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Terry F Bidleman - One of the best experts on this subject based on the ideXlab platform.
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interlaboratory study of Toxaphene analysis in ambient air
Atmospheric Environment, 2004Co-Authors: Terry F Bidleman, Sylvia Cussion, Liisa M JantunenAbstract:Abstract An interlaboratory study was conducted for total Toxaphene and selected congeners in an extract of ambient air from the southern United States. All participating labs were experienced in Toxaphene analysis and used GC-MS techniques. Ten labs reported the concentration of total Toxaphene in a technical Toxaphene solution, with a 113% average recovery of the target value and 40% relative standard deviation (RSD). Only six of the 10 labs fell within ±30% of the target value, a criterion recommended by good laboratory practice standards. The interlaboratory RSD was 65% for total Toxaphene in the air sample extract (lowered to 43% when one outlying lab was omitted). Nine labs reported the concentrations of five Toxaphene components (B8-1413, B8-1414+B8-1945, B8-806+B8-809, B8-2229 and B9-1679) with 33–47% RSD for the technical Toxaphene unknown and 34–62% for the air sample. The precision was poorer for a sixth component, congener B9-1025, which has a very low response by electron capture negative ion mass spectrometry (ECNI): 59% RSD for the technical Toxaphene unknown and 196% for the air sample. Factors contributing to the interlaboratory variability for total Toxaphene and single components are discussed, and follow-up studies are required to identify and minimize the causes of variability. Based on the average analysis, B8-1413 was enriched and B8-806+B8-809 was depleted in the air sample relative to the technical Toxaphene standard.
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air water gas exchange of Toxaphene in lake superior
Environmental Toxicology and Chemistry, 2003Co-Authors: Liisa M Jantunen, Terry F BidlemanAbstract:Parallel air and water samples were collected in Lake Superior during August 1996 and May 1997, to determine the levels and air-water exchange direction of Toxaphene. Concentration of Toxaphene in water did not vary across Lake Superior or between seasons (averaging 918 +/- 218 pg/L) but atmospheric levels were lower in May (12 +/- 4.6 pg/m3) than in August (28 +/- 10 pg/m3). Two recalcitrant congeners, Parlar 26 and 50, also were determined. These congeners were enriched in the air samples, compared to a standard of technical Toxaphene, but not in the water. Water-air fugacity ratios varied from 1.4 to 2.6 in August and 1.3 to 4.7 in May, implying volatilization of Toxaphene from the lake. Estimated net fluxes ranged from 5.4 to 13 and 1.8 to 6.4 nm/m2d, respectively. The temperature dependence of Toxaphene partial pressure (P) in air was log P/Pa = -3.291/T(a) + 1.67, where T(a) is air temperature. By using this relationship, the atmospheric levels of Toxaphene, fugacity ratios, and net fluxes were estimated for the entire year. Fugacity ratios were highest in the winter and lowest in the summer; thus Toxaphene was predicted to undergo net volatilization from the lake during all months. A net removal of approximately 220 kg/year by gas exchange was estimated.
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Toxaphene in the united states 2 emissions and residues
Journal of Geophysical Research, 2001Co-Authors: Terry F Bidleman, L A BarrieAbstract:Emission factors of Toxaphene for spraying and tilling events are distributed for the United States on a 1°×1° latitude and longitude grid system. By using the gridded usage and emission factors, inventories of gridded Toxaphene emissions and residues in agricultural soil in the United States with 1/6°×1/4° latitude and longitude resolution have been created. Total Toxaphene emissions were around 190 kt between 1947 and 1999. At the beginning of 2000, almost 20 years after banning the use of Toxaphene, there were still around 29 kt of Toxaphene left in the agricultural soil, of which 360 t will emit to the air in 2000. The calculated Toxaphene emissions and residues are in general consistent with published monitoring data. The trends of Toxaphene emissions due to current use and residues in agricultural soil in the United States match both the historical atmospheric input function for Toxaphene extending over the past 40 years derived from the composition of Toxaphene in peat core from eastern Minnesota to Nova Scotia, and the trends of air concentration of Toxaphene in the Arctic. This indicates that Toxaphene residues in the United States agricultural soil could be a major source of Toxaphene in the Canadian Arctic and the Great Lakes region.
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soil air exchange model of persistent pesticides in the united states cotton belt
Environmental Toxicology and Chemistry, 2001Co-Authors: Tom Harner, Terry F Bidleman, Liisa M Jantunen, Donald MackayAbstract:Measurements of organochlorine pesticides (lindane, cis-chlordane [CC], trans-chlordane [TC], trans-nonachlor [TN]), dieldrin, p,p′-dichlorodiphenyldichloroethylene [DDE], and Toxaphene) in Alabama, USA, air and soil were used to assess the soil-air equilibrium status and to identify compounds with significant contributions to observed air burdens. Of the compounds tested, p,p′-DDE and Toxaphene showed a significant potential for outgasing, followed by dieldrin and trans-nonachlor, which showed moderate outgasing potentials. Lindane, cis-chlordane, and trans-chlordane were near soil-air equilibrium. A fugacity-based, multilayered soil-air exchange model was used to predict temporal trends of chemical in air and soil resulting from reemission of soil residues to a presumed clean atmosphere (maximum emission scenario). Results showed that p,p′-DDE and Toxaphene accounted for up to 50% of the observed air burden and that approximately 200 to 600 kg of p,p′-DDE and 3,000 to 11,000 kg of Toxaphene are released to the atmosphere each year by soils in Alabama (area = 1.23 × 1011 m2). High annual net fluxes were also predicted for dieldrin and trans-nonachlor (300–1,100 kg and 150–500 kg, respectively), but these only account for up to ∼20% of their observed air burdens.
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temperature dependent henry s law constant for technical Toxaphene
Chemosphere - Global Change Science, 2000Co-Authors: Liisa M Jantunen, Terry F BidlemanAbstract:Abstract 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 log H=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.
Rojas Mora, Angélica María - One of the best experts on this subject based on the ideXlab platform.
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Biodegradación anaeróbica de toxafeno en suelos contaminados del municipio de El Copey
'Universidad Nacional Hermilio Valdizan - Facultad de Ciencias de la Educacion', 2016Co-Authors: Rojas Mora, Angélica MaríaAbstract:El toxafeno es un contaminante orgánico persistente, compuesto por una mezcla de miles de congéneres policlorados. En Colombia, fue el plaguicida más utilizado en los campos de algodón en el departamento del Cesar. Este estudio evaluar la biodegradación anaeróbica de Toxafeno en suelos contaminados del municipio de El copey Utilizando una muestra compuesta de suelo, se evaluaron 7 tratamientos en microcosmos anaeróbicos durante 270 días, para determinar el efecto de los biosólidos, la melaza, el material vegetal, el hienro cero Valente (ZVI) y la cal, sobre la degradación de toxafeno. También, se realizó un enriquecimiento del suelo contaminado, evaluando el efecto priming de 3 moléculas halorgánicas, y la participación de 7 grupos de bacterias halorespiradoras. Con un análisis del área relativa de 11 picos, utilizando GC-ECD, se pudo evidenciar cambios en el patrón de toxafeno, para los microcosmos y los cultivos enriquecidos. Los tratamientos que presentaron mayor transformación en microcosmos, fueron los que tuvieron adición de melaza, bisólidos y ZVI. Los cultivos enriquecidos, presentaron mayor potencial de transformación en un periodo de tiempo más corto (30dias), con respecto a los microcosmos (hasta los 120 días). No se logró identificar microorganismos halorespiradores en la segunda fase del cultivo, probablemente dada a la alta concentración de toxafeno que se presentó en los suelos. La molécula trans-1,2-dibromociclohexano, presentó un mayor cambio en los picos iniciales y finales de la huella, lo que sugiere un efecto potenciador (o priming) sobre los procesos de deshalogenación reductiva en cultivos enriquecidos para este plaguicida.Toxaphene is a persistent organic pollutant, which consists of a mixture of thousands of polychlorinated congeners. In Colombia, Toxaphene was the most widely used pesticide in cotton fields located on Cesar department. This study evaluated the anaerobic biodegradation of Toxaphene contaminated soil in El Copey, Cesar. Seven treatments were evaluated using a sample of soil in anaerobic microcosm for 270 days, to determine the effect of biosolids, molasses, vegetable material, zero valent iron (ZVI) and lime, on the degradation of Toxaphene. It was also made an enrichment culture of Toxaphene contaminated soil, evaluating the effect of 3 priming molecules, and the participation of 7 groups of halorespiring bacteria. An analysis of relative area of 11 peaks of Toxaphene, using GC-ECD, was used to give evidence of changes in the Toxaphene fingerprint for microcosm and enriched cultures. The microcosm treatments with an addition of molasses, biosolids and ZVI had higher transformation in the first peaks of the retention time than other treatments. On the other hand, enriched cultures showed a higher potential of Toxaphene transformation in a shorter time period (30days), with respect to the microcosms (up to 120 days). However, it was not possible to identify halorespiring microorganisms in the second stage of the enriched cultures, probably because of a high initial concentration of Toxaphene showed on the soils. The molecule Trans-1,2-dibromocyclohexane demostrated a major change in the initial and final footprint peaks, which suggest an enhancer (or priming) effect on reductive dehalogenation processes enriched for this pesticide.Magíster en Ciencias BiológicasMaestrí
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Biodegradación anaeróbica de toxafeno en suelos contaminados del municipio de El Copey
Maestría en Ciencias Biológicas, 2016Co-Authors: Rojas Mora, Angélica MaríaAbstract:El toxafeno es un contaminante orgánico persistente, compuesto por una mezcla de miles de congéneres policlorados. En Colombia, fue el plaguicida más utilizado en los campos de algodón en el departamento del Cesar. Este estudio evaluar la biodegradación anaeróbica de Toxafeno en suelos contaminados del municipio de El copey Utilizando una muestra compuesta de suelo, se evaluaron 7 tratamientos en microcosmos anaeróbicos durante 270 días, para determinar el efecto de los biosólidos, la melaza, el material vegetal, el hienro cero Valente (ZVI) y la cal, sobre la degradación de toxafeno. También, se realizó un enriquecimiento del suelo contaminado, evaluando el efecto priming de 3 moléculas halorgánicas, y la participación de 7 grupos de bacterias halorespiradoras. Con un análisis del área relativa de 11 picos, utilizando GC-ECD, se pudo evidenciar cambios en el patrón de toxafeno, para los microcosmos y los cultivos enriquecidos. Los tratamientos que presentaron mayor transformación en microcosmos, fueron los que tuvieron adición de melaza, bisólidos y ZVI. Los cultivos enriquecidos, presentaron mayor potencial de transformación en un periodo de tiempo más corto (30dias), con respecto a los microcosmos (hasta los 120 días). No se logró identificar microorganismos halorespiradores en la segunda fase del cultivo, probablemente dada a la alta concentración de toxafeno que se presentó en los suelos. La molécula trans-1,2-dibromociclohexano, presentó un mayor cambio en los picos iniciales y finales de la huella, lo que sugiere un efecto potenciador (o priming) sobre los procesos de deshalogenación reductiva en cultivos enriquecidos para este plaguicida.Toxaphene is a persistent organic pollutant, which consists of a mixture of thousands of polychlorinated congeners. In Colombia, Toxaphene was the most widely used pesticide in cotton fields located on Cesar department. This study evaluated the anaerobic biodegradation of Toxaphene contaminated soil in El Copey, Cesar. Seven treatments were evaluated using a sample of soil in anaerobic microcosm for 270 days, to determine the effect of biosolids, molasses, vegetable material, zero valent iron (ZVI) and lime, on the degradation of Toxaphene. It was also made an enrichment culture of Toxaphene contaminated soil, evaluating the effect of 3 priming molecules, and the participation of 7 groups of halorespiring bacteria. An analysis of relative area of 11 peaks of Toxaphene, using GC-ECD, was used to give evidence of changes in the Toxaphene fingerprint for microcosm and enriched cultures. The microcosm treatments with an addition of molasses, biosolids and ZVI had higher transformation in the first peaks of the retention time than other treatments. On the other hand, enriched cultures showed a higher potential of Toxaphene transformation in a shorter time period (30days), with respect to the microcosms (up to 120 days). However, it was not possible to identify halorespiring microorganisms in the second stage of the enriched cultures, probably because of a high initial concentration of Toxaphene showed on the soils. The molecule Trans-1,2-dibromocyclohexane demostrated a major change in the initial and final footprint peaks, which suggest an enhancer (or priming) effect on reductive dehalogenation processes enriched for this pesticide
James E. Klaunig - One of the best experts on this subject based on the ideXlab platform.
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Toxaphene-induced mouse liver tumorigenesis is mediated by the constitutive androstane receptor.
Journal of applied toxicology : JAT, 2017Co-Authors: Zemin Wang, James C. Lamb, James E. KlaunigAbstract:Toxaphene was shown to increase liver tumor incidence in B6C3F1 mice following chronic dietary exposure. Preliminary evidence supported a role for the constitutive androstane receptor (CAR) in the mode of action of Toxaphene-induced mouse liver tumors. However, these results could not rule out a role for the pregnane X receptor (PXR) in liver tumor formation. To define further the nuclear receptors involved in this study, we utilized CAR, PXR and PXR/CAR knockout mice (CAR-/- , PXR-/- and PXR-/- /CAR-/- ) along with the wild-type C57BL/6. In this study CAR-responsive genes Cyp3a11 and Cyp2b10 were induced in the liver of C57BL/6 (wild-type) mice by Toxaphene (30-570-fold) (at the carcinogenic dose 320 ppm) and phenobarbital (positive control) (16-420-fold) following 14 days' dietary treatment. In contrast, in CAR-/- mice, no induction of these genes was seen following treatment with either chemical. Cyp3a11 and Cyp2b10 were also induced in PXR-/- mice with Toxaphene and phenobarbital but were not changed in treated PXR-/- /CAR-/- mice. Similarly, induction of liver pentoxyresorufin-O-deethylase (CAR activation) activity by Toxaphene and phenobarbital was absent in CAR-/- and PXR-/- /CAR-/- mice treated with phenobarbital or Toxaphene. Ethoxyresorufin-O-deethylase (EROD, represents aryl hydrocarbon receptor activation) activity in CAR-/- mice treated with Toxaphene or phenobarbital was increased compared with untreated control, but lower overall in activity in comparison to the wild-type mouse. Liver EROD activity was also induced by both phenobarbital and Toxaphene in the PXR-/- mice but not in the PXR-/- /CAR-/- mice. Toxaphene treatment increased 7-benzyloxyquinoline activity (a marker for PXR activation) in a similar pattern to that seen with pentoxyresorufin-O-deethylase. These observations indicate that EROD and PXR activation are evidence, as expected, of secondary overlap to primary CAR receptor activation. Together, these results definitively show that activation of the CAR nuclear receptor is the mode of action of Toxaphene-induced mouse liver tumors. Copyright © 2017 John Wiley & Sons, Ltd.
