Occurrence, Characteristics, and Mixed Reproductive Exposure Risk Assessment of Traditional Phthalates and Their Novel Alternatives in Campus Indoor Dust

Phthalates (PAEs) constitute the primary components of indoor dust pollutants and significantly impact human reproductive health. However, research on novel alternatives to PAEs and the risk assessment of mixed exposure has remained relatively sparse. In this study, 193 indoor dust samples were collected in 2022 from various campus locations, including classrooms, canteens, dormitories, offices, and laboratories. Forty-four traditional PAEs and their alternatives were identified, with concentrations ranging from 0.44 to 91.5 μg/g. Di(2-ethylhexyl) phthalate (DEHP) and dioctyl terephthalate (DEHTH) were the predominant compounds, with mean concentrations of 86.3 and 59.2 μg/g, respectively. The ingestion pathway was the principal route of exposure, with dormitories identified as the primary exposure sites. The mixed reproductive toxicity equivalent factor (TEFmix) of PAEs and their alternatives was developed using a quantitative structure–activity relationship (QSAR) model in conjunction with machine learning algorithms. The TEFmix was found to be lower than the sum of individual PAEs, potentially due to the antagonistic effects of PAE monomers on reproductive health. Under high-exposure scenarios, the TEFmix of PAEs in canteen dust was determined to be 0.245, surpassing values observed in other environments. Females exhibited a higher risk, with dormitories presenting a greater exposure risk than those in other indoor locations. This study provided essential data to inform regulatory measures aimed at mitigating the impact of PAEs and their alternatives in indoor dust on human reproductive health.