SEASONAL EVALUATION OF WATER AND SURFACE SEDIMENT OF THE RIO DAS BICAS SUB-BASIN IN SÃO LUÍS IN THE STATE OF MARANHÃO, BRAZIL.
DOI:
https://doi.org/10.16891/2317-434X.v11.e3.a2023.pp2788-2798Abstract
This work aims to evaluate the seasonality of the surface physical-chemical parameters of water and sediments from Rio das Bicas in São Luís, Maranhão state, Brazil. Water samples were collected linearly with equidistance from 8 points, in both dry and rainy seasons of 2020. Physical-chemical parameters were analyzed based on the Methods for Water Analysis, Standard Methods for Examination of Water and Wastewater. The samples were transported to the CEUMA University Environmental Science Laboratory. The parameters analyzed were: water temperature, turbidity, conductivity, hydrogen potential, nitrite, nitrate, total phosphorus, total dissolved solids and dissolved oxygen. For sediment, samples were stored in plastic bags and conserved in styrofoam boxes, and then sent to the laboratory for pH, total phosphorus, nitrite, nitrate, calcium and magnesium, granulometry, organic matter, inorganic matter and organic carbon analysis. The results of the water samples showed that salinity, nitrate, total phosphorus, BOD and dissolved oxygen are not in compliance with the requirements of Resolution CONAMA 357/05. The pH value, however, was within the standard limit at all 8 analyzed points during both rainy and dry periods. The results of sediment samples showed that nitrate and total phosphate are not in compliance with EMBRAPA's requirement. It is concluded that the current environmental quality of these environments must be evaluated to generate elements that can contribute to political decision-making aimed at mitigating anthropic pressures and preserving the environment.