Sunlight mediated cadmium release from colored microplastics containing cadmium pigment in aqueous phase. (August 2020)

• Record Type: Journal Article
• Authors: Liu, Huiting; Liu, Kun; Fu, Heyun; Ji, Rong; Qu, Xiaolei
• Is Part Of: Environmental pollution. Volume 263(2020)Supplement Part A
• Publication Date: 2020-08
• Subjects: Microplastics -- Cadmium pigments -- Aquatic systems -- Photochemistry -- Cadmium ion; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2020.114484
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The plastics industry is the biggest consumer of cadmium pigments. Little is known about the leaching of hazardous Cd 2+ from colored microplastics containing cadmium pigment in aquatic systems. Here, we reported the release of Cd 2+ from different sized microplastics containing cadmium pigment in aqueous phase under simulated sunlight. The release of Cd 2+ was caused by the photo-dissolution of cadmium pigment. The release kinetics is highly size-dependent. It was relatively low for microplastics with size larger than 0.85 mm but increased significantly with decreasing size for microplastics smaller than 0.85 mm. The polymer matrix was oxidized during light exposure, leading to lower average molecular weight and the formation of oxygen-containing groups. Part of the polymer matrix was degraded into soluble organic carbon under simulated sunlight, resulting in continuous Cd 2+ release from the pigment particles embedded in the polymer. The polymer degradation rate is also highly size-dependent. The degradation of the polymer matrix and the release of Cd 2+ were intertwined. Cadmium leaching from microplastics from a commercial product containing cadmium pigment was confirmed in water under simulated sunlight. This work suggests that the photochemical processes of inorganic pigments will lead to the release of heavy metals from colored plastic debris. Graphical abstract: Image 1 Highlights: Microplastics containing cadmium pigment can readily release Cd 2+ under sunlight. The release of Cd 2+ was caused by the photo-dissolution of cadmium pigment. The Cd 2+ release kinetics highly depends on the size of microplastics. The photodegradation of microplastics is highly size-dependent. The degradation of the polymer matrix and the release of Cd 2+ were intertwined.