Purpose <p>Sediments are both reservoirs and polycyclic aromatic hydrocarbons (PAHs) sources in the environment. Exploring the sedimentary record of PAHs and their linkage to anthropogenic activities is essential for ecological risk mitigation.</p> Methods <p>This study used gas chromatography-mass spectrometry (GC-MS) to measure 16 PAHs in a sediment core collected from northern Taihu Lake, China. PAHs sources were discriminated using diagnostic ratio and positive matrix factorization (PMF) model. Health risks were assessed using the fuzzy synthetic evaluation method.</p> Results <p>The Σ₁₆PAHs levels varied between 236.98 and 11085.29 ng g^− 1 (mean 2354.58 ng g^− 1). Before the 1930s, 2–3-ring PAHs were dominantly observed. From the 1930s to early 1990s, sharply increasing levels and a high proportion of 4–6-ring PAHs were recorded, reflecting shifts in energy structure. The 4-ring PAHs value was associated with growing coal consumption. Since the late 1990s, the decline in the levels of 4–6-ring PAHs was a result of the promotion of environmental protection policies and reduced coal consumption. Source identification results reflected the contribution of coal combustion (45.93%), traffic emissions (27.42%), biomass burning and petroleum sources (26.65%). TN, TP, TOC and coarse silt had greater adsorption effects on 4–6-ring PAHs than on 2–3-ring PAHs. The sediment core was moderately polluted between the 1960s and 1990s.</p> Conclusion <p>Before the 1930s, low temperature combustion of biomass/coal was the primary source of PAHs. After that, high temperature combustion of coal/petroleum has been the main source. The temporal trend of influencing factor contributions was consistent with socio-economic parameters. PAHs may cause toxicity effects to aquatic organisms.</p>