Oskar Hagelskjær, Frederik Hagelskjær, Henar Margenat, Nadiia Yakovenko, Jeroen Sonke , Gaël Le Roux

Microplastic (MP) content in nutrition including potable water is unregulated, although MP concentrations in bottled water can diverge by several orders of magnitude. The EU Directive 2020/2184 on consumable water quality recently proposed methodological approaches to the detection of MPs in potable water in the size range of 20-5000 µm. However, small MPs in the 1-20 µm range are far more likely to pass the human intestine into blood and organs. We therefore investigated MP concentrations down to 1 µm in ten individual polyethylene terephthalate (PET) bottled water brands and one tap water sample by Raman microspectroscopy. Our analyses are supported by procedural blank- (negative control) and analytical recovery correction (positive control) using red polyethylene fragments in the 5-100 µm range. We find that MP concentrations range from 19 to 1,154 (n/L) [0.001 to 0.250 µg/L]. Importantly, 98 and 94% of MPs measured less than 20 and 10 µm in diameter, respectively, demonstrating the importance of small MP inclusion in potable water analyses and regulation.