Children's exposure to perfluoroalkyl acids - a modelling approach
Fabian G P Balk1, Kerstin Winkens Pütz2, Anton Ribbenstedt3
1Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, Svante Arrhenius väg 8c, 10691 Stockholm, Sweden. Ian.Cousins@aces.su.se Fabian.Balk@eawag.ch and Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland.
Insights
Diet is a primary exposure route for per- and polyfluoroalkyl substances (PFASs) in children. This study modeled serum PFAS levels, finding children
Area of Science:
- Environmental Health
- Toxicology
- Pediatric Health
Background:
- Per- and polyfluoroalkyl substances (PFASs) are widespread environmental contaminants.
- Adult exposure routes are known, but children's exposure pathways remain unclear.
- PFASs are linked to various adverse health outcomes.
Purpose of the Study:
- To reconstruct serum concentrations of PFOA, PFOS, and PFHxS in children aged 1 to 10.5 years.
- To determine if dietary intake is the main exposure pathway for these PFASs in children.
- To compare modeled and measured serum PFAS concentrations.
Main Methods:
- Utilized data from a Finnish child cohort study.
- Measured serum concentrations of PFOA, PFOS, and PFHxS.
- Assessed PFAS concentrations in dust and air samples.
- Employed a pharmacokinetic (PK) model to reconstruct serum PFAS levels based on calculated dietary intake.
Main Results:
- Diet was identified as the major exposure medium for 10.5-year-old children.
- The PK model accurately reconstructed median PFOA and PFOS serum concentrations.
- Modeled PFHxS serum concentrations were consistently underestimated, indicating a need for further investigation.
- PFOA and PFOS exposure levels were close to regulatory thresholds.
Conclusions:
- Children's exposure to PFOA and PFOS after infancy resembles adult exposure patterns.
- Exposure to PFOA and PFOS remained relatively constant for children between 1 and 10.5 years.
- Further research is needed to understand PFHxS exposure sources and PK parameters in children.
Abstract:
Adults are mainly exposed to per- and polyfluoroalkyl substances (PFASs) via ingestion of food, inhalation of air and ingestion of dust, whereas for children the exposure to PFASs is largely unknown. This study aimed to reconstruct the serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in children after infancy up to 10.5 years of age and to test if dietary intake is the major exposure pathway for children to PFOA, PFOS and PFHxS after infancy. For this work, a dataset from a Finnish child cohort study was available, which comprised serum concentrations of the studied perfluoroalkyl acids (PFAAs) and PFAS concentration measurements in dust and air samples from the children's bedrooms. The calculated PFAA intakes were used in a pharmacokinetic model to reconstruct the PFAA serum concentrations from 1 to 10.5 years of age. The calculated PFOA and PFOS intakes were close to current regulatory intake thresholds and diet was the major exposure medium for the 10.5 year-olds. The one-compartment PK model reconstructed median PFOA and PFOS serum concentrations well compared to corresponding measured median serum concentrations, while the modelled PFHxS serum concentrations showed a constant underestimation. The results imply that children's exposure to PFOA and PFOS after breastfeeding and with increasing age resembles the exposure of adults. Further, the children in the Finnish cohort experienced a rather constant exposure to PFOA and PFOS between 1 and 10.5 years of age. The PFHxS exposure sources and respective pharmacokinetic parameter estimations need further investigation.
