Ecotoxicologycal and physical-chemical evaluation of Ribeirão Tatu in the country of Limeira - SP / Avaliação fisico-quimica e ecotoxicologica do Ribeirão Tatu no municipio de Limeira - SP

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Water is a finite and essential resource for all life forms. Studies have shown that many illnesses can be caused by contaminated water. The ribeirão Tatu basin comprises much of the urban area of the county of Limeira, SP, Brazil. It originates in the agricultural zone of the county of Cordeirópolis and empties into rio Piracicaba. According to CONAMA Resolution 357/2005, the river has a classification of 4 in urban area. It has countless problems, such as the release of untreated domestic, industrial and agricultural sewage, urban pollution, as well as an almost total absence of riverside woods. The present study carried out an ecotoxicologycal evaluation of the ribeirão Tatu?s surface water from March of 2005 to March of 2006, using the microcrustacean Daphnia similis as a bioindicator of acute toxicity and the microcrustacean Ceriodaphnia dubia as a bioindicator of chronic toxicity. In addition to this, the water was characterized in relation to physical an chemical variables, such as temperature, pH, dissolved oxygen (OD), conductivity, hardness, alkalinity, biochemical demand of oxygen (DBO5) and chemical demand of oxygen (DQO). For this, four collection points were determined along the watercourse. The results show the most vulnerable areas in relation to toxicity; point 3 and 4 showing greater acute and chronic toxicity. June an July, a drop in the quality of ribeirão Tatu water was recorded, probably due to the presence of toxic substances in the water, due to the release of untreated industrial sewage. The results of the physical-chemical showed acceptable pH and temperature levels. The dissolved oxygen decreases closer to the urban areas, thus indicating an increase in pollution. The conductivity, hardness and alkalinity values were seen in point 3 and 4. Such values may alter biological activities of aquatic organisms. The values for biochemical an chemical demand of oxygen indicates the possibility of the release of industrial sewage without proper treatment

ASSUNTO(S)

toxicologia - testes poisons bacias hidrograficas poluentes experimental toxicology toxicologia experimental river basins pollutants

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