APES Aquatic Pollution Practice Test 2025 – Complete Exam Prep

The primary source of nutrients that contribute to cultural eutrophication in aquatic systems is often linked to wastewater discharge. This is because wastewater from residential, industrial, and agricultural sources typically contains high levels of nitrogen and phosphorus. These nutrients promote excessive growth of algae when they enter water bodies, leading to eutrophication.

Cultural eutrophication is primarily caused by human activities, and wastewater discharge represents a direct input of these nutrients into aquatic environments. When wastewater treatment plants do not adequately remove nutrients or when septic systems fail, the result can be nutrient-enriched waters that catalyze algal blooms. These blooms can disrupt aquatic ecosystems by reducing oxygen levels and harming aquatic life when decomposing.

While agricultural runoff, atmospheric deposition, and stormwater runoff also contribute to nutrient loading in water bodies, wastewater discharge tends to be the more concentrated and localized source, often associated with significantly high loads of nutrients entering aquatic systems rapidly. This concentrated nutrient pollution is a major factor in the eutrophication process, especially in urban areas where treatment facilities may struggle to keep up with the volume and nutrient load of wastewater.