Waterborne describes anything carried or transmitted through water. When something is waterborne, water acts as its vehicle or transportation system.

Diseases are often waterborne when germs travel through drinking water. Before cities built modern water treatment plants, waterborne illnesses like cholera and typhoid fever spread rapidly because contaminated water carried bacteria from person to person. Today, water treatment and testing help prevent waterborne diseases, which is why we can safely drink tap water in most American cities.

The word also describes transportation on water. A waterborne invasion happens when military forces travel by ships or boats, like the famous D-Day landing in World War II. Cargo becomes waterborne when it's loaded onto ships for ocean transport. Throughout history, waterborne trade connected distant civilizations: spices from India, silk from China, and coffee from Arabia all traveled along waterborne routes to reach Europe and America.

Scientists also use waterborne to describe particles floating in water. Waterborne sediment makes rivers look muddy brown after rainstorms, as tiny bits of soil wash downstream. Understanding what's waterborne in our rivers, lakes, and oceans helps us protect water quality and the health of everyone who depends on it.