The effects of oxytetracycline chronic toxicity on the population dynamics of D. Magna in the presence of UV-B

Abstract

Oxytetracycline is a broad-spectrum antibiotic which is mainly used to improve the health of aquaculture and livestock animals, which is the reason why it is released into water bodies through the discharges of these industries potentially causing an imbalance in the freshwater ecosystems. Additionally, the depletion of stratospheric ozone has caused an increase in the levels of ultraviolet radiation, which can increase the toxicity of the drug, due to the interaction between oxytetracycline and the UV-B region of the electromagnetic spectrum in particular, thus deteriorating the conditions necessary for the survival of aquatic species. This work analyzes the toxicity of oxytetracycline in presence of UV-B radiation using model organism Daphnia magna and the impact of these stressors on the population development, and expands the subject with a mathematical model that explores its effects on freshwater ecosystems. A chronic test was performed by combined exposures of oxytetracycline and UV-B radiation. Results showed that the effect of the stressors significantly decreased the growth rate coinciding with the alterations identified in the reproduction, thus modifying the population dynamics. This was simulated with mathematical modeling which shows that both oxytetracycline and UV-B radiation are factors that reduce survival and modify the reproductive cycle of the model organism.