Toxicidad aguda por plata en Cnesterodon decemmaculatus (Pisces) y aplicación del Modelo del ligando biótico en agua del río Pilcomayo

CASARES, MV.; DE CABO, L.; SEOANE, R. Y NATALE, O.

Tandil

Congreso; XVII Congreso Argentino de Toxicología; 2011

Asociación Toxicologica Argentina

  A 96 h acute silver toxicity test was performed in order to determine silver toxicity (LC50) to a local fish species (Cnesterodon decemmaculatus) in a surface water with elevated hardness (Pilcomayo River water, South America)    and evaluate a cross-fish-species extrapolation of Biotic Ligand Model. The dissolved silver concentrations tested were 0.095, 0.148, 0.175 and 0.285 mg Ag L−1. The 96 h Ag LC50 calculated for C. decemmaculatus was 0.14 mg L−1 (0.18 - 0.10)  and the value predicted by BLM for Pimephales promelas was 0.051 mg Ag L−1. Test water elevated hardness may have exerted some protective effect. High mean water pH may have exerted a major protective effect by reducing silver free ion form and causing silver precipiation. The mortality pattern observed in this toxicity test may lend some support to a relationship between gill silver accumulation and mortality. A cross-fish-species extrapolation of the P. promelas Ag BLM was not valid in Pilcomayo River water and experimental conditions of this toxicity test.