In the context of the large-scale grain farm relying on an adjacent river for irrigation, drainage, and pesticide use, a negative externality resulting from this activity would be "Damage to downstream plant and animal life."
Here's why:
1. Pesticides Contamination: The use of pesticides to protect crops can lead to runoff into the adjacent river. This pesticide-laden water flowing downstream can harm the plant and animal life in the river ecosystem. The chemicals in the pesticides can disrupt the natural balance, impacting aquatic plants, fish, and other organisms.
2. Impact on Biodiversity: The introduction of these pesticides into the river can lead to a decrease in biodiversity as certain species may be more sensitive to the chemicals, causing population declines or even local extinctions. This disruption can have far-reaching consequences on the overall health and stability of the downstream ecosystem.
3. Ecosystem Imbalance: Damage to plant and animal life downstream can create an imbalance in the food chain and ecosystem dynamics. For example, if certain fish species are adversely affected by the pesticides, their predators may also suffer due to a lack of food supply, leading to cascading effects throughout the ecosystem.
In conclusion, the negative externality of "Damage to downstream plant and animal life" is a significant consequence of the activities of the large-scale grain farm, highlighting the importance of considering environmental impacts in agricultural practices.
