Which sustainability metric addresses the impacts of designs on the aquatic environment?

Eutrophication is the correct choice as it specifically addresses the impacts of nutrient loading in aquatic systems. This occurs when excess nutrients, particularly nitrogen and phosphorus, enter water bodies, often from agricultural runoff or wastewater. Such nutrient enrichment can lead to algal blooms, which deplete oxygen in the water and create dead zones that are harmful to aquatic life. By measuring eutrophication potential, designers can gauge how their products or processes may contribute to these detrimental effects on marine and freshwater ecosystems.

Other metrics like air acidification or carbon footprint focus on air quality and greenhouse gas emissions, respectively, and do not directly measure impacts on aquatic environments. Non-renewable lifecycle energy demand pertains to resource consumption in the production process rather than to ecological consequences for water bodies. Thus, each of these alternatives lacks the specific focus on water quality and aquatic ecosystems that eutrophication provides.