Human Indoor Exposome of Chemicals in Dust and Risk Prioritization Using EPA’s ToxCast Database

Humans
spend most of their time indoors and thus have long-term
exposure to chemicals. Dust is a sink for most indoor chemicals, and
its ingestion is an important pathway for chemical uptake. Therefore,
the chemical atlas from dust is an ideal environmental sample to investigate
the indoor exposome and associated risk. In this study, we aimed to
establish an indoor exposome database through comprehensive data mining
on the occurrence of identified compounds in dust, and we prioritize
chemicals of health concern. Through an extensive literature review
(2849 articles), 355 chemicals and their concentrations were documented
and analyzed for human exposure. Together with 81 compounds without
concentration and 75 volatile organic compounds, we have established
an indoor exposome database with 511 chemicals. Sixteen toxicological
end points were selected for toxicity prioritization. Toxic equivalency
factor (TEF)-based toxicity, calculated from EPA’s ToxCast
database, revealed a comprehensive atlas of the chemicals that had
a primary contribution. Many of the prioritized compounds are currently
neglected or are not actively studied. Overall, this investigation
provides one of the most comprehensive analyses on chemical occurrence
in indoor dust and prioritizes their chemical toxicity. Our findings
can be used as a database for future exposome studies of the indoor
environment and provide guidance for indoor risk assessments.