Abstract
Microplastics are prevalent emerging pollutants with widespread distribution in air, land and water. They have been detected in human stool, blood, lungs, and placentas. However, human fetal microplastic exposure remains largely under-studied. To assess fetal microplastic exposure, we investigated microplastics using 16 meconium samples. We used hydrogen peroxide (H(2)O(2)), nitric acid (HNO(3)) and a combination of Fenton's reagent and HNO(3) pretreatment methods respectively to digest the meconium sample. We analyzed 16 pretreated meconium samples with an ultra-depth three-dimensional microscope and Fourier transform infrared microspectroscopy. The result showed that H(2)O(2), HNO(3) and Fenton's reagent combined with HNO(3) pretreatment methods could not digest our meconium samples completely. Alternatively, we developed a novel approach with high digestion efficiency using petroleum ether and alcohol (4:1, v/v), HNO(3) and H(2)O(2). This pretreatment method had good recovery and non-destructive advantages. We found no microplastics (≥10 μm) in our meconium samples, indicating that microplastic pollution levels in the fetal living environment are miniscule. Different results between previous studies' and ours underscore that comprehensive and strict quality control are necessary for further studies on microplastic exposure using human bio-samples.