En este artículo se hace una revisión sobre estudios de caracterización fisicoquímica de los residuos lignocelulósicos, usos en la industria del papel, combustible, precursor de otros compuestos químicos y la experiencia en la optimización de materiales filtrantes. Para el efecto se establece materiales que han sido estudiados con este fin y los análisis fisicoquímicos que se han realizado como parte de la caracterización. También se revisó el potencial de los materiales filtrantes aptos para ser usados como filtros, en los cuales se probó su desempeño en lixiviado de suelo bajo condiciones controladas, potencial como combustible (Castillo et al., 2012), tecnologías de membranas (Mulder, 1996), bioadsorbente de cromo (Pinzón-Bedoya, M. L.; Cardona Tamayo, 2008), remoción de plomo y níquel con restos de cereales y cítricos (Quiñones, E.; Tejada, C.; Arcia, C.; Ruiz, 2013), remoción de plomo residuos de palma (Tejada Tovar, C.; Ruiz Paternina, E.; Gallo Mercado, J.; Moscote Bohorquez, 2015).

The objective of this study is to evaluate the contamination by pesticides in food grown in the parish of Chugchilán. From 258 families that were part of the main project, a sub‐sample of 26 families was obtained and, for each of them, a sample of food was extracted and evaluated by chromatographic methods. The main pesticides found in the locality are from the group of organophosphates, carbamates, dithiocarbamates, and glyphosate. Contamination by organophosphates, carbamates, and dithiocarbamates is well below the maximum residue limits while glyphosate is found in most foods exceeding the maximum residue limit, mainly in radish with 8.36 mg/kg being the limit of .1 mg/kg. There is evidence of contamination in food by pesticides, however, the values obtained are below the maximum residue limits with the exception of glyphosate. Organochlorines usage was not detected in any sample.Practical applicationsThis study may be of interest to the scientific community as it learns about the impact of pesticides on population food security, mainly vulnerable. Similarly, it can be a contribution to the agricultural community interested in eliminating pesticides from their production by implementing new cultivation techniques that are friendly to the environment and consumers health. It benefits the population of Chugchilán, since the information about the crops in the area allowing them to take actions and strategies that improve food quality and its population health.

An inexpensive. alternative, simple technique to decontaminate and clean used-up oils slightly contaminated with Co-GO, Mm54 and Zn-65 is presented. This technique takes advantage of the ferromagnctic properties of the material suspended in the contaminated oils and is based on the use OS small, con~mercial, inexpensive magncts. The preliminary results, which are also presented, demonstrate the feasibility of this technique when applied to oils at the laboratory scale. The efficiency of the technique rnakes possible an easy separation of the radioactive material in the form of sludge, which may be disposed of as any lowlevel radioactive wask. In accordance with Mexican normativity on radioactive wastes. the cleaned part of the oil is ready to be handled without the need of an incineration process.