Aspectos qualitativos físico-químicos das águas subterrâneas freáticas da faixa costeira do porto das dunas e prainha, Aquiraz — Ceará

Abstract

This work was conducted in the coastal county of Aquiraz comprising the localities of Porto das Dunas with 17.62 km2 and Prainha, Metropolitan Region of Fortaleza, to evaluate groundwater remediation as to its hydrogeology, current status of wells and water quality . Methodological steps was to the literature, the updating of the wells, the development of thematic bases, stages of field with the first step of the visit to the 34 wells and in situ measurements of electrical conductivity, total dissolved solids, temperature, pH and salinity. The second stage was related to the collection of 16 samples for chemical analysis. 92.5% of the area belong to the Aquifer System Dunes. There were 177 registered wells with 70% of the wells in the area are used for domestic purposes including human consumption, and 89.3% of the wells are equipped, but the area is devoid of basic sanitation, focusing on serious risks to contamination of the aquifer. As the depth of 36.7% are considered deep wells and the evolution of construction has increased by 11.9% in the last 11 years. Regarding the in situ measurements of electrical conductivity and STD prevalence is less than 500 us / cm and 500 mg / L, respectively. he pH measurements showed groundwater of acidic character (67.6%). Groundwater were characterized as hard water (62.5%), but within the standards of the Ordinance No. 518/2004 MS (500 mg / L). Through the analysis of laboratory parameters of nitrate, nitrite, ammonia and chloride, it was found that of 16 samples, 06 of them (37.5%) had nitrate contamination and these wells are located in Prainha, which are the main contaminant cesspools, indicating pollution old; for nitrite analysis revealed only a change of 1.07 mg / L and ammonia concentrations did not show off the potability standards, ie, the water pollution had not recent. Analyzing the concentration of chloride, there was only one anomalous point with 276 mg / L (Well No. 158), but still within the potability standards of the Ordinance 518/2004 of the World Health Organization (250 mg / L) for human consumption.