Atrazine and Diuron Effects on Survival, Embryo Development, and Behavior in Larvae and Adult Zebrafish

Abstract

Atrazine and Diuron are widely used herbicides. The use of pesticides contaminates the aquatic environment, threatening biodiversity and non-target organisms such as fish. In this study, we investigated the effects of acute exposure for 96 h hours to atrazine and diuron commercial formulations in zebrafish (Danio rerio, wild-type AB) embryos and larvae and adult stages. We observed a significant concentration-dependent survival decrease and hatching delays in animals exposed to both herbicides and in the frequency of malformations compared to the control groups. Morphological defects included cardiac edema, tail reduction, and head malformation. At 7 days post-fertilization (dpf), atrazine exposure resulted in a reduction in the head length at 2, 2.5, and 5 mg/L and increased the ocular distance at 1, 2, 2.5, and 5 mg/L atrazine when compared to controls. At the same age, diuron increased the ocular distance in animals exposed to diuron (1.0 and 1.5 mg/L) and no effects were observed on the head length. We also evaluated a behavioral repertoire in larvae at 7 dpf, and there were no significant differences in distance traveled, mean speed, time in movement, and thigmotaxis for atrazine and diuron when animals were individually placed in a new environment. The cognitive ability of the larvae was tested at 7 dpf for avoidance and optomotor responses, and neither atrazine nor diuron had significant impacts when treated groups were compared to their corresponding controls. Adults’ behavior was evaluated 7 and 8 days after the end of the acute herbicide exposure. Exploration of a new environment and associated anxiety-like parameters, social interaction, and aggressiveness were not altered. Our results highlight the need for further studies on the sublethal effects of both herbicides and the consideration of the effects of commercial formulas vs. isolated active ingredients. It also emphasizes the need to take sublethal effects into consideration when establishing the environmental limits of residues.

Rapid Assessment of Ocular Toxicity from Environmental Contaminants Based on Visually Mediated Zebrafish Behavior Studies

“…Similarly, male zebrafish exposed to BPS exhibited a significant reduction in their tracking ability during OMR testing [ 56 ]. However, no significant difference was observed in the OMR tests of zebrafish following acute exposure to the insecticides atrazine and diazauron, as all groups exhibited positive visuomotor responses [ 66 ].…”

Residues of atrazine and diuron in rice straw, soils, and air post herbicide-contaminated straw biomass burning

“…ATZ and DIU disrupt both photosystem II and I in plants and photosynthetic microorganisms by inhibiting the chloroplast electron transport chain 12 . These herbicides exhibit high mobility within soil and aquatic environments due to their water-soluble characteristics and polar functional groups 13 , 14 . They are frequently detected in surface waters, underground reservoirs, and well water sources 15 .…”

A systematic evidence map and bibliometric analysis of the behavioural impacts of pesticide exposure on zebrafish

“…This preference stems from several key characteristics of zebrafish, such as ease of manipulation (Avdesh et al, 2012), genetic homology with humans (Howe et al, 2013) and rapid embryonic development (Lawrence et al, 2012;Meyers, 2018). While all life stages of zebrafish offer valuable insight for aquatic ecotoxicology, the investigation of long-term impacts, as well as complex social behaviours such as aggression, requires consideration of post-larvae life stages (i.e., juvenile, adolescent and adult) (Zaluski et al, 2022). The significance of behaviour as a valuable endpoint, combined with the amenability of zebrafish to laboratory experimentation, has spurred an increasing trend of studies leveraging post-larvae zebrafish as a behavioural model in aquatic ecotoxicology (Gonçalves et al, 2020;Tao et al, 2022).…”