Toxic effects of a mancozeb-containing commercial formulation at environmental relevant concentrations on zebrafish embryonic development

• Published in: Environmental science and pollution research international 2020-06, Vol.27 (17), p.21174-21187
• Main Authors: Vieira, Raquel, Venâncio, Carlos A. S., Félix, Luís M.
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase; Anaerobic respiration; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Blastula; Carboxylesterase; Catalase; Danio rerio; Earth and Environmental Science; Ecotoxicology; Edema; Embryogenesis; Embryonic growth stage; Embryos; Environment; Environmental Chemistry; Environmental Health; Environmental risk; Environmental science; Enzymes; Exposure; Fertilization; Fungicides; Glutathione; Glutathione peroxidase; Glutathione reductase; Glutathione transferase; Hatching; Heart rate; L-Lactate dehydrogenase; Lactate dehydrogenase; Light effects; Locomotor activity; Metabolites; Neurotransmission; Oxidative stress; Parameters; Peroxidase; Phenotypes; Reactive oxygen species; Reductases; Research Article; Superoxide dismutase; Toxicity; Toxicology; Waste Water Technology; Water Management; Water Pollution Control; Yolk; Zebrafish
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-08412-0

The toxicological knowledge of mancozeb (MZ)-containing commercial formulations on non-target species is scarce and limited. Therefore, the objective of this work was to represent a realistic application scenario by evaluating the toxicity of environmental relevant and higher concentrations of a commercial formulation of MZ using zebrafish embryos. Following determination of the 96-h LC 50 value, the embryos at the blastula stage (~ 2 h post-fertilisation, hpf) were exposed to 0.5, 5, and 50 μg L −1 of the active ingredient (~ 40× lower than the 96-h LC 50 ). During the exposure period (96 h), lethal, sublethal, and teratogenic parameters, as well as behaviour analysis, at 120 hpf, were assayed. Biochemical parameters such as oxidative stress–linked enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR)), reactive oxygen species (ROS) levels, and glutathione levels (GSH and GSSG), as well as the activity of degradation (glutathione S -transferase (GST) and carboxylesterase (CarE)), neurotransmission (acetylcholinesterase (AChE)), and anaerobic respiration (lactate dehydrogenase (LDH))–related enzymes, were analysed at the end of the exposure period. Exposed embryos showed a marked decrease in the hatching rate and many malformations (cardiac and yolk sac oedema and spinal torsions), with a higher prevalence at the highest concentration. A dose-dependent decreased locomotor activity and a response to an aversive stimulus, as well as a light-dark transition decline, were observed at environmental relevant concentrations. Furthermore, the activities of SOD and GR increased while the activity of GST, AChE, and MDA contents decreased. Taken together, the involvement of mancozeb metabolites and the generation of ROS are suggested as responsible for the developmental phenotypes. While further studies are needed to fully support the hypothesis presented, the potential cumulative effects of mancozeb-containing formulations and its metabolites could represent an environmental risk which should not be disregarded.