The hydrophobicity of dissolved organic matter (DOM) is a key property influencing the environmental risks of organic pollutants. Our understanding of the spatial and seasonal pattern of DOM hydrophobicity in aquatic systems and the major controlling factors is still limited. In this study, the hydrophobicity of 124 DOM samples collected from northern Lake Taihu, a typical eutrophic lake, was quantified using the partition coefficient of DOM in the aqueous two-phase system (K_ATPS). The results revealed high-resolution spatial patterns and seasonal variations of DOM hydrophobicity in Lake Taihu. The riverine input, algae activity, and photodegradation were identified as important processes shaping the spatial and seasonal pattern of DOM hydrophobicity. The riverine input and algae activity strongly affected DOM hydrophobicity in the west part and the central area of the lake. Photodegradation process played a significant role in DOM hydrophobicity in the east part of the lake in summer. The high-resolution spatial and seasonal pattern of the hydrophobic organic pollutant partition affinity of DOM (K_OC) was assessed based on the two-phase system model and the K_ATPS dataset. The K_OC values vary significantly in Lake Taihu between spring and summer, especially in the Zhushan Bay and east coast areas, highlighting the need for considering DOM dynamics in sorption assessment. Our results detailly profiled the spatial and seasonal patterns of DOM hydrophobicity and sorption behavior and elucidated the major controlling factors, which is crucial for environmental risk assessment.

溶解有机物（DOM）的疏水性是影响有机污染物环境风险的关键特性。我们对水生系统中DOM疏水性的空间和季节模式及其主要控制因素的了解仍然有限。在这项研究中，使用DOM在水两相系统中的分配系数（K _ATPS）对从典型富营养化湖泊太湖北部收集的124个DOM样品的疏水性进行了定量）。结果揭示了太湖的高分辨率空间格局和DOM疏水性的季节性变化。河流输入，藻类活性和光降解被认为是影响DOM疏水性的空间和季节模式的重要过程。河流的输入和藻类活动强烈影响了湖泊西部和中部地区的DOM疏水性。夏季，光降解过程在湖泊东部的DOM疏水性中起着重要作用。基于两相系统模型和K _ATPS数据集，对DOM（K _OC）的疏水性有机污染物分配亲和力的高分辨率空间和季节格局进行了评估。该ķ _OC春季和夏季之间，太湖的水相值变化很大，尤其是在珠山湾和东海岸地区，这突出表明在吸附评估中需要考虑DOM动力学。我们的结果详细描述了DOM疏水性和吸附行为的空间和季节模式，并阐明了主要控制因素，这对于环境风险评估至关重要。