Characterizing the contribution of residential phthalate dust concentrations to internal phthalate dose in the US population: an updated systematic review & meta-analysis

Abstract

Objectives: Phthalates are prevalent chemical substances that have been linked to endocrine disruption, reproductive disorders, and other adverse health effects. Although exposure to phthalates is widespread, few studies provide information on the relative contributions of exposure sources and routes of exposure. The objective of this systematic review and meta-analysis is to quantify the contribution of phthalates and phthalate alternatives in residential dust to internal human dose in the US general population. Methods: This review updates a pre-existing systematic review and meta-analysis published in 2015. It includes 12 studies published between January 2000 and April 2022 identified from Web of Science and PubMed using a predetermined search strategy. Pooled weighted median phthalate and phthalate alternative dust concentrations were determined from the studies included in our literature review. The phthalate and phthalate alternative dust concentrations were then used to calculate daily intake rates. Separately, using a reverse dosimetry model, the daily intake rate representing total phthalate and phthalate alternative internal dose was estimated from urinary phthalate metabolite concentrations measured in the 2017-2018 National Health and Nutrition Examination Survey (NHANES). The daily intake rates predicted from the indoor dust (systematic review/meta-analysis) and the urinary metabolites (NHANES) were then compared to drive the percent contribution of phthalates and phthalate alternatives measured in residential dust to internal dose. A summary showing the potential human health hazards associated with the measured chemical substances was compiled to provide context for risk. Results: ATBC (phthalate alternative) had the highest dust concentrations (systematic review/meta-analysis) while DEHTP (phthalate alternative) had the highest internal exposure level in children and adults (NHANES). Dust had a greater contribution to the internal phthalate and phthalate alternative concentration levels of children than adults when all exposure pathways (i.e., dust ingestion (direct), inhalation (indirect), and dermal absorption from air (indirect)) were considered. It was also observed that the dust ingestion pathway contributed significantly to the overall dust intake rate for high-molecular weight (HMW) phthalates. Conversely, the inhalation and dermal absorption from air exposure pathways were more significant for low-molecular weight (LMW) phthalates. The relative contribution of dust to the overall intake of the chemical substances varied depending on the physio-chemical characteristics, with dust being a more important contributor for LMW phthalates such as DEP and BBP. Conclusion: The relative contribution of dust to overall internal exposure of individuals is greater for LMW than HMW phthalates. This is linked to the increased likelihood of LMW phthalates partitioning from dust to indoor air, which makes the indirect contribution of dust to internal phthalate exposure greater than its direct contribution.