Combined endosulfan and cypermethrin-induced toxicity to embryo-larval development of Rhinella arenarum

GABRIELA SVARTZ; CAROLINA ARONZON; CRISTINA PÉREZ-COLL

JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2016 vol. 79 p. 197 - 209

1093-4529

The combined effects of two widely used pesticides, endosulfan and cypermethrin, on survival of embryo?larval development of the South American toad (Rhinella arenarum) were examined. The toxicity bioassays were performed according to the AMPHITOX test. Embryos and larvae wereexposed to mixtures of these pesticides at equitoxic ratios from acute or chronic exposure to evaluate interaction effects. The results were analyzed using both Marking?s additive index and combination index (CI)?isobologram methods. Acute (96-h) and intermediate (168-h) toxicity ofendosulfan?cypermethrin mixtures remained almost constant for larvae and embryos, but when exposure duration was increased, there was a significant elevation in toxicity, obtaining chronic (240-h) no-observed-effect concentrations (NOEC) values of 0.045 and 0.16 mg/L for embryos and larvae, respectively. These are environmentally relevant concentrations that reflect a realistic risk of this pesticide mixture to this native amphibian species. The toxicity increment with the exposure duration was coincident with the central nervous system development on embryos reaching the larval period, the main target organ of these pesticides. The interactions of the pesticide mixtures at acute and chronic exposure were antagonistic for embryo development (CI > 1), and additive (CI = 1) for larvae, while chronic exposure interactions were synergistic (CI < 1) for both developmental periods. Data indicated that endosulfan?cypermethrin mixtures resulted in different interaction types depending on duration and developmental stage exposed. As a generalpattern and considering conditions of overall developmental period and chronic exposure, this pesticide mixture usually applied in Argentine crop fields is synergistic with respect to toxicity for this native amphibian species.