Abstract
With more than a half-century in operation, the industrial chemical complex of Estarreja (ICCE) in northern Portugal has left serious environmental liabilities in the region. Although protective measures were implemented, soils, surface, and groundwater contamination caused by persistent pollutants are still prevalent. This study presents data from several geophysical and hydrochemical campaigns carried out to monitor groundwater contamination in the Estarreja region over a period of 30 years. Both geophysical and hydrochemical data showed a good agreement and revealed an important anomaly caused by groundwater contamination (high levels of Na, Cl, SO4, and Fe, among others) in 2006–2007, likely caused by the remobilization of waste pollutants (roasted pyrites, soils, and sludge) during their deposition in a sealed landfill (operating between 2003 and 2005). More recently, in 2016, this impact persists, but was more attenuated and showed a general migration pattern from E to SW according to one of the main groundwater flow paths. Groundwater flow in this region has a local radial behaviour. Drainage effluent systems, such as ditches and buried pipes formerly used by ICCE, are also likely to contribute to some contamination “hotspots”. Finally, the results obtained by the combined use of these two approaches allowed for the delineation of the contamination plume for future monitoring.
Highlights
IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The extensively tested EM34 was used by repeating the measurements in the same position and measuring both vertical fields (VF) with horizontal coils, and horizontal fields (HF) with vertical coils
It was necessary to investigate seasonal effects in shallow geophysical measurements if readings taken at different times of the year are to be compared
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Chemical industry can cause severe environmental damages, especially those that operated in the past when environmental protection measures were scarce or absent. This degradation is often not limited to the area next to the industries themselves, but instead is likely to affect a much larger area. This is relevant when saturated media is affected, since its limited adsorption capability and continuous movement result in the subsurface migration and easy dispersion of contaminants
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