The World Health Organization (WHO) has launched a review into the potential health risks of microplastics in drinking water after a study found that over 90% of popular bottled water brands contain tiny plastic particles. Researchers analyzed 259 bottles from 11 brands across nine countries, discovering an average of 325 plastic particles per liter, with some bottles containing up to 10,000 particles. The most common plastic found was polypropylene, used in bottle caps. While the health impacts are still unclear, this emerging concern highlights the importance of safe, clean drinking water.