Concentrations of Organophosphate Esters in Drinking Water from the United Kingdom: Implications for Human Exposure

Abstract

Data on the presence of organophosphate esters (OPEs) in drinking water and its significance as a pathway of exposure are limited. In this study, we measure for the first time, concentrations of eight OPEs in 52 UK drinking water samples. Arithmetic mean concentrations of ∑8OPEs were: 2.6, 6.4 and 11 ng/L in water dispenser (n=2), bottled (n=25), and tap water samples (n=25), respectively. The predominant OPEs detected were: TBOEP, TCEP, and TCIPP with arithmetic mean concentrations in the 3 water sample types ranging between (1.5 – 3.8 ng/L), (0.49 – 3.0 ng/L), and (0.29 – 2.9 ng/L), respectively. Estimated daily intakes (EDIs) (mean and high-end exposure) via drinking water for different sectors of the UK population were: infants (1.1 and 6.8 ng/kg body weight/day) ˃ toddlers (0.53 and 3.3 ng/kg body weight/day) ˃ children (0.40 and 2.5 ng/kg body weight/day) ˃ adults (0.32 and 2.2 ng/kg body weight/day). Based on these data, exposure to Σ8OPEs via drinking water is much lower than via: food, indoor dust ingestion, inhalation, and dermal uptake for adults and toddlers. Reassuringly, our EDIs were lower than relevant reference dose (RfD) values. However, combining our drinking water ingestion data with exposure via other pathways revealed overall exposure to EHDPP and TCIPP to approach health-based limit values for UK toddlers under a high-end exposure scenario.

Keywords: organophosphate esters, exposure risk, dispenser water and hazard quotients