Health Implications and Risk Assessment of Gestational Exposure to Polycyclic Aromatic Hydrocarbons in Mbarara, Uganda

This study examined health risks and outcomes associated with polycyclic aromatic hydrocarbon (PAH) exposure among pregnant women in Mbarara, Uganda. Thirty-two women in their third trimester were recruited from Mbarara Regional Referral Hospital, and maternal blood samples were analysed for PAHs using Gas Chromatography–Mass Spectrometry. Risks were evaluated using the U.S. EPA models and Monte Carlo simulations (MCS). Multiple PAHs were detected, with fluorene (16.38 ± 0.31 mg/L) and chrysene (5.51 ± 4.15 mg/L) showing the highest concentrations. Regression and Spearman correlation analyses revealed significant associations between certain maternal PAH concentrations and adverse outcomes, notably low birth weight and postpartum haemorrhage. Hazard indices exceeded 1, while benzo[a]pyrene toxic and mutagenic equivalents and incremental lifetime cancer risk (ILCR; 1.3×10⁰; 3.19×10⁻¹) surpassed regulatory thresholds, indicating considerable non-cancer and cancer risks. The MCS ILCR estimates further suggested that, in a population of 10 pregnant women, about three could develop cancer from long-term PAH exposure. These findings highlight the urgency for public health actions and policy reforms to reduce PAH exposure among pregnant women in Mbarara, as well as the necessity for further research to evaluate long-term developmental impacts on children exposed in utero .