title: 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 LC50: 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.
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica. michael586@gmail.com.
authors: Michael
authors: M
authors: Méndez
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica.
authors: Priscilla
authors: P
authors: Obando
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica.
authors: Margaret
authors: M
authors: Pinnock-Branford
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica.
authors: Clemens
authors: C
authors: Ruepert
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica.
authors: Luisa E
authors: LE
authors: Castillo
authors: Central American Institute for Studies on Toxic Substances/Instituto Regional de Estudios en Sustancias Toxicas (IRET), Universidad Nacional, Heredia, Costa Rica. fmena@una.cr.
authors: Freylan
authors: http://orcid.org/0000-0002-1215-0378
authors: F
authors: Mena
authors: School of Biology, Universidad de Costa Rica, San Pedro, Costa Rica.|Centro de Investigación en Estructuras Microscópicas (CIEMIC), Universidad de Costa Rica, San Pedro, Costa Rica.|Department of Pathology, Laboratory of Comparative Wildlife Pathology (LAPCOM), School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors: Gilbert
authors: G
authors: Alvarado
mesh_terms: D000383:Agriculture; D000818:Animals; D001001:Anura; D002802:Cholinesterases / Q000378:metabolism; D057231:Climate Change; D004305:Dose-Response Relationship, Drug; D054750:Ecotoxicology; D004785:Environmental Pollutants / Q000633:toxicity*; D005659:Fungicides, Industrial / Q000633:toxicity*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007814:Larva / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects; D009570:Nitriles / Q000633:toxicity*; D023382:Toxicity Tests, Acute
chemical_list: D004785:Environmental Pollutants; D005659:Fungicides, Industrial; D009570:Nitriles; D005982:Glutathione Transferase; D002802:Cholinesterases; C005806:tetrachloroisophthalonitrile
keywords: Amphibians; Chlorothalonil; Pesticides; Toxicity