The pollution of microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) in the environment is a global problem, but there are few joint monitoring studies on them. In present study, MPs and PAHs are investigated to study the impact of human activities and their possible relationship in China's second largest urban lake – East Lake. The abundance of MPs are 3329.19 ± 2059.26 particles/m³ and 2207.56 ± 1194.04 particles/kg in water and sediment, respectively. MPs are predominantly characterized by fibers, polypropylene (PP) and polyethylene (PE), colorlessness in water and sediment. The abundance of MPs in water with frequent human activities is higher, which is reversed in sediments, indicating that disturbance is not conducive to the enrichment of MPs in sediments. The concentration of 16 PAHs are 36.95 ± 13.76 ng/L and 897.08 ± 232.34 ng/g in water and sediment, respectively. PAHs in water are mainly 2-3-ring, while they are 4-ring in sediments. The good corresponding relationship between MPs and PAHs indicates that human activities have an important impact on the distribution of pollutants compared to the interaction of pollutants. In addition, the significant positive correlation between lakeshore length and water MPs abundance indicates that surface runoff is an important source of water MPs. The pollution load index shows that MPs in sediment has reached moderate to severe pollution level, while the water is slightly polluted. The potential ecological risk assessment results show that more than half of the sediment sites have dangerous or very dangerous ecological risks.

Microplastics; Polycyclic aromatic hydrocarbons; Distribution; Influencing factors, Risk assessment.