What is a potential environmental hazard caused by uncontrolled nitrate in wastewater?

Nitrate pollution in wastewater is a significant environmental concern primarily because it contributes to the process known as eutrophication. Eutrophication occurs when excess nutrients, particularly nitrogen and phosphorus, enter water bodies. This nutrient overload stimulates the rapid growth of algae and aquatic plants, leading to algal blooms.

These blooms can deplete oxygen in the water as they die off and decompose, creating "dead zones" where aquatic life cannot survive due to lack of oxygen. The resulting decline in water quality can affect fish populations and other aquatic organisms, disrupt ecosystems, and make water unsafe for recreational use. Additionally, some algal blooms can produce toxins harmful to both wildlife and humans, further exacerbating the environmental impact.

Therefore, controlling nitrate levels in wastewater is crucial to prevent these harmful effects on aquatic ecosystems, making eutrophication the correct response.