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Objective. In this study the biomass of the yeast Saccharomyces cerevisiae was used to remove lead, mercury and nickel in the form of ions dissolved in water. Materials and methods. Synthetic solutions were prepared containing the three heavy metals, which were put in contact with viable microorganisms at different conditions of pH, temperature, aeration and agitation. Results. Both individual variables and the interaction effects influenced the biosorption process. Throughout the experimental framework it was observed that the biomass of Saccharomyces cerevisiae removed a higher percentage of lead (86.4%) as compared to mercury and nickel (69.7 and 47.8% respectively). When the pH was set at a value of 5 the effect was positive for all three metals. Conclusions. pH was the variable that had a greater influence on the biosorption of lead on the biomass of Saccharomyces cerevisiae. The affinity of the heavy metals for the biomass followed the order Pb>Hg>Ni.

Los plaguicidas han sido utilizados en todo el mundo desde mediados del siglo XX, en campañas de Salud Pública y en prácticas agrícolas. Los Plaguicidas Organoclorados (POCs) presentan mayor impacto sobre el ambiente porque no son biodegradables, son lipofílicos, tienen gran movilidad por todo el planeta y gran tendencia a la bioacumulación, através de la cadena trófica. Con el objetivo de identificar y cuantificar plaguicidas organoclorados en leche entera pasteurizada de dos marcas (A y B), que se comercializan en la ciudad de Cartagena de Indias, se realizó la presente investigación, utilizando Microextracción en Fase Sólida en Espacio de Cabeza y Cromatografía de Gases con Detector de Captura de Electrones (HS-SPME-GC/ECD). Fueron analizadas 36 muestras (n=36), 18 de cada marca. El 100% de las muestras (n=36) resultaron positivas para el plaguicida lindano (γ-HCH), superando el Límite Máximo Residual (LMR) de 0,01 mg/kg, establecido por la Food and Agriculture Organization y la Organización Mundial de la Salud (FAO/OMS). Las concentraciones promedio de lindano obtenidas para la marca A fueron de 0,042 mg/kg ± 0,003 y 0,062 ± 0,0016 mg/kg (base grasa) para la marca B, no superando la Ingesta Diaria Admisible (IDA) de 0,001 mg/kg de peso corporal.Os pesticidas têm sido usados em todo o mundo desde meados do século XX, as campanhas de saúde pública e práticas agrícolas. Os inseticidas organoclorados (AP) têm maior impacto sobre o meio ambiente porque não são biodegradáveis, são lipofílicas, têm grande mobilidade ao redor do mundo e maior tendencia para a bioacumulação através da cadeia alimentar. A fim de identificar e quantificar pesticidas organoclorados em leite integral, duas marcas (A e B), comercializada na cidade de Cartagena das Índias, a presente investigação foi realizada por cromatografia em Fase Sólida, Microextração Headspace Gás com Detector de Captura de Elétrons(HS-SPME-GC/ECD). 36 amostras foram analisadas (n = 36), 18 de cada marca. 100% das amostras (n = 36) foram positivas para o pesticida lindano (γ-HCH), ultrapassando o limite máximo residual (LMR) de 0,01 mg/kg, definido pela Organização para a Alimentação e Agricultura eo Mundo Organização Mundial da Saúde (FA0 / OMS). As concentrações médias obtidas para o tipo A foi de 0,042 mg/kg± 0,003 e 0,062 ± 0,0016 mg / kg B (gordura) Base para a marca, não superior a Ingestão Diaria Aceitável (IDA) de 0,001 mg/kg de peso corporal.Pesticides have been used worldwide since the mid-twentieth century, public health campaigns and agricultural practices. Organochlorine pesticides (POCs) have greater impact on the environment because they are not biodegradable, are lipophilic, have great mobility around the globe and greater tendency to bioaccumulate through the food chain. In order to identify and quantify organochlorine pesticides in pasteurized whole milk, two brands (A and B), sold in the city of Cartagena de Indias, the present investigation was carried out using Solid Phase Microextraction Headspace Chromatography Gas with Electron Capture Detector(HS-SPME-GC/ECD). 36 samples were analyzed (n = 36), 18 from each brand. 100% of the samples (n = 36) were positive for the pesticide lindane (γ-HCH), exceeding the Maximum Residual Limit (MRL) of 0.01 mg / kg, set by the Food and Agriculture Organization and the World Health Organization (FAO/WHO). The average concentrations obtained for brand A were of 0.042 mg/ kg ± 0.003and0.062 ± 0.0016mg/kg (fatbasis) for brand B, notexceeding the Acceptable Daily Intake (ADI) of 0.001 mg / kg body weight.