Aldrin and dieldrin: loss under sterile conditions.

After their application to sterile nutrient agar, both aldrin and dieldrin disappeared rather rapidly from the agar in glass-covered petri dishes. In most instances this disappearance was considerably retarded from agar inoculated with either fungi or bacteria. In the presence of microorganisms, aldrin was also epoxidized into dieldrin. Half of the applied aldrin volatilized from the agar during the first day of incubation; dieldrin volatilized more slowly and at a constant rate.