Which process can lead to water impurities due to human activity?

Industrial discharge is a significant process that can lead to water impurities due to human activity. This occurs when industries release pollutants directly into water bodies, either through intentional disposal of waste materials or accidental spills. These pollutants can include heavy metals, chemicals, and other hazardous substances that contaminate water supplies, posing risks to both human health and the environment.

In contrast, natural evaporation, rainfall, and organic growth are processes that do not inherently result from human activity, and while they can influence water quality, they are not direct sources of impurities attributable to human actions. Natural evaporation is a physical process by which water turns into vapor, rainfall is part of the natural hydrological cycle, and organic growth refers to the natural development of vegetation and microorganisms, which can occur independently of human influence.