Nickel toxicity in embryos and larvae of the South American toad: Effects on cell differentiation, morphogenesis, and oxygen consumption.

SZTRUM, A A, D´ERAMO, JL, AND HERKOVITS, J.

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Año: 2011 vol. 30 p. 1146 - 1152

0730-7268

Abstract—Nickel, a widely distributed heavy metal in the biosphere, produces systemic, carcinogenic, and teratogenic effects. Theobjectives of the present study are to report the acute, short-term chronic, and chronic toxicity of Ni in Rhinella arenarum embryos aswell as the stage-dependent susceptibility to this heavy metal, including oxygen consumption, teratogenesis, and adverse effects on celldifferentiation processes. The stages evaluated were blastula (S.7), gastrula (S.11), tail bud (S.17), fin circulation (S.22), and completeoperculum (S.25), in this last case by means of toxicity profile curves. Nickel increases its adverse effects gradually, with a maximumvalue after 96 h. The 50% lethal concentrations (LC50s) for 96, 168, and 240 h at S.25 were 1.14, 0.60, and 0.48 mg Ni2þ/L, respectively;S.11 and S.22 were the least and most susceptible to Ni with, LC50s 96 h of 6.12 and 0.19 mg Ni2þ/L, respectively. A reduction ofapproximately 25% in oxygen consumption anticipates lethal effects from S.17 onward. The main teratogenic effects were retardedgrowth and development, extremely severe axis incurvations, persistent yolk plug, asymmetry, microcephaly and mouth and gillagenesia, and limited neuromuscular activity. Ciliated cells were not functional. The possibility of associating the remarkablestage-dependent susceptibility to Ni with environmental changes during the evolutionary process is also considered. Environ. Toxicol.Chem. 2011;30:xxx–xxx. # 2011 SETAC