Hidrodinâmica ambiental no baixo São Francisco e suas relações antrópicas

• Autor(a) principal: Santana, Neuma Rubia Figueiredo
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/7850
• topic: Meio ambiente; Hidrodinâmica; Educação ambiental; Salinização da água; Ação antrópica; Environmental hydrodynamics; Salinization; Anthropogenic action; Environmental education; OUTROS

The hydrodynamics of the waters of a river that flow to the sea establishes important control in the volume and direction of the watercourse, among them the physical and chemical salinity that represents the measurement of the concentration of salts dissolved by the water body. This is because water reflects the environmental conditions of a river. The present study had as objective to evaluate the hydrodynamics of the mouth and its relations. The mouth of the São Francisco river is located between the states of Sergipe and Alagoas presents a fluviomarinha plain consisting of river and river basins and terraces, represents an area of extreme natural beauty and of economic relevance for local population and is aggregated in the geographic division of the low San Francisco. With the use of a boat leased in the municipality of Brejo Grande (SE) and with the aid of a digital GPS Garmin e-trex, the information of latitude and longitude in UTM was recorded to map the points of water collection. For the environmental modeling of the salinity and flow coefficients, the SiSbahia program was used. Sampling point identifications were carried out through measurements with HI9828 Multiparameter probe during the months of February, March, April, May, September, November, 2015 and March, 2017. The probe recorded salinity , Electrical conductivity, turbidity, dissolved oxygen, total solids, temperature and pH. For drinking water, water samples were collected in residences to verify pH, sodium and chlorides. Interviews were conducted to verify the perception of salinity with the residents of Brejo Grande / SE and Saramém. Then the quantitative and qualitative data were treated through statistical software and compared with CONAMA Resolution 357/2005 and Portaria MS 2914/2011. The results presented for the environmental modeling showed the action of the tide after the municipality of Penedo / AL, the salinity was recorded by the presence of the salt wedge reached 11 km of the mouth. The pH ranged from 6.80 to 9.47 and the maximum value occurred in February 2015. The values of dissolved oxygen in the evaluated area ranged from 4.68 to 9.27 ppm. Total dissolved solids ranged from 7.0 mg.L-1 to 7522 mg.L-1. The highest concentration of total dissolved solids occurred in the first month of November, dry period and with tidal regime of sizígia with elevation of the water level in 2.2m. The turbidity values recorded were between 2.9 NFU and 47.07 NFU. The values of electrical conductivity ranged from 10.00 (μS / cm-1) to 13130.00 (μS / cm-1). The mean salinity concentration ranged from 0.17 to 28.87 (‰), with the highest values being recorded in the municipality of Brejo Grande / SE and points 39, 40 and 43 located in Piaçabuçu in the state of Alagoas. The pH in drinking water between the municipalities of Brejo Grande / SE and the village Saramém presented average values within the limit established by the Ministry of Health Ordinance 2914/2011. In the evaluation of the parameter of sodium and chlorides the average values obtained in May of 2015 were between 1962.85 mg.L-1 and 2938.62 mg.L-1. In response to the semi-structured interviews the residents reported that the change in the taste of water was perceived during high tide. It was concluded that salinity concentrations were significant and signaled the performance of the tide period to increase the tidal period. Salinity is a worrying factor for directly compromising water uses and directly affecting biota in the region. The environmental education activity enabled the perception of the fishermen about the main types of environmental degradation that operate in the region investigated.