Sublethal effects of atrazine to embryo-larval development of Rhinella arenarum (Anura: Bufonidae).

SVARTZ, G. V., HERKOVITS J*,. PÉREZ-COLL2 C S (* CORRESPONDING AUTHOR)

ECOTOXICOLOGY

SPRINGER

Lugar: ). Ecotoxicology 2012 May;21(4):1251-9 ; Año: 2012 vol. 21 p. 1251 - 1259

0963-9292

Abstract Atrazine (ATR), one of the most widely used herbicides in the world, affects not only target organisms but also the biota in general. Here, the teratogenic and neurotoxic effects of ATR on Rhinella arenarum (South American toad) embryos and larvae were evaluated by means of standardized bioassays during acute and chronic exposures. The herbicide had a significant incidence of malformations, with a Teratogenic Index (TI) of 3.28. The main effects were delayed development, reduced body size, microcephaly, axial flexures, wavy tail and edema. In addition, delayed development, reduced development of forelimbs, and edema were recorded at metamorphosis stages. Scanning electron microscopy allowed observing different degrees of cellular dissociation and persistent cilliar cells in specific regions like the adhesive structure and tail fin. Results obtained by ATR 24-h pulse exposures at six developmental stages pointed out blastula as the most susceptible developmental stage both for immediate and delayed adverse effects. A noteworthy recovery capacity from acute toxic effects was recorded from the neural plate stage onwards. Regarding neurotoxic effects, abnormal and erratic swimming and spasmodic contractions were recorded. Both the teratogenic and neurotoxic effects reported in this study demonstrate the importance of evaluating sublethal effects in non-target organisms as they could imply reduced fitness of individuals and eventually a population decline. The Hazard Quotients (HQ) for ATR ranged from 0.14 to 10.80, being some of these values above USEPA’s level of concern, indicating that ATR is a likely potential risk for Rhinella arenarum.