The acute effects of fipronil and 2,4-D, individually and in mixture: a threat to the freshwater Calanoida copepod Notodiaptomus iheringi

• Published in: Environmental science and pollution research international 2023-07, Vol.30 (33), p.80335-80348
• Main Authors: de Palma Lopes, Laís Fernanda, Rocha, Giseli Swerts, de Medeiros, Jéssyca Ferreira, Montagner, Cassiana Carolina, Espíndola, Evaldo Luiz Gaeta
• Format: Article
• Language: English
• Subjects: 2,4-D; 2,4-Dichlorophenoxyacetic Acid - toxicity; Acute effects; Acute toxicity; Animals; Aquatic ecosystems; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Copepoda; Earth and Environmental Science; Ecosystem; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Exposure; Feeding rates; Filaments; Fipronil; Formulations; Fresh Water; Insecticides; Mixtures; Mortality; Neivamyrmex iheringi; Pesticide toxicity; Pesticides; Pesticides - toxicity; Research Article; Synergistic effect; Toxicity; Toxicity testing; Waste Water Technology; Water Management; Water Pollutants, Chemical - toxicity; Water Pollution Control
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-28066-y

The magnitude of copepods’ responses to pesticides, individually and in mixture, is little understood. The aims of this study were to evaluate: (i) the effects of the pesticides fipronil and 2,4-D, individually and in mixture, on the freshwater copepod Notodiaptomus iheringi ; and (ii) the survival and the feeding rate of copepods after the exposure. Acute toxicity tests using the commercial formulations of fipronil and 2,4-D, individually and in mixture, were performed. The LC 10–48h , LC 20–48h , and LC 50–48h of fipronil to N. iheringi were 2.38 ± 0.48, 3.08 ± 1.14, and 4.97 ± 3.30 μg L −1 , respectively. For 2,4-D the LC 10–48h , LC 20–48h , and LC 50–48h were 371.18 ± 29.20, 406.93 ± 53.77, and 478.24 ± 107.77 mg L −1 , respectively. Morphological damages on the copepods exposed to pesticides were observed at all concentrations. Fungal filaments covering dead organisms were presented at the treatment highest concentration (R5:7.43 ± 2.78 μg L −1 fipronil). The mixture of the pesticides presented synergistic effects on the mortality of N. iheringi . Post-exposure tests showed no difference between the treatments and the control on the mortality and on the feeding rate for 4 h. However, since delayed toxicity of pesticides can occur, longer post-exposure tests using N. iheringi should be tested. N. iheringi is a key species in the aquatic Brazilian ecosystem and showed sensitivity to fipronil and 2,4-D; thus, more studies with this species assessing other responses are recommended.