Characterization of the surface water of a municipal natural park by quality indexes

Conservation units are important for maintaining environmental resources. In this study, the water quality of the Lages Natural Park was evaluated by commonly used indexes: WQI, BMWP' and Shannon Diversity. Water and sediments were collected at seven points inside the CU and at one point outside it. For the evaluation of the WQI, nine parameters were measured: dissolved oxygen and temperature at the site, and the others at the laboratory. For the calculation of the BMWP' and Diversity indexes, the benthic macroinvertebrates in the sediment were identified. The BMWP' and Shannon indexes indicate a worse quality of the waters at the points 1, 2, 6, 7 and 8 (contaminated water and less diversity) than the WQI (quality ranging from good to optimal). The points 3, 4 and 5 had little polluted water according to BMWP' and optimal according to WQI. The results show the contamination of the water inside the park. There is a need for an investigation of its surroundings to determine the sources of contamination. It was also possible to prove the influence the riparian forest exerts in preserving the quality of the water. The difference in the sensitivity of the indexes proves the need to use biological analysis in water monitoring systems.