Technical Toxaphene Research Articles

Prominent chlorobornane residues in estuarine sediments contaminated with toxaphene

Soils and sediments contaminated with residues of technical toxaphene may require remedial action to reduce human health and ecological risks. Sediments were collected from a coastal wetland impacted by discharge from a former toxaphene production facility and analyzed by gas chromatography-electron capture detection and conventional and enantioselective gas chromatography-mass spectrometry in the electron capture negative ion mode. The prominent chlorobornanes (CHBs) in all samples were 2-exo,3-endo,6-exo,8,9,10-hexachlorobornane (B6-923 or Hx-Sed) and 2-endo,3-exo,5-endo,6-exo,8,9,10-heptachlorobornane (B7-1001 or Hp-Sed), metabolites of higher chlorinated components of technical toxaphene (CTTs). Pentachlorobornanes, toxaphene homologs not previously reported in environmental samples, and likely precursor CTTs were also detected. Several CHB congeners were enantioresolved, the majority of which exhibited racemic composition. These results indicate that the profile of CHBs persisting in estuarine sediment is highly modified relative to the technical mixture, and also provides strong evidence of in situ reductive dechlorination, a process that if enhanced could act to reduce bioaccumulation and toxicity of sediment-bound CTTs at toxaphene-contaminated sites.

Liquid chromatographic profiles of individual compounds of technical toxaphene

The elution orders of 20 hexa- to nonachlorobornanes and five hexa- to octachlorocamphenes were studied with normal-phase silica and amino phase HPLC, reversed-phase HPLC, as well as gel-permeation chromatography (GPC). Twenty-one compounds of technical toxaphene (CTTs) are commercially available and four were isolated from environmental samples. Structure-activity relationships and chromatographic properties were deduced from the data sets derived on these LC systems. The retention on silica (low-resolution LC and HPLC) increased with the polarity of the CTTs. The elution order of CTTs on amino normal-phase HPLC was, for the most part, the same as on silica normal-phase HPLC. The degree of chlorination determined the elution order of CTTs on C 18 RP-HPLC. CTTs eluted from medium-pressure GPC with decreasing molecular size. Chlorobornanes with dichloro substituents on the six-membered ring eluted after the chlorobornanes without geminal chlorine atoms on secondary carbons, indicating that these congeners are larger. Altogether, the results increase the knowledge of complex substance class and may serve as a tool in order to gain further standard components.

FTIR Spectroscopic Characterization of Chlorinated Camphenes and Bornenes in Technical Toxaphene

The unsaturated C10-components and their amounts in technical toxaphene have been characterized with the help of column chromatography/FTIR spectroscopy using the typical absorption bands of the >C...

Discrimination and thermal degradation of toxaphene compounds in capillary gas chromatography when using split/splitless and on-column injection

Technical toxaphene and a 22-component Reference Mixture were analyzed using capillary gas chromatography with split/splitless injection (SSL) and on-column injection (OC). In both techniques, electron-capture, negative ionization mass spectrometry (ECNI-MS) was used for detection of chlorobornanes, chlorocamphenes and related compounds. Significant discrimination of highly chlorinated congeners was observed as a result of incomplete transfer of these compounds from the vaporizer to the analytical column when using SSL. This resulted in a much lower response for nona- and decachloro congeners than when using OC. In addition, several toxaphene components, especially the chlorobornanes with gem dichloro substitution on the six-member carbon ring, undergo thermal degradation when using SSL. Some of these congeners are major components of technical toxaphene, but generally are not present, except at low concentrations, in environmental and biological samples. Therefore, technical toxaphene may be discriminated and/or degraded differently than toxaphene compounds in environmental samples when using SSL. This results in significant bias of the quantitative data when using the technical material as a reference. OC suffers much less from these deficiencies and, therefore, is a preferable technique for toxaphene analysis.

The determination of toxaphene in environmental samples by negative ion electron capture high resolution mass spectrometry

A method is described for the analysis of toxaphene in environmental samples by high resolution gas chromatography high resolution mass spectrometry in selected ion electron capture negative ion mode. Toxaphene is detected by monitoring [M–Cl] −fragments ions of chlorobornanes (Cl 6–Cl 10) and chlorobornenes (Cl 6–Cl 7) using formal ion ratio criteria. The method shows high sensitivity and excellent specificity for the detection of chlorobornanes with negligible interference from of a wide range of common environmental organochlorines including chlordanes, PCBs and PCB-oxygen adducts. The analytical scheme is applicable to sediment and biological tissue samples and typically provide sample detection limits of less than 0.2 ng/g technical toxaphene for a 10 g sample.

Temperature dependent Henry’s law constant for technical toxaphene

Toxaphene is an abundant organochlorine (OC) pesticide in Great Lakes and Arctic ecosystems and the Henry's Law constant (HLC, Pa m3/mol) is a critical factor in describing its gas exchange between air and water. The HLCs for technical toxaphene and two hexachlorocyclohexane (HCHs) isomers (α- and γ-HCH) were determined by the gas stripping method over a temperature range of 10–40°C. The relationship to temperature (K) was described by logH=m/T+b. Parameters of this equation were: toxaphene m=−3209, b=10.42; α-HCH m=−3298, b=10.88; γ-HCH m=−3005 and b=9.51. The HLCs (Pa m3/mol) at 293.15 K were: toxaphene=0.30, α-HCH=0.43 and γ-HCH=0.18.

Rapid anaerobic degradation of toxaphene in sewage sludge

We studied the degradation of technical toxaphene in anaerobic sewage sludge from a municipal waste water treatment plant. Chlorobornanes, chlorocamphenes and related compounds were rapidly degraded, with degradation rates in the order of decachloro>nonachloro>octochloro>heptachloro≈hexachloro compounds. The half-lives of individual congeners ranged from <1 day to several days. We also studied the degradation of technical toxaphene in previously sterilized sludge (control), and found it was slower than in the anaerobic sludge. The chlorobornanes that degraded most rapidly in the non-sterilized anaerobic sludge were those with gem chloro substitution on the 6-member carbon-ring, including the toxic congeners, Toxicant A and B. Non-gem chloro substituted congeners, like the biologically persistent P26 and P50, also degraded, but less rapidly. Toxaphene degradation in sewage sludge proceeded primarily via reductive dechlorination, leading to HxSed, HpSed, TC2 and other persistent metabolites. Enantioselective determinations indicated little, if any, enantioselectivity in the formation and/or degradation of these compounds. The isomer and enantiomer profiles of the hexa-, hepta-, and octachlorobornanes are similar to those observed in sediment from the Baltic Sea, suggesting that technical toxaphene is the source of these compounds and that its composition was changed via similar anaerobic degradation pathways.

Studies of toxaphene in technical standard and extracts of background air samples (Point Petre, Ontario) using multidimensional gas chromatography–electron capture detection (MDGC–ECD)

MDGC–ECD procedures have been used to provide insight into the compositional complexity of some of the specific peaks or clusters observed in the gas chromatographic analysis of a technical toxaphene standard, with reference to individual toxaphene congeners (Parlar # components) that are now commercially available. These investigations have focussed initially upon those peaks and clusters recently identified (Shoeib, M., Brice, K.A., Hoff, R., 1999. Chemosphere 39, 849–871) as dominant constituents of background ambient air. Multiple electron-capturing components have been found to be present in all the species studied: the available individual toxaphene congeners have been matched against these components where possible. In similar fashion, the responses obtained in equivalent gas chromatographic elution windows from the analysis of typical processed air sample extracts have been investigated, with the results showing clear differences relative to the patterns found in the technical toxaphene standard. In most cases, the air sample shows reduced complexity with fewer components present in the cluster. Also, the presence of interfering responses (due to PCBs and other organochlorines) is quite apparent and significant, showing that major problems and errors could arise when using single-column GC–ECD procedures for quantitation of toxaphene in environmental samples. The presence of certain of the Parlar species in the air samples has been confirmed and in most cases these represent the dominant toxaphene component found in the targeted cluster. Furthermore, the persistence of certain congeners in the atmospheric samples appears to be strongly dependent upon chemical structure, since the congeners in question possess an alternating exo–endo chlorine substitution pattern around the six-membered ring in the bornane skeleton. Such persistence is probably the result of lower metabolization of toxaphene residues in soils, water and sediments leading to a similar pattern in the atmosphere following volatilization.

INDUCTION OF HEPATIC CYTOCHROME P450 ACTIVITIES BY TOXAPHENE IN RAT AND JAPANESE QUAIL

Several organochlorine compounds can induce hepatic cytochrome P450 activities. We exposed female Japanese quail and female rats to a single oral dose of technical toxaphene ranging from 0.012 to 40 mg/kg body weight to investigate a possible dose-response relationship for P450 activity induction. The hepatic microsomal alkoxyresorufin dealkylation and steroid hydrox-ylation activities (testosterone, 17β-estradiol) were determined. Only in the highest dose groups (40 mg/kg) of rats and Japanese quail were some P450 activities induced. Pentoxyresorufin-O-dealkylation, formation of 15β-hydroxytestosterone, and formation of 2-hydroxyestradiol were induced significantly (p ≤ 0.05) in rat hepatic microsomes with a factor of 3.9, 3.1, and 2.4, respectively. In Japanese quail hepatic microsomes, the formation rates of 6β-, 15α-, 16β-hydroxytestosterone and androstenedione were induced significantly (p ≤ 0.05) with a factor of 2.4, 6.5, 3.3, and 1.6, respectively. It is concluded that exposure to toxaphene can lead to specific P450 activity induction in rats and Japanese quail but only at doses near reported LD50 values. Because reported toxaphene levels in biota are lower compared with liver residue levels that we have measured in our study, we conclude that it is unlikely that P450 activity induction occurs in wildlife higher in the food chain due to environmental toxaphene exposure.

Application of well-defined ?-cyclodextrins for the enantioseparation of compounds of technical toxaphene and further organochlorines

Enantioselective gas chromatography with 11 columns that contained different modified cyclodextrins was applied to chiral organochlorines. We initially investigated columns that contained pure heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (β-TBDM) and six fractions resulting from liquid chromatographic separation of randomly silylated β-TBDM. Four β-TBDM fractions investigated with liquid chromatography–mass spectroscopy had an excess of 1–4 methyl groups instead of tert-butyldimethylsilyl groups. In contrast to randomly silylated β-TBDM (enantioseparation of all compounds except one), relatively few compounds (2–7 of 21 organochlorines) were enantioresolved on the fractionated chiral stationary phases. No fraction with high enantioselectivity for compounds of technical toxaphene (CTTs) was obtained. A second series of experiments evaluated columns coated with chemically bonded (CB) or polysiloxane-diluted (PD) permethyl-β-cyclodextrin (β-PMCD). Of the two, only CB-β-PMCD separated the enantiomers of CTTs and atropisomeric PCBs and not PD-β-PMCD. Additionally, a column coated with PD-γ-PMCD was tested. © 2000 John Wiley & Sons, Inc. J Micro Sep 12: 541–549, 2000

Octanol/water partition coefficients of toxaphene congeners determined by the “slow-stirring” method

The octanol/water partition coefficients (K OW) for a series of technical toxaphene peaks and congeners ( n = 36) and organochlorines (pentachlorobenzene (PCIBz), hexachlorobenzene (HClBz), mirex and polychlorinated biphenyl congeners (CB) 105, 153 and 209) were determined using the “slow-stirring” technique with two different concentrations at 25°C. K OWS of the organochlorines were consistent with published values and results from the two treatments were in good agreement, suggesting the toxaphene congener K OWs are accurate and precise. Log K OW of toxaphene components / congeners ranged from 4.77 ± 0.076 to 6.64 ± 0.074, and were significantly related to chlorine number (log K OW = 3.4 + [0.28∗ # Cl], r 2 = 0.44, p < 0.001). Additional variation in toxaphene congener K OW, and likely other physical chemical properties, is due to chlorine position and the structure of the carbon skeleton. These results represent some of the first physical-chemical properties of individual toxaphene congeners.

Enantioselective determination of two persistent chlorobornane congeners in sediment from a toxaphene‐treated yukon lake

AbstractThe composition of toxaphene residuesand the enantiomeric ratios of the major congeners were studied in the top 10 slices (1935–1992) of a sediment core collected from Hanson Lake in the Yukon Territories (Canada). This lake was treated with toxaphene as a picsicide in July 1963. Electron‐capture negative ion mass spectrometry and electron‐capture detection were applied in combination with enantioselective gas chromatography using modified cyclodextrin columns. Of the 10 toxaphene peaks identified in each of the sediment slices, two congeners, 2‐exo,3‐endo,6‐exo,8,9,10‐hexachlorobornane (B6‐923 or Hx‐Sed) and 2‐endo,3‐exo, 5‐endo,6‐exo, 8,9,10‐heptachlorobornane (B7‐1001 or Hp‐Sed), were the most abundant. Each of the three chiral stationary phases used in this study was successful at resolving the enantiomers in at least of one of the two congeners. Among them was permethylated β‐cyclodextrin (Chirasil‐Dex), which, up until now, has never been used for enantiomer separation of compounds of technical toxaphene. B6‐923 and another less abundant, as of yet unknown, hexachlorobornane were racemic in all sediment core slices. For B7‐1001, the latter eluting enantiomer was always more predominant. Furthermore, the enantiomeric ratio was found to consistently decrease with time from approximately 0.8 in the early slices (∼1950) to 0.7 in the slice representing 1992, implying that the first eluted B7‐1001 enantiomer is less persistent than the second. B6‐923 and B7‐1001 are most likely metabolites of the more highly chlorinated congeners. A structural evaluation provided evidence that reductive dechlorination at carbons with geminal chlorine atoms is the primary microbial degradation pathway in sediments from Hanson Lake.

The relative estrogenic activity of technical toxaphene mixture and two individual congeners

Toxaphene is the most abundant persistent organic pollutant in the Arctic and in the Great Lakes. Toxaphene technical mixture (Tox) applied as a pesticide consists of over 800 congeners. Through processes of environmental degradation, selected metabolism, and bioaccumulation, two congeners are prominent in humans; 2- exo,3- endo,5- exo,6- endo,8,8,10,10-octachlorobornane (T2 or Parlar 26) and 2- exo,3- endo,5- exo,6- endo,8,8,9,10,10-nonachlorocamphene (T12 or Parlar 50). The MCF7-E3 human breast cancer cell model was used to screen for the estrogenic activities of Tox, T2, and T12. A concentration of 10 μM was required by all three compounds to elicit an estrogenic response as indicated by a proliferative effect (PE) upon the cells. The congeners, however, showed significantly different PEs from Tox. Both T2 and T12 had a lower PE (16 and 30%) and than Tox, and T2 had a higher PE than T12 (19%). Results from binary combination studies showed that the effects of Tox, T2, and T12 were additive. Tox, T2, and T12 had no significant effects on estrogen receptor and progesterone receptor levels. Our results suggest that the two environmental prevalent congeners had lower estrogenic activities than Tox and there is no synergistic effect.

Levels of Organochlorines (DDT, PCBs, Toxaphene, Chlordane, Dieldrin, and HCHs) in Blubber of South African Fur Seals ( Arctocephalus pusillus pusillus) from Cape Cross/Namibia

Organochlorines (DDT, toxaphene, PCBs, chlordane, HCHs, dieldrin) were quantified in the blubber of eleven fur seals of the species Arctocephalus pusillus pusillus. The sample clean-up included microwave-assisted extraction (MAE), gel-permeation chromatography (GPC), adsorption chromatography on silica gel and quantitation with GC/ECD. Compounds of technical toxaphene (CTTs) were determined after separation from the PCBs. Highest levels arose for p, p′-DDE (7–1000 μg/kg). A so far unknown compound labelled Q1 caused the second most abundant peak in the samples. Q1 was identified as a heptachloro compound by GC/MS in the electron capture negative ionisation and electron impact ionisation mode. Levels of Q1 were estimated relative to the ECD response factor of trans-nonachlor. These estimated Q1 levels ranged from 27 to 351 μg/kg being in the range or higher than the levels of PCBs (6–697 μg/kg), toxaphene (10–97 μg/kg), chlordane (3–159 μg/kg), and dieldrin (4–36 μg/kg). One sample which showed significantly higher DDT and PCB levels (but not toxaphene, dieldrin, Q1, and chlordane) than the others is most likely migrated from an area higher polluted with DDT and PCBs. Another one showed very low levels which were not explained. Except these samples, the levels determined in the blubber were among the lower levels reported for this kind of tissue. The data also confirmed that the organochlorine levels in Africa are varying from region to region, and that there is still a need for further research.

Airborne concentrations of toxaphene congeners at point petre (Ontario) using gas-chromatography-electron capture negative ion mass spectrometry (GC-ECNIMS)

A reliable analytical method has been developed using GC-ECNIMS for the determination of individual toxaphene congeners in ambient air. To allow a reasonable comparison with previous data for toxaphene reported by Muir and co-workers using GC-ECD, this method has adopted their approach of focussing upon the identification and quantification of specific peaks or clusters (“T” species) typically observed in environmental samples, with the sum of these “T” species then being reported as “total toxaphene”. Technical toxaphene has been used as the analytical standard, but independent response factors have been assigned to the target peaks and clusters. Because of the appreciable variability in ECNIMS response shown by individual toxaphene congeners, this is considered to be a reasonable and potentially more accurate procedure than the application of a “single response factor” used by many other workers. The methodology has been used for the determination of toxaphene in air samples collected over the annual cycle in 1992 and then from October 1995 to September 1997 at Point Petre, Ontario. Of the forty-four calibrated components, only 10 were detected in all of the air samples collected over the latter 2-year period. Airborne concentrations of toxaphene (defined as the sum of the calibrated components) range from 0.9 pg/m 3 to 10.1 pg/m 3. A clear seasonality has been observed, with a summer-to-winter concentration ratio of about 6.

The role of biotic and abiotic degradation processes during the formation of typical toxaphene peak patterns in aquatic biota

Toxaphene residues in cod liver and fish oil samples from different countries have been analyzed by HRGC-ECD and HRGC-MS as well as with multidimensional gas chromatography. The results have been compared to patterns obtained by photolysis and microbial degradation of selected single chlorobornanes and technical toxaphene. Enantiomeric ratios of the components Parlar #44 and #62 showed significant deviations from 1, indicating metabolism in cod fish and perhaps other species at least for some congeners. Parlar #50 was found to be a racemate, which corresponds to its known stability under biotic and abiotic conditions.

Determination of Organochlorine Levels in Antarctic Skua and Penguin Eggs by Application of Combined Focused Open-Vessel Microwave-Assisted Extraction, Gel-Permeation Chromatography, Adsorption Chromatography, and GC/ECD

Levels of organochlorines (PCBs, DDT, toxaphene, chlordane, hexachlorobenzene (HCB), hexachlo-rocyclohexanes (HCHs), dieldrin, Q1) were determined in eggs of both penguins (Adelie Pygoscelis adeliae, Chinstrap Pygoscelis antarctica, Gentoo Pygoscelis papua) and skuas (South Polar Skua Catharacta maccormicki, Brown Skua Catharacta antarctica lonnbergi, Mixed Pair Skua Catharacta maccormicki x lonnbergi) from the Antarctic. Focused open-vessel microwave-assisted extraction (FOV-MAE) was performed for the extraction of entire, partly lyophilised eggs (approx. 50 g). After gel-permeation chromatography (GPC) and adsorption chromatography on deactivated silica gel, the quantitation was performed by GC/ECD on two capillary columns of different polarity. Compounds of technical toxaphene (CTTs) were determined after separation of the PCBs. The sample clean-up method was validated with certified reference material SRM 1588. In general, skua eggs revealed higher organochlorine levels than penguin eggs. Main contaminants in skua eggs were p,p'-DDE, PCB 153, and PCB 180 with levels about 10 − 350 μg/kg wet weight without shell (ww). Eggs of penguins were topped by levels of hexachlorobenzene (HCB) and p,p'-DDE (2 − 22 μg/kg ww), respectively. In skua eggs, the most abundant CTTs were B9-1679 (Parlar #50) > B8-1413 (Parlar #26) > B9-1025 (Parlar #62) > B8-1412, the levels were about 1-20 μg/kg ww. In penguin eggs, however, the order was B8-1413 (Parlar #26) > B9-1679 (Parlar #50) > B8-1412 > B9-1025 (Parlar #62), and the levels ranged from 0.02 − 0.8 μg/kg ww. A so far unknown heptachloro compound labelled Q1 caused an abundant peak in some samples. Levels of Q1 (2 − 126 μg/kg ww in skua eggs and 0.3 − 1.2 μg/kg ww without shell in penguin eggs) were estimated relative to the ECD response factor of trans-nonachlor.

Environmental occurrence, analysis, and toxicology of toxaphene compounds.

Toxaphene production, in quantities similar to those of polychlorinated biphenyls, has resulted in high toxaphene levels in fish from the Great Lakes and in Arctic marine mammals (up to 10 and 16 microg g-1 lipid). Because of the large variabiliity in total toxaphene data, few reliable conclusions can be drawn about trends or geographic differences in toxaphene concentrations. New developments in mass spectrometric detection using either negative chemical ionization or electron impact modes as well as in multidimensional gas chromatography recently have led researchers to suggest congener-specific approaches. Recently, several nomenclature systems have been developed for toxaphene compounds. Although all systems have specific advantages and limitations, it is suggested that an international body such as the International Union of Pure and Applied Chemistry make an attempt to obtain uniformity in the literature. Toxicologic information on individual chlorobornanes is scarce, but some reports have recently appeared. Neurotoxic effects of toxaphene exposure such as those on behavior and learning have been reported. Technical toxaphene and some individual congeners were found to be weakly estrogenic in in vitro test systems; no evidence for endocrine effects in vivo has been reported. In vitro studies show technical toxaphene and toxaphene congeners to be mutagenic. However, in vivo studies have not shown genotoxicity; therefore, a nongenotoxic mechanism is proposed. Nevertheless, toxaphene is believed to present a potential carcinogenic risk to humans. Until now, only Germany has established a legal tolerance level for toxaphene--0.1 mg kg-1 wet weight for fish.

The use of a microsomal in vitro assay to study phase I biotransformation of chlorobornanes (toxaphene®) in marine mammals and birds : Possible consequences of biotransformation for bioaccumulation and genotoxicity

The factors determining the bioaccumulation of lipophilic compounds in wildlife are often poorly understood, partly because it is difficult to do in vivo experiments with animals such as marine mammals and birds. To evaluate the role of phase I biotransformation in the bioaccumulation process of chlorobornanes (toxaphene®), this was studied in in vitro assays with hepatic microsomes of animals that could be sampled shortly after death. The capacity of microsomes to metabolise a technical toxaphene mixture decreased in the order Phoca vitulina (harbour seal)⪢ Lagenorhynchus albirostris (whitebeaked dolphin)≅ Diomedea immutabilis (Laysan albatross)> Physeter macrocephalus (sperm whale). Harbour seal microsomes metabolised the chlorobornane (CHB) congeners CHB-32 and CHB-62; whitebeaked dolphin and Laysan albatross microsomes only metabolised CHB-32. Metabolism of CHB-26 and CHB-50 was never observed. The negative chemical ionisation (NCI−) mass spectra of some of the hydroxylated metabolites were obtained. The number of peaks in the toxaphene residues of wildlife extracts decreased in the order of increasing in-vitro biotransformation capacity. Thus, the results of the in vitro assays and residue analysis were in accordance, although assays with microsomes of more individuals of the same species are required for a more general conclusion at the species level. Finally, the effect of in vitro biotransformation was evaluated in terms of the genotoxic potential using the Mutatox® assay. Only technical toxaphene and CHB-32 were genotoxic in the direct assay, whereas the addition of rat S9 fraction or microsomes of harbour seal and albatross decreased the genotoxic response. Thus, organisms with a low ability to metabolise chlorobornanes, such as whales, may be most affected by the carcinogenic properties of toxaphene. A hypothetical reaction which fits the experimental results is discussed. Based on these results it is concluded that in vitro assays with microsomes of wildlife animals which died a natural cause can act as a valuable tool to assess the occurrence and effects of phase I metabolism. Some precautions are discussed, that should be taken to reduce the chance of false negative results.

Determination of (+/−) Elution Orders of Chiral Organochlorines by Liquid Chromatography with a Chiral Detector and by Enantioselective Gas Chromatography

Abstract Enantioselective gas chromatography (GC) with 5 modified cyclodextrins was applied to chiral organochlorines. A prerequisite for determining GC elution orders of enantiomers is the availability of enantioenriched standard solutions. In addition to compounds reported before (e.g., α-HCH, PCB 174, oxychlordane), we determined the sign of optical rotation of enantioenriched solutions of e-aeee-pentachlorocyclohexene-1 (β-PCCH), perdeuterated α-HCH (α-PDHCH), perdeuterated β-PCCH, and the persistent compound of technical toxaphene—2-exo,3-endo,5-exo,9,9,10,10-heptachlorobornane (B7-1453)—by liquid chromatography (LC) with a chiral detector. An enantioenriched solution of (β-PCCH was obtained by enantioselective degradation of α-HCH with (-)-brucine. In addition to forming an enantiomeric excess of (-)-α- HCH, we formed enantioenriched (+)-(α-PCCH. In a similar study, α-PDHCH showed the same behavior with respect to enantioselectivity. Dextrorotation of an enantioenriched solution of B7-1453 was also confirmed by LC with a chiral detector. Enantioseparation of chiral organochlorines on 5 chiral stationary phases resulted in several reversed elution orders. These results indicate that a careful check of elution orders of organochlorine enantiomers is necessary prior to comparison of literature data for the study of enantioselective processes in the environment.