Browsing by Autor "R. Sanabria"

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    Diversidad acuática en la zona de influencia de un campo de gas y petróleo en la provincia Carrasco (Cochabamba, Bolivia)
    (2000) Franklin Horacio Lozada Maldonado; Paul Van Damme; R. Sanabria; Fabio Araya Carvajal; Carlo Vandecasteele; Joel Rojas Acuña
    AQUATIC DIVERSITY IN A RIVER ADJACENT TO A GAS AND PETROLEUM EXPLOITATION SITE IN THE PROVINCE CARRASCO (COCHABAMBA, BOLIVIA) El rio Izozog (Carrasco, departamento de Cochabamba) recibe desechos liquidos difusos de la actividad petrolera desarrollada en la zona. La diversidad acuatica en este rio fue estudiada, y los impactos posibles de contaminacion por los derrames sobre la diversidad acuatica fueron investigados. El efecto sobre la calidad del agua es poco apreciable tanto en epoca de estiaje como en periodo de lluvias: unicamente en la zona de muestreo rio abajo de las descargas, se detecto un incremento en conductividad, D00 (Demanda Quimica de Oxigeno) e Hidrocarburos Totales. Macroinvertebrados bentonicos fueron muestreados con un surber sampler en rapidos y con una draga Van Veen en pozas. La comunidad de peces fue muestreada con un equipo portatil de pesca electrica (Smith-Rooth) en rapidos. Los macroinvertebrados bentonicos del rio Izozog pertenecen a 19 familias. Los 497 peces que fueron capturados pertenecen a 17 taxas. Characidae y Loricariidae fueron las familias mejor representadas tanto en terminos de numero de especies como en numero de individuos. B imii>8cto de la contaminacion se evidencio sobre las comunidades de bentos rio abajo del area de contaminacion difusa durante la epoca seca; sin embargo, en epoca de lluvias el efecto sobre el bentos no fue significativo. No hubo un impacto detectable de la contaminacion sobre los peces. Empero, fue dificil discriminar entre variaciones naturales y cambios inducidos por contaminacion. Una discusion sobre estrategias de muestreo para detectar impactos ambientales esta incluida. Palabras clave: Contaminacion, petroleo, bentos, peces, rio Izozog, Cochabamba, Bolivia. ABSTRACT The Izozog River receives contaminated water from a number of non-point sources, generated by oil exploration activities in the Carrasco Province of the State of Cochabamba. The aquatic diversity in this river was studied and possible impacts of oil contamination on aquatic diversity were assessed. In general, the effect on water quality was minor in both the rainy and dry season. Only in samples collected downriver from the pollution source, was an increase in conductivity, 00D (Chemical Oxygen Oemand), and Total Hydrocarbon Concentration observed. In rapids, the benthic macroinvertebrates were sampled with a surber sampler while in pools, a Van Veen sampler was used. In rapids, the fish community was sampled with a portable electrical fishing apparatus (Smith-Root). The benthic macroinvertebrates recorded in the Izozog River belonged to 19 different families. A total of 497 fish, belonging to 17 different taxa, were collected. In terms of species number and number of individuals, Characidae and Loricariidae were most numerous. The impact of the contamination on the benthic community in the sample point immediately downstream from the non-point contamination sources was observed during the dry season, whereas the impact on the fish community was never detectable. The overall impact during the rainy season was small. However; it was difficult to distinguish between natural variation and contamination-induced changes in community structure. A discussion on sample strategies to detect environmental impacts of petroleum contamination is also presented. Key words: Contamination, petroleum, benthos, bio-indication, river Izozog, Cochabamba, Bolivia.
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    EL IMPACTO DE CONTAMINACIÓN POR HIDROCARBUROS SOBRE LA CALIDAD DE AGUAS Y SOBRE MACROINVERTEBRADOS BENTÓNICOS DEL RIO HONDO (CARRASCO, COCHABAMBA, BOLVIA)
    (2000) Francisco Maldonado; PA Van Damme; Joel Rojas Acuña; R. Sanabria; Claude Creemers; Carlo Vandecasteele
    THE IMPACT OF PETROLEUM CONTAMINATION ON THE WATER AUALITY AND THE BENTHIC MACROINVERTEBRATES OF RIVER HONDO (CARRASCO, COCHABAMBA, BOLIVIA) El impacto que ejercen las descargas de residuos liquidos y solidos petroleros sobre los ecosistemas acuaticos de agua dulce es muy poco conocido. Este estudio investiga el impacto ambiental causado por la actividad petrolera en la provincia Carrasco del Departamento de Cochabamba (Bolivia). El estudio de caso es un derrame continuo de desechos liquidos con hidrocarburos, que afecta a al calidad de aguas superficiales y a la comunidad de macroinvertebrados bentonicos en el rio Hondo, un rio pequeno de bajo caudal, en dos periodos, epoca seca y epoca de Iluvias. El agua en el punto de descarga presento valores elevados de hidrocarburos totales. En la torrentera que recibe los desechos y en los tramos mas contaminados del rio Hondo no se encontro ningun organismo. La concentracion de los contaminantes disminuyo notablemente a lo largo del rio Hondo, principalmente por efecto de dilucion. En los tramos rio abajo, con contaminacion intermedia, se observo poco impacto sobre la diversidad de macroinvertebrados acuaticos, pero si sobre la densidad y sobre la estructura tropica de las comunidades. Los efectos de contaminacion fueron mas severos en epoca de estiaje que en epoca de lluvias, probablemente debido a una mayor dilucion en la ultima epoca. Palabras clave: Contaminacion, petroleo, bentos, bio-indicaccion, rio Hondo, Cochabamba, Bolivia. ABSTRACT The environmental impact of solid and liquid petroleum contamination on aquatic freshwater systems is poorly understood. The impact of small, continuous petroleum spills was studied in the province Carrasco in the department of Cochabamba (Bolivia) in the Hondo rivet; a river with small discharge. The impact of hydrocarbon waste on river water quality and on the macroinvertebrate community structure was studied during two periods, the dry season and the rainy season. In the small brook, which received hydrocarbon containing liquid waste and in the upper parts of Hondo rivet; no organisms were recorded as a result of hydrocarbon contamination. There was a downstream decrease of contamination levels due to dilution effects. In downstream segments with intermediate contamination levels, the impact of petroleum contamination on macroinvertebrate diversity was small, whereas the impact on the density of macroinvertebrates and on the trophic structure of the benthic communities was significant in both seasons. The effects of contamination were always more severe in the dry season than in the rainy season, probably because of dilution effect during the rainy season. Key words: Contamination, petroleum, benthos, bio-indication, Hondo river, Cochabamba, Bolivia.