Transformações no uso do solo e riscos à contaminação das águas subterrâneas: um estudo em Campina Grande

Abstract

Groundwater in Campina Grande is susceptible to contamination due to the incompatibility between urban activities and the areas that should be protected. Changes in land use and occupation exacerbate this risk. The general aim of this study is therefore to assess changes in land use and occupation and the risks of groundwater contamination in Campina Grande. As specific objectives, this research seeks to: (a) analyze the spatio-temporal distribution of wells in the municipality of Campina Grande between 1995 and 2022, (b) analyze the recent evolution of land use and occupation in the municipality of Campina Grande between 1995 and 2022, and (c) evaluate the natural vulnerability to groundwater contamination in Campina Grande. The methodology was conducted in several stages, including: (a) location and temporal analysis of the wells by collecting data from public agencies, (b) assessment of natural vulnerability to groundwater contamination using the GOD method, (c) spatio-temporal analysis of land use and occupation using Google Earth Engine, (d) identification of point sources of contamination and assessment of the potential risk of contamination of the study area using the POSH method, and (e) mapping of vulnerability and risk of groundwater contamination using QGIS. The results point to an increase in the abstraction of subsurface water from the 1990s onwards, specifically between 1995 and 2000, revealing a strong demand for drilling wells, most of which is strongly related to periods of drought. It also indicates that the study area has three distinct classes of natural vulnerability (low, medium and high). It was found that urban areas may have expanded even more since 1995, and changes in land use patterns can be seen. The influence of factors such as population growth, economic development and urban planning policies may have contributed to these transformations. These factors are related to the sources of pollution identified, i.e. those that are included in the city's dynamics, such as industries, petrol stations and mechanic workshops, which were categorized as low, moderate and medium risks. The study therefore highlights the need for effective land use management and provides valuable insights for the conservation of groundwater sources, contributing to understanding and mitigating the risks associated with groundwater contamination.