The category that includes nitrates and phosphates from agricultural sources is called?

• A. Saltwater Intrusion
• B. Nutrient Runoff
• C. Harmful Algal Blooms
• D. Primary Sewage Treatment

Answer: (B)

Nitrates and phosphates from agricultural sources are nutrients that enter water bodies mainly through runoff from fields and manure management. This movement of nutrients from land to water is called nutrient runoff, describing how fertilizer-derived nutrients are transported into streams, rivers, and lakes. When these nutrients accumulate in water, they fuel rapid algal growth, and as the algae die and decompose, oxygen is consumed, leading to hypoxia and harms to aquatic life—a process known as eutrophication. Saltwater intrusion refers to saline water moving into freshwater aquifers and isn’t about nutrient inputs. Primary sewage treatment is about removing solids from wastewater, not agricultural nutrient inputs. Harmful algal blooms are a consequence of nutrient enrichment, but the category that includes the nutrients themselves is nutrient runoff—the mechanism by which these farm-derived nutrients reach water bodies.