What is the environmental impact of D&C Red No. 33?

• A. It is non-toxic to aquatic systems.
• B. It is produced from plant sources and is harmless to aquatic life.
• C. It is a nutrient for aquatic organisms.
• D. It is toxic to aquatic systems and is produced from petroleum sources.

Answer: (D)

The key idea here is that many synthetic dyes are not benign to aquatic life and their origin matters. D&C Red No. 33 is a synthetic dye derived from petroleum. Synthetic, petroleum-derived dyes often contain aromatic rings and other complex structures that can be toxic to aquatic organisms, may persist in the environment, and can disrupt ecosystems even at low concentrations. Saying it is toxic to aquatic systems and petroleum-sourced reflects this reality about many dyes in this class, which contrasts with plant-based, naturally derived substances or harmless nutrients. The other statements imply it’s non-toxic, plant-derived, or a nutrient, which don’t fit the chemical nature and environmental behavior of this dye.