RESUMO
Since early 1900s, with the beginning of mining operations and especially in the last decade, small, although repetitive spills of fuel oil had occurred frequently in the Chilean mining desert industry during reparation and maintenance of machinery, as well as casual accidents. Normally, soils and sawdust had been used as cheap readily available sorbent materials of spills of fuel oil, consisting of complex mixtures of aliphatic and aromatic hydrocarbons. Chilean legislation considers these fuel oil contaminated mixtures of soil and sawdust as hazardous wastes, and thus they must be contained. It remains unknown whether it would be feasible to clean-up Chilean desert soils with high salinity and metal content, historically polluted with different commercial fuel oil, and contained during years. Thus, this study evaluated the feasibility of aerated in-vessel composting at a laboratory scale as a bioremediation technology to clean-up contaminated desert mining soils (fuel concentration>50,000 mg kg(-1)) and sawdust (fuel concentration>225,000 mg kg(-1)) in the Atacama Region. The composting reactors were operated using five soil to sawdust ratios (S:SD, 1:0, 3:1, 1:1, 1:3, 0:1, on a dry weight basis) under mesophilic temperatures (30-40 degrees C), constant moisture content (MC, 50%) and continuous aeration (16 l min(-1)) during 56 days. Fuel oil concentration and physico-chemical changes in the composting reactors were monitored following standard procedures. The highest (59%) and the lowest (35%) contaminant removals were observed in the contaminated sawdust and contaminated soil reactors after 56 days of treatment, respectively. The S:SD ratio, time of treatment and interaction between both factors had a significant effect (p<0.050) on the contaminant removal. The results of this research indicate that bioremediation of an aged contaminated mixture of desert mining soil and sawdust with fuel oil is feasible. This study recommends a S:SD ratio 1:3 and a correct nutrient balance in order to achieve a maximum overall hydrocarbon removal of fuel oil in the weathered and aged contaminated wastes.
Assuntos
Biodegradação Ambiental , Poluentes do Solo/análise , Solo , Reatores Biológicos , Chile , Meio Ambiente , Poluição Ambiental , Recuperação e Remediação Ambiental , Desenho de Equipamento , Substâncias Perigosas , Metais/química , Óleos , Temperatura , Fatores de TempoRESUMO
Noctuid moths flutter in the high Andes nights at 4,000 m. s. n. m. Their larvae feed on aerial or underground parts of succulent plants. Many of these species are new to science. Strategies and adaptations of the moths for survival in the high Andes mountains are: a circulatory system that includes an abdominal thoracic countercurrent heat exchanger, and they are insulated from the environment by a coat of dense hair like scales. Recently, during January and July 2004, in the northern desert of Chile, called Salar de Punta Negra, under the salt crust we found a large number of pupae and larvae that correspond to three new species of noctuid moth - this pupation site is located in a 10 m wide area surrounding a water body; the mean observed density is 13 to 15 pupae per 100 cm(2). This is a new extreme habitat conquered by noctuid moths.
Assuntos
Mariposas , Animais , Chile , Ecossistema , Densidade DemográficaRESUMO
Noctuid moths flutter in the high Andes nights at 4,000 m. s. n. m. Their larvae feed on aerial or underground parts of succulent plants. Many of these species are new to science. Strategies and adaptations of the moths for survival in the high Andes mountains are: a circulatory system that includes an abdominal thoracic countercurrent heat exchanger, and they are insulated from the environment by a coat of dense hair like scales. Recently, during January and July 2004, in the northern desert of Chile, called Salar de Punta Negra, under the salt crust we found a large number of pupae and larvae that correspond to three new species of noctuid moth - this pupation site is located in a 10 m wide area surrounding a water body; the mean observed density is 13 to 15 pupae per 100 cm². This is a new extreme habitat conquered by noctuid moths.
Las polillas revolotean en las noches andinas a los 4000 m. s. n. m.; sus larvas se alimentan de las partes aéreas y subterráneas de las plantas suculentas. Muchas de estas especies son nuevas para la ciencia. Las estrategias y adaptaciones de las polillas para sobrevivir en los Andes son poseer un sistema circulatorio que incluye un sistema de contracorriente intercambiador de calor abdominal y torácico, y ellos se encuentran aislados del ambiente por una densa cubierta de escamas piliformes. Recientemente, durante Enero y Julio del 2004, en el norte desértico de Chile, en el Salar de Punta Negra, bajo costras de sal, donde se encontraron un gran número de pupas y larvas que corresponden a tres especies nuevas; su pupación está localizada a 10 m en una amplia área alrededor de un cuerpo de agua; la densidad media observada es de 13 a 15 pupas por 100 cm². Este es un nuevo hábitat extremo conquistado por los nóctuidos.