Many toxic xenobiotics that enter the aquatic environment exert their effects through redox cycling. Oxidative stress, which incorporates both oxidative damage and antioxidant defenses, is a common effect induced in organisms exposed to xenobiotics in their environment. The results of the present study aimed to determine the oxidative stress induced in the common carp Cyprinus carpio by contaminants [metals and nonsteroidal anti-inflammatory drugs (NSAIDs)] present in Madín Reservoir. Five sampling stations (SSs), considered to have the most problems due to discharges, were selected. Carp were exposed to water from each SS for 96 h, and the following biomarkers were evaluated in gill, blood, and muscle: hydroperoxide content, lipid peroxidation, protein carbonyl content, and the activity of antioxidant enzymes superoxide dismutase and catalase. Results show that contaminants (metals and NSAIDs) present in water from the different SSs induce oxidative stress. Thus, water in this reservoir is contaminated with xenobiotics that are hazardous to C. carpio, a species consumed by the local human population.

No abstract

Amoxicillin (AMX) is an antibiotic that has been added to the watch list of substances by the European Union, through the Water Framework Directive (WFD; 2000/60/EC) and its daughter regulation (Decision 2018/840) for which monitoring data have to be gathered with a possibility for future regulation. Previous studies have demonstrated that this antibiotic generates toxic effects, among which oxidative stress in aquatic organisms is noteworthy. The aim of this study was to evaluate the effect on embryonic development and the teratogenic effects induced by AMX at environmentally relevant concentrations in oocytes and embryos of Danio rerio. Furthermore, oxidative stress biomarkers were evaluated at 72 and 96 hpf. The LC 50 was 14.192 μgL −1 , EC 50 was 7.083 μgL −1 , and TI was 2.003. Biomarkers of cellular oxidation and antioxidant enzymes were modified in a concentration-dependent way with respect to the control group (p<0.05). The main malformations identified were tail malformation, pericardial edema, yolk sac malformation, scoliosis, pectoral fin absence, and no hatching. The results allow us to conclude that AMX at environmentally relevant concentrations is capable of inducing embryotoxic and teratogenic effects and oxidative damage. This compound represents a risk to aquatic organisms such as Danio rerio. Clinical Trials Registration Not applicable.