Carolina Merlo

Integral assessment of pollution in the Suquía River (Córdoba, Argentina) as a contribution to lotic ecosystem restoration programs.

The Suquía River lower-middle basin (Córdoba, Argentina) is subject to a strong anthropic impact because it receives pollutants from different sources (industries, wastewaters, heavy traffic, agricultural land use, etc.) We have assessed the degree of watershed degradation of Suquía River lower-middle sections through the analysis of different ecosystem compartments (air, water, riparian soil, sediments and biota), in order to provide useful data to be considered in future river restoration programs. Four study sites were selected along the river (La Calera city, Córdoba city, Corazón de María village and Río Primero city) which were sampled during the low- and high-water flow periods. We analyzed: a) chemical and physical characteristics of water, sediments, and riparian soil; b) heavy metal content of water and sediments, and c) semi-volatile organic compounds in air. Besides, pollutant bioindicators such as fish assemblages, lichens (Usnea amblyoclada), vascular plants (Tradescantia pallida), and microorganisms (fecal coliform and Escherichia coli) were used to further assess the status of the river. All analyzed ecological compartments were affected by water pollution, particularly, fish assemblages, sediments and riparian soils by heavy metal and coliform bacteria. Moreover, we detected a possible contribution of sulfur and a high pollutant content in air that merit further research about other air-water exchanges. Accordingly, we strongly suggest that an action to restore or remediate the anthropic effect on the Suquía River be extended to all possible compartments along the river.

Parotid sialosis: morphometrical analysis of the glandular parenchyme and stroma among diabetic and alcoholic patients

BACKGROUND Among the agents that cause parotid sialosis, diabetes mellitus type 2 and chronic alcoholism are included. In this study, the morphometrical modifications in the diabetic parotid sialosis were determined to compare them with the histopathological characteristics of alcoholic parotid sialosis. METHODS Five parotid biopsy samples obtained from patients with diabetic sialosis, 12 samples from patients with alcoholic sialosis and seven from individuals without these pathologies (control group) were analyzed. A morphometrical study of parotid parenchyme and stroma, using a digital image analyzer attached to an optical microscope, was carried out. Dimensions of serous acini and striated ducts, the area occupied by the fatty tissue, and the number of ducts were recorded. Mean values were compared using the Mann-Whitney U-test (P <or= 0.05). RESULTS The variables analyzed in diabetic patients did not show significant differences with respect to the control group. However, when diabetics were compared with alcoholics, the alcoholics exhibited a noticeable reduction in the proportion of fatty tissue of stroma and a significant development of ductal epithelium that contributed to increase the caliber of the striated ducts. CONCLUSIONS These results indicate that the glandular hypertrophy in the diabetic parotid sialosis is not directly associated with the ductal and acinar size, amount of fatty tissue and ductal hyperplasy. Nevertheless, these findings show that the ductal dimensions and the proportion of adipose tissue are variables that allow us to establish histopathological differences between diabetic and alcoholic sialosis.

Morphometric analysis of the parotid gland affected by alcoholic sialosis.

BACKGROUND In alcoholic parotid sialosis, the gland is frequently enlarged due to ductal and/or acinar hypertrophy, ductal hyperplasy and stromal fat infiltration. The aim of this study was to determine acinar and ductal dimensions, the number of striated ducts and the proportion of fat tissue in patients with and without alcoholic parotid sialosis. METHODS Twelve parotid biopsy samples from patients with hepatic alcoholic cirrhosis and those from seven controls were used. A morphometrical study with a digital image analyser attached to an optical microscope was carried out. Direct and indirect indicators from acinar and ductal dimensions were recorded. The number of striated ducts and the proportion of fat tissue in stroma were determined. Fifteen records for each variable were taken. Mean values were compared using the Mann-Whitney U-test (P <or= 0.05). RESULTS There were no significant differences in acinar and ductal dimensions and the number of striated ducts between alcoholic and control patients. The proportion of fat tissue in alcoholic parotides was significantly lower than that in the controls. CONCLUSIONS These results do not corroborate previous qualitative descriptions about acinar and ductal hypertrophy and ductal hyperplasy in alcoholic patients. The main cause of parotid enlargement could not be stromal fat infiltration. The data could be used for differential diagnoses of sialosis.

Sustainability/resilience of soil organic matter components in an Argentinean arid region

Se analizo el grado de resiliencia de los componentes de la materia organica del suelo para establecer la sustentabilidad de las practicas productivas en una region arida de Argentina. Se trabajo en cuatro sitios en el Chaco Arido de la provincia de Cordoba: un sitio testigo, 2 sitios con ganaderia (con desmonte total y selectivo) y un sitio con agricultura. En cada sitio se tomaron tres muestras de suelo y se analizo en contenido de materia organica total, acido fulvicos, acidos humicos y sustancias no humificadas. Se calculo la variacion (%) de cada componente entre los sitios productivos y el sitio testigo, para establecer el grado de resiliencia. En los sitios con ganaderia las sustancias no humificadas fueron moderadamente resilientes, la materia organica total y los acidos humicos escasamente resilientes y los acidos fulvicos no resilientes. En el sitio con agricultura la materia organica total y las sustancias no humificadas fueron escasamente resilientes, mientras que los acidos fulvicos y humicos fueron no resilientes. Se concluye que este metodo de evaluacion de la sustentabilidad es una excelente herramienta para establecer las practicas de manejo de acuerdo a cada situacion en particular, permitiendo mejorar la productividad de las regiones aridas.

Multidisciplinary approach to assess the water self-depuration characteristics of Suquía River (Córdoba, Argentina)

BackgroundWe analyzed the following characteristics of water self-depuration capacity along a polluted river (Suquía River) in Argentina: (a) abundance of microbial metabolic groups, (b) cover and type of vegetation, and (c) type and concentration of soil and sediment humic substances. The objective was to establish the modifications of water self-depuration characteristics of the polluted sites in comparison to a reference site in order to provide basic data for ecological restoration programs. Five samples of riparian soil, water, and sediments were collected at a reference site and five polluted sites during low- and high-flow water periods. In each site the vegetation type and soil cover were recorded. In all samples the abundance of ammonifiers, nitrate reducers, sulfate reducers, cellulolytic microorganisms, aerobic heterotrophs, and fermenters was measured. Besides, soil and sediment organic matter and humic and fulvic acids content were analyzed.ResultsOur results showed that all sites differed in their water self-depuration characteristics with respect to the reference site and that these variations are due to a combination of natural and anthropic factors. The Suquía River presents a great heterogeneity of water self-depuration characteristics but it does not achieve a mitigation of the anthropogenic impact produced by Córdoba city.ConclusionsWe concluded that restoration actions in lotic ecosystems should be adapted for each river sector.