Eutrophication in Lakes: Causes and Solutions

Eutrophication: A Threat to Lakes

Rivers, due to their erosive power, carry salts, organic matter, and suspended solids. To this, human action adds waste from domestic and industrial activities (solids and metals mining), agriculture, and livestock (nitrates, phosphates, pesticides, etc.). The self-purification capacity of rivers cannot always handle this load, which triggers pollution processes. The effects of this pollution include:

• Restriction on the use of water
• Alteration in wildlife and/or aquatic flora
• Unpleasant appearance and odor

Rivers are better equipped to handle pollution dynamics, allowing them to dilute pollutants. In contrast, lakes tend to accumulate waste. One of the main problems affecting lakes is the process of eutrophication.

What is Eutrophication?

Eutrophication occurs when large amounts of organic matter reach a small body of water, such as a lake. Microbial decomposition of organic matter consumes oxygen and releases a series of compounds. Both are vital nutrients for plants, which reproduce explosively. In cold weather, the algae die and sink to the bottom, where they release nutrients into the water. These nutrients are utilized in the following favorable season and also produce an acidification of the bottom. Thus, the eutrophication of the lake continues regardless of new external inputs of organic matter, in what some authors call a biophysicochemical chain reaction. This is equivalent to what happens in living beings: death by overeating.

Measures to Combat Eutrophication

• Minimize, limit, or prohibit domestic and agricultural discharges
• Treat wastewater
• Reduce the use of polyphosphate detergents
• Inject pure O₂
• Add N

The Self-Purification Process in Natural Waters

Self-purification is a system that occurs in natural waters. It consists of a series of mechanisms, including the sedimentation of particles and chemical and biological processes. These processes cause the degradation of organic matter, converting it into inorganic matter. This inorganic matter serves as a nutrient for algae, increasing their photosynthetic activity and enriching the water with O₂. Through these processes, extraneous matter is removed from the water, and the natural balance is restored.