Dieldrin cancellation

Dieldrin [60-57-1] or l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, Aro-5,8-dimethanonaphthalene (34) (mp 176°C, vp 0.4 mPa at 20°C) is formed from aldrin by epoxidation with peracetic or perben2oic acids. It is soluble in water to 27 / g/L. Aldrin and dieldrin have had extensive use as soil insecticides and for seed treatments. Dieldrin, which is very persistent, has had wide use to control migratory locusts, as a residual spray to control the Anopheles vectors of malaria, and to control tsetse flies. Because of environmental persistence and propensity for bio accumulation, registrations in the United States were canceled in 1974. 

Endrin was introduced in the United States in 1951 as an avicide, rodenticide and insecticide. Its principal use to control the cotton bollworm and tobacco budworm peaked in the early 1970s. In 1979, the EPA canceled some uses of endrin and indicated its intent to cancel all uses of endrin (EPA 1979f USDA 1995). By 1986, all uses were voluntarily canceled (Bishop 1984, 1985, 1986 EPA 1993e USDA 1995), except for its use as a toxicant on bird perches, which was canceled in 1991 (USDA 1995). Endrin also was a contaminant in dieldrin (Verschueren 1983) however, all uses of this pesticide have been canceled since the mid-1980s (EPA 1992b). Consequently, there are no longer any significant releases of endrin to the environment in the United States. 

In Hong Kong, the nine intentional POPs pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, HCB, mirex and toxaphene) targeted for global elimination or restricted production and use were not registered, or their registration status had been cancelled for many years due to toxicological or environmental concern. 

As mentioned earlier, registrations are for 15 years. However, the administrator of the EPA can cancel a registration or change the classification of the pesticide if he or she becomes aware of new data or other developments that would warrant such action. Because of the provisions, pesticide manufacturers must provide the EPA with any new adverse information. The use of many pesticides, including such insecticides as aldrin, chlordane, DDT, dieldrin, and heptachlor, has been cancelled or suspended. 

Table 6.3 shows penetration rates of four insecticides dimethoate, paraoxon, dieldrin, and DDT, through cockroach cuticle. It is seen that the rates of penetration are inversely related to their partition coefficient in the olive oil-water system. In other words, the compound with the best solubility in water, as indicated by its partition coefficient, moved through the cuticle most rapidly. In this experiment, the insecticides were applied to the cuticle as acetone solutions, and it was suggested by the authors that this may have neutralized or canceled any barrier presented by the epicuticle. Thus, the data indicate the... 

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