MODELING THE NUCLEOPHILIC REACTIVITY OF SMALL ORGANOCHLORINE ELECTROPHILES - A MECHANISTICALLY BASED QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP

Environmental pollutants can be divided into four broad categories, na rcosis-type chemicals, less inert (''polar narcosis'') chemicals, reac tive chemicals, and specifically acting chemicals. For narcosis-type, or baseline, chemicals and for less inert chemicals, adequate quantita tive structure-activity relationships (QSARs) are available for estima tion of toxicity to aquatic species. This is not the case for reactive chemicals and specifically acting chemicals. A possible approach to d evelop aquatic toxicity QSARs for reactive chemicals based on simple c onsiderations regarding their reactivity is given. It is shown that qu antum chemical calculations on reaction transition states can be used to quantitatively predict the reactivity of sets of reactive chemicals . These predictions can then be used to develop aquatic toxicity QSARs .