Microplastics are plastic fragments smaller than 5 millimeters, shed from packaging, synthetic fabrics, and larger plastic breaking down. They've been found in bottled and tap water, sea salt, seafood, and produce. In 2022, researchers reported detecting microplastics in human blood for the first time, and other studies have since found them in the placenta and lungs.
What this means for health is still being worked out — most evidence so far is from lab and animal studies, not proof of harm in people. Still, you can lower your exposure: choose filtered tap over bottled water, avoid microwaving food in plastic, and cut back on heavily packaged ultra-processed foods. The science is young, but reducing single-use plastic is a low-risk move.