Georgia Pest Control Practice Test

What is the primary source of groundwater contamination?

1. Drift

2. Leaching

3. Runoff

4. Volatilization

The correct answer is: Leaching

Leaching is recognized as the primary source of groundwater contamination because it refers to the process through which soluble substances, including pesticides, fertilizers, and other chemicals in the soil, are washed away down through the soil layers and into groundwater. This process can be particularly impactful in areas with heavy rainfall or poor soil structure, which facilitates the movement of contaminants. When these substances enter the groundwater, they can persist for long periods, adversely affecting the quality of water and posing risks to human health and the environment. This mechanism highlights the importance of responsible agricultural practices and the need to manage chemical use effectively to prevent leaching into the groundwater supply. In contrast, drift involves the movement of pesticides through the air during application and typically affects surface areas rather than penetrating soil layers into groundwater. Runoff refers to surface water that carries contaminants into larger bodies of water, while volatilization involves the transformation of substances into vapor, which can also lead to air contamination but does not directly explain how groundwater is contaminated. Thus, leaching stands out as the primary mechanism leading to groundwater contamination.