The plastics industry is the biggest consumer of cadmium pigments. Little is known about the leaching of hazardous Cd2+ from colored microplastics containing cadmium pigment in aquatic systems. Here, we reported the release of Cd2+ from different sized microplastics containing cadmium pigment in aqueous phase under simulated sunlight. The release of Cd2+ 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 Cd2+ 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 Cd2+ 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.

中文翻译：

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阳光从水相中含有镉颜料的有色微塑料中释放镉。

塑料行业是镉颜料的最大消费者。对于从水生系统中含有镉颜料的有色微塑料中浸出有害Cd2 +知之甚少。在这里，我们报道了在模拟阳光下水相中不同大小的含镉颜料的微塑料中Cd2 +的释放。Cd2 +的释放是由于镉颜料的光溶解引起的。释放动力学高度依赖于尺寸。对于尺寸大于0.85 mm的微塑料，它相对较低，但是对于尺寸小于0.85 mm的微塑料，其尺寸随着减小而显着增加。聚合物基质在曝光过程中被氧化，导致较低的平均分子量和含氧基团的形成。在模拟阳光下，部分聚合物基质被降解为可溶性有机碳，导致Cd2 +从嵌入聚合物中的颜料颗粒连续释放。聚合物降解速率也高度依赖于尺寸。聚合物基质的降解和Cd2 +的释放相互交织。在模拟的阳光下，水中的微量塑料从含有镉颜料的商品中浸出的镉得到了证实。这项工作表明，无机颜料的光化学过程将导致有色塑料碎片中重金属的释放。在模拟的阳光下，水中的微量塑料从含有镉颜料的商品中浸出的镉得到了证实。这项工作表明，无机颜料的光化学过程将导致有色塑料碎片中重金属的释放。在模拟的阳光下，水中的微量塑料从含有镉颜料的商品中浸出的镉得到了证实。这项工作表明，无机颜料的光化学过程将导致有色塑料碎片中重金属的释放。