ABSTRACT
In order to determine copper toxicity (LC50) to a local species (Cnesterodon decemmaculatus) in the South American Pilcomayo River water and evaluate a cross-fish-species extrapolation of Biotic Ligand Model, a 96 h acute copper toxicity test was performed. The dissolved copper concentrations tested were 0.05, 0.19, 0.39, 0.61, 0.73, 1.01, and 1.42 mg Cu L(-1). The 96 h Cu LC50 calculated was 0.655 mg L(-1) (0.823 - 0.488). 96-h Cu LC50 predicted by BLM for Pimephales promelas was 0.722 mg L(-1). Analysis of the inter-seasonal variation of the main water quality parameters indicates that a higher protective effect of calcium, magnesium, sodium, sulphate, and chloride is expected during the dry season. The very high load of total suspended solids in this river might be a key factor in determining copper distribution between solid and solution phases. A cross-fish-species extrapolation of copper BLM is valid within the water quality parameters and experimental conditions of this toxicity test.
ABSTRACT
The biotic ligand model (BLM) was used to assess copper (Cu) bioavailability, toxicity, water-effect ratios (WER), and Cu site-specific water-quality criteria (SSWQC) in the Matanza River and Pilcomayo River, Argentina, where anthropogenic inputs and natural phenomena have led to high concentrations of chemical species capable of reducing metal toxicity: Sodium, total hardness, alkalinity, dissolved organic carbon, and suspended particulate matter (SPM), as well as other metals. The purpose of this study was to evaluate the feasibility of developing Cu-SSWQC from a modified scenario of the BLM-Monte-Carlo method model. The response of the BLM model in these rivers, with water quality near its application boundary conditions, was evaluated during the 2003 to 2004 hydrological cycle. Cu toxicity tests were conducted with Daphnia magna as the test organism. The BLM (Version ap08) toxicity estimates for D. magna were within a factor of 2 of the line of perfect agreement with toxicity test results, although highly variable relevant water-quality parameters showed that mean estimates were more than 2 times the mean 50% effective concentration (EC50) derived from the corresponding toxicity tests. Suspended particulate matter was an important sink for Cu added to unfiltered water of the Pilcomayo River, but it also exerted some toxic effect. Minimums WER, estimated with a modified scenario of the BLM-MONTE, ranged from 1.5 (Pilcomayo River, at Misión La Paz) up to 11 (Matanza River, at Route 3). The corresponding Cu-SSWQC values were 30 and 105 microg/L, respectively.
Subject(s)
Fresh Water/analysis , Models, Theoretical , Rivers , Argentina , Environmental Monitoring/methods , Geography , Water Pollutants, Chemical/analysisABSTRACT
Se propone una metodología para calcular estándares locales de calidad de agua para consumo humano. Esta contempla la información toxicológica a través de ingestas diarias tolerables y parámetros de carcinogenicidad provistos por la OMS y la U.S EPA y caracteriza el riesgo asociado a los estándares locales vigentes considerando las variables vinculadas a la exposición real de la población. Se ejemplifica aplicándola al agua suministrada en la Provincia de La Pampa (arsénico y flúor). Esta metodología está dirigida a proveer criterios básicos comunes en las distintas jurisdicciones responsables de la fijación de normas de agua de bebida en la Republica Argentina
Subject(s)
Water Quality , Drinking WaterSubject(s)
Dominican Republic , Water Monitoring , Water Quality , Industrial Effluents , Legislation , Urban AreaABSTRACT
Se presentan las normas preliminares para las descargas masicas maximas de hidrocarburos provenientes de industrias petroquimicas y destilerias ubicadas sobre el rio Parana entre los km 452-420,de acuerdo a los niveles guia seleccionados para la proteccion de la vida acuatica del rio Parana y las tomas de agua potable de la localidades de Fray Luis Beltran y Rosario.Estos caudales masicos maximos surgieron de la aplicacion de un modelo de dispersion de estado estacionario,que asume mezcla instantanea total en el eje vertical y ausencia de decaimiento de los hidrocarburos prioritarios.El caudal de diseño para el rio Parana fue de 8500 m3/seg. (frecuencia media anual para Rosario 12,41 dias/año)