Geochemical studies in the drainage basin of the Rio Vouga, Portugal. IV. Impact of land use on the hydrogeochemistry of natural waters in the Vouzela region

摘要: A hydrogeochemical study of the impact land use on composition natural waters in Vouzela region northern Portugal was carried out during summer 1983. Water samples were collected from spring and major streams area analyzed for constituents some trace elements. Analysis variance subsequent pairwise contrast tests demonstrated that agricultural areas are significantly enriched constiluents such as Na, K, Ca, Mg, Sr, Cl, SO4, NO3. High concentrations these ions result both application fertilizers enhanced evaporation by intensive irrigation lands. Constitutents H4SiO4, HCO3, F, probably Li, which typically related to mineral weathering, not affected use. In forested concentration most about 20% higher than uncultivated with mainly a grass cover. This reflects difference evapotranspiration two vegetation types. The chemistry Rio Zela clearly differences valley.