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mechanistic investigation of Toxaphene induced mouse liver tumors
Toxicological Sciences, 2015Co-Authors: Zemin Wang, James C. Lamb, Barbara H Neal, James E. KlaunigAbstract:Chronic exposure to Toxaphene resulted in an increase in liver tumors in B6C3F1 mice. This study was performed to investigate the mode of action of Toxaphene induced mouse liver tumors. Following an initial 14 day dietary dose range-finding study in male mice, a mechanistic study (0, 3, 32, and 320 ppm Toxaphene in diet for 7, 14, and 28 days of treatment) was performed to examine the potential mechanisms of Toxaphene induced mouse liver tumors. Toxaphene induced a significant increase in expression of constitutive androstane receptor (CAR) target genes (Cyp2b10, Cyp3a11) at 32 and 320 ppm Toxaphene. aryl hydrocarbon receptor (AhR) target genes (Cyp1a1 and Cyp1a2) were slightly increased in expression at the highest Toxaphene dose (320 ppm). No increase in peroxisome proliferator-activated receptor alpha activity or related genes was seen following Toxaphene treatment. Lipid peroxidation was seen following treatment with 320 ppm Toxaphene. These changes correlated with increases in hepatic DNA synthesis. To confirm the role of CAR in this mode of action, CAR knockout mice (CAR(-/-)) treated with Toxaphene confirmed that the induction of CAR responsive genes seen in wild-type mice was abolished following treatment with Toxaphene for 14 days. These findings, taken together with previously reported studies, support the mode of action of Toxaphene induced mouse liver tumors is through a nongenotoxic mechanism involving primarily a CAR-mediated processes that results in an increase in cell proliferation in the liver, promotes the clonal expansion of preneoplastic lesions leading to adenoma formation.
Thomas M Holsen - One of the best experts on this subject based on the ideXlab platform.
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Toxaphene trends in the great lakes fish
Journal of Great Lakes Research, 2012Co-Authors: Xiaoyan Xia, Bernard S Crimmins, Philip K Hopke, James J Pagano, Michael S Milligan, Thomas M HolsenAbstract:Abstract As part of the U.S. Great Lakes Fish Monitoring and Surveillance Program (GLFMSP), more than 300 lake trout ( Salvelinus namaycush ) and walleye ( Stizostedion vitreum vitreum ) collected from the Laurentian Great Lakes each year from 2004 to 2009, have been analyzed for total Toxaphene and eight selected congeners. The analytical results show fish Toxaphene concentrations are quite different among lakes. Between 2004 and 2009, Lake Superior lake trout had the highest concentration (119 to 482 ng/g) and Lake Erie walleye had the lowest concentration (18 to 47 ng/g). Combining these results with the historical total Toxaphene data (1977–2003), temporal changes were examined for each lake. Because of different analytical methods used in the previous studies, the historical data were adjusted using a factor of 0.56 based on a previous inter-method comparison in our laboratory. Trend analysis using an exponential decay regression showed that Toxaphene in Great Lakes fish exhibited a significant decrease in all of the lakes with t 1/2 (confidence interval) of 0.9 (0.8–1.1) years for Lake Erie walleye, 3.8 (3.5–4.1) years for Lake Huron lake trout, 5.6 (5.1–6.1) years for Lake Michigan lake trout, 7.5 (6.7–8.4) years for Lake Ontario lake trout and 10.1 (8.2–13.2) years for Lake Superior lake trout. Parlars 26, 50 and 62 were the dominant Toxaphene congeners accounting for 0.53% to 41.7% of the total Toxaphene concentration. Concentrations of these congeners generally also decreased over time.
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modeling Toxaphene behavior in the great lakes
Science of The Total Environment, 2011Co-Authors: Xiaoyan Xia, Philip K Hopke, Thomas M Holsen, Bernard S CrimminsAbstract:Chlorinated camphenes, Toxaphene, are persistent organic pollutants of concern in the Great Lakes since elevated concentrations are found in various media throughout the system. While concentrations have decreased since their peak values in the 1970s and 80s, recent measurements have shown that the rate of this decline in Lake Superior has decreased significantly. This modeling study focused on Toxaphene cycling in the Great Lakes and was performed primarily to determine if elevated water and fish concentrations in Lake Superior can be explained by physical differences among the lakes. Specifically, the coastal zone model for persistent organic pollutants (CoZMo-POP), a fugacity-based multimedia fate model, was used to calculate Toxaphene concentrations in the atmosphere, water, soil, sediment, and biota. The performance of the model was evaluated by comparing calculated and reported concentrations in these compartments. In general, simulated and observed concentrations agree within one order of magnitude. Both model results and observed values indicate that Toxaphene concentrations have declined in water and biota since the 1980s primarily as the result of decreased atmospheric deposition rates. Overall the model results suggest that the CoZMo-POP2 model does a reasonable job in simulating Toxaphene variations in the Great Lakes basin. The results suggest that the recent findings of higher Toxaphene concentrations in Lake Superior can be explained by differences in the physical properties of the lake (primarily large volume, large residence time and cold temperatures) compared to the lower lakes and increased recent inputs are not needed to explain the measured values.
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Toxaphene analysis in great lakes fish a comparison of gc ei ms ms and gc ecni ms individual congener standard and technical mixture for quantification of Toxaphene
Analytical and Bioanalytical Chemistry, 2009Co-Authors: Xiaoyan Xia, Bernard S Crimmins, Philip K Hopke, James J Pagano, Michael S Milligan, Thomas M HolsenAbstract:Toxaphene is considered to be a problematic organochlorine pollutant because of its bioaccumulation potential and persistence in aquatic environments. In this study, whole lake trout and walleye composites were used to evaluate two analytical techniques for total Toxaphene and selected congener analysis. The efficacy of using gas chromatography electron ionization tandem mass spectrometry (GC-EI/MS/MS) and electron capture negative ionization mass spectrometry (GC-ECNI-MS) were compared. Although the sensitivity using GC-ECNI-MS was approximately five times greater than GC-EI/MS/MS, the latter provided more consistent inter-Parlar relative response factors (RRF). When using technical calibration mixtures, these results suggest a more accurate total Toxaphene measurement was obtained using the GC-EI/MS/MS method. Total Toxaphene concentrations in lake trout composites from both methods were highly correlated (R(2) = 0.985) with the MS/MS concentrations approximately half of those determined by ECNI, suggesting systematic high bias in Toxaphene concentrations when measured using GC-ECNI.
Shuai Zhu - One of the best experts on this subject based on the ideXlab platform.
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determining indicator Toxaphene congeners in soil using comprehensive two dimensional gas chromatography tandem mass spectrometry
Talanta, 2014Co-Authors: Shuai Zhu, Lirong Gao, Minghui Zheng, Huimin Liu, Bing Zhang, Lidan Liu, Yiwen WangAbstract:Toxaphene, which is a broad spectrum chlorinated pesticide, is a complex mixture of several hundred congeners, mainly polychlorinated bornanes. Quantifying Toxaphene in environmental samples is difficult because of its complexity, and because each congener has a different response factor. Toxaphene chromatograms acquired using one-dimensional gas chromatography (1DGC) show that this technique cannot be used to separate all of the Toxaphene congeners. We developed and validated a sensitive and quantitative method for determining three indicator Toxaphene congeners in soil using an isotope dilution/comprehensive two-dimensional gas chromatography-tandem mass spectrometry (GC × GC-MS). The samples were extracted using accelerated solvent extraction, and then the extracts were purified using silica gel columns. (13)C₁₀-labeled Parlar 26 and 50 were used as internal standards and (13)C₁₀-labeled Parlar 62 was used as an injection standard. The sample extraction and purification treatments and the GC × GC-MS parameters were optimized. Subsequently the samples were determined by GC × GC-MS. The limits of detection for Parlar 26, 50, and 62 were 0.6 pg/g, 0.4 pg/g, and 1.0 pg/g (S/N=3), respectively, and the calibration curves had good linear correlations between 50 and 1000 μg/L (r(2)>0.99). Comprehensive two-dimensional GC gave substantial improvements over one-dimensional GC in the Toxaphene analysis. We analyzed soil samples containing trace quantities of Toxaphene to demonstrate that the developed method could be used to analyze Toxaphene in environmental samples.
