MDARD Michigan Core Pesticide Applicator Practice Exam

Which characteristic of pesticides makes them more likely to leach into groundwater?

1. High adsorption

2. Low persistence

3. High solubility

4. Low volatility

The correct answer is: High solubility

The characteristic that makes pesticides more likely to leach into groundwater is high solubility. When a pesticide is highly soluble in water, it can easily dissolve and move through the soil profile when it rains or when irrigation occurs. This allows the pesticide to travel with water and potentially reach groundwater sources. In contrast, pesticides with high adsorption tend to stick to soil particles, which reduces their movement through the soil and the likelihood of leaching. Low persistence means that a pesticide breaks down quickly in the environment, leading to less time for it to move through the soil and into groundwater. Low volatility indicates that a pesticide does not easily evaporate, which can also reduce the potential for it to leach into groundwater, as evaporation generally does not contribute to water movement in soil layers.