Types of Water Pollution in Rivers & Lakes

Water can be polluted by both humans and nature.

The International Joint Commission's Great Lakes Water Quality Board stated in 1985 that 500 chemicals that are reported to be unhealthy for humans were found in the Great Lakes, the world's largest single fresh surface water system. Pollution can be caused by humans or the environment. While the effects of water pollution on humans is relatively unknown, fish and plants die when there is a decrease in oxygen supply.

Toxic

Toxic pollutants enter lakes and rivers in the form of pesticides, herbicides and industrial compounds. These pollutants are not naturally occurring. Toxic contaminants in the Great Lakes have prompted governors to raise quality management.

Organic

Water can become polluted when too much organic material such as manure and sewage is deposited. Organic material in water produces decomposers, which grow fast and use a high amount of oxygen. Low oxygen levels in water can kill marine life. Additional decomposers grow when the aquatic life dies, worsening the condition of the water. Nitrogen and phosphates are other types of organic material. They lead to excessive growth of plants and algae. When these plants decay, decomposers grow and reduce the amount of oxygen in the water.

Thermal

Thermal pollution occurs after water is used to cool heavy machinery. The water is heated when it is used and then returned to the source at a higher temperature. Much of the oxygen has left the water by that time. Plants and animals now have a decreased supply of oxygen, putting strain on the rest of the water in the area.

Ecological

Ecological pollution is the result of the environment polluting itself. A volcanic eruption is an example of ecological pollution because toxic components in the lava could make their way into the water. Dead animals and landslides are other examples of ecological pollution. The temperature of the water can cause thermal pollution which can be the result of weather. An increase in temperature, or shallower water, can allow an increased number of plants to grow. This can deplete the oxygen resource for the marine life.

References

• The Great Lakes Toxic Substances Control Agreement: Findings
• Water Pollution Guide: Welcome to Water Pollution Guide
• Missouri Botanical Garden: Water Pollution