Individual and mixture toxicity of commercial formulations containing glyphosate, metsulfuron-methyl, bispyribac-sodium, and picloram on Rhinella arenarum tadpoles

LAJMANOVICH, R.C.,; C. JUNGES; ATTADEMO A.M.,; PELTZER P.,; CABAGNA ZENKLUSEN M.; BASSÓ A

WATER AIR AND SOIL POLLUTION

SPRINGER

Lugar: Berlin; Año: 2013 vol. 224 p. 1404 - 1415

0049-6979

We investigated the effects of four commercialformulations of herbicides (glyphosate [GLY],metsulfuron-methyl [MET], bispyribac-sodium [BIS],and picloram [PIC]) individually, and in three 50:50mixtures (GLY?MET, GLY?BIS, GLY?PIC) on thecommon toad Rhinella arenarum (Anura: Bufonidae)tadpoles. Enzymatic parameters such as, glutathioneS-transferase (GST), butyrylcholinesterase (BChE)and acetylcholinesterase (AChE) activities, as well aserythrocyte nuclear abnormalities (ENA) were studied.Interactions between herbicides in mixtures wereevaluated and classified as additive, synergistic, orantagonistic. Toxicity results (48-h LC50) showed thatPIC was the most toxic herbicide, followed by BIS,GLY, and MET, while GLY?PIC was the most toxicmixture, followed by GLY?BIS, and GLY?MET. Allcommercial herbicide formulations and their mixturessignificantly inhibited BChE activity in exposed tadpoles.The AChE activity was also inhibited by all herbicides and their mixtures, except by GLY?BIS. The inhibition of GST activity was onlysignificant for GLY, MET, PIC, and GLY?MET.A significant increase in the frequency of ENAwas found for tadpoles exposed either to commercialherbicide formulations or to mixtures, exceptfor GLY. All the mixtures showed synergism forBChE activity while for AChE only the GLY?MET and GLY?PIC mixtures acted synergistically.GLY?MET showed synergism for GST, whereasfor ENA, the mixture GLY?BIS was antagonistic.This study with R. arenarum tadpoles demonstratesthat the interactions between three of the mostintensively used herbicides in soybean cropsresults in synergistic effects on mortality and neurotoxicityand synergistic or additive effects ingenotoxicity.