt de Haye, 54505 Vandoeuvre-lès-Nancy Cedex, France
b LABERCA, ENVN, route de Gachet, 44307 Nantes Cedex 3, France
(Accepted 24 July 2006; published online 21 October 2006)
Abstract - The impact of chronic exposure to polycyclic aromatic hydrocarbons (PAHs) on milk contamination was evaluated by oral administration of a mixture of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(k)fluorene, benzo(a)pyrene and benzo(g,h,i)perylene at 0.02 mg/kg to lactating goats for 28 days. We analysed PAHs and their major metabolites in milk by gas chromatography-mass spectrometry. The results evidence several major points: (1) benzo(k)fluorene, benzo(a)pyrene and benzo(g,h,i)perylene were not detected in the milk; (2) unexpectedly, the concentration of fluorene, phenanthrene, anthracene, fluoranthene, pyrene and chrysene did not change with time; (3) monohydroxylated PAH metabolites (-OH), namely 2-OH-fluorene, 3-OH-phenanthrene and 1-OH-pyrene were detected shortly after administration. The concentrations of 2-OH-fluorene and 3-OH-phenanthrene reached, respectively, maxima of 0.41 and 0.22 ng/mL during the first exposure week, whereas the concentration of 1-OH pyrene increased to reach a maximum of 0.97 ng/mL on day 14, then slightly decreased during the last two exposure weeks. Those findings suggest a lack of activation of a metabolism that could lead to an excretion of PAHs into milk under native forms. However, a slight increase in concentration could induce the metabolism, which should lead to an increase in the excretion of metabolites into the milk. In spite of the absence of a significant transfer of parent PAHs to milk, the appearance of metabolites in milk raises questions of their impact on human health.
Key words: Chronic exposure / PAHs / metabolites / milk contamination
Corresponding author: Nathalie Grova firstname.lastname@example.org
© INRA, EDP Sciences 2006