Water pollution is the contamination of rivers, lakes, oceans, and groundwater by harmful substances. It comes from factories, farms, sewage, and urban runoff. Oil spills, chemical discharges, and plastic waste make headlines. Nutrients from fertilizer cause quieter but widespread damage.

The health effects are severe. Contaminated drinking water spreads cholera, typhoid, and other diseases. The World Health Organization estimates that unsafe water kills hundreds of thousands of children each year. Industrial chemicals cause cancer and organ damage. Heavy metals accumulate in fish and reach people who eat them.

Cleanup is difficult and expensive. Once pollutants enter a water body, they disperse and settle into sediments. Dredging contaminated sediment can cost millions. Preventing pollution at the source is far cheaper. Wastewater treatment, buffer strips along streams, and stricter industrial rules all help. Protecting watersheds upstream protects drinking water downstream. The connection is direct and often ignored.

Common sources

• Industrial discharge
• Agricultural runoff
• Sewage
• Oil spills
• Plastic and microplastics