The mutagenic effects of organophosphorus pesticides on micro-organisms

Nine organophosphorus pesticides and twelve known chemical mutagens were applied to agar plate cultures ofEscherichia coli WP 2. After incubation, the cultures were examined for an increase in reverse mutation rate.Dicrotophos and dichlorvos, and four alkylating agents were tested against two mutant strains of Serratia marcescens using the paper disc technique.The organophosphorus pesticides did not increase the reversion rate inEscherichia coli WP 2. Dicrotophos was also negative when tested against Serratia marcescens. Dichlorvos induced a dose-related increase in reversion rate in both strains of Serratia marcescens.The significance of the results are discussed in relation to the rapid metabolism of dichlorvosin vivo and the absence of any mutagenic effect in mammalian test systems.