Mirex. By: Peta Walker. Structure. Molecular formula : C 10 Cl 12 Chemical name : 1,1a,2,2,3,3a,4,5,5,5a,5b,6-dodeca- chloroocta-hydro-1,3,4-metheno-1H- cyclobuta[ cd]pentalene. Physical and Chemical Properties.
By: Peta Walker
First synthesized in 1946 by Prins but was not used in pesticide formulations until 1955.
Made by the dimerization of hexachlorocyclopentadiene in the presence of aluminum chloride.
In 1976 the EPA ordered a phasing out of the use of mirex for pest control and brought in a ban with exemptions on June 30, 1978.Production History
Activities associated with the disposition of residual pesticides.
Direct use as a pesticide.
Most likely to enter surface waters as a result of soil runoff.
Strongly adsorbed on sediments in aquatic systems.Mode of Entry in Aquatic Environment
Biomagnification of mirex is supported by a study of various aquatic organisms that comprise an aquatic food chain in Lake Ontario (Oliver and Niimi 1988). The following concentrations (+ standard deviation) of mirex were found:Biomagnification of Mirex
Mirex is a neurotoxic compound. It disrupts the normal transmission of impulses along nerves and across synapses.
Mirex is a GABA (gamma-aminobutyric acid) antagonist. It binds to GABA receptors, reducing the flow of Cl- ions.
Results in convulsions.
Toxicity increases with increasing ambient temperature.Molecular Mode of Toxic Interaction
Mirex is one of the most stable and persistent organochlorine compounds known.
It is resistant to chemical, photolytic, microbial, metabolic, and thermal degradation processes.
Degradation products include hexachlorobenzene, hexachlorocyclopentadiene, and kepone.Biochemical Metabolism and Breakdown