Análise do grau de eutrofização nas águas do furo da Laura, Vigia – PA - Brasil.

Abstract

In aquatic environments, the presence of phosphate and nitrogen compounds from both human activities and natural processes, such as, respectively, the dumping of untreated sewage and the decomposition of living organisms, which alter the trophic state and quality Of the environment. In this sense, the objective of this work was to verify the levels of trophic status (by IET and TRIX indices) and water quality to protect aquatic life (by IQAPVA) in the estuary system of Laura 's Hole, Vigia de Nazaré - According to the tides (ebb and flood) and seasonality (rainy season and dry period). The collection points were in four strategic areas: points 1 (of lower anthropogenic influence) and 2 (with little circulation of vessels) located in the inner portion of the Hole; Point 3, located in front of the city of Vigia with great circulation of boats and visible anthropic influences; And point 4 - site of material exchanges of the Hole with the Bay of Marajó. The values of TRIX and IQAPVA presented significant differences between the dry (lower values) and rainy (higher values) periods. Between tides, salinity and TRIX, there were no differences. For IQAPVA there was a difference between the tides (flood and ebb). For the EIT, there were no significant differences either seasonally or between tides. The points considered most eutrophic and worse for protection of aquatic life were points (3 and 4) closest to the city of Vigia. Thus, the information obtained and discussed in this study can serve as a basis for future studies and even basic sanitation improvements for the population.