Water quality diagnosis front anthropic changes in the São Nicolau River basin

Abstract

The São Nicolau River Basin is located in the north-central region of Piauí in the semiarid domain. It covers an area of approximately 5,389.8 km2 and covers part of the municipalities of Assunção do Piauí, São Miguel do Tapuio, Pimenteiras, Aroazes, Santa Cruz dos Milagres and São João da Serra. Fresh water is a scarce resource, and studies are needed to plan and manage it appropriately and in keeping with local reality. The objective of this work is to make a diagnosis of the water quality of the main water wells and springs that supply the population inserted in the São Nicolau river basin, Piauiense Semiárid relating to the socio-environmental conditions in it. It was bibliographical surveys, field visits for material collection and water analysis of wells and springs in the dry season and in the rainy season. PH, temperature, salinity, total dissolved solids (TDS), conductivity, ammonia and nitrite of 16 samples were analyzed. With low demographic density and most of the land occupied by agriculture and extractivism, when analyzing the quality of the water in the basin, It was observed, an asset still preserved. However, some wells and sources presented in some parameters values above the recommended limit for drinking water. Eleven of them exhibited conductivity above the allowed, especially in the rainy period. The investment in infrastructure, planning and management in the area, in favor of an exploration of resources based on the reality of the unit in geoenvironmental and socioeconomic terms, will certainly be able to build a development model based on the sustainable use of resources, for maintain the acceptable drinking water standards for the region.