Sobre la contaminación de las aguas del estuario de los ríos Tinto y Odiel (Huelva)

Abstract

The waters of the Huelva Estuary are polluted because of indiscriminate dumping of urban effluents. The nutrient contents of samples taken at the surface and from the bottom of the estuary were analysed to characterise the pollution of the waters. The pH values found range between 5.88 and 7.65. Salinity levels range between 34 and 42 g/L and show that the waters are very homogeneous. The 02 water content ranges between 7 and 13.8 mg/L, indicating a good level of oxygenation derived form the large amount of photosynthetic activity. Nitrate, nitrite and ammonia concentrations range between 0.1 and 0.4 mg/L, 2 and 12 fJg/L, and 0.1 and 0.6 mg/L respectively. The orthophosphate and total phosphate contents are high and usually similar, which indicate that a large part of the total phosphorus is present in form of orthophosphate that can be easily assimilated by the organisms. The high nutrient content of the water favours photosynthesis, which can lead to eutrophication