Technical Toxaphene Research Articles

Characterization of technical toxaphene using combined high-performance liquid chromatography-gas chromatography-electron capture negative ionization mass spectrometry techniques

More than 300 congeners in technical toxaphene were distinguished by combined HPLC-GC/electron capture negative ionization mass spectrometry (ECNIMS) techniques. Good separation of most congeners on a 60-m DB-5 GC column was achieved when the mixture was pre-separated into five fractions by silica gel HPLC. ECNI spectra of high chlorinated congeners were dominated by M  Cl while both M and M  Cl ions were important in low chlorinated ones. Other ions such as M - 3Cl, M  Cl  HCl and M  Cl - 2HCl can be used to distinguish congeners. Peaks referred to as T2 and T12 in the environment by many authors coelute with several congeners in toxaphene. The 2,5-exo-3,6-endo tetrachloro partial structure existing in both T2 and T12 may be responsible for their persistency in living systems. Results from EI-SIM mode indicated many other low chlorinated congeners not detectable by ECNI in the mixture.

Atmospheric toxaphene in the high Arctic

The lack of information on seasonal variation of toxaphene (polychlorobornanes) in the arctic atmosphere has prompted a study in the Canadian north. Using high volume impactors with a 10 μm diameter size-selective inlet for particles and a collection cartridge consisting of a glass fiber filter followed by two polyurethane foam plugs, weekly samples were collected at Alert N.W.T. on a routine basis during the first six months of 1992. Samples were extracted and analysed by GC-ECD and confirmed by low and high resolution GC-MS. Total toxaphene concentrations ranged from < 1.6 to 27 pg m −3. They were lowest in January and rose to a peak in June at the end of the measurement period. GC-MS showed that in general, fewer chlorobornanes were observed in the PUF samples than in the technical toxaphene standard and the less volatile components of each homolog group (with longer GC retention times) were reduced in their relative proportions. Samples were dominated by hepta- and octachlorobornanes. Routine analysis by GC-ECD with occasional confirmatory analysis by higher resolution GC-MS techniques is a promising practical approach to atmospheric toxaphene measurements in remote areas.

Identification of polychlorocamphenes (PCCs) in the polar bear ( Ursus maritimus) food chain

Fifteen congeners of polychlorocamphenes (PCCs) were identified in polar bear fat and ringed seal blubber using HRGC/ECNI-MS techniques. Several of these compounds coeluted with chlordane and PCB congeners, but could be identified by analysis of the ECNI spectra of the chromatographic peaks and by comparison of their retention times with components in a technical toxaphene mixture and authentic standards. ECNI spectra of pure PCC congeners are also presented. Three nonachlorobomene compounds not in toxaphene were also detected. One of these was at higher levels relative to total PCCs in polar bear than in ringed seal. The pattern of PCC congener distribution in polar bear and ringed seal was more complicated than previously described in arctic mammals and fish. In particular, the octachlorobornane (T2) and nonachlorobomane (T12), which dominate in arctic amphipods, burbot, narwhal and beluga, were only 8–11% of total PCCs in ringed seal and polar bear. Levels of PCCs were 1.0 mg/kg in polar bear and 0.25 mg/kg in ringed seal. The bioaccumulation potential of PCCs in polar bear is similar to that of HCH and DDE, but much less than that of PCBs and oxychlordane. Analysis of polar bear tissues may provide a useful measure of the geographical distribution of PCCs in the arctic environment.

Mass spectrometric and gas chromatographic identification of the two main toxaphene congeners present in marine mammals as minor constituents in the technical product

The most abundant toxaphene congeners in marine mammals such as seals are an octa- and nonachloro bornane. They were recently isolated in μg-quantities from seal blubber and their structures elucidated. Several abundant even mass fragment ions were observed in their electron impact ionisation mass spectra. Only a limited number of congeners in the technical toxaphene mixture form these fragments with a comparable intensity. They were used to search for the presence of both congeners in the technical mixture. The nonachloro isomer could be identified as a minor congener in the pesticide mixture. There are strong indications that the octachloro isomer also is present but no unequivocal confirmation could be made due to an interfering octachloro isomer which could not be completely separated. A gas chromatographic stationary phase was found which allows the complete separation of the nonachloro isomer in the technical mixture as well as a much better separation of the octachloro isomer compared to the usually applied nonpolar stationary phases.

