Rice straw returning causes a considerable amount of dissolved organic matter (DOM) can release into aquatic croplands in a relatively short-term. The presence of rice straw-derived DOM in cropland waters may alter the photochemical behaviors of organic pollutants. However, the photochemical activity and photosensitization role of the DOMs are poorly understood. Here, eight DOM samples were extracted from decomposing rice straw at different times in 49 days to explore their photosensitizing capacities toward diuron (DIU), 17β-estradiol (E2), and sulfamethoxazole (SMX). All of the DOMs were photosensitive and mainly composed of tryptophan-, tyrosine- and fulvic-like substances. Over the decomposition period, the amount of photochemically produced reactive intermediates (PPRIs) by the DOMs peaked on days 7 and 14. The evolution of the DOM photosensitizing capacity towards DIU and E2 was consistent with the variations of PPRIs, and HO• was confirmed as a critical factor. However, the influence of the DOMs on SMX photodegradation was opposite to that on DIU and E2. The positive role of the DOMs in SMX photodegradation was attributed to the tryptophan-like components. The results suggest that straw-derived DOM is an important photosensitizer and that its photosensitization towards organic pollutants is dependent on straw decomposing time and pollutant type.

稻草还田导致相当多的溶解有机物（DOM）可以在相对较短的时间内释放到水生农田中。稻田中稻草衍生的DOM的存在可能会改变有机污染物的光化学行为。但是，对DOM的光化学活性和光敏作用了解得很少。在这里，在49天的不同时间从分解稻草中提取了8个DOM样品，以研究它们对敌草隆（DIU），17β-雌二醇（E2）和磺胺甲恶唑（SMX）的光敏能力。所有的DOM都是光敏的，并且主要由色氨酸，酪氨酸和黄腐素样物质组成。在分解期间，DOM产生的光化学反应性中间体（PPRI）数量在第7天和第14天达到峰值。DOM对DIU和E2的光敏能力的演变与PPRI的变化一致，并且HO•被确认是一个关键因素。但是，DOM对SMX光降解的影响与对DIU和E2的影响相反。DOM在SMX光降解中的积极作用归因于色氨酸样成分。结果表明，秸秆来源的DOM是一种重要的光敏剂，其对有机污染物的光敏性取决于秸秆的分解时间和污染物类型。DOM在SMX光降解中的积极作用归因于色氨酸样成分。结果表明，稻草来源的DOM是一种重要的光敏剂，其对有机污染物的光敏性取决于稻草的分解时间和污染物类型。DOM在SMX光降解中的积极作用归因于色氨酸样成分。结果表明，稻草来源的DOM是一种重要的光敏剂，其对有机污染物的光敏性取决于稻草的分解时间和污染物类型。