In the paper, the nanoplastics were measured in demineralized water that had been sitting in a regular disposable polystyrene cup (like the ones that people dri

In the paper, the nanoplastics were measured in demineralized water that had been sitting in a regular disposable polystyrene cup (like the ones that people drink coffee from) for five minutes. So the measurement reflects the nanoplastics that one ingests when drinking a cup of coffee from a polystyrene cup. Because nanoplastics sizes are of the order of the wavelength of visible light, the particles were measured with fluorescence microscopy. Nanoplastics were also found in high concentrations in store bought plastic bottles of mineral water as well as in water that had been sitting in baby bottles.