Partial structure elucidation of the most abundant octa and nonachlorotoxaphene congeners in marine mammals by using conventional electron ionization mass spectrometry and mass spectrometry/mass spectrometry

Conventional electron ionization (EI) mass spectrometry (MS) and MS/MS techniques were applied to the analysis of two abundant octa and nonachlorobornanes isolated from seals of the Baltic sea and originating from technical toxaphene. The exact sterical structures of the two compounds were previously determined using nuclear magnetic resonance (NMR) spectroscopy by two independent research groups. The MS and MS/MS data generated in this study allowed partial structure elucidation of these polychlorobornanes, in particular revealing the distribution of the Cl substituents between the six-membered carbon ring, the bridge and the bridgehead in the parent bornane structure. Fragmentation of the six-membered carbon ring and the bridge by retro-Diels-Alder (RDA) and related mechanisms was discovered by studying specific parent/daughter ion transitions. The detailed fragmentation pathways formulated may be applicable to the structure elucidation of other toxaphene congeners and the monitoring of strategic transitions is highly selective for the detection of these compounds in technical toxaphene and in environmental samples.

Feasibility of toxaphene transport through sandy soil.

Toxaphene, produced by the chlorination of camphene, is a chlorinated hydrocarbon insecticide that was widely used to control a variety of insects on crops and to control livestock skin parasites. It is known to be a toxic and a highly persistent chemical in soil where its half-life can be in excess of ten years, depending on the environmental conditions. This study was conducted in an attempt to explain a finding in this lab of high concentrations of toxaphene (2600 ppm) in soil sampled at a depth of 1 m. The source of the sample was from a pesticide waste facility in northern California. The paradox of this discovery was that toxaphene, being hydrophobic, has been shown to be restricted in its movement from agricultural applications to a reported maximum of 30 cm, with the bulk of material concentrated in the upper 10 cm. Toxaphene is known to undergo anaerobic degradation that changes its gas chromatography profile. The toxaphene analyzed in this sample had an unweathered profile similar to technical toxaphene, implying that no degradation had occurred. Since a waste disposal facility is faced with abnormally high concentrations of pesticides and formulation components, it was of interest to ascertain if movementmore » in a soil profile was possible when such concentrations prevail in a waste facility.« less

Photoinduced reactions of two toxaphene compounds in aqueous medium and adsorbed on silica gel

Two pure chlorinated bornanes isolated from technical toxaphene R (1 and 2) were irradiated at different wavelength in neutral aqueous medium, and in a near-monomolecular layer adsorbed on a silica gel surface. Both compounds react to give products which are formed by reductive dechlorination (1a–b and 2a–b), dehydrochlorination (1e and 2e), oxydation (1c, 2c, 1f and 2f) and a combination of these reactions (1d and 2d). In heterogeneous phase the formed ketons (1f and 2f) were converted rapidly to bicyclo-[2,1,1]-hexane derivatives (1g and 2g). Photochemical data e.g. quantum yields, triplet energies and reaction rate constants were presented in this report in order to estimate the half-life of the model substances (1 and 2) in water and, adsorbed on surfaces under simulated environmental conditions.

Anaerobic microbial dechlorination: an approach to on-site treatment of toxaphene-contaminated soil.

Enhanced microbial degradation of toxaphene by natural microorganisms occurred in soil and sediment amended with organic matter kept under anaerobic (flooded) conditions. Laboratory experiments yielded a dissipation half-life of approximately 3 and 1 week for soil and sediment, respectively, containing 10 ppm of technical toxaphene and a 1% alfalfa meal amendment. Dissipation was accompanied by an increase in early eluting gas chromatographic peaks and a decrease in later eluting peaks, indicating that dechlorination had occurred. Enhanced anaerobic dissipation also took place in soil containing 500 ppm of toxaphene, although at a lesser rate than at 10 ppm, and when cotton gin waste was used as amendment in place of alfalfa meal. Sediment in a toxaphene-contaminated pesticide waste disposal ditch was amended with 10% steer manure and flooded to ascertain field utility of the technique for on-site decontamination. Toxaphene residues were reduced from 63 to 23 ppm in 120 days, and some degradation activity still occurred up to 8 months after this single treatment.

