Glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. Its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. Ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based herbicides (GBHs) residues. Previous studies on larval anuran species highlighted increased mortality and growth effects after exposure to different GBHs in comparison to glyphosate itself, mainly because of the surfactants such as polyethoxylated tallow amine present in the formulations. Nevertheless, these conclusions are not completely fulfilled when the early development, characterized by primary organogenesis events, is considered. In this study, we compare the embryotoxicity of Roundup® Power 2.0, a new GBH formulation currently authorized in Italy, with that of technical grade glyphosate using the Frog Embryo Teratogenesis Assay–Xenopus (FETAX). Our results evidenced that glyphosate was not embryolethal and only at the highest concentration (50 mg a.e./L) caused edemas. Conversely, Roundup® Power 2.0 exhibited a 96 h LC50 of 24.78 mg a.e./L and a 96 h EC50 of 7.8 mg a.e./L. A Teratogenic Index of 3.4 was derived, pointing out the high teratogenic potential of the Roundup® Power 2.0. Specific concentration-dependent abnormal phenotypes, such as craniofacial alterations, microphthalmia, narrow eyes and forebrain regionalization defects were evidenced by gross malformation screening and histopathological analysis. These phenotypes are coherent with those evidenced in Xenopus laevis embryos injected with glyphosate, allowing us to hypothesize that the teratogenicity observed for Roundup® Power 2.0 may be related to the improved efficacy in delivering glyphosate to cells, guaranteed by the specific surfactant formulation. In conclusion, the differences in GBH formulations should be carefully considered by the authorities, since sub-lethal and/or long-term effects (e.g. teratogenicity) can be significantly modulated by the active ingredient salt type and concentration of the adjuvants. Finally, the mechanistic toxicity of glyphosate and GBHs are worthy of further research.

Bonfanti, P., Saibene, M., Bacchetta, R., Mantecca, P., Colombo, A. (2018). A glyphosate micro-emulsion formulation displays teratogenicity in Xenopus laevis. AQUATIC TOXICOLOGY, 195, 103-113 [10.1016/j.aquatox.2017.12.007].

A glyphosate micro-emulsion formulation displays teratogenicity in Xenopus laevis

Bonfanti, P
Primo
;
Saibene, M
Membro del Collaboration Group
;
Bacchetta, R
Membro del Collaboration Group
;
Mantecca, P
Membro del Collaboration Group
;
Colombo, A
Ultimo
Membro del Collaboration Group
2018

Abstract

Glyphosate is the active ingredient in broad-spectrum herbicide formulations used in agriculture, domestic area and aquatic weed control worldwide. Its market is growing steadily concurrently with the cultivation of glyphosate-tolerant transgenic crops and emergence of weeds less sensitive to glyphosate. Ephemeral and lentic waters near to agricultural lands, representing favorite habitats for amphibian reproduction and early life-stage development, may thus be contaminated by glyphosate based herbicides (GBHs) residues. Previous studies on larval anuran species highlighted increased mortality and growth effects after exposure to different GBHs in comparison to glyphosate itself, mainly because of the surfactants such as polyethoxylated tallow amine present in the formulations. Nevertheless, these conclusions are not completely fulfilled when the early development, characterized by primary organogenesis events, is considered. In this study, we compare the embryotoxicity of Roundup® Power 2.0, a new GBH formulation currently authorized in Italy, with that of technical grade glyphosate using the Frog Embryo Teratogenesis Assay–Xenopus (FETAX). Our results evidenced that glyphosate was not embryolethal and only at the highest concentration (50 mg a.e./L) caused edemas. Conversely, Roundup® Power 2.0 exhibited a 96 h LC50 of 24.78 mg a.e./L and a 96 h EC50 of 7.8 mg a.e./L. A Teratogenic Index of 3.4 was derived, pointing out the high teratogenic potential of the Roundup® Power 2.0. Specific concentration-dependent abnormal phenotypes, such as craniofacial alterations, microphthalmia, narrow eyes and forebrain regionalization defects were evidenced by gross malformation screening and histopathological analysis. These phenotypes are coherent with those evidenced in Xenopus laevis embryos injected with glyphosate, allowing us to hypothesize that the teratogenicity observed for Roundup® Power 2.0 may be related to the improved efficacy in delivering glyphosate to cells, guaranteed by the specific surfactant formulation. In conclusion, the differences in GBH formulations should be carefully considered by the authorities, since sub-lethal and/or long-term effects (e.g. teratogenicity) can be significantly modulated by the active ingredient salt type and concentration of the adjuvants. Finally, the mechanistic toxicity of glyphosate and GBHs are worthy of further research.
Articolo in rivista - Articolo scientifico
Developmental toxicity; Fetax; GBHs; Roundup; Teratogenicity; Xenopus laevis;
Developmental toxicity; Fetax; GBHs; Roundup; Teratogenicity; Xenopus laevis; Aquatic Science; Health, Toxicology and Mutagenesis
English
24-dic-2017
2018
195
103
113
partially_open
Bonfanti, P., Saibene, M., Bacchetta, R., Mantecca, P., Colombo, A. (2018). A glyphosate micro-emulsion formulation displays teratogenicity in Xenopus laevis. AQUATIC TOXICOLOGY, 195, 103-113 [10.1016/j.aquatox.2017.12.007].
File in questo prodotto:
File Dimensione Formato  
Bonfanti-2018-Aquatic Toxicol-VoR.pdf

Solo gestori archivio

Descrizione: Research Article
Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 1.1 MB
Formato Adobe PDF
1.1 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Bonfanti-2018-Aquatic Toxicol-AAM.pdf

accesso aperto

Descrizione: Research Article
Tipologia di allegato: Author’s Accepted Manuscript, AAM (Post-print)
Dimensione 1.01 MB
Formato Adobe PDF
1.01 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/182794
Citazioni
  • Scopus 40
  • ???jsp.display-item.citation.isi??? 38
Social impact