Quaternary Ammonium Compounds in Paired Samples of Blood and Indoor Dust from the United States

Abstract

Previous studies of quaternary ammonium compounds (QACs) in the indoor environment have reported widespread presence of QAC in indoor dust. However, there are limited data on the contribution of dust ingestion to the QAC body burden. In this study, 18 QACs (6 benzylalkyldimethylammonium compounds [BACs], 6 dialkyldimethylammonium compounds [DADMACs], and 6 alkyltrimethylammonium compounds [ATMACs]) were analyzed in 81 paired samples of blood serum and dust collected in Indiana, United States. QACs were detected in 51–100% of the dust samples with the total QAC concentrations (∑QAC) ranging from 0.613 to 427 μg/g (median 56.9 μg/g). In contrast to dust samples, QACs were detected less frequently in blood serum with a median ∑QAC concentration of 3.66 ng/mL. The relative source contribution (RSC) of dust ingestion to serum levels was calculated using the PROTEX (PROduction-To-EXposure) model and was estimated as less than 1%, suggesting that hand-to-mouth contact, dietary intake, or inhalation could be more important exposure routes than dust ingestion. This is the first study to simultaneously measure QAC concentrations in indoor dust and blood, providing comprehensive assessment of the role of dust ingestion in QAC human exposure.