There are no convincing data indicating possible in vivo genotoxic actions of the PCBs.
The dioxin-like PCB congeners presumably exert their toxic effects through a receptormediated
mechanism. At very low doses we presume these PCB congeners to show highly
non-linear dose-response relationships, i.e. virtual dose thresholds. We further presume
that the other, non-dioxin-like congeners exhibit threshold dose responses.