What is one major concern associated with high animal density in farming?

High animal density in farming leads to a surplus of nutrients, particularly nitrogen and phosphorus, which can have significant environmental impacts. When livestock populations are concentrated, the amount of manure produced can exceed the capacity of the land to effectively process and absorb these nutrients. This excess can lead to runoff into nearby waterways, contributing to nutrient pollution, which can cause issues such as algal blooms, water quality degradation, and harm to aquatic ecosystems.

This concern is particularly relevant in states like Pennsylvania, where agriculture plays a significant role in the economy, but also faces regulatory scrutiny due to water quality issues connected with nutrient runoff. Proper nutrient management strategies are essential to mitigate these environmental risks while ensuring sustainable agricultural practices are maintained. The other options do not encapsulate the primary environmental and regulatory concerns linked with high animal density in farming.