Photochemical dissolution of buoyant microplastics to dissolved organic carbon: Rates and microbial impacts
Photochemical dissolution of buoyant microplastics to dissolved organic carbon: Rates and microbial impacts
复制标题
浮力微塑料光化学溶解为溶解有机碳：速率和微生物影响
DOI：
10.1016/j.jhazmat.2019.121065
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发表时间：
2020-02-05
影响因子：
13.6
通讯作者：
Li, Daoji
中科院分区：
文献类型：
--
作者：
Zhu, Lixin;Zhao, Shiye;Li, Daoji
数以万亿计的塑料碎片漂浮在海上，但它们仅占每年进入海洋的塑料的1-2%。失踪塑料的命运及其对海洋生物的影响在很大程度上仍然未知。为了解决这些未知因素，我们在太阳模拟器下照射了消费后微塑料（聚乙烯，PE;聚丙烯，PP;和发泡聚苯乙烯，EPS），标准PE和从北太平洋环流表面沃茨收集的塑料碎片。我们报告说，模拟阳光可以从海面上去除塑料。模拟的阳光也会使被照射的聚合物破碎、氧化并改变其颜色。溶解有机碳（DOC）是塑料光降解的主要副产物。去除率取决于聚合物化学与EPS降解速度比PP，和PE是最耐光聚合物的研究。大多数塑料光降解释放的DOC很容易被海洋细菌利用。然而，一个PE微塑料样本释放出抑制微生物生长的有机物或共浸出物。因此，尽管阳光可以从海洋表面去除塑料，但塑料光降解过程中形成的沥滤物可能对海洋微生物及其所支持的食物网产生混合影响。
Trillions of plastic fragments are afloat at sea, yet they represent only 1-2% of the plastics entering the ocean annually. The fate of the missing plastic and its impact on marine life remains largely unknown. To address these unknowns, we irradiated post-consumer microplastics (polyethylene, PE; polypropylene, PP; and expanded polystyrene, EPS), standard PE, and plastic-fragments collected from the surface waters of the North Pacific Gyre under a solar simulator. We report that simulated sunlight can remove plastics from the sea surface. Simulated sunlight also fragmented, oxidized, and altered the color of the irradiated polymers. Dissolved organic carbon (DOC) is identified as a major byproduct of sunlight-driven plastic photodegradation. Rates of removal depended upon polymer chemistry with EPS degrading more rapidly than PP, and PE being the most photo-resistant polymer studied. The DOC released as most plastics photodegraded was readily utilized by marine bacteria. However, one sample of PE microplastics released organics or co-leachates that inhibited microbial growth. Thus, although sunlight may remove plastics from the ocean's surface, leachates formed during plastic photo-degradation may have mixed impacts on ocean microbes and the food webs they support.