Wu Xinni, Tan Zongyi, Liu Ruijuan, Liao Zhianqi, Ou Huase
Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China; Center for Environmental Microplastics Studies, Jinan University, Guangzhou 511443, China.
Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China; Key Laboratory of Philosophy and Social Science in Guangdong Province of Community of Life for Man and Nature, Jinan University, Guangzhou 511443, China.
Sci Total Environ. 2023 Jun 10;876:162717. doi: 10.1016/j.scitotenv.2023.162717. Epub 2023 Mar 11.
The generation of various degradation products from microplastics (MPs) has been confirmed under ultraviolet (UV) irradiation. The gaseous products, primarily volatile organic compounds (VOCs), are usually overlooked, leading to potential unknown risks to humans and the environment. In this study, the generation of VOCs from polyethylene (PE) and polyethylene terephthalate (PET) under UV-A (365 nm) and UV-C (254 nm) irradiation in water matrixes were compared. More than 50 different VOCs were identified. For PE, UV-A-derived VOCs mainly included alkenes and alkanes. On this basis, UV-C-derived VOCs included various oxygen-containing organics, such as alcohols, aldehydes, ketones, carboxylic acid and even lactones. For PET, both UV-A and UV-C irradiation induced the generation of alkenes, alkanes, esters, phenols, etc., and the differences between these two reactions were insignificant. Toxicological prioritization prediction revealed that these VOCs have diverse toxicological profiles. The VOCs with the highest potential toxicity were dimethyl phthalate (CAS: 131-11-3) from PE and 4-acetylbenzoate (3609-53-8) from PET. Furthermore, some alkane and alcohol products also presented high potential toxicity. The quantitative results indicated that the yield of these toxic VOCs from PE could reach 10 μg g under UV-C treatment. The degradation mechanisms of MPs included direct scission by UV irradiation and indirect oxidation induced by diverse activated radicals. The former mechanism was dominant in UV-A degradation, while UV-C included both mechanisms. Both mechanisms contributed to the generation of VOCs. Generally, MPs-derived VOCs can be released from water to the air after UV irradiation, posing a potential risk to ecosystems and human beings, especially for UV-C disinfection indoors in water treatments.
在紫外线（UV）照射下，微塑料（MPs）会产生各种降解产物，这一点已得到证实。气态产物主要是挥发性有机化合物（VOCs），通常被忽视，从而给人类和环境带来潜在的未知风险。在本研究中，比较了在水基质中，紫外线A（365nm）和紫外线C（254nm）照射下，聚乙烯（PE）和聚对苯二甲酸乙二酯（PET）产生挥发性有机化合物的情况。共鉴定出50多种不同的挥发性有机化合物。对于PE，紫外线A产生的挥发性有机化合物主要包括烯烃和烷烃。在此基础上，紫外线C产生的挥发性有机化合物包括各种含氧有机物，如醇类、醛类、酮类、羧酸甚至内酯。对于PET，紫外线A和紫外线C照射均会诱导烯烃、烷烃、酯类、酚类等的产生，且这两种反应之间的差异不显著。毒理学优先排序预测表明，这些挥发性有机化合物具有不同的毒理学特征。潜在毒性最高的挥发性有机化合物是PE中的邻苯二甲酸二甲酯（CAS：131-11-3）和PET中的4-乙酰苯甲酸（3609-53-8）。此外，一些烷烃和醇类产物也具有较高的潜在毒性。定量结果表明，在紫外线C处理下，PE产生的这些有毒挥发性有机化合物的产量可达10μg/g。微塑料的降解机制包括紫外线照射直接断裂和各种活性自由基诱导的间接氧化。前一种机制在紫外线A降解中占主导地位，而紫外线C则包括这两种机制。两种机制都导致了挥发性有机化合物的产生。一般来说，微塑料衍生的挥发性有机化合物在紫外线照射后可从水中释放到空气中，对生态系统和人类构成潜在风险，尤其是在水处理中室内紫外线C消毒的情况下。
