Detection of Polycyclic Aromatic Hydrocarbons (PAHs) in Human Breast Milk

The concentration of polycyclic aromatic hydrocarbons (PAHs) in mother milk: A global systematic review, meta-analysis and health risk assessment of infants

Background

Bio-monitoring of polycyclic aromatic hydrocarbons (PAHs) contaminants in mother milk is essential to keep mothers and infants healthy against potential risks. The current study assesses the concentration of PAHs in mother milk through a meta-analytic and systematic review approach.

Methods

All the published studies up to December 2020 regarding the concentrations of various PAHs in mother milk were searched throughout major international databases such as PubMed, Scopus, and Web of Science. Moreover, the possible carcinogenic and mutagenic risks to infants were evaluated based on the BaP (benzo[a]pyrenee) equivalent dose.

Results

According to the results of 13 articles included among 936 retrieved studies, the lowest and highest concentration of PAHs was (0.125 ng/g) and (76.36 ng/g) related to benz(a)anthracenem and 1-methylnaphthalene, respectively. The highest (9.830 ng/g) and lowest (0.009 ng/g) concentration of PAHs was related to Mexico and Japan, respectively. Besides, carcinogenetic and mutagenic risk assessment of the PAHs indicated that risk pattern was different across countries. It can be concluded that the consumption of mother milk is safe and does not pose a risk due to the ingestion of PAHs to the health of infant consumers.

Aquaculture Contributes a Higher Proportion to Children's Daily Intake of Polycyclic Aromatic Hydrocarbons Than to That of Adults in Eastern China

Asia, especially China, shares a large proportion of global aquaculture production. Consequently, aquaculture food quality and safety with regard to contamination with polycyclic aromatic hydrocarbons (PAHs) were assessed in eastern China, which is a typical area of aquaculture. The concentrations of ∑PAHs ranged from 42 to 600 ng/g dry weight in a variety of dietary species from farm ponds in eastern China. With regard to the total daily intake of PAHs estimated based on the literature data on urinary hydroxy-PAHs in this region, there was a significant difference between children (mean = 130 ng/kg/d) and adults (mean = 600 ng/kg/d for pregnant women, 1700 ng/kg/d for women, and 2300 ng/kg/d for men). Furthermore, we provided a novel estimation on the fractional contribution of aquatic products to the overall human daily intake of PAHs. Specifically, the contribution of aquatic foodstuffs to total daily intake for children and pregnant women reached more than 50 and 10%, respectively, indicating that children and pregnant women were more vulnerable to the PAH-contaminated aquaculture foodstuffs. Meanwhile, no significant region-specific pattern between different provinces was observed. In summary, these results suggested that sensitive subpopulations were vulnerable to exposure to PAH-contaminated aquatic products, and it is necessary to pay attention to the dietary intake pattern of these sensitive subgroups in eastern China. Environ Toxicol Chem 2019;00:1-9. © 2019 SETAC.

In vitro metabolism of benzo[a]pyrene and dibenzo[def,p]chrysene in rodent and human hepatic microsomes

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and often carcinogenic contaminants released into the environment during natural and anthropogenic combustion processes. Benzo[a]pyrene (B[a]P) is the prototypical carcinogenic PAH, and dibenzo[def,p]chrysene (DBC) is a less prevalent, but highly potent transplacental carcinogenic PAH. Both are metabolically activated by isoforms of the cytochrome P450 enzyme superfamily to form reactive carcinogenic and cytotoxic metabolites. Metabolism of B[a]P and DBC was studied in hepatic microsomes of male Sprague-Dawley rats, naïve and pregnant female B6129SF1/J mice, and female humans, corresponding to available pharmacokinetic data. Michaelis-Menten saturation kinetic parameters including maximum rates of metabolism (VMAX, nmol/min/mg microsomal protein), affinity constants (KM, μM), and rates of intrinsic clearance (CLINT, ml/min/kg body weight) were calculated from substrate depletion data. CLINT was also estimated from substrate depletion data using the alternative in vitro half-life method. VMAX and CLINT were higher for B[a]P than DBC, regardless of species. Clearance for both B[a]P and DBC was highest in naïve female mice and lowest in female humans. Clearance rates of B[a]P and DBC in male rat were more similar to female human than to female mice. Clearance of DBC in liver microsomes from pregnant mice was reduced compared to naïve mice, consistent with reduced active P450 protein levels and elevated tissue concentrations and residence times for DBC observed in previous in vivo pharmacokinetic studies. These findings suggest that rats are a more appropriate model organism for human PAH metabolism, and that pregnancy's effects on metabolism should be further explored.