Pollution can harm aquatic ecosystems by contaminating water, reducing oxygen levels, and harming aquatic life, leading to ecosystem imbalances and declines in biodiversity.
Chemicals and heavy metals from industrial and municipal wastewater contaminate waterways as well. These contaminants are toxic to aquatic life—most often reducing an organism's life span and ability to reproduce—and make their way up the food chain as predator eats prey.
Problems occur when the natural characteristics of a river are altered by pollutant discharges. We now consider the effects of the following categories of pollutants:
