Abstract
The organochlorine pesticides chlordane and heptachlor were evaluated for their genotoxicity and epigenetic membrane effects. Both compounds were non-genotoxic in the ARL-HGPRT mutagenesis assay in which the genotoxic carcinogens 7,12-dimethylbenz[a]anthracene and benzo[a]pyrene induced significant increases in mutant incidence. The pesticides both markedly inhibited intercellular communication between cultured liver cells, a property demonstrated by many tumor promoting agents, whereas benzo[a]pyrene did not produce this epigenetic effect.