Polychlorocycloalkane insecticide-induced convulsions in mice in relation to disruption of the GABA-regulated chloride ionophore

The toxicity to mice of intraperitoneally-administered polychlorocycloalkane (PCCA) insecticides is generally correlated with their potency as in vitro inhibitors of the brain specific [ 35S]- t -butylbicyclophosphorothionate ([ 3S]TBPS) binding site with correction for metabolic activation and detoxification. These findings from our earlier studies are extended here to in vivo investigations relating convulsant action to inhibition of the TBPS binding site in poisoned mice. Radioligand binding assays involved brain P 2 membranes washed three times with 1 mM EDTA to remove endogenous γ-aminobutyric acid (GABA) or other modulator(s) which otherwise serves as a noncompetitive inhibitor of [ 35S]-TBPS binding at the GABA-regulated chloride ionophore. Examination of lindane, technical toxaphene, toxaphene toxicant A, and 10 polychlorocyclodiene insecticides revealed 62 ± 4% binding site inhibition 30 min after their LD 50 doses with 32 ± 3% inhibition at one-half and 6 ± 3% inhibition at one-quarter of their LD 50 doses. This correlation between binding site inhibition and convulsant action is also evident in dose- and time-dependency studies with endosulfan sulfate. The brain P 2 membranes of treated mice contain the parent compound with each of the PCCAs plus activation products of some of the cyclodienes, i.e. endosulfan sulfate from α- and ß-endosulfan and 12-ketoendrin from isodrin and endrin. The finding that the brains of treated mice contain sufficient PCCA or its activation products to achieve a magnitude of [ 35S]TBPS binding site inhibition correlated with the severity of the poisoning signs supports the hypothesis that the acute toxicity of PCCA insecticides to mammals is due to disruption of the GABA-regulated chloride ionophore.

Ein Beitrag zur Zusammensetzung des Insektizides "Toxaphen®" Gaschromatographisch-massenspektroskopische Charakterisierung eines öligen und eines kristallinen Anteils des technischen Toxaphens und dessen insektizide Wirksamkeit / A Contribution to the Composition of the Insecticide "Toxaphene®" Gaschromatographic-Masspectroscopical Characterisation of the Oily and the Crystalline Fraction of Technical Toxaphene and their Insecticidal Activity

Abstract Technical Toxaphene can be separated in two fractions by recrystallisation which are investigated with the help of GC/MS and toxicological methods. Especially the Retro-Diels-Alder-fragmentations give specific informations on the structure of highly chlorinated bornane derivatives representing the main components of the technical mixture. For this study lower chlorinated bornanes are used as model substances. Toxicological investigations show that both fractions have lower activity than technical toxaphene.

Isolation and gas chromatographic characterization of some toxaphene components.

Column chromatography of technical toxaphene on activated alumina reproducibly yields eight major fractions from which 2,2,5-endo,6-exo,8,9,10-heptachlorobornane and 2,5,6-exo,8,8,9,10-heptachlorodihydrocamphene may be readily isolated by preparative gas--liquid chromatogrpahy. These and some other reported toxaphene components were characterized by gas--liquid chromatographic retentions relative to aldrin on packed columns of OV-101, OV-17, and QF-1, and on a capillary open-tubular column of OV-101. Structural assignments were revised for some components on the basis of retentions. The fractionation and isolation procedure may have general utility for separating toxaphene components, and the retention data form a convenient basis for component comparison.

THE EFFECT OF INSECTICIDES ON THE ACTION POTENTIALS OF INSECT NERVE

Solutions of 17 insecticides in corn oil were applied to the leg of Periplaneta americana (L), and their effect on the sensory impulses of the crural nerve was determined by means of a preamplifier and cathode-ray oscillograph. DDT, methoxychlor, and DDD induced well-marked trains of repetitive discharge. Aldrin and dieldrin evoked low-voltage trains of repetitive discharge after a latent period of two to four hours. Technical chlordane, heptachlor, α-chlordan, β-chlordan, and toxaphene all showed considerable latent periods before stimulating the action potentials. Lindane rapidly induced the appearance of tiny sets of repeat spikes. The pyrethrins increased the frequency of impulses, while the dinitro compounds increased both the voltage and frequency. Schradan showed no effect, TEPP a transient stimulation, while parathion induced trains of repetitive discharge after a latent period of three hours.