engleski

Polybrominated diphenyl ethers in indoor dust of different microenvironments in Zagreb, Croatia and assessment of toddlers’ exposure

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants used as additives in a wide range of consumer products, such as polyurethane foam in furniture and car seats, textile, building and plastic materials, as well as electrical and electronic equipment from which they are easily released and bonded to dust particles. Growing evidence on their persistency and adverse health effects (thyroid hormone and endocrine disruption, neurotoxicity) has led to a global ban of their production and use. Given the dominantly indoor lifestyle in developed cities, dust ingestion and dermal absorption are considered the main routes of human exposure to PBDEs. Toddlers are identified as being the most exposed and vulnerable population group due to their frequent hand-to-mouth activity and extensive contact with floors, carpets, and other dusty surfaces, in combination with their lower body weight. The levels of seven PBDE congeners (BDE-28, -47, -99, -100, 153, -154, and -183) were determined in dusts collected in different microenvironments in Zagreb, Croatia. Although comparable median levels of Σ7PBDEs were measured (4.34, 6.08, and 8.26 ng g-1 dust) significantly different maximum values of 200.09, 14.42 and 5666.98 ng g-1 dust were detected in dust from homes, kindergartens, and cars, respectively. Based on the obtained data, toddlers’ exposure to PBDEs via dust ingestion and dermal absorption was estimated. Total estimated daily intake (EDI) values for the Σ7PBDEs in each microenvironment calculated as the sum of two individual intake pathways ranged from 1.27 × 10-3 (cars) to 1.07 × 10-2 ng kg-1 bw day-1 (homes) at central, and from 2.37 × 10-2 (kindergartens) to 1.69 ng kg-1 bw day-1 (cars) at worst case scenarios. Intake via dust ingestion is the dominant pathway, with contributions of over 94 %. All EDI values, even at worst case scenarios were several orders of magnitude lower than the reference dose (RfD) of 2000 ng kg-1 bw day-1 set for pentaBDEs. We calculated the EDI based on a time-weighted model that integrates the time fraction spent in each microenvironment, which is 4 %, 22% and 64 % for cars, kindergartens, and homes. It was observed that daily intake of dust from homes contributes to overall exposure with the largest proportion of 63 % at central case scenarios, while at worst case scenarios the highest contribution was from intake of car dust, because of the higher PBDE levels found. Calculated values of hazard indexes (HI) presenting non-carcinogenic risk of investigated exposure pathways was several orders of magnitude below 1 indicating that PBDE uptake via ingestion and dermal absorption of dust originating from various microenvironments poses a low risk for toddlers. Nevertheless, care should be taken considering that dust ingestion is not the only exposure pathway to PBDEs as well as that these are not the only contaminants present in dust.

PBDEs, toddlers’ exposure, daily intake, dust ingestion, dermal absorption

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