Which category consists of nitrates and phosphates?

• A. Nitrates and Phosphates
• B. Heavy Metals
• C. Sediments
• D. Toxic Chemicals

Answer: (A)

Excess nutrients in water, especially nitrates and phosphates, drive nutrient pollution. Nitrates (NO3−) and phosphates (PO4^3−) come from sources like fertilizers, wastewater, and detergents, and when they accumulate in a aquatic system they fuel rapid growth of algae and aquatic plants. This leads to eutrophication, where dense plant blooms block sunlight and, as they decompose, consume dissolved oxygen, harming aquatic life. In pollution categorization, these substances are grouped as nutrients or nutrient pollutants, which is why choosing the category that specifically names nitrates and phosphates is the best fit. They are distinct from heavy metals (toxic metals), sediments (particulate matter), and toxic chemicals (hazardous organic/inorganic compounds).