Plastic photodissolution into dissolved organic carbon (DOC) is a key proposed loss pathway for plastic in aquatic environments. However, the specific solar excitation wavelengths that drive photodissolution remain unknown, limiting our ability to model and predict photodissolution rates in natural aquatic environments. To better understand the impact of solar excitation wavelength on plastic photodissolution rates, we measured the wavelength sensitivity of photodissolution for a variety of transparent and semitransparent commercial and postconsumer plastic films with wide-spanning polymer chemistries. We irradiated plastic films using custom-built light-emitting diode (LED) photoreactors that emit light in the range of 275 to 445 nm and found that plastics exhibit a strong wavelength sensitivity, producing the highest DOC release rates for short wavelength ultraviolet (UV) light. We additionally calculated photodissolution quantum yield trends for transparent plastic films and then calculated photodissolution activation spectra. We found that solar UV light between 300–350 nm is responsible for most of the plastic photodissolution for all plastic compositions and predicted plastic photodissolution rates within water columns. Results advance our ability to model plastic photodissolution in natural aquatic environments.

中文翻译：

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波长敏感塑料光溶解：阐明太阳活化光谱的量子产率趋势


塑料光溶成溶解有机碳 （DOC） 是塑料在水生环境中的一个关键拟议损失途径。然而，驱动光溶解的特定太阳激发波长仍然未知，这限制了我们在自然水生环境中建模和预测光溶解速率的能力。为了更好地了解太阳激发波长对塑料光溶解速率的影响，我们测量了具有广泛聚合物化学成分的各种透明和半透明商业和消费后塑料薄膜的光溶解波长敏感性。我们使用定制的发光二极管 （LED） 光反应器照射塑料薄膜，该光反应器发射的光范围为 275 至 445 nm，发现塑料表现出很强的波长敏感性，对短波长紫外线 （UV） 产生最高的 DOC 释放率。我们还计算了透明塑料薄膜的光溶解量子产率趋势，然后计算了光溶解活化光谱。我们发现 300-350 nm 之间的太阳紫外光是所有塑料成分的大部分塑料光溶解的原因，并预测了水柱内的塑料光溶解速率。结果提高了我们在自然水生环境中模拟塑料光溶解的能力。