Polycyclic Aromatic Hydrocarbons in the Water Bodies of Dong Lake and Tangxun Lake, China: Spatial Distribution, Potential Sources and Risk Assessment

Polycyclic aromatic hydrocarbons (PAHs) are a group of highly toxic organic pollutants. At present, there has only been limited research into PAH contamination in Tangxun Lake and Dong Lake, which are the first and second largest urban inland lakes in China, respectively. This study investigated the concentration, spatial distribution, sources, and ecological risks of PAHs in the water from Dong Lake and Tangxun Lake. The focus of this study is to use models to analyze the sources of PAHs, as well as their potential toxicity to humans, in the water bodies of Dong Lake and Tangxun Lake. This study performed liquid–liquid extraction to extract PAHs from lake water samples using dichloromethane and then used gas chromatography–mass spectrometry (GC-MS) to quantitatively analyze the PAHs in the samples. The total concentration of the ∑₁₆PAHs showed high variability among different sampling points, ranging from 12.92 to 989.09 ng/L, with an arithmetic mean of 121.97 ng/L. The composition of the ∑₁₆PAHs was mainly concentrated at a low molecular weight (>70%). The molecular distributions of PAH studies, combined with positive matrix factorization (PMF), indicate that oil and coal combustion are the main sources of PAHs in Dong Lake and Tangxun Lake. The model of PMF succeeded in identifying and quantifying five sources with similar contributions: the combustion of petroleum products, heavy oil burning, coal combustion, traffic emissions, and natural gas and oil combustion mixed. According to toxicity equivalency (TEQ) and lifelong cancer risk (ILCR) research, PAHs from traffic sources in the environment may be more toxic, and the potential carcinogenic risk of PAH pollution to humans in Tangxun Lake and Dong Lake water bodies is relatively inferior.