Exposure to environmental concentrations of fipronil and 2,4-D mixtures causes physiological, morphological and biochemical changes in Raphidocelis subcapitata

Author(s)

Moreira, Raquel Aparecida ^{[1, 2]} ; Rocha, Giseli Swerts ^{[1, 2]} ; Menezes da Silva, Lais Conceicao ^{[1, 2]} ; Goulart, Bianca Veloso ^[3] ; Montagner, Cassiana Carolina ^[3] ; Gama Melao, Maria da Graca ^[4] ; Gaeta Espindola, Evaldo Luiz ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Engn Sch, NEEA CRHEA SHS, Av Trabalhador Sao Carlene 400, BR-13560970 Sao Carlos - Brazil

^[2] Univ Sao Paulo, Sao Carlos Engn Sch, PPG SEA, Av Trabalhador Sao Carlene 400, BR-13560970 Sao Carlos - Brazil

^[3] Univ Estadual Campinas, Inst Chem, Analyt Chem Dept, Campinas, SP - Brazil

^[4] Univ Fed Sao Carlos UFSCar, Dept Hydrobiol, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY; v. 206, DEC 15 2020.
• Web of Science Citations: 0

Abstract

The occurrence of pesticides and their mixtures in the environment can alter the ecological relationships between aquatic food chains. Since fipronil and 2,4-dichlorophenoxyacetic acid (2,4-D) are commonly found together in Brazilian water bodies, the present study aimed to investigate through an integrative approach the toxicity mechanisms of environmentally relevant concentrations of pesticides Regent (R) 800 WG (active ingredient - a.i. fipronil), DMA (R) 806 BR (a.i. 2,4-D) isolated and in mixtures on the green alga Raphidocelis subcapitata using multiple parameters: physiological (growth rate and chlorophyll a fluorescence), morphological (cell complexity and size), biochemical (composition of lipid classes) and related to the photosynthetic activity (variable fluorescence, the maximum quantum yield of the photosystem II - PSII - and the efficiency of the oxygen evolving complex - OEC - of PSII). The results indicated that fipronil significantly inhibited algal population growth, increased the chlorophyll a content (observed by fluorescence), cell size and lipid class content of triacylglycerol (TAG), free fatty acid (FFA) and acetone mobile polar lipid (AMPL) and, on the other hand, decreased variable fluorescence of algae. The tested concentrations of 2,4-D increased the chlorophyll a fluorescence, the cell size and the lipid classes TAG and FFA. The pesticide mixtures have had more effects on algae than isolated compounds, causing alterations in all parameters analyzed, including photosynthetic activity (maximum quantum yield and efficiency of the oxygen evolving complex of the PSII), in which no alterations were observed for the toxicity of the single pesticides. The results suggest that these analyses are important to evaluate pesticide toxicity mechanisms in ecological risk assessments of tropical regions. Thus, here we demonstrate the importance of using multiple parameters in ecotoxicological studies to obtain a better understanding of the toxicity of these compounds for phytoplankton. (AU)

• 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
• FAPESP's process: 17/24126-4 - EFFECTS OF THE PESTICIDES FIPRONIL AND 2,4-D, ISOLATELY AND IN MIXTURE, ON NATIVE SPECIES OF THE NEOTROPICAL AQUATIC BIOTA
• Grantee: Raquel Aparecida Moreira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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