Influencing factors and risk assessment of polycyclic aromatic hydrocarbons in the sediments of Beilianchi Lake, China

While climate change and human activities increasingly threaten lake ecosystems, their combined impacts on persistent organic pollutant (POP) deposition remain poorly understood. This study investigated centennial-scale polycyclic aromatic hydrocarbon (PAH) records in Beilianchi Lake sediments to identify sources and drivers. PAH concentrations were 57–375 ng.g −1 .dw (mean: 136 ng.g −1 .dw), peaking in 2012. Sediment analysis revealed PAHs were correlated negatively with clay content (%) but positively with silt (%), total organic carbon (TOC), and total nitrogen (TN). Among anthropogenic factors, urban population, primary industry, and oil usage most strongly influenced PAH accumulation. Meteorological analysis showed PAH concentrations were negatively correlated with wind speed but positively with temperature and humidity. Positive matrix factorization (PMF) source apportionment identified coal combustion (35 %) and vehicle emissions (24 %) as dominant PAH sources, followed by biomass burning (21 %) and petrogenic sources (20 %). Notably, energy shifts and stricter vehicle emission standards altered toxicity equivalent (TEQ) contributions; coal-derived TEQ rose sharply, whereas vehicle and biomass combustion contributions declined.