Which setting is most likely associated with higher nitrate levels in water?

Agricultural settings are most likely associated with higher nitrate levels in water due to the extensive use of nitrogenous fertilizers that are commonly applied to crops. In these areas, fertilizers containing nitrates are absorbed by plants; however, excess nitrates can leach into the groundwater and runoff into surface water bodies. This contamination can lead to elevated nitrate concentrations in nearby water sources, which poses risks to both environmental and public health.

In contrast, municipal parks and residential backyards may have some level of nitrate from lawn fertilizers and landscaping, but these are typically much lower in concentration compared to the agricultural runoff from large-scale farming operations. Coastal areas, while they can experience pollution from various sources, do not directly contribute to elevated nitrate levels from fertilizers in the same way agricultural settings do, as their characteristic land uses and nutrient sources differ. Thus, the direct link between agricultural practices and nitrate pollution makes agricultural settings the most significant contributors to higher nitrate levels in water.