Epoxide dieldrin

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 [72-20-8] is l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, <7o-5,8-dimethanonaphthalene (35) (mp 245 dec, vp 0.022 mPa at 25°C) and is soluble in water to 23 / g/L. It is produced by a Diels-Alder reaction of hexachloronorbomadiene with cyclopentadiene, followed by epoxidation. This reaction produces the endo,endo isomer of dieldrin, which is less stable and more toxic with rat LD q values of 17.8 and 7.5 (oral) and 15 (dermal) mg/kg. It is used as a cotton insecticide but because of its high toxicity to fish it has been restricted. 

Musial CJ, Peach ME, Stiles DA. 1976. A simple procedure for the confirmation of residues of alpha-and beta-endosulfan, dieldrin, endrin, and heptachlor epoxide. Bull Environ Contam Toxicol 16 98-100. 

Thus, as with studies on the double-crested cormorant in the Great Lakes (see Chapter 16 in Walker et al. 2006), there is evidence of a continuing (although reduced) effect of p,p -DDE on reproductive success even after environmental levels had fallen and eggshell thinning was much less. This raises the possibility that p,p -DDE may have had toxic effects other than eggshell thinning on these species (Nisbet 1989). There is the further complication that other OCs such as PCBs, dieldrin, and hep-tachlor epoxide were present in the same samples and may have had toxic effects. 

As mentioned earlier (Figure 5.5), aldrin and heptachlor are rapidly metabolized to their respective epoxides (i.e., dieldrin and heptachlor epoxide) by most vertebrate species. These two stable toxic compounds are the most important residues of the three insecticides found in terrestrial or aquatic food chains. In soils and sediments, aldrin and heptachlor are epoxidized relatively slowly and, in contrast to the situation in biota, may reach significant levels (note, however, the difference between aldrin and dieldrin half-lives in soil shown in Table 5.8). The important point is that, after entering the food chain, they are quickly converted to their epoxides, which become the dominant residues. 

In one example (Lawrence and Casida 1984, Abalis et al. 1985) rat brain microsacs were used to test the action of cyclodiene insecticides such as dieldrin and endrin on the GABA receptors contained therein. The influx of radiolabeled CL into the microsacs via the pore channel of the receptor was inhibited by these chemicals. A similar assay was developed using microsacs from cockroach nerve. Assays with this preparation showed again the inhibitory effect of a cyclodiene (this time heptachlor epoxide) on CL influx. Also, that microsacs from cyclodiene resistant cockroaches were insensitive to the inhibitory effect of picrotoxinin, which binds to the same site on the GABA receptor (Kadous et al. 1983). 

The insecticide heptachlor oxidizes in the soil, and becomes a more toxic epoxide, capable of remaining for a long time. The insecticide aldrin transforms in the soil into dieldrin, maintaining its toxicity [15, 30]. Mirex (FDso=300-600 mg/kg), used to fight ants, just like kelevan (FDS0=255-325 mg/kg), used to fight the Colorado beetle, transform in the soil into the more toxic chlordekon (FD50 decreases to 95-140 mg/kg) [30]. 

The procedure described by Suzuki et al. [11, 12], discussed in section 9.1.1.1 for the determination of chlorinated insecticides in soils has also been applied to hexane extracts of river sediments using high-resolution gas chromatography with glass capillary columns. Minimum detectable levels of a-BHC, fs-BHC, -BHC, P-BHC, Heptachlor, Heptachlor epoxide, Aldrin, Dieldrin, Endrin, p,p -DDE, p,p -TDE and p,p -DDT in lOOg samples of bottom sediment were 0.0005, 0.0032, 0.0014, 0.0040, 0.0012, 0.0020, 0.0014, 0.0020, 0.0056, 0.0032, 0.0080 and 0.0120mg kgr1 respectively. 

Endrin is a stereoisomer of dieldrin produced by the reaction of vinyl chloride and hexachloro-cyclopentadiene to yield a product which is then dehydrochlorinated and condensed with cyclopentadiene to produce isodrin. This intermediate is then epoxidized with peracetic or perbenzoic acid to yield endrin. An alternative production method involves condensation of hexachlorocyclopentadiene with acetylene to yield the intermediate for condensation with cyclopentadiene (EPA 1985e IARC 1974). 

Savage EP, Keefe TJ, Tessari JD, et al. 1981. National study of chlorinated hydrocarbon insecticide residues in human milk, USA I. Geographic distribution of dieldrin, heptachlor, heptachlor epoxide, chlordane, oxychlordane, and mirex. Am J Epidemiol 113(4) 413-422. 

Chemicals. Antipyrine, carbon monoxide (Matheson, Coleman and Bell, Los Angeles, CA), and 1 CH3-N-antipyrine (11.1 mCi/mM, ICN, Irvine, CA) were purchased. Aldrin (1,8,9,10,11,11-hexa-chloro-2,3-7,6-endo-2,1-7,8-exo-tetracyclo (6.2.1.13,6.02 7) dodeca-A,9-diene) and its epoxide, dieldrin were gifts of Shell Development Co. (Modesto, CA). Each was recrystallized from methanol-water solutions and was greater than 99% pure as determined by gas chromatography. l CH30-p-Nitroanisole (1.9 mCi/mmole) was synthesized (1A) and 3H-benzo(a)pyrene (8.3 Ci/ mmole) was purchased (Amersham-Searle Co., Arlington Heights,... 

During a 30 minute incubation period, low levels of aldrin epoxidation (30-150 picomoles dieldrin/mg protein) were measured compared to those observed using enzyme sources such as aquatic Trichoptera Limnephilus sp. gut homogenates (1 pmole/mg protein 28) or rat liver homogenates (3000 pmoles/mg protein unpublished) under similar incubation conditions. Anisole metabolism based upon substrate disappearance was detectable but less than 5 picomoles/mg protein were transformed during the incubation period. Characteristics of the enzyme system are incompletely described owing to the low and variable levels of activity which have been obtained. 

Establishing Optima for Aldrin Epoxidation Using Whole Body Homogenates. The addition of all component chemicals increased dieldrin production greater than 3X compared to the unmodified homogenate (Table IV). As the optimum of each factor was established, it was used in all subsequent experiments. 

Dieldrin accumulated in proportion to incubation time during the first 30 min and declined thereafter, like the biphasic curves for aldrin epoxidation in other insects (11, 26). The rate curve declined continuously to 50% of maximum after 60 min of incubation at 30°C. BSA did not increase epoxidase activity in 15 min incubations (Table V) or 60 min incubations (Table IV). Consequently, reduced epoxidase activity is probably not due to endogenous proteases in the homogenate (1). 

Midge larvae rapidly accumulate aldrin or dieldrin and readily epoxidize aldrin to dieldrin without further conversion. 

For example, diethylamine sensitizes the photodegradation of DDT to yield DDE, TDE, dichlorobenzophenone, and two other unidentified compounds (6).. These reactions are thought to involve a charge transfer from the amine to DDT. Similarly, rotenone is highly effective in enhancing the photochemical alteration of dieldrin to photodieldrin ( 7). Rotenone also catalyzes the photochemical alteration of aldrin, isodrin, endrin, heptachlor, and heptachlor epoxide but it is less effective or ineffective with DDT, DDE, lindane, and endosulfan (7, 8). 

The decrease in cytochrome P-450 content correlated with a lowering of trout AE activity observed in hepatic microsomes recovered from fish fed high levels of casein, versus those from fish fed low casein diets. As shown in Table III, up to a 32% decrease in the production of the epoxide dieldrin was noted. Similar results have been observed in 10 month old rainbow trout with a nearly identical maximum decrease (unpublished data). Since AFB activation has been shown to involve a cytochrome P-450 dependent enzyme system (19, 20, 22) and trout... 

Our final (and contrasting) examples are dieldrin (10.135) and endrin (10.136), two isomeric polychlorinated insecticides that contain exo-epoxide... 

Heptachlor is formed through the metabolism of chlordane. Heptachlor epoxide is formed through the epoxidation of heptachlor and has been shown to be a cosubstrate of the same enzyme responsible for the epoxidation of aldrin to dieldrin (Gillett and Chan 1968). Heptachlor epoxide is considered more toxic than its parent compound and, like heptachlor, is primarily stored in adipose tissue (Barquet et al. 1981 Burns 1974 Greer etal. 1980 Harradine and McDougall 1986). 

Since the metabolized form of heptachlor, heptachlor epoxide, is the most toxic, it may be possible to reduce the toxic effects of heptachlor by inhibiting the enzyme catalyzing this conversion. This is the same enzyme that catalyzes the epoxidation of aldrin to dieldrin (Gillett and Chan 1968). Further research into the specificity of this enzyme, drugs that could inhibit the enzyme, and any side effects of these drugs could help to determine the feasibility of such a treatment strategy. 

Gannon N and Decker GC. 1960. The excretion of dieldrin, DDT, and heptachlor epoxide in milk of dairy cows fed on pastures treated with dieldrin, DDT, and heptachlor. J Econ Entomol 53(3) 411-415. 

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