Impact of Caffeine on Aquatic Ecosystems: Assessing Trophic-Level Biological Responses.

This study evaluates the effects of caffeine (CAF) on the bacteria , the microalga , the macrophyte , and the larvae of , aiming to understand its environmental impact and contribution to ecological risk assessment. Bioluminescence inhibition in (EC = 998.5 mg/L) and growth inhibition in and (EC = 60.1 mg/L and EC = 649.2 mg/L, respectively) were observed. For , reduced catalase (CAT) activity and non-linear responses in glutathione S-transferases (GSTs) were recorded. No significant changes were observed in proline, malondialdehyde (MDA), and pigment contents. In , acute mortality (LC = 644.5 mg/L) was observed, and growth was significantly affected after 10 days of CAF exposure (EC = 81.62 mg/L for fresh biomass). After 10 days of exposure, there was an increase in CAT activity and thiobarbituric acid reactive substances, with TBARS levels both at concentrations ≥82.64 mg/L, and a decrease in GSTs (92.18 mg/L) and acetylcholinesterase (AChE) (≤62.09 mg/L) activities of . The results show that CAF exposure affects organisms' metabolic and physiological functions, with varying sensitivities among species, potentially leading to ecological disturbances in aquatic ecosystems. The hazardous concentration for 5% of species was 4.42 mg/L. Long-term studies are necessary to understand the risk of caffeine under more realistic scenarios.