Acute, chronic and biochemical effects of chlorothalonil on Agalychnis callidryas, Isthmohyla pseudopuma and Smilisca baudinii tadpoles

Abstract

Declines of amphibian populations have been a worldwide issue of concern for the scientific community during the last several decades. Efforts are being carried out to elucidate factors related to this phenomenon. Among these factors, pathogens, climate change, and environmental pollution have been suggested as possible causes. Regarding environmental pollutants, some pesticides are persistent in the environment and capable of being transported long distances from their release point. In Costa Rica, some pesticides have been detected in protected areas, at locations where amphibian populations have declined. Information about toxicity of pesticides used in Costa Rican agriculture to amphibians is still scarce, particularly for native species.Toxicity tests with chlorothalonil, a fungicide intensively used in Costa Rica, were carried out exposing tadpoles of three Costa Rican native species: Agalychnis callidryas, Isthmohyla pseudopuma, and Smilisca baudinii in order to evaluate acute and chronic toxicity as well as the biomarkers cholinesterase activity (ChE), glutathione-S transferase activity (GST), and lipid peroxidation (LPO).96-h LC: 26.6 (18.9-35.8) μg/L to A. callidryas, 25.5 (21.3-29.7) μg/L to I pseudopuma and 32.3 (26.3-39.7) μg/L to S. baudinii were determined for chlorothalonil. These three species of anurans are among the most sensitive to chlorothalonil according to the literature. Besides, GST was induced in S. baudinii after exposure to sub-lethal concentrations of chlorothalonil while evisceration occurred in S. baudinii and A. callidryas tadpoles exposed to lethal concentrations of the fungicide. Chronic exposure to sub-lethal concentrations accelerated development in S. baudinii and caused lesions in tail of S. baudinii and I. pseudopuma tadpoles. Our results demonstrate that chlorothalonil is highly toxic to native amphibian species and that low concentrations can cause biochemical responses related to phase II of biotransformation and effects on development.

Ecotoxicological Effects of Imidacloprid and Lambda-Cyhalothrin (Insecticide) on Tadpoles of the African Common Toad, Amietophrynus Regularis (Reuss, 1833) (Amphibia: Bufonidae)

“…The tadpole developmental stage may be more relevant to determining toxicity than tadpole age. In a study carried out in Costa Rica, it was found that chlorothalonil (fungicide) is highly toxic to native amphibian species and that low concentrations can cause biochemical responses related to phase II of biotransformation and effects on development [19].…”

“…Existing risk assessment procedures for pesticide regulation are not protecting amphibians [18]. Declines of amphibian populations have been a worldwide issue of concern for the scientific community during the last several decades [19]. Indeed, amphibians may be at greater risk of toxic effects of pesticides than other aquatic vertebrates because their preferred breeding habitats are often shallow lentic or ephemeral water bodies [3].…”

Perspectives on the specific targeting of Fusarium graminearum for the development of alternative head blight treatment approaches

“…Chlorothalonil (chloronitrile) is a low‐cost, broad‐spectrum, nonsystemic fungicide that also has antibacterial, anti‐algal and insecticidal properties. While it is widely used in the field, it has been listed by EPA as a likely carcinogen (EPA‐738‐F‐99‐008, April 1999) possibly with major negative effects on the environment (Méndez et al ., ). Chlorothalonil effects are mediated by reducing fungal intracellular glutathione molecules, making this important cellular antioxidant ineffective, while at the same time preventing essential enzymatic reactions that use specific conformations of glutathione as their reaction centres (Tillman et al ., ; Yang et al ., ).…”

“…As alluded to above, if used properly during early flowering (Yoshida et al ., ) they can reduce FHB spread. However, increases in fungicide resistance and environmental problems caused by these conventional fungicides is an increasing concern (Brown et al ., ; Méndez et al ., ; Yan et al ., ; Zhou et al ., ). Chlorothalonil (chloronitrile) is a low‐cost, broad‐spectrum, nonsystemic fungicide that also has antibacterial, anti‐algal and insecticidal properties.…”

Effects of insecticides on aquatic ecosystems in Bangladesh

“…A few studies, however, have been conducted to understand the fate and effects of pesticides for the (sub-) tropical freshwater environments over the last decades. These study included single species toxcitity tests (Maltby et al, 2005;Kwok et al, 2007;Freitas and Rocha, 2012;Mansano et al, 2016;Daam and Rico, 2016;Amid et al, 2017), multiple species toxicity tests (Rico et al, 2010(Rico et al, , 2011Echeverría-Sáenz et al, 2016;Méndez et al, 2016;Stadlinger et al, 2016;Svensson et al, 2017) and model ecosytem studies (i.e. microcosms) (Laabs et al, 2007;Daam et al, 2008aDaam et al, , 2008bDaam et al, , 2009aDaam et al, , 2009bDaam et al, , 2010Van den Brink, 2010, 2011;Leboulanger et al, 2011).…”