Nanoplastic release in infant feed (“baby”) bottles

Thomas C. Meisel and Katharina Heider

General and Analytical Chemistry, Montanuniversität Leoben, Franz-Josef Straße 18, 8700 Leoben, Austria

Polypropylene based infant feeding bottles (baby bottles) are known to release microplastics which might cause health related issues (Li et al., 2020). To the best of our knowledge, nanoplastic particles are thought to be even more hazardous for our environment and the human health. Characterising particles on the sub-micrometre scale is challenging already for inorganic particles. In the case of nanoplastic particles additional challenges arise, making the use of conventional characterisation techniques virtually impossible. In cooperation with a start-up company “Brave Analytics” (Graz), we used opto-fluidic force induction characterisation to analyse nanoplastic particles generated during the use of infant feeding bottles. Additionally, we qualitatively describe the influence of heat and general handling of the bottle on the amount of released particles. For analysing microplastic particles we could draw on more established characterization methods, like Raman spectroscopy. The content of an infant feeding bottle was filtered and afterwards analysed using optical microscopy and Raman spectroscopy. We were able to determine an average microplastic particle concentration of 3.2*107 particles per litre per baby bottle, which was handled according to WHO standards. Electron microscopy images show alterations to the inner surface of the infant feeding bottle over the time of use. After sterilising the bottle with 95 °C hot water, scales were found on the inner surface. These scales decreased in both size and number over the time of use. We assume, that the thermal stress on the bottle during the sterilisation step is strong enough to damage the surface and particles make their way into the infant formula.