Toxicological characterization of the thermal decomposition products of chemicals: A new approach to an old problem

Different calorimetrie techniques coupled with chemical analyses and ecotoxicological bioassay led to the proposal of suitable protocol for the definition of a KPI (Key Process Index) useful to rank a compound in respect to the toxicological profile of its thermal decomposition products. Fenitrothion was used as example and showed to decompose through a seri es of two mai n processes, the first being less severe than the second. lt is demonstrated that similar ecotoxicological results can be gathered both using adiabatic and Isothermal conditions. This allows to exclude a priori the necessity of carrying out the more difficult and time and money consuming adiabatic experiments. The analytical characterization of the samples collected during a series of isoperibolic (quasi­ isothermal) experiments allowed to calculate, using the software ECOSAR, the toxicological profile of the intermediate compounds.