Exposure Levels and Health Risks of Phthalate Alternatives: A Urinary Metabolite Study

Phthalate alternatives are increasingly replacing traditional phthalates (PAEs) as plasticizers due to growing regulatory and health concerns. However, these alternatives and their metabolites have been detected in both environmental and biological matrices, raising concerns regarding potential health risks. Here, we used ultrahigh performance liquid chromatography-tandem mass spectrometry to detect nine metabolites of four PAE alternatives (aPAEs) in 176 urine samples collected from residents of Chengdu and Suining, Sichuan Province, China. Our results revealed that seven metabolites were commonly present in the urine samples, with total metabolite concentrations ranging from 2.52 to 6300 ng/mL. The median concentrations were 21.1 ng/mL in Chengdu and 39.8 ng/mL in Suining. The compositional profiles of these metabolites in urine samples from both cities were similar, with mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) identified as the predominant metabolite, representing over 50% of the total concentration. Notably, teenagers exhibited higher exposure levels compared to other age groups. Despite these findings, the estimated internal exposures remained well below health-based guidance values and toxicological reference levels, suggesting that the current exposure level may not pose acute health risks. This study highlights the widespread occurrence of aPAE metabolites in human urine and underscores continued biomonitoring and risk assessment of these emerging pollutants.