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Biofiltration was used to eliminate volatile organic compounds from air streams in bench-scale reactors inoculated with an adapted consortium. Organic and inert supports were tested on 100 days of operation. The supports were: peat, vermiculite, a mixture of vermiculite and activated carbon, tree bark and, porous glass Rashig rings. A mixture of benzene, toluene and xylene vapors with a load of 200 gC m(-3) h(-1) was fed to the biofilters with an empty bed residence time of 60 s. Removal efficiencies higher than 95% were obtained with the mixture of vermiculite and activated carbon, 85% for peat and bark, 80% for vermiculite and 65% for the Rashig rings. In all cases, drying problems in beds were observed after several days of operation. Water addition with or without nutrients was required to maintain and increase the performance of biofilters. In steady state operation, experiments at loads ranging from 50 to 400 gC m(-3) h(-1) were carried out and a maximum elimination capacity of 260 gC m(-3) h(-1) was obtained for vermiculite-activated carbon support. The three xylene isomers were degraded. Observations of the supports surface by scanning electronic microscopy at the end of the biofiltration experiment showed abundant growth of fungi, which were not in the inoculum, had colonized the biofilter.

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ResumenEl presente documento describe la situación actual referente a la reglamentación de la producción, distribución, almacenamiento y uso de los plaguicidas en México. Se muestran datos de morbilidad como consecuencia del uso de estos productos como un referente de sus efectos sobre la salud humana, así como, los sitios en la República Mexicana en donde la incidencia es mayor. Adicionalmente, se presenta una revisión de la regulación nacional e internacional sobre plaguicidas, así como, las distintas dependencias gubernamentales, organizaciones civiles y centros de investigación involucrados en el tema en México. La información presentada sugiere que a pesar de las regulaciones y restricciones de uso de los plaguicidas, éstos pueden representar un grave problema de salud para los trabajadores y poblaciones expuestas, así como, de contaminación de suelos y aguas en México. Palabras clave: plaguicidas, compuestos persistentes, organoclorados, legislación, exposición. AbstractThis paper describes the current situation of the regulation in the production, distribution, storage and application of pesticides in Mexico. Moreover, morbidity due to the application of these products is shown as reference of effects on human health, as well as, the Mexican states with higher incidences. Additionally, a review of national and international regulation on pesticides is presented, as well as, the governmental departments, non-governmental organizations and research centers involved in the issue in Mexico. The presented information suggest that despite the regulation and restriction of use of some pesticides, they could represent a serious health problem for farmers and exposed population and they can also represent a soil and water pollution problem in Mexico.

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