Which of the following nutrients is commonly monitored in water quality assessments?

Nitrogen is commonly monitored in water quality assessments because it plays a key role in aquatic ecosystems and can significantly impact water quality and health. In its various forms—such as nitrate, nitrite, and ammonia—nitrogen influences nutrient cycling, algae growth, and overall ecosystem dynamics. High levels of nitrogen compounds can lead to eutrophication, a process where excessive nutrients promote harmful algal blooms, which deplete oxygen levels in the water and harm aquatic life.

Monitoring nitrogen is crucial for understanding the health of water bodies, as it can originate from agricultural runoff, wastewater discharge, and other human activities. By tracking nitrogen levels, water resource managers can take actions to mitigate pollution, restore water quality, and protect aquatic environments. This focus on nitrogen is essential in managing issues related to water safety, ecosystem health, and sustainable water use.