Synergistic effects of glyphosate- and 2,4-D-based pesticides mixtures on Rhinella arenarum larvae

Abstract

Glyphosate and 2,4-D are two herbicides commonly used together. Since there is little information about the interactions between these pesticides, the aim of this study was to evaluate the single and joint lethal toxicity of the glyphosate-based herbicide (GBH) ATANOR® (43.8% of glyphosate, isopropylamine salt) and the 2,4-D-based herbicide (2,4-DBH) Así Max 50® (602000 mg/L of 2,4-D) on Rhinella arenarum larvae. Equitoxic and non-equitoxic mixtures were prepared according to the recommendation for their combination and analyzed with a fixed ratio design at different exposure times and levels of lethality (LC10, LC50, and LC90). GBH (504h-LC50=38.67 mg ae/L) was significantly more toxic than 2,4-DBH (504h-LC50=250.31 mg ae/L) and their toxicity was time-dependent. At 48h, the equitoxic mixture toxicity was additive and from the 96h was antagonistic at LC10 and LC50 effect level. The non-equitoxic mixture toxicity was additive at LC10 effect level from the 48h to the 168h, and synergistic from the 240h. At LC50 and LC90 effect level, the mixture interaction resulted synergistic for all exposure times. This is the first study to report the synergistic interactions between GBH and 2,4-DBH on amphibians, alerting about its negative impact on aquatic ecosystems.

Water and sediment quality of an agro‐industrial area through different approaches: Physicochemical parameters and ecotoxicity with amphibians

“…Studies with neotropical anurans integrating several biomarkers are scarce and limited to some studies (Brodeur et al, 2012; Peltzer et al, 2013; Peluso et al, 2020; Peluso, Furió Lanuza, et al, 2022). In this context, this is one of the few studies that evaluate, in a laboratory context, a real exposure scenario that integrates the effects of pesticides, metals, and physicochemical parameters at multiple biological levels using a species that inhabits agricultural environments.…”

“…Metals were analyzed in sediment and water samples using a fluorescence spectrometer of X-ray by total reflection (TXRF) S2 Picofox, Bruker with a molybdenum tube as previously described in Peluso, Furi o Lanuza, et al (2022).…”

“…Lethal effects on R. arenarum larvae Grass and roots were removed from sediment samples. The bioassays were performed following the ASTM (2014) protocols with the adaptations proposed by Peluso, Furi o Lanuza, et al (2022). Shortly, 200 mL of sediment samples was placed on a glass flask (2-cm homogeneous layer) with 2-cm column of unfiltered water samples (approx.…”

“…Other authors had proved the oxidative stress can be induced by some of the detected compounds, such as pesticides like glyphosate, atrazine (Dornelles & Oliveira, 2014), and 2,4-D (Freitas et al, 2022) and metals as Cu (Huang et al, 2020) and As (Mardirosian et al, 2015). In addition, interaction between different substances and/or the physicochemical parameters can produce synergistic effects, such as is the case of glyphosate and As (Lajmanovich et al, 2019;Peluso, Furi o Lanuza, et al, 2022).…”

Gonadal morphogenesis in the South American toad Rhinella Arenarum (Anura, Bufonidae) unveils an extremely delayed rate of sex differentiation

“…This species has been subject of extensive research in areas such as endocrinology (e.g., Czuchlej et al, 2019; Scaia et al, 2019; Volonteri & Ceballos, 2010) and organ histology (e.g., Farias et al, 2003; Hermida & Farías, 2009; Regueira et al, 2016). In addition, early life stages have been used in ecotoxicological studies (e.g., Aronzon et al, 2020; Asparch et al, 2020; Liendro et al, 2015; Mardirosian et al, 2017; Peluso et al, 2022; Svartz et al, 2012), including the assessment of the effects of agrochemicals on gonadal development (Svartz et al, 2016). However, there is no information on the early gonadogenesis of this species.…”