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

Author(s)

de Palma Lopes, Lais Fernanda ; Rocha, Giseli Swerts ; de Medeiros, Jessyca Ferreira ; Montagner, Cassiana Carolina ; Espindola, Evaldo Luiz Gaeta

• Document type: Journal article
• Source: Environmental Science and Pollution Research; v. 30, n. 33, p. 14-pg., 2023-06-09.

Abstract

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 LC10-48h, LC20-48h, and LC50-48h of fipronil to N. iheringi were 2.38 +/- 0.48, 3.08 +/- 1.14, and 4.97 +/- 3.30 mu g L-1, respectively. For 2,4-D the LC10-48h, LC20-48h, and LC50-48h 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 mu g 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. (AU)

• FAPESP's process: 15/18790-3 - Environmental effects of the pasture-sugarcane conversion and pasture intensification
• Grantee: Luiz Antonio Martinelli
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 15/25436-1 - Influence of copper and cadmium in algae and their ecotoxicological effects in freshwater zooplankton
• Grantee: Giseli Swerts Rocha
• Support Opportunities: Scholarships in Brazil - Post-Doctoral