Milk and Urine Excretion of Polycyclic Aromatic Hydrocarbons and Their Hydroxylated Metabolites After a Single Oral Administration in Ruminants

Abstract

The aim of this study was to establish the transfer of phenanthrene, pyrene, and benzo[a]pyrene and their major hydroxylated metabolites to milk and to urine after a single oral administration (100 mg per animal of each compound) in 4 lactating goats. Detection and identification of the analytes (native compounds, 1-OH pyrene, 3-OH phenanthrene, 3-OH benzo[a]pyrene) were achieved using gas chromatography-mass spectrometry. Benzo[a]pyrene, phenanthrene, and pyrene were rapidly detected in the plasma stream, whereas 1-OH pyrene and 3-OH phenanthrene appeared later in plasma. These data suggest that pyrene and phenanthrene are progressively metabolized within the organism. Recovery rates of pyrene and phenanthrene in milk over a 24-h period appeared to be very low (0.014 and 0.006%, respectively), whereas the transfer rates of their corresponding metabolites were significantly higher: 0.44% for 1-OH pyrene and 0.073% for 3-OH phenanthrene. Recovery rates in urine were found to be higher (1 to 10 times) than recovery rates in milk. The 1-OH pyrene was found to be the main metabolite in urine as well as in milk. Thus, as has been established for humans, 1-OH pyrene could be considered as a marker of ruminant exposure to polycyclic aromatic hydrocarbons. Because 1-OH pyrene and 3-OH phenanthrene were measured in milk (unlike their corresponding native molecules), metabolites of polycyclic aromatic hydrocarbons should be taken into consideration when evaluating the safety of milk. Benzo[a]pyrene and 3-OH benzo[a]pyrene were (less than 0.005%) transferred to milk and urine in very slight amounts. This very limited transfer rate of both compounds suggests a low risk of exposure by humans to benzo[a]pyrene or its major metabolite from milk or milk products.

Transfer of Phenanthrene and Its Hydroxylated Metabolites to Milk, Urine and Faeces

“…The analysis of the blood kinetic showed that 3 hours after the oral administration of phenanthrene, the metabolites were detected in blood at very much higher levels than the parent compound (693.4 ng/mL and 2.32 ng/mL respectively). This result is in accordance with a recent study by our group on milk and urine excretion of PAHs and their hydroxylated metabolites in lactating ruminant (14). The authors showed that concentrations of phenanthrene were highest during the first 4 hours after oral administration of PAHs mixture.…”

Prenatal exposure to benzo(a)pyrene impairs later-life cortical neuronal function

“…Findings from the present study corroborate our earlier findings (Wu et al, 2003; Brown et al, 2007) demonstrating transplacental translocation of metabolites from dam to fetus during gestation and subsequent persistence in tissues throughout the preweaning period. Lactational transfer of B(a)P from mother to the newborn has been reported for rats (Yoshiko et al, 2004), ruminants (Lapole et al, 2007) and humans (Zanieri et al, 2007). Thus, the developing rat pups will not only have a constant infusion of B(a)P in utero (via placental transfer; Sanyal and Li, 2007) but also during the neonatal period (lactational transfer; cited above).…”

Developmental Brain and Behavior Toxicity of Air Pollutants: A Focus on the Effects of Polycyclic Aromatic Hydrocarbons (PAHs)

“…Following a single oral administration (100 mg per animal for each compound) in lactating goats, absorption of phenanthrene and pyrene was about 75%, whereas absorption was 12% for BaP. 32,49 In 2006, Grova et al 33 reported the impact of a chronic oral administration of a mixture of nine PAHs (fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(k)fluorene, BaP, and benzo(g,h,i)perylene; 0.02 mg/kg bw/day for each compound for 28 days) on milk contamination in lactating goats. The results showed a significant increase of monohydroxylated metabolites in milk over the time, whereas levels of native compounds remained constant.…”