What is a likely impact resulting from pesticide runoff?

Pesticide runoff can lead to the contamination of groundwater, which is a significant environmental concern. When pesticides are applied to crops, they can be washed away by rainfall or irrigation and enter nearby water systems. This runoff can seep through the soil, ultimately reaching aquifers that supply drinking water and irrigation for other crops. The presence of pesticides in groundwater can pose serious risks to human health and the environment, affecting drinking water quality and disrupting ecosystems.

In contrast, improved crop yields, increased soil fertility, and healthy aquatic ecosystems are generally positive outcomes that do not arise from pesticide runoff. Instead, pesticide runoff often leads to detrimental effects such as harm to aquatic life, reduced biodiversity, and long-term soil health issues. Thus, the contamination of groundwater is a realistic and concerning impact of pesticide runoff.