Sorption behaviors of a persistent toxaphene congener on marine sediments under different physicochemical conditions.

Sorptive processes are important parameters affecting the mobility, availability and fate of persistent organic pollutants (POPs), such as toxaphene, in aquatic systems. The sorption and desorption behaviors of the B7-1450, a stable toxaphene congener in environment, on marine sediment was studied under different temperature and salinity conditions to better understand the B-1450 distribution in estuarine systems. The data were fitted to different sorption models to characterize sorption behaviors by evaluating sorption coefficients and sequestrated fraction of B7-1450 on sediments. High carbon-normalized sorption coefficients (Koc) of the B7-1450 were observed with values ranging from 3.2×104 to 6.0×104 mL g(-1) under experimental conditions. The data showed an increase of B7-1450 sorption coefficients with the salinity and a decrease with temperature. These investigations indicate that B7-1450 is three times more sequestred on sediments in cold (2°C, 30 psu) than in warm marine conditions (20°C, 30 psu). These results suggest that the mobility and bioavailable of B7-1450 or other POPs from the sediments could be less important in cold marine comparatively in warm marine and warm freshwater media. As a result of climate changes, the warming of mid and high latitudes coastal waters could enhance the mobility of POPs.

Comparing the mutagenicity of toxaphene after aging in anoxic soils and accumulating in fish.

A test program was conducted to evaluate the mutagenicity of toxaphene residuals extracted from aged soils and from fish collected in creeks near a toxaphene-contaminated site. The ultimate objective was to determine if the residual toxaphene congeners were more or less mutagenic than those in technical-grade toxaphene. The study showed that the mutagenicity of the bioaccumulated toxaphene congeners in fish, expressed as colony revertants per microg of residual toxaphene, was no greater than that of technical-grade toxaphene. The mutagenic impact of the toxaphene residuals in aged soil statistically was less than that for technical-grade toxaphene. Two specific congeners, a hexachlorobornane (labeled Hx-Sd) and a heptachlorobornane (labeled Hp-Sd), were found to accumulate over time in both soil and fish extracts, but did not show increased mutagenic impacts relative to that produced by technical-grade toxaphene.

Photolytic clean-up of biological samples for gas chromatographic analysis of chlorinated paraffins.

A method based on gas chromatography electron capture detection (GC-ECD) for the analysis of chlorinated paraffins (CPs) in biological samples has been investigated. The method includes photolytic destruction of halogenated aromatic compounds, such as PCBs, to eliminate some of the interferences in the analysis of CPs in environmental samples. Gel permeation chromatography was used to isolate CPs from the interfering components of Toxaphene and chlordane after the photolysis. GC-ECD gave a detection limit of 20 ng CPs/g fresh muscle tissue. The recovery of CPs from a spiked moose liver sample was estimated to 94%.

Separation of toxaphene by high resolution gas chromatography.

A summary is given about the separation of toxaphenes by high resolution gas chromatography (HRGC). The suitability of different stationary phases for isomer and/or enantiomer-selective separations is compared. Multidimensional and tandem techniques are also presented. In addition, problems caused by thermal degradation in the injector and on the column are addressed. Furthermore, a brief survey is included about detection methods such as electron capture detection and different mass spectrometric methods.

PCB/toxaphene group separation on silica prior to congener specific determination of toxaphene residues in fish and other samples by GC/ECD.

A precise quantification of toxaphene residues of environmental samples by gas chromatography/ electron capture detection (GC/ECD) requires the separation of the bulk of the polychlorinated biphenyls (PCBs) from the compounds of technical toxaphene (CTT) fraction. For this reason, a PCB/CTT group separation on silica was developed. B8-1413 (Parlar #26) and B7-515 (Parlar #32) eluted as first and last out of ten important CTT standards, and can be used to determine the elution volume of the CTT fraction on silica. GC/ECD quantification of CTTs was possible after separation of PCBs on 8.0 g activated silica eluted with 48 mL n-hexane followed by quantitative elution of CTTs with n-hexane/toluene (65:35; v/v). This method is a compromise between separation efficiency and consumption of material. Finally, eight CTTs were quantified in cod liver samples from Iceland and the Baltic Sea.

Congener specific analysis of toxaphene in serum using ECNI-MS.

A method for the determination of environmentally relevant toxaphene congeners (eg chlorinated bornanes (CHBs)) in serum is described. Four chlorinated bornane congeners are predominant in serum.

Separation of lipophilic substances in environmental samples with special reference to toxaphene.

A microcolumn of alumina, activated at 250 degrees C over night and deactivated with 2% water in an oven at 150 degrees C, has shown better separation characteristics than similar ones, deactivated at room temperature, for a great number of organochlorine compounds, particularly with respect to multicomponent toxaphene and PCB. The microcolumn is a simple disposable Pasteur pipette. Three fractions are collected: one with PCB and DDE, one with toxaphene components having similar lipophilicity to DDT and the third, toxaphene components similar to DDD in lipophilicity. Two such toxaphene fractions give a better GLC-pattern than only one fraction. DDD and DDT, which interfere with the analysis of toxaphene can be eliminated, after their GLC analysis, from the "Toxaphene fractions" by nitration followed by reduction of the nitro compounds formed to their corresponding amines. Performance of the column using environmental samples showed that it is a useful tool in routine pesticide residue analysis, especially when toxaphene is present.

Toxicities and description of some toxaphene fractions: isolation and identification of a highly toxic component.

Toxaphene was separated into 13 fractions and the toxicity of each fraction was determined. The acute toxicities (LD50) to houseflies (topical in acetone) ranged from 21 to greater than 246 mg/kg (toxaphene LD50 = 33 mg/kg) and the relative toxicities ranged from 0.6 to greater than 7.5. A similar pattern was found in mice when the toxicities of several fractions were determined. The acute toxicities (LD50, ip injection in dimethyl sulfoxide) in mice ranged from 20 to 67 mg/kg (toxaphene LD50 = 33 mg/kg) for the fractions tested. The most toxic fraction was further separated into six subfractions and their toxicities (housefly LD50) were found to range from 10 to 74 mg/kg. The most toxic subfraction appeared to be an almost pure compound and was purified for further identification. It was found to be identical to a previously reported highly toxic C10H10Cl8 mixture of predominantly two components. The components were reported to be 2,2,5-endo,6-exo, 8,8,9,10-octachlorobornane and 2,2,5-endo,6-exo,8,9,9,10-octachlorobornane. This highly toxic mixture has now been isolated independently by three research teams using different separation schemes.

Toxaphene insecticide: a complex biodegradable mixture.

Adsorption and gas-liquid chromatography separate toxaphene into at least 175 polychlorinated 10-carbon compounds including Cl(6), Cl(7), Cl(8), Cl(9), and Cl(10) derivatives. One toxic component is 2,2,5-endo,6-exo,8,9,10-heptachlorobornane. Rats metabolically dechlorinate toxaphene, removing about half of the chlorine from the technical insecticide and from each of seven subfractions of varying composition and toxicity.