Phthalate metabolites in breast milk from mothers in Southern China: Occurrence, temporal trends, daily intake, and risk assessment

The extensive production and use of phthalates means that these compounds are now ubiquitous in the environment and various biota, which raises concerns about potential harmful health effects. In this study, phthalate metabolites (mPAEs) were measured in breast milk (n = 100) collected from mothers of southern China between 2014 − 2022. Of the nine target mPAEs, five were detected in all of the samples, including mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP). The total levels of mPAEs in breast milk ranged from 4.76 to 51.6 ng/mL, with MiBP and MnBP being the predominant isomers (MiBP + MnBP > 48.3%). Increasing trends were observed in MMP (5.7%/year) and MEHP (7.1%/year) levels during the study period, while a decreasing trend were observed in MiBP (−6.6%/year); no clear temporal trends were found for the other metabolites and total mPAE levels. The results indicate that exposure to phthalates is still prevalent in southern China. Breastfeeding was found to contribute to estimated daily phthalate intakes of 0.383–6.95 μg/kg-bw/day, suggesting insignificant health risks to infants based on dietary exposure. However, the increasing exposure to MMP and MEHP calls for more research into the possible sources and potential risks.