Toxicity of four herbicide formulations with glyphosate on Rhinella arenarum (anura: bufonidae) tadpoles: B-esterases and glutathione S-transferase inhibitors.
In this study, amphibian tadpoles Rhinella arenarum were exposed to different concentrations of Roundup Ultra-Max (ULT), Infosato (INF), Glifoglex, and C-K YUYOS FAV. Tadpoles were exposed to these commercial formulations with glyphosate (CF-GLY) at the following concentrations (acid equivalent [ae]): 0 (control), 1.85, 3.75, 7.5, 15, 30, 60, 120, and 240 mg ae/L for 6-48 h (short-term). Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carboxylesterase (CbE), and glutathione S-transferase (GST) activities were measured among tadpoles sampled from those treatments that displayed survival rates >85%. Forty-eight-hour LC(50) for R. arenarum tadpoles exposed to CF-GLY in the static tests ranged from ULT = 2.42 to FAV = 77.52 mg ae/L. For all CF-GLY, the LC(50) values stabilized at 24 h of exposure. Tadpoles exposed to all CF-GLY concentrations at 48 h showed decreases in the activities of AChE (control = 17.50 ± 2.23 nmol/min/mg/protein; maximum inhibition INF 30 mg ae/L, 71.52%), BChE (control = 6.31 ± 0.86 nmol/min/mg/protein; maximum inhibition INF 15 mg ae/L, 78.84%), CbE (control = 4.39 ± 0.46 nmol/min/mg/protein; maximum inhibition INF 15 mg ae/L, 81.18%), and GST (control = 4.86 ± 0.49 nmol/min/mg/protein; maximum inhibition INF 1.87 mg ae/L, 86.12%). These results indicate that CF-GLY produce a wide range of toxicities and that all enzymatic parameters tested may be good early indicators of herbicide contamination in R. arenarum tadpoles.
Lajmanovich
Rafael C
RC
Faculty of Biochemistry and Biologic Sciences, National Council for Scientific and Technical Research, FBCB-UNL, Paraje el Pozo s/n (3000), Santa Fe, Argentina. lajmanovich@hotmail.com
Attademo
Andrés M
AM
Peltzer
Paola M
PM
Junges
Celina M
CM
Cabagna
Mariana C
MC
D000704:Analysis of Variance; D000818:Animals; D002025:Bufonidae; D043182:Carboxylesterase / Q000037:antagonists & inhibitors*; D004784:Environmental Monitoring / Q000379:methods*; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors*; D006540:Herbicides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D007928:Lethal Dose 50; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D006540:Herbicides; D014874:Water Pollutants, Chemical; D005982:Glutathione Transferase; D043182:Carboxylesterase