engleski

Polybrominated diphenyl ethers in Croatian human milk samples

Introduction: Polybrominated diphenyl ethers (PBDEs) are a class of commonly used brominated flame retardants added to polymers that were used in a variety of consumer products, including furniture, textiles, plastics, and electronic equipment. Diet, indoor air and dust are the main sources of PBDE exposure for the general population, while human milk is the main PBDE source for breastfeeding infants. Because of PBDEs' resistance to egradation and the increasing evidence of their toxic potential, concerns have been raised about the association between human exposure to PBDEs and their adverse effects on human health, specially on nursing infants who are far more sensitive than adults. Materials and Methods: The levels of 7 PBDE congeners (BDE-28, -47, -99, -100, -153, -154, and - 183) were measured in individual human milk samples from Zagreb, Croatia, collected in 2010 (N=16) and in 2020 (N=7), and the associated risk to breastfed infants via PBDE exposure was investigated. An accelerated solvent extraction (ASE) was used as the extraction technique (90 °C, 1500 psi, extracted cycle was 3 times with 70 % flush volume of n-hexane:dichloromethane (1:1)) followed by gas chromatography with tandem mass spectrometry for identification and quantification of the target compounds at the low pg g-1 lipid weight (lw) level. Results: The most frequently detected congener was BDE-153, with a detection frequency of 94 % in 2010, and 100 % in 2020. Its mass fraction contributed from 31 % to 100 % to the sum of the mass fractions of all detected congeners (∑PBDEs) (median 96 %) in samples from 2010, while it was the only detected congener in samples collected in 2020 (140.38 to 307.89 pg g-1 lw ; median value 246.19 pg g-1 lw). Among the 2010 samples, only one sample had none of the analyzed congeners detected. BDE-99 and BDE-100 were <LOD in all samples, while BDE-47 was measured in only two samples from 2010 with a contribution of > 65 % to the ∑PBDEs, which ranged from 169.91 to 3532.79 pg g-1 lw (median value 285.50 pg g-1 lw). The mass fractions obtained for positive samples were used to calculate estimated daily intakes (EDI) for breastfeeding infants and they ranged from 0.517 to 18.94 ng g-1 bw day-1 (median 1.429 ng g-1 bw day-1 ) for samples from 2010, and from 0.751 to 1.958 ng g-1 bw day-1 (median 0.984 ng g-1 bw day- 1) for samples from 2020. The non-cancerogenic risk of individual pollutants, assessed using the hazard quotient (HQ) calculated by dividing the EDI by the corresponding threshold reference value suggested by the USEPA for BDE-47 (100 ng kg-1) and BDE-153 (200 ng kg-1), was calculated. HQ values obtained for both periods were all well below 1, which indicates that infants born in this area had no health risk from exposure to PBDEs from human milk. Conclusions: The levels of analyzed contaminants were generally very low in both observed periods. Predominance of congener BDE-153 in human milk samples may indicate the use of penta-BDE commercial mixtures in the Zagreb area, as it has a higher bioaccumulation potential than the more abundant congeners in those mixtures. On the other hand, BDE-153 can be formed as a result of a metabolic degradation of BDE-209, which is the main component of the latest banned deca-BDE commercial mixture. Although the number of samples is relatively low and they are not representative of the entire Croatian population, the results of the present study serve as the first data on PBDE levels in human milk from Croatia, providing evidence of a decreasing trend in concentrations over a ten-year period.

PBDE ; Human milk ; ASE ; exposure of breastfeeding infants

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