Vulnerability to Anthropogenic Pollution in the Dunas/Barreiras Aquifer System from the Metropolitan Region of Natal

Abstract

Traditionally, groundwater has been considered protected by the subsurface. However, the disposal of stable pollutants in favorable infiltration zones can generate contamination of the hydric resource, jeopardizing the health of the population. To tackle the increasing contamination of aquifers by anthropic activities, vulnerability assessment is one of the fundamental requirements to generate guidelines, strategies, and policies to prevent and minimize groundwater contamination. The present study aims to evaluate the vulnerability to anthropogenic pollution in aquifers of the Metropolitan Region of Natal (MRN). In this research, the GODS (Groundwater hydraulic confinement, Overlaying strata, Deph to groundwater and Soil type) method was used, proposing a vulnerability calculation through the multiplication of four geological and hydrological parameters, which are: degree of hydraulic confinement, the occurrence of the underlying substratum, distance to the groundwater level, and type of soil. Tools from a Geographic Information System (GIS) were used. The results show that most of the territory is in a low vulnerability level with 39.75%, in moderate level with 24.26%, followed by very high vulnerability level with 14.7%, 10.68% with high level, and 10.61% insignificant level. The research contributed to highlighting how the intrinsic characteristics of the Dunas-Barreiras aquifer in the Metropolitan Region of Natal, allow the transport of pollutants to the water table in some areas such as in the coastal zone and in the lower portions of the river basins.

Keywords:
Geoprocessing; Map Algebra; Intrinsic Vulnerability; Lithology; Hydraulic Confinement