Iria Sartor Araujo,Denilson Dortzbach,Éverton Blainski,Ivan Luiz Zilli Bacic, Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina - Epagri, Setor de Gestão e Saneamento Ambiental, iriaaraujo@epagri.sc.gov.br
ABSTRACT:
River pollution caused by soil management and fertilizer use is a problem in the state of Santa Catarina. Pre-germinated rice production in paddy fields is the main economic activity in the Ribeirão Gustavo watershed, located in the municipality of Massaranduba. The aim of this study is to evaluate the physic-chemical and microbiological water quality parameters in the Ribeirão Gustavo stream and relate them to current land uses and occupancy. Five sampling points were selected in the hydrologic network. The samples were collected fortnightly from July 2009 to October 2010. The parameters analyzed were: nitrate, orthophosphate, turbidity, fecal coliforms and dissolved oxygen. Ribeirão Gustavo’s river mouth had the highest nutrient concentrations, Escherichia coli and turbidity in July and August. This is the time of paddy field soil preparation and water drainage from rice fields to the hydrological network. The correlations between the water quality parameters and the percentage of forest and rice were significant, showing that water quality in the watershed Ribeirão Gustavo is greatly influenced by human actions, such as the presence of complex domestic and agricultural production.
Keys-words: hydrologic network, pollution, agriculture