Identification of microplastics in human placenta using laser direct infrared spectroscopy

Microplastics are ubiquitous in the environment, including in food and drinking water. Consequently, there is growing concern about the human health risks associated with microplastic exposure through diet. However, the occurrence of microplastics in the human body, particularly in mothers and fetuses, is incompletely understood because of the limited amount of data on their presence in the body and the human placenta. This study evaluated the presence and characteristics of microplastics in 17 placentas using laser direct infrared (LD-IR) spectroscopy. Microplastics were detected in all placenta samples, with an average abundance of 2.70 ± 2.65 particles/g and a range of 0.28 to 9.55 particles/g. Among these microplastics, 11 polymer types were identified. The microplastics were mainly composed of polyvinyl chloride (PVC, 43.27 %), polypropylene (PP, 14.55 %), and polybutylene succinate (PBS, 10.90 %). The sizes of these microplastics ranged from 20.34 to 307.29 μm, and most (80.29 %) were smaller than 100 μm. Most of the smaller microplastics were fragments, but fibers dominated the larger microplastics (200-307.29 μm). Interestingly, the majority of PVC and PP were smaller than 200 μm. This study provides a clearer understanding of the shape, size, and nature of microplastics in the human placenta. Importantly, these data also provide crucial information for performing risk assessments of the exposure of fetuses to microplastics in the future.