Retrospective prediction of environmental emerging contaminants exposure using human hair: Insights into suitability, reliability, and availability.

Hair is a widely utilized non-invasive matrix for human biomonitoring assessment. Nevertheless, its efficacy in reflecting various pollutants, along with the concentrations and time-scales of exposure, remains undetermined. In this panel study, hair and indoor dust samples were collected quarterly from May 2022 to June 2023. The concentrations of 34 types of plasticizers, belonging to three categories - organophosphate flame retardants (OPFRs), phthalate esters (PAEs), and alternative plasticizers (APs) - were measured. The study aimed to identify which pollutants hair is suitable for monitoring and to determine the exposure levels and time periods over which it can retrospectively predict contamination, using generalized linear mixed models. A one-unit increase in the hair concentration of acetyl tributyl citrate (ATBC) was associated with a 40.3 % (95 % CI: 7.2 %, 83.5 %) rise in its level in dust over the preceding 3 months. Retrospective predictions revealed that the levels of di (2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DOP) in dust increased by 83.6 % (95 % CI: 31.9 %, 155.7 %) and 76.7 % (95 % CI: 13.5 %, 174.9 %), respectively, over the previous 6-9 months. Furthermore, the DEHP and DOP concentrations in hair accounted for 99.60 % and 100 % of the variance in their levels in dust, respectively. Our findings provide valuable insights into the time-concentration relationships of plasticizers in paired hair and dust samples, advancing the understanding of hair as a retrospective biomarker for environmental exposure.