Toxicity of three pesticides, related formulations, metabolites and mixtures assessed by microtox system.

The toxicity of the insecticide Fenitrothion and two of its metabolites, 3- methyl-4-nitrophenol and 3-methyl-4-nitroanisole, and the herbicides Thiobe ncarb and Molinate, commonly used in rice fields near of Mediterranean Natu ral Parks, has been tested by using Microtox(TM) system. The 15 min EC50 va lues obtained with the marine luminiscent bacterium Vibrio fischeri showed that the Thiobencarb was the most toxic of the three pesticides with an EC5 0 of 0.03 mg/l. The toxic effects of some formulations and mixtures of the mentioned pesticides were also evaluated.