How to Keep Leaching from Polluting Water Sources?
What You Need to Know
Potable water is water that is safe to drink. The downward flow of water through the spaces that are in soil is called percolation. Runoff is water that does not get absorbed by the soil; instead, it flows across the ground. Nitrate is a type of chemical substance that contains nitrogen, which is necessary for plant growth. Leaching is the process by which nutrients in soil are dissolved in water and carried away. Groundwater is water that is found below the ground surface.
How Does Leaching Work?
When the spaces between soil particles become filled with water, gravity pulls the water down through the soil. This is called percolation. The water that is not absorbed by the soil runs across its surface, and is called runoff. In both methods of water movement, chemical substances in the soil, such as nitrates, dissolve in the water and are carried away. This movement of water and dissolved materials is called leaching.
In tropical rain forests, very little nutrients accumulate in the soil. This is because they are quickly absorbed by plants or leached away by rain. Because the soil of tropical rain forests is so nutrient- poor, areas that are cleared for growing crops (plants grown for food) are soon not very productive.
What Does This Have to Do with Chemicals Polluting Water Sources?
Chemical substances, such as fertilizers and pesticides, leached out of the soil due to percolation can mix with and pollute groundwater. Chemical substances leached out of the soil by runoff can drain into rivers, lakes, or streams and pollute the water.
Real-Life Science Challenge
In areas where nitrates tend to be leached from the soil, other forms of nitrogen fertilizers, such as ammonium, can be used. Unlike nitrate, ammonium tends to attach to the soil particles and resists being leached by moving water.
Now, start experimenting with ways to keep leaching from polluting water sources.
- Food coloring can be used to represent chemicals in the soil.
- Does the type of soil affect the amount of leaching?
- How do different plants affect leaching?
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.