Answer:
The pollutants may be defined as the substance that can changes the characteristics of pure water, air and soil. Pollutants are known to cause different types of environmental pollution.
The use of the fertilizers in the crops are rich in the nitrogen and phosphorus element. When these fertilizers is run off to the water bodies, the nutrients causes the enrichment and growth of dinoflagellates and other algae in the water bodies. This can also be considered as eutrophication.