Heat can be a source of water pollution primarily through a process known as thermal pollution. When heat is introduced into natural water bodies such as rivers, lakes, or oceans, it causes several harmful effects:
- Heat raises the temperature of water, which reduces its ability to hold dissolved oxygen essential for aquatic life. For example, water at 30°C holds 20% less oxygen than water at 20°C, leading to suffocation risks for fish and other organisms.
- Elevated temperatures disrupt aquatic ecosystems by stressing or killing temperature-sensitive species, causing imbalances where native species may disappear and invasive species thrive.
- Warmer water promotes excessive algae growth (algal blooms), which can choke waterways and produce toxins harmful to fish, other wildlife, and even humans.
- Sources of thermal pollution include power plants (nuclear and fossil-fuel based) discharging heated water, industrial cooling processes, urban runoff from heated surfaces, and the removal of shading vegetation near water bodies.
Overall, thermal pollution from heat changes the physical, chemical, and biological characteristics of water, leading to depleted oxygen, ecological disruption, toxic conditions, and reduced biodiversity in aquatic environments.
Summary of Effects of Heat as Water Pollution
Effect| Description| Example/Source
---|---|---
Reduced dissolved oxygen| Warm water holds less oxygen, suffocating aquatic
life| Fish die-offs in heatwaves
Disrupted ecosystems| Temperature-sensitive species decline| Coral bleaching,
invasive species proliferation
Increased algal blooms| Heat stimulates toxic algae growth| Lakes turning
green from blooms
Heat sources| Power plants, industrial cooling, urban runoff| Heated effluent
from nuclear plants, asphalt runoff
This explains how heat acts as an environmental pollutant in water, negatively impacting aquatic ecosystems.
