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Martínez Ortega, Maria José - One of the best experts on this subject based on the ideXlab platform.
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Optimización del análisis de pesticidas limitados por la ECOETIQUETA Europea sobre algodón crudo
Universitat Politècnica de Catalunya, 2001Co-Authors: Martínez Ortega, Maria JoséAbstract:El documento base de este trabajo es el aprobado el 1-de marzo de 1996 por la comisión Europea que establece los criterios para la concesión de la ecoetiqueta a ropa de cama y camisetas de algodón o algodón-poliéster. Uno de los criterios, delimita el contenido de la fibra de algodón cruda en ciertos pesticidas. El trabajo realizado ha consistido en:-Recabar datos sobre la producción de algodón a nivel mundial: principales países productores, volumen de producción, sistemas de cultivo etc.-Recopilar datos de la legislación de diferentes países productores de algodón sobre uso de pesticidas en las diferentes fases productivas de dicha fibra.-Comparar el criterio en contenido de pesticidas sobre algodón crudo de la Etiqueta europea con la legislación de países productores sobre aplicación de pesticidas sobre algodón, estableciendo paralelismos y divergencias.-Establecer y optimizar, dentro de los recursos disponibles, el protocolo de análisis de los pesticidas limitados por la Etiqueta europea sobre algodón crudo, haciendo especial hincapié en las fases de extracción y purificación, para las cuales la Etiqueta europea no establece método alguno.-Realizar un estudio del contenido de aquellos pesticidas limitados por la Etiqueta europea sobre muestras de algodón crudo procedente de diferentes áreas productoras.El análisis de pesticidas se puede desglosar en tres fases bien diferenciadas: extracción, purificación y análisis de la muestra. La Ecoetiqueta de 1996, define la técnica de análisis propiamente dicho a emplear: US EPA 8270 pero no hace ninguna mención a los métodos de extracción, purificación y concentración de las muestras. Se focalizaron los esfuerzos en determinar un procedimiento de extracción, de purificación y de concentración que fuera el óptimo en cuanto a sencillez del material empleado y a volumen de solvente (datos que redundan en el coste final del análisis. Las conclusiones generales obtenidas son:- El documento inicialmente aprobado por la Comisión europea para la concesión de la Ecoetiqueta europea para artículos textiles, a nivel de pesticidas está sobradamente alejado de la situación real en cuanto a pesticidas limitados/empleados sobre algodón.- Existen discrepancias entre las legislaciones internas de los países miembros de la Unión Europea en cuanto a uso de pesticidas, existiendo un grupo de países europeos más permisivos.-Los pesticidas limitados por la Ecoetiqueta europea se corresponden con los más limitados a nivel mundial, en cambio en los principales países productores. China (1er productor mundial 22%), India (3er productor mundial 13%) y Pakistán (4º productor mundial 8%) presentan una legislación en la que se admite el uso de la mayoría de los pesticidas prohibidos por la ecoetiqueta europea. Estados Unidos (2º productor mundial 21%) permite el uso de algunos de ellos.- Se establece un protocolo de análisis de pesticidas sobre algodón considerado óptimo consistente en: Extracción con diclorometano de los pesticidas mediante un Soxhlet automatizado, con lo que se reduce el consumo de solvente (se recupera en un 60-70%) y el tiempo de análisis, presentando una recuperación de promedio superior al 80%.Purificación del extracto graso mediante un sistema de Florisil en el que se minimiza también el volumen de solvente empleado y que presenta una recuperación promedio de un 90%. Análisis del extracto graso mediante un sistema de CG-MS que presenta una elevada reproducibilidad de los tiempos de retención y que permite una cuantificación automatizada de muestras una vez establecidas las rectas de calibración pertinentes para cada analito a determinar.The European Union countries have included the environmental protection in their main goals since the mid-80's. One of the most important keys for this new European policy is the Ecolabeling. This project is based in the law passed the 1rst. of March, 1996, which sets up the requirements to qualify with the Ecolabel bedlinen, cotton or cotton-polyester t-shirts. Later on, the Comision reviewed and amended the law whose last version dates of the 17th of February, 1999. The Comision sets up in this document a generic Ecolabel for textile products. The main modified points which affect this experimental project are: the number and the kind of pesticides to analyze:(1996) Aldrine, Captafol, Camphechlor, Chlordane, DDT, Dieldrine, Endrine, Heptachlor, Hexachlorobenzene and 2,4,5- T. In addition to Pentachlorophenol, with a different criterion.(1999) Aldrine, Captafol, Chlordane, DDT, Dieldrine, Endrine, Heptachlor, Hexachlorobenzene, Hexachlorociclohexane, 2,4,5- T, Chlordimerform, Chlorbenzilate, Dinoseb and its sales and Monocrotophos.In both documents the limit allowed for each pesticide it is 0.005 ppm when the methods sensitivity enables it. Analysis regularityTests must be carried out 4 times a year. No kind of periodicity is specified.ECONOMICAL CONTEXTAfter the first version of the enacted law for the cotton and cotton-polyester manufactures ecolabeling was necessary a experimental project like this focused in the analysis of the cotton pesticides mentioned in the law.On one hand, there is an important European textile industry although the European Comunity countries (Greece and Spain excluded) produce almost no cotton. In the context of cotton textile industry most of the raw material is imported. On the other hand, the main cotton producer areas are in Asia (Pakistan, China, India), EEUU and the ex-URSS. In these countries the legislation about the use of the cotton pesticides waves from strict to almost inexistent.With regard to this, the European textile industry can find incongruent to try to make products which fulfil the ecological criterion, set up by the European Comision, (which have to be qualified with the Ecolabel), and the fact that they import the raw material from permissive countries.EXPERIMENTAL CONTEXTThere is huge information abaut the difficulty to determinate the pesticides in solid material in an analylitcal context. That is the problem of the cotton fibre. The general method to analyze the quality and quantity of the pesticides consists of three steps: extraction, purification and later, gas chromatography analysis with electron detector de captura de electrones, en el caso de organoclorados (GC-ECD) o espectrómetro de masas (GC-MS).For the reason stated before this project consisted of:· Compiling topical information about the production of cotton in the world and about the use of pesticides in cotton growing, harvesting, transport in the main cotton producer countries.· Comparing the European legislation (Ecolabel, 1996) to the legislation of some producer countries to stablish parallelisms and divergences.· Stablishing a working protocol to analize the pesticides on yarn cotton which are limited by the Ecolabel. · Studying the pesticides contexts on yarn cotton samples from different producer areas for the evaluation of the imported cotton. Once again the main work guidelines are stablished, it is important to point out the research institutes where the development of the experimental protocol has been carried out.· Laboratorio de Control de la Contaminación del Institut d'Investigació Tèxtil i Cooperació Industrial de Terrassa (INTEXTER).· Universidad Nacional de Misiones (Posadas, Argentina)· Southwest Research Institute (San Antonio, Texas, EEUU).EXPERIMENTAL PROTOCOLThe analysis of pesticides can be set aside in three different steps: extraction, purification, and the anlysis of the samples itself (we can consider the concentration of the samples as a fourth step as much important as the other ones). The basic law of this project, Ecolabel, 1996, explains the methods to make the anlysis: US EPA 8270 "Compuestos orgánicos semivolátiles por GC/MS:"(), but it doesn't mention the methods for the pesticide extraction from the samples. They talk, for the first time, about the extraction step in the document of 1999. In the document is recommended the ultrasonic and solvents but no conditions are specified.Considering the document of the beginning of the experimental project all the efforts were focused to determine the most favorable extraction, purification and concentration procedures in relation with the simplicity of the material used and the volume of solvent (both are noticeable in the analysis final cost).The different procedures carried out were:The following is the considered the very best analysis protocole:· Extraction from the yarn cotton samples (5 grams wighted on an analytical balance using an automatized Soxleth during two hours at 105ºC in at about 100 ml of DCM. One hour in "boiling" position and the other in "rinsisng" position.· Quantitative transference of extract to a 12 ml vial adding DCM 3 times to take away any residuum left from the Soxleth glasses.· Concentrate the extracts with nitrogenum placing los viales into warm water: 30- 35ºC.· Purification of the samples using Florisil, activated and moistened with about 10 ml of n-hexane, increase with the samples to be purifies and use a solvent to eluir it to a total of 25m l0% (v/v) acetona-n-hexano, just prepared.· Concentration of the extracts final volume which had been purified with nitrogenum placing los viale, when it's possible in warm water, 30-35ºC. Analysis using GC-MS US EPA 8270 from the final samples.Postprint (published version
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Optimización del análisis de pesticidas limitados por la ECOETIQUETA Europea sobre algodón crudo
Universitat Politècnica de Catalunya, 2001Co-Authors: Martínez Ortega, Maria JoséAbstract:DE LA TESIS DOCTORALEl documento base de este trabajo es el aprobado el 1-de marzo de 1996 por la comisión Europea que establece los criterios para la concesión de la ecoetiqueta a ropa de cama y camisetas de algodón o algodón-poliéster. Uno de los criterios, delimita el contenido de la fibra de algodón cruda en ciertos pesticidas. El trabajo realizado ha consistido en:-Recabar datos sobre la producción de algodón a nivel mundial: principales países productores, volumen de producción, sistemas de cultivo etc.-Recopilar datos de la legislación de diferentes países productores de algodón sobre uso de pesticidas en las diferentes fases productivas de dicha fibra.-Comparar el criterio en contenido de pesticidas sobre algodón crudo de la Etiqueta europea con la legislación de países productores sobre aplicación de pesticidas sobre algodón, estableciendo paralelismos y divergencias.-Establecer y optimizar, dentro de los recursos disponibles, el protocolo de análisis de los pesticidas limitados por la Etiqueta europea sobre algodón crudo, haciendo especial hincapié en las fases de extracción y purificación, para las cuales la Etiqueta europea no establece método alguno.-Realizar un estudio del contenido de aquellos pesticidas limitados por la Etiqueta europea sobre muestras de algodón crudo procedente de diferentes áreas productoras.El análisis de pesticidas se puede desglosar en tres fases bien diferenciadas: extracción, purificación y análisis de la muestra. La Ecoetiqueta de 1996, define la técnica de análisis propiamente dicho a emplear: US EPA 8270 pero no hace ninguna mención a los métodos de extracción, purificación y concentración de las muestras. Se focalizaron los esfuerzos en determinar un procedimiento de extracción, de purificación y de concentración que fuera el óptimo en cuanto a sencillez del material empleado y a volumen de solvente (datos que redundan en el coste final del análisis. Las conclusiones generales obtenidas son:- El documento inicialmente aprobado por la Comisión europea para la concesión de la Ecoetiqueta europea para artículos textiles, a nivel de pesticidas está sobradamente alejado de la situación real en cuanto a pesticidas limitados/empleados sobre algodón.- Existen discrepancias entre las legislaciones internas de los países miembros de la Unión Europea en cuanto a uso de pesticidas, existiendo un grupo de países europeos más permisivos.-Los pesticidas limitados por la Ecoetiqueta europea se corresponden con los más limitados a nivel mundial, en cambio en los principales países productores. China (1er productor mundial 22%), India (3er productor mundial 13%) y Pakistán (4º productor mundial 8%) presentan una legislación en la que se admite el uso de la mayoría de los pesticidas prohibidos por la ecoetiqueta europea. Estados Unidos (2º productor mundial 21%) permite el uso de algunos de ellos.- Se establece un protocolo de análisis de pesticidas sobre algodón considerado óptimo consistente en: Extracción con diclorometano de los pesticidas mediante un Soxhlet automatizado, con lo que se reduce el consumo de solvente (se recupera en un 60-70%) y el tiempo de análisis, presentando una recuperación de promedio superior al 80%.Purificación del extracto graso mediante un sistema de Florisil en el que se minimiza también el volumen de solvente empleado y que presenta una recuperación promedio de un 90%. Análisis del extracto graso mediante un sistema de CG-MS que presenta una elevada reproducibilidad de los tiempos de retención y que permite una cuantificación automatizada de muestras una vez establecidas las rectas de calibración pertinentes para cada analito a determinar.DOCTORAL THESIS SUMMARYSTATUTORY CONTEXTThe European Union countries have included the environmental protection in their main goals since the mid-80's. One of the most important keys for this new European policy is the Ecolabeling. This project is based in the law passed the 1rst. of March, 1996, which sets up the requirements to qualify with the Ecolabel bedlinen, cotton or cotton-polyester t-shirts. Later on, the Comision reviewed and amended the law whose last version dates of the 17th of February, 1999. The Comision sets up in this document a generic Ecolabel for textile products. The main modified points which affect this experimental project are: the number and the kind of pesticides to analyze:(1996) Aldrine, Captafol, Camphechlor, Chlordane, DDT, Dieldrine, Endrine, Heptachlor, Hexachlorobenzene and 2,4,5- T. In addition to Pentachlorophenol, with a different criterion.(1999) Aldrine, Captafol, Chlordane, DDT, Dieldrine, Endrine, Heptachlor, Hexachlorobenzene, Hexachlorociclohexane, 2,4,5- T, Chlordimerform, Chlorbenzilate, Dinoseb and its sales and Monocrotophos.In both documents the limit allowed for each pesticide it is 0.005 ppm when the methods sensitivity enables it. Analysis regularityTests must be carried out 4 times a year. No kind of periodicity is specified.ECONOMICAL CONTEXTAfter the first version of the enacted law for the cotton and cotton-polyester manufactures ecolabeling was necessary a experimental project like this focused in the analysis of the cotton pesticides mentioned in the law.On one hand, there is an important European textile industry although the European Comunity countries (Greece and Spain excluded) produce almost no cotton. In the context of cotton textile industry most of the raw material is imported. On the other hand, the main cotton producer areas are in Asia (Pakistan, China, India), EEUU and the ex-URSS. In these countries the legislation about the use of the cotton pesticides waves from strict to almost inexistent.With regard to this, the European textile industry can find incongruent to try to make products which fulfil the ecological criterion, set up by the European Comision, (which have to be qualified with the Ecolabel), and the fact that they import the raw material from permissive countries.EXPERIMENTAL CONTEXTThere is huge information abaut the difficulty to determinate the pesticides in solid material in an analylitcal context. That is the problem of the cotton fibre. The general method to analyze the quality and quantity of the pesticides consists of three steps: extraction, purification and later, gas chromatography analysis with electron detector de captura de electrones, en el caso de organoclorados (GC-ECD) o espectrómetro de masas (GC-MS).For the reason stated before this project consisted of:· Compiling topical information about the production of cotton in the world and about the use of pesticides in cotton growing, harvesting, transport in the main cotton producer countries.· Comparing the European legislation (Ecolabel, 1996) to the legislation of some producer countries to stablish parallelisms and divergences.· Stablishing a working protocol to analize the pesticides on yarn cotton which are limited by the Ecolabel. · Studying the pesticides contexts on yarn cotton samples from different producer areas for the evaluation of the imported cotton. Once again the main work guidelines are stablished, it is important to point out the research institutes where the development of the experimental protocol has been carried out.· Laboratorio de Control de la Contaminación del Institut d'Investigació Tèxtil i Cooperació Industrial de Terrassa (INTEXTER).· Universidad Nacional de Misiones (Posadas, Argentina)· Southwest Research Institute (San Antonio, Texas, EEUU).EXPERIMENTAL PROTOCOLThe analysis of pesticides can be set aside in three different steps: extraction, purification, and the anlysis of the samples itself (we can consider the concentration of the samples as a fourth step as much important as the other ones). The basic law of this project, Ecolabel, 1996, explains the methods to make the anlysis: US EPA 8270 "Compuestos orgánicos semivolátiles por GC/MS:"(), but it doesn't mention the methods for the pesticide extraction from the samples. They talk, for the first time, about the extraction step in the document of 1999. In the document is recommended the ultrasonic and solvents but no conditions are specified.Considering the document of the beginning of the experimental project all the efforts were focused to determine the most favorable extraction, purification and concentration procedures in relation with the simplicity of the material used and the volume of solvent (both are noticeable in the analysis final cost).The different procedures carried out were:The following is the considered the very best analysis protocole:· Extraction from the yarn cotton samples (5 grams wighted on an analytical balance using an automatized Soxleth during two hours at 105ºC in at about 100 ml of DCM. One hour in "boiling" position and the other in "rinsisng" position.· Quantitative transference of extract to a 12 ml vial adding DCM 3 times to take away any residuum left from the Soxleth glasses.· Concentrate the extracts with nitrogenum placing los viales into warm water: 30- 35ºC.· Purification of the samples using Florisil, activated and moistened with about 10 ml of n-hexane, increase with the samples to be purifies and use a solvent to eluir it to a total of 25m l0% (v/v) acetona-n-hexano, just prepared.· Concentration of the extracts final volume which had been purified with nitrogenum placing los viale, when it's possible in warm water, 30-35ºC. Analysis using GC-MS US EPA 8270 from the final samples
Walter Vetter - One of the best experts on this subject based on the ideXlab platform.
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analysis and characterization of polychlorinated hydroxybornanes as metabolites of toxaphene using a polar bear model
Environmental Science & Technology, 2017Co-Authors: Lea Reger, Christoph Gallistl, Karl Skirnisson, Walter VetterAbstract:Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) ...
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Analysis and Characterization of Polychlorinated Hydroxybornanes as Metabolites of Toxaphene Using a Polar Bear Model
2017Co-Authors: Lea Reger, Christoph Gallistl, Karl Skírnisson, Walter VetterAbstract:Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) deactivated and (iii) activated silica gel. Hence, up to 320 and 4350 μg/kg lipid weight of octa- and nonachlorinated CTTs were detected in four liver samples and adipose tissue of polar bears, respectively. Furthermore, the presence of one hexachlorinated OH-CTT isomer could be verified in the samples, which was about 1% of the octachlorinated CTTs determined in the liver samples
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synthesis of low and high chlorinated toxaphene and comparison of their toxicity by zebrafish danio rerio embryo test
Environmental Toxicology and Chemistry, 2006Co-Authors: Thomas Kapp, Ulrike Kammann, Michael Vobach, Walter VetterAbstract:Toxaphene, also known as camphechlor, is a persistent organochlorine pesticide of complex composition. It is technically produced by photochlorination of camphene with elemental chlorine gas under ultraviolet irradiation. In the present work, a novel, laboratory-scale synthesis using sulfuryl chloride as a chlorinating reagent is described. This approach allowed the degree of chlorination of the resulting mixtures to be arbitrarily adjusted by varying the reaction conditions. Both the compositions and the chlorine contents of the low- and high-chlorinated mixtures acquired using this method were similar to those of environmentally altered toxaphene and technical toxaphene, respectively. For comparison of these mixtures regarding toxicity, they were subjected to the zebrafish (Danio rerio) embryo test. Median effective concentrations (EC50s) were calculated based on the presence of lethal and nonlethal embryonic malformations. Surprisingly, low-chlorinated toxaphene, comprising compounds that also are present in environmentally transformed toxaphene, exhibited a twofold-higher toxicity (according to the EC50 for nonlethal effects) toward the test organisms compared with high-chlorinated toxaphene, the composition of which resembled that of the technical product. Although the effective concentrations in the embryo test were much higher than those in aquatic ecosystems burdened with toxaphene, the present results lead to the assumption that toxaphene is becoming more toxic during transformation in the environment. A decrease in the total amount of toxaphene during environmental breakdown would then be compensated for, at least in part, by the higher toxicity of weathered toxaphene in sediments, soils, and biota of contaminated ecosystems.
A Cruzgranja - One of the best experts on this subject based on the ideXlab platform.
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toxaphene residues from cotton fields in soils and in the coastal environment of nicaragua
Chemosphere, 2003Co-Authors: Fernando P Carvalho, S Montenegroguillen, Jeanpierre Villeneuve, Chantal Cattini, Imma Tolosa, J Bartocci, M Lacayoromero, A CruzgranjaAbstract:Toxaphene (camphechlor) was intensively used in the cotton growing fields of Nicaragua for decades with application rates as high as 31 kg ha � 1 in 1985. Although the use of this compound has recently been discontinued in the country, its intensive use in the past and its long persistence in soil allowed for the build up of large reservoirs of toxaphene in agriculture soils and a wide dispersal of residues in the environment. Measurements of toxaphene in coastal areas on the coast of the Pacific Ocean show that environmental concentrations are particularly high in the district of Chinandega, the traditional cotton growing region. Toxaphene residues measured in soils attained 44 l gg � 1 (dry weight) while concentrations in lagoon sediments attained 6.9 l gg � 1 (dry weight) near the mouth of the rivers flowing across the agricultural region. Measurements in aquatic biota showed concentrations as high as 1.6 l gg � 1 (dry weight) in the soft tissues of clams. The toxaphene reservoir in soils combined with the obvious persistence of this compound in soils and lagoon sediments allows predicting that toxaphene will remain in the coastal ecosystem at relatively high concentrations for many years. Toxic effects in lagoon fauna are likely to be observed especially in benthic species that may recycle this compound from sediments. Consumption of seafood, in particular of clams (Anadara spp.) from the more contaminated areas, may expose the population to unacceptably high intake of toxaphene, 30 l gd � 1 per person, with the diet. 2003 Elsevier Ltd. All rights reserved.
Lea Reger - One of the best experts on this subject based on the ideXlab platform.
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analysis and characterization of polychlorinated hydroxybornanes as metabolites of toxaphene using a polar bear model
Environmental Science & Technology, 2017Co-Authors: Lea Reger, Christoph Gallistl, Karl Skirnisson, Walter VetterAbstract:Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) ...
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Analysis and Characterization of Polychlorinated Hydroxybornanes as Metabolites of Toxaphene Using a Polar Bear Model
2017Co-Authors: Lea Reger, Christoph Gallistl, Karl Skírnisson, Walter VetterAbstract:Abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (CTTs) are degraded. Until now, there has been little knowledge on oxidation transformation of toxaphene. For instance, the existence of hydroxylated CTTs (OH-CTTs) in authentic environmental and food samples has not been proven. For this reason, we synthesized a mixture consisting of tetra- to heptachlorinated OH-CTTs and simplified it by countercurrent chromatography (CCC). Thus, 227 OH-CTTs were detected in the CCC fractions (12 tetra-, 117 penta-, 81 hexa-, and 17 heptachlorinated OH-CTTs), which was >50% more than detected before the fractionation. One CCC fraction consisting of only 18 OH-CTTs was used to develop a sample cleanup method which aimed to remove CTTs, isobaric PCBs, and sample matrix. The final cleanup procedure consisted of (i) gel permeation chromatography (GPC) and adsorption chromatography using (ii) deactivated and (iii) activated silica gel. Hence, up to 320 and 4350 μg/kg lipid weight of octa- and nonachlorinated CTTs were detected in four liver samples and adipose tissue of polar bears, respectively. Furthermore, the presence of one hexachlorinated OH-CTT isomer could be verified in the samples, which was about 1% of the octachlorinated CTTs determined in the liver samples
Fernando P Carvalho - One of the best experts on this subject based on the ideXlab platform.
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toxaphene residues from cotton fields in soils and in the coastal environment of nicaragua
Chemosphere, 2003Co-Authors: Fernando P Carvalho, S Montenegroguillen, Jeanpierre Villeneuve, Chantal Cattini, Imma Tolosa, J Bartocci, M Lacayoromero, A CruzgranjaAbstract:Toxaphene (camphechlor) was intensively used in the cotton growing fields of Nicaragua for decades with application rates as high as 31 kg ha � 1 in 1985. Although the use of this compound has recently been discontinued in the country, its intensive use in the past and its long persistence in soil allowed for the build up of large reservoirs of toxaphene in agriculture soils and a wide dispersal of residues in the environment. Measurements of toxaphene in coastal areas on the coast of the Pacific Ocean show that environmental concentrations are particularly high in the district of Chinandega, the traditional cotton growing region. Toxaphene residues measured in soils attained 44 l gg � 1 (dry weight) while concentrations in lagoon sediments attained 6.9 l gg � 1 (dry weight) near the mouth of the rivers flowing across the agricultural region. Measurements in aquatic biota showed concentrations as high as 1.6 l gg � 1 (dry weight) in the soft tissues of clams. The toxaphene reservoir in soils combined with the obvious persistence of this compound in soils and lagoon sediments allows predicting that toxaphene will remain in the coastal ecosystem at relatively high concentrations for many years. Toxic effects in lagoon fauna are likely to be observed especially in benthic species that may recycle this compound from sediments. Consumption of seafood, in particular of clams (Anadara spp.) from the more contaminated areas, may expose the population to unacceptably high intake of toxaphene, 30 l gd � 1 per person, with the diet. 2003 Elsevier Ltd. All rights reserved.