The research developed in the region of the Scientific Station Ferreira Penna (ECFPn) in Caxiuanã - Pará, is a complementary study to the work carried out by the LBA-EUSTACH Projects and other projects of the Museu Paraense Emilio Goeldi in the ECFPn. The region has several types of soils, including Latosols, Neosols and Gleissols. It has an extensive drainage network that is distributed by various pedological patterns and remains practically free from anthropic influence, thus being important for studies related to the influence of soil type on the physical and chemical composition of surface water. Water samples were collected for physical and chemical analyses, as well as pedological variations along the main drainages of Caxiuanã River and Curuá Igarapé in two periods: September 1994 and November 2004. Water samples were collected from points influenced by Latossolo Amarelo, Neossolo Flúvico and gleysol. The pH of the water at these points remained constant (5.5) in 1994. In the 2004 collections there was a higher acidity of the water with pH values between 3.9 and 4.3. The variation in electrical conductivity, which was between 23.0 and 55.0 in 1994, decreased in 2004, varying between 26.30 and 28.80. On the other hand, the temperature variation was greater in September 1994 than in November 2004. The water pH was higher in 1994 than in 2004, the electrical conductivity was higher in 2004 and the temperature had a small increase in 2004 (31,9°C) in relation to 1994 (31,0°C). The data suggest that the watercourses are influenced by the soil types and mainly by the climatic period.
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