skip to main content

Title: Toxicity of Bacillus thuringiensis var. israelensis in aqueous suspension on the South American common frog Leptodactylus latrans (Anura: Leptodactylidae) tadpoles

The effects of commercial formulations of Bacillus thuringiensisvar.israelensis (Bti) on non-target organisms are still a matter of debate; in amphibians, the risks of Bti are little known. To evaluate the toxicity of a commercial liquid (aqueous suspension, AS) formulation of Bti (Introban{sup ®}) on Leptodactylus latrans tadpoles, including median lethal concentration (LC{sub 50}) and no-and lowest–observed-effect concentrations (NOEC and LOEC, respectively), as well as the possible effects of Bti on oxidative responses, erythrocytes genotoxicity, and histology of the intestines. In the laboratory, tadpoles were exposed to nominal concentrations of 0 (control), 2.5, 5, 10, 20 and 40 mg/L of formulated Bti-AS. Glutathione S-transferase (GST) and catalase (CAT) activities, as well as formation of erythrocyte nuclear abnormalities (ENAs), and histological effect were measured in tadpoles displaying survival rates >85%. L. latrans tadpoles were sensitive to exposure to Bti-AS, reaching 100% mortality after 48 h of exposure at the highest concentration. Bti-AS induced GST and CAT enzymes and genotoxicity (erythrocyte's nuclear abnormalities), and caused intestine's histopathology. Our results demonstrate that toxicity of Bti-AS is dose-dependent for L. latrans tadpoles and that sublethal exposure alters enzymes of oxidative stress, induces genotoxicity, and causes intestine damage. Further research is needed to evaluate the ecotoxicologicalmore » risk of the massive use of Bti formulations on amphibian populations that commonly used suburban wastewater or urban waterbodies to reproduce and where this biopesticide is frequently applied. - Highlights: • An ecotoxicological evaluation of a Bti formulation on amphibian was conducted. • Toxicity of Bti-AS was dose-dependent for Leptodactylus latrans tadpoles. • Sublethal exposure altered the enzymes of oxidative stress (GST and CAT). • Bti-AS was genotoxic because increased MN frequencies (CO: 0.82–2.74‰). • Bti-AS caused the inflammatory infiltration in the lamina propria of intestine.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ; ;  [1] ;  [2] ; ; ;  [3]
  1. National Council for Scientific and Technical Research (CONICET), Buenos Aires (Argentina)
  2. (FBCB-UNL), Ciudad Universitaria Paraje el Pozo s/n, 3000 Santa Fe (Argentina)
  3. Faculty of Biochemistry and Biological Sciences (FBCB-UNL), Ciudad Universitaria Paraje el Pozo s/n, 3000 Santa Fe (Argentina)
Publication Date:
OSTI Identifier:
22447568
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Research; Journal Volume: 136; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AMPHIBIANS; BACILLUS; BIOLOGICAL MARKERS; CARBON MONOXIDE; CATALASE; CONCENTRATION RATIO; ECOLOGICAL CONCENTRATION; ERYTHROCYTES; GLUTATHIONE; HAZARDS; HISTOLOGY; INFLAMMATION; INTESTINES; LARVAE; MAGNESIUM 40; MORTALITY; OXIDATION; SUSPENSIONS; TOXICITY; WASTE WATER