Quantification of microplastics in bottled water by Pyr-GC-Orbitrap-MS, human exposure, and in vitro hepatotoxicity assessment

In 2010, the United Nation General Assembly, with resolution 64/292, identified drinking water as human right essential for the full enjoyment of life. Among drinking water, bottled water (BW) is regulated as food by the Food and Drug Administration (FDA). There is much concern whether humans are exposed to microplastics (MP) through BW ingestion. This study aims at quantifying 9 types of plastic polymers in 40 BW brands made with pristine or recycled polyethylene terephthalate (PET) bottles purchased from 5 different countries. High-resolution pyrolysis gas chromatography coupled to Orbitrap mass spectrometry (Pyr-GC-Orbitrap-MS) method was developed to determine PET, high-density polyethylene (HDPE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), polycarbonate (PC), acrylonitrile butadiene-styrene (ABS), polymethyl methacrylate (PMMA) and nitrile rubber (NBR). The MP concentration ranged from 0.016 to 0.439 μg/L in 31 out of 40 samples, with no differences among BW from different countries nor among pristine or recycled PET bottles. HDPE used in the bottle cap, was the dominant polymer detected in BW followed by PS. Our results show that an adult might ingest an average of 0.004 μg HDPE kg -1 bw per day only from BW consumption. Moreover, we performed in vitro studies with hepatocellular carcinoma (HepG2) cells to assess the potential hepatotoxicity of HDPE leachates, which resulted in no cytotoxicity nor reactive oxygen species (ROS) generation.