New research confirms that bottled water contains significantly more microscopic plastic particles than earlier studies estimated. The discrepancy comes from improved detection methods — earlier analyses couldn’t identify the smallest nanoplastic particles, which turn out to be the most numerous.

How much more? The new counts run into the hundreds of thousands of particles per liter, depending on the brand and bottle type. Previous estimates were in the thousands.

The health implications remain contested. Research on what nanoplastics do inside the human body at these concentrations is ongoing, and there is no scientific consensus yet on the threshold at which harm becomes measurable. What is clear: the particles are there, they are abundant, and they are small enough to cross biological membranes.