ACUTE TOXICITY OF 2 CARBAMATES TO THE GUPPY (POECILIA-RETICULATA) ANDTHE ZEBRAFISH (BRACHYDANIO-RERIO)

In this study the acute toxicity of two carbamate pesticides, Carbaryl and Aldicarb, to the Guppy and the Zebrafish has been separately asse ssed with 96-h toxicity tests, performed using a semistatic procedure according to EEC guidelines. There was no significant difference in th e toxicity of Aldicarb and Carbaryl to the Zebrafish, but Aldicarb was similar to 4 times more toxic than Carbaryl to the Guppy. Moreover, t he toxicity of both carbamates was higher to the Guppy than to the Zeb rafish. Values for the 96-h LC50 obtained with Aldicarb were 52.9 mu m ol/l for the Zebrafish and 3.5 mu mol/l for the Guppy. LC50 values obt ained with Carbaryl were 46.0 mu mol/l for the Zebrafish and 12.5 mu m ol/l for the Guppy. Analysis of test substance concentrations in the t est system demonstrated, for each substance, a loss during each 24-h e xposure period. In spite of the variability observed, the losses of Ca rbaryl appeared independent of time, whereas the losses of Aldicarb we re higher during the initial exposure days. In addition, there was an indication that the rate of loss observed with both substances was gre ater in the presence of the Guppy than in the presence of the Zebrafis h.