What describes thermal pollution?

Thermal pollution refers to the increase in water temperature caused by human activities, which can negatively affect aquatic ecosystems. When industries or power plants use water as a cooling agent and discharge it back into natural water bodies at elevated temperatures, it raises the overall temperature of the water. This change can be detrimental to fish and other aquatic organisms, as many species are sensitive to temperature changes and require specific ranges for optimal health and reproduction. Elevated temperatures can reduce oxygen levels in water and alter species composition, leading to reduced biodiversity and ecosystem imbalances.

The other options describe different environmental issues: introducing harmful chemicals into water refers to water pollution, contamination of the air with radioactive particles pertains to air pollution and radiological hazards, and treating wastewater is a process aimed at cleaning water but does not involve temperature changes.