Infant Exposure and Risk Assessment of Organophosphorus Flame Retardants in Human Breast Milk from The Southeast City, China

Numerous epidemiological studies have investigated the endocrine disruption of Organophosphorus Flame Retardants (OPFRs) and the potential mechanisms of toxicity. However, in the southeastern region of China, where OPFRs are produced in large amounts, information about the occurrence of OPFRs in breast milk and their potential health risks to infants is still not well known. Herein, we analyzed the levels of OPFRs in 105 breast milk samples collected from Hangzhou, Zhejiang Province by using UPLC-MS/MS and explored the association between maternal population characteristics and the levels of OPFRs. At least two OPFRs were detected in breast milk, and 62% of samples were detected with more than five OPFRs, with the highest detection rate for tris(2-butoxy ethyl) phosphate (TBEP) (96%). The sum concentrations of 9 OPFRs in human milk ranged from 0.44 to 9.61 ng/mL with a mean value of 2.80 ng/mL. TBEP, Triphenyl phosphate (TPHP), and tributyl phosphate (TBP) were the three dominant OPFRs found in breast milk with average concentrations at 0.40, 0.69, and 0.66 ng/mL, respectively. The association between OPFRs and the age of mothers was positively significant, but no significant difference was found between residual concentrations of OPFRs and maternal body mass index (BMI). The noncarcinogenic and carcinogenic risks of OPFR exposure to infants via breast milk are negligible. The data here clarified the occurrence and potential risk of OPFRs in human breast milk, and also reveal that the ingestion of OPFRs through breast milk may be the main route for infants.