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Dai J, Liu P, Wang C, Li H, Qiang H, Yang Z, Guo X, Gao S. Which factors mainly drive the photoaging of microplastics in freshwater? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:159845. [PMID: 36461563 DOI: 10.1016/j.scitotenv.2022.159845] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/14/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Light irradiation is considered as most important process for the aging of microplastics (MPs); however, which factors drive the process is still unknown. This study investigated the role of typical environmental factors including ultraviolet (UV), oxygen, temperature and physical abrasion in the photoaging of polystyrene (PS) in freshwater. Results showed that UV irradiation and abrasion were dominant factors for affecting photoaging of PS based on dynamic analysis in the property of MP itself and leachate. Especially, when both factors worked together on MPs, they caused more destructive effect. Mechanical exploration revealed that photoaging of MPs was mainly controlled by reactive oxygen species (ROS, 1O2) generated from the reaction of dissolved oxygen/water molecules with polymer radicals initiated by UV energy. As an attacker on MPs, ROS formation was significantly linked with UV intensity, highlighting the important role of UV. The fragmentation was correlated to abrasion intensity, where a higher abrasion generated stronger physical force to tear MPs into fragments. The low roles of oxygen and temperature were presumably related to multiple effects of ROS formation and UV absorption. The findings firstly clarify the drivers in the photoaging of MPs, and contribute our effort to assess their fate and pollution risk in the environment.
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Affiliation(s)
- Jiamin Dai
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Peng Liu
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China.
| | - Chenyang Wang
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Huang Li
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Hong Qiang
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China
| | - Zeyuan Yang
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Xuetao Guo
- College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China.
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China
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