Assessment of groundwater quality and contamination problems ascribed to an abandoned uranium mine (Cunha Baixa region, Central Portugal)

• Published in: Environmental earth sciences Vol. 53; no. 8; pp. 1799 - 1810
• Main Authors: Neves, O, Matias, M. J
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.02.2008; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Abandoned mines; Bioaccumulation; Contamination; Cunha Baixa (Central Portugal); Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental impact; Exact sciences and technology; Geochemistry; Geology; Groundwater; groundwater contamination; Groundwater flow; Groundwater pollution; Health hazards; Hydrogeology; Hydrology. Hydrogeology; Irrigation water; Irrigation water quality; Mineralogy; Original Article; Pollution, environment geology; Radium isotopes; Radium radioisotopes; Silicates; Soil and crop hazards; Soil degradation; Studies; Uranium; Uranium mine; Water analysis; Water geochemistry; Water pollution; Water quality; Water sampling; Water supply; Wells; Iberian Peninsula; Southern Europe; Portugal; Europe; Groundwater contamination; Cunha Baixa (Central Portugal); Irrigation water quality; Soil and crop hazards; Uranium mine; Uranium mine, Groundwater contamination; time variations; ground water; effluents; metals; degradation; pollution; Irrigation water quality, Soil and crop hazards; irrigation; aquifers; hydrochemistry; abandoned mines; pH; soils; flow; Ra-226; water supply; mining; contamination; mines; physicochemical properties; water quality; uranium; seasonal variations
• ISSN: 0943-0105; 1866-6280; 1432-0495; 1866-6299
• DOI: 10.1007/s00254-007-0785-8

The assessment of groundwater quality and its environmental implications in the region of the abandoned Cunha Baixa uranium mine (Central Portugal) was carried out from 1995 to 2004. Shallow groundwater is the major water supply source for irrigation in the neighbourhood of Cunha Baixa village. Water samples from the mine site as well as from private wells were collected in order to identify the mining impact on water composition, the extent of contamination and the seasonal and temporal groundwater quality variations. Some of the sampled private wells contