In which setting are nitrates most commonly found?

Nitrates are primarily associated with agricultural fields due to the common use of nitrogen-based fertilizers in farming practices. These fertilizers contribute nitrates to the soil to promote plant growth. When it rains, the excess nitrates can leach into groundwater and surface water. The agricultural environment not only uses these fertilizers extensively but also can lead to nutrient runoff and subsequent water quality concerns, such as eutrophication in nearby water bodies.

Forested areas typically have lower levels of nitrates due to natural nutrient cycling and lower human intervention. Urban neighborhoods may have nitrogen sources related to septic systems and lawn fertilizers, but the concentrations are generally not as significant as those found in agricultural settings. Similarly, while industrial zones can have various pollutants, they are not primarily known for high nitrate levels as they do not usually involve the same nitrogen fertilizers associated with agricultural activities. Hence, agricultural fields stand out as the main setting for higher concentrations of nitrates.