Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States.
Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue North, St. Paul, Minnesota 55108-6112, United States.
Environ Sci Technol. 2020 Jun 2;54(11):6671-6681. doi: 10.1021/acs.est.0c00344. Epub 2020 May 21.
Absorption of solar radiation by colored dissolved organic matter (CDOM) in surface waters results in the formation of photochemically produced reactive intermediates (PPRIs) that react with pollutants in water. Knowing the steady-state concentrations of PPRIs ([PPRI]) is critical to predicting the persistence of pollutants in sunlit surface waters. CDOM levels () can be measured remotely for lakes over large areas using satellite imagery. Laboratory measurements of [PPRI] and apparent quantum yields (Φ) of three PPRIs (DOM*, O, and OH) were made for 24 lake samples under simulated sunlight. The total rate of light absorption by the water samples (), the rates of formation (), and [PPRI] of DOM* and O linearly increased with incresing . The production rate of OH was linearly correlated with , but the steady-state concentration was best fit by a logarithmic function. The relationship between measured and Landsat 8 reflectance was used to map for more than 10 000 lakes across Minnesota. Relationships of with , [PPRIs], and were coupled with satellite-based assessments to map reactive species production rates and concentrations as well as contaminant transformation rates. This study demonstrates the potential for using satellite imagery for estimating contaminant loss via indirect photolysis in lakes.
水体中有色溶解有机物（CDOM）对太阳辐射的吸收会形成光化学反应产生的活性中间体（PPRI），这些中间体与水中的污染物发生反应。了解 PPRI 的稳态浓度 ([PPRI]) 对于预测污染物在阳光照射的地表水的持久性至关重要。可以使用卫星图像对大面积的湖泊进行 CDOM 水平（）的远程测量。在模拟阳光下，对 24 个湖泊样本进行了三种 PPRI（DOM*、O 和 OH）的 [PPRI] 和表观量子产率（Φ）的实验室测量。水样的总吸光率（）、形成速率（）和 DOM*和 O 的 [PPRI] 随的增加呈线性增加。OH 的生成速率与呈线性相关，但稳态浓度最好用对数函数拟合。将测量的与 Landsat 8 反射率之间的关系用于绘制明尼苏达州 10,000 多个以上湖泊的分布图。与、[PPRIs] 和的关系与基于卫星的评估相结合，以绘制活性物质生成速率和浓度以及污染物转化速率的图。本研究证明了使用卫星图像估算湖泊中间接光解导致的污染物损失的潜力。
