Occurrence and exposure assessment of organophosphate flame retardants (OPFRs) through the consumption of drinking water in Korea.

Organophosphate flame retardants (OPFRs) have been widely used as flame retardants and plasticizers in commercial products. Limited data are available on the occurrence and exposure of OPFRs via drinking water consumption. In this study, 127 drinking water samples were collected from tap water, purified water (tap water that is passed through in-house filters) and bottled water from major cities in Korea in 2014. The total concentrations of OPFRs (ΣOPFR) in all of the samples ranged from below the method detection limit (MDL) to 1660 (median: 48.7) ng/L. The predominant OPFR compounds in drinking water were tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroethyl) phosphate (TCPP), and tris(2-butoxyethyl) phosphate (TBEP). Significant differences were observed in the levels of TCPP, TBEP and ΣOPFR among various types of drinking water. TCPP is introduced in the drinking water during the water purification process. Regional differences existed in the levels and patterns of OPFRs in water samples, which indicated the existence of diverse sources of these contaminants. Purified water was a significant contributor to the total OPFR intake by humans. The estimated daily intake of OPFRs was lower than the tentative oral reference dose (RfD) values. In comparison with exposure of OPFRs via dust ingestion, water consumption was a significant source of chlorinated PFRs (99% for TCEP and 34% for TCPP to the total intakes) for Koreans.