Epoxidation aldrin

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. 

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

Endosulfan Sulfate p,p -DDT -Endrin aldehyde p,p -DDD Endosulfan-ll Endrin p,p -DDE -Dieldrin Endosulfan-I Heptachlor epoxide Aldrin s-BHC Heptachlor BHC rBHC -a-BHC -... 

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. 

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. 

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]. 

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. 

Additions of mussel viscera from animals taken directly rom the ocean and from others held several days in Instant Ocean did not alter rat liver microsomal aldrin epoxidation. In other experiments, inhibition by tissue homogenates has been observed. Homogenates will continue to be screened against rat liver micro-somes until this uncertainty is resolved. Characterization of the inhibitory activity in the homogenates may provide leads for stabilization of the mussel preparations. 

Assay of Homogenate for Aldrin Epoxidation. The following experimental sequence was designed to determine the optimum in vitro conditions for aldrin epoxidation in larval whole body homogenates 1) the effect of component chemicals generally included in an incubation mixture, 2) a pH profile, 3) a temperature profile, 4) a molarity profile, 5) a reaction time profile, 6) a larval concentration (enzyme concentration) profile, 7) a substrate concentration profile, and 8) a restudy of the effects of component chemicals in the initial incubation mixture (Step 1) upon aldrin epoxidation under optimum conditions as defined by steps 2-7 above. The effect of PBO, FMN, and FAD upon enzyme activity was also tested. 

Assay of Subcellular Fractions for Aldrin Epoxidation. Mitochondrial and microsomal pellets were resuspended in Tris-HCl buffer. Each 5 ml incubation mixture contained the following ... 

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. 

Figure 1. Effect of pH on aldrin epoxidation by midge homogenate (mean of 2...

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). 

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). 

This epoxidation of AFB has been associated with aldrin epoxidase (AE) activity in trout (30). As with other epoxide carcinogens, OAFB may be a substrate 7or epoxide metabolizing enzyme systems such as epoxide hydrase (EH) (EC4.2.1.63) and glutathione-S-epoxide transferase (GTr) (EC4.4.1.7) found in mammals and fish (31, 32, 33, 34). AFB also undergoes a variety of other reactions, generally to less toxic metabolites depending on the species of animal involved (35, 36). The primary AFB metabolite in rainbow trout has been shown to be a reduced form of AFB, aflatoxicol (AFL) (24). 

In the case of insecticides, this oxidation converts the precursor to a product which is more toxic (e. g., the conversion of Heptachlor and Aldrin to epoxides). 

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. 

Synonyms AI3-16225 AIDS-166922 Aldrin epoxide Alvit Caswell No, 333 CCRIS 233 Compound 497 Dieldrine Dieldrite Dieldrix EINECS 200-484-5 ENT 16225 EPA pesticide chemical code 045001 HEOD (>85% active ingredient) Hexachloroepoxyoctahydro-e/3c/o,eYO-diethanonaphthalene l,2,3,4,10,10-Hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8a-octahydro-l,4-... 

Park. K.S. and Brace, W.N. The determination of the water solubility of aldrin, dieldrin, heptachlor, and heptachlor epoxide. J. Econ. Entomol, 61(3) 770-774, 1968. 

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