Water pollution
Water pollution is the contamination of water bodies by substances or energy that harms ecosystems or makes water unsafe for use.
Point source pollution: Pollution discharged from an identifiable source, such as a pipe or industrial outlet. Pipes and outlets release pollutants directly into rivers and coastal waters.
Drinking water quality: The chemical, physical, and microbial properties that determine whether water is safe to drink. Pollution can introduce hazards that require treatment or make sources unsafe.
Industrial wastewater: Water discharged after use in industrial processes, often containing process residues or contaminants. Industrial discharges can carry metals, chemicals, or heat into receiving waters.
Aquatic ecosystem: A community of organisms interacting with one another and with the physical environment in water. Pollution changes habitat conditions and relationships among aquatic organisms.
Water quality: The physical, chemical, and biological condition of water relative to particular uses or ecosystems. Water pollution is one cause of degraded water quality, but quality also reflects natural conditions.
Nonpoint source pollution: Pollution carried from diffuse sources across land, often by rainwater runoff. Runoff transports contaminants from many scattered sources rather than one discharge point.
Waterborne disease: Illness caused by pathogens transmitted through contaminated water. Sewage and fecal contamination can spread infectious organisms through water.
Sewage: Wastewater containing human excreta and other domestic wastes. Untreated or poorly treated sewage adds pathogens and nutrients to water bodies.
Fish kill: A sudden mass death of fish in a body of water. Toxic exposure or oxygen depletion can cause fish kills.
Water scarcity: A shortage of available freshwater relative to human and ecological needs. Scarcity concerns the amount of usable water; pollution concerns its contamination.