What is defined as any change in water that has harmful effects on living things?

Water pollution is defined as any change in water that has harmful effects on living organisms. It encompasses a broad range of contaminants—chemical, physical, or biological—that may degrade water quality, making it unsafe for drinking, recreation, and habitat for aquatic life. Pollution can arise from various sources such as agricultural runoff, industrial discharges, sewage leaks, and plastic waste, leading to detrimental effects on ecosystems.

The term effectively captures not only chemical impurities but also physical changes in water quality, such as turbidity or temperature alterations that can impact aquatic life. Understanding water pollution is crucial for environmental protection efforts and for implementing effective policies and regulations to safeguard water resources against harmful activities.

The other options refer to related but distinct concepts. Water contamination refers more specifically to the presence of harmful substances rather than the broad implication of changing water quality. Water scarcity pertains to the lack of sufficient water resources to meet demand, while water depletion refers to the reduction of water supplies due to overuse, thus not directly addressing the harmful changes.