Chemical name: 1,3,4-Metheno-1H-cyclobuta[cd]pentalene, 1,1a,2,2,3,3a,4,5,5,5a,5b,6-dodecachlorooctahydro-

Final regulatory action has been taken for the category: Industrial

Final regulatory action: The chemical is Severely Restricted

Use or uses prohibited by the final regulatory action:

All uses other than those specified below are prohibited.

Use or uses that remain allowed:

For use in a laboratory for scientific research purposes or as a laboratory analytical standard.

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

The Prohibition of Certain Toxic Substances Regulations, 2005 prohibit the manufacture, use, sale, offer for sale and import of toxic substances listed in Schedules 1 and 2 to the Regulations. Mirex is found in Schedule 1, which lists prohibited toxic substances subject to total prohibition, with the exception of incidental presence.

The reasons for the final regulatory action were relevant to: Human health

Summary of known hazards and risks to human health:

In humans, mirex is stored mainly in fat tissue, where it is not broken down. Mirex has been demonstrated to cause cancer in experimental animals and possibly carcinogenic to humans.

Expected effect of the final regulatory action in relation to human health:

-

Summary of known hazards and risks to the environment:

Quantitative information describing the persistence of mirex is limited. However, the available information consistently indicates that the substance is persistent in the environment. For example, 12 years after its application to a clay soil, 50% of the mirex originally applied was recovered as mirex and mirex-related compounds with mirex representing between 65-70% of the total residues. Mirex decomposition in the environment takes place chiefly by photolysis. Anaerobic decomposition by microorganisms can occur, but it is not extensive. Mirex is also recognized to be subject to long-range transport and has been demonstrated to persist in sediment. On the basis of the available information, it was concluded that mirex is persistent in the environment.

Mirex can accumulate in living tissues. In experimental work with aquatic organisms, all species at all trophic levels have been found to accumulate this substance. Bioaccumulation factors of 15,000 and 51,000 have been observed in lake trout captured in Lake Ontario and fathead minnows. A comparison of concentrations of mirex in lake trout, a predator species, with those in smelt, a prey species, gives a ratio of 1.26, indicating that biomagnification is occurring. A biomagnification factor of 108 for mirex between its concentration in water of Lake Ontario and the St. Lawrence River and in beluga whale oil has been reported.

In experimental studies with birds mirex has been shown to accumulate particularly in fatty tissues. A study showed that mirex fed to roosters accumulated to about 100 times the concentration in the feed in thirty-two weeks. When the roosters were given clean food the mirex residues slowly decreased. Similar studies were conducted on mammals with similar findings. On the basis of the available information, it was concluded that mirex is a bioaccumulative substance.

Date of entry into force of the final regulatory action: 15/05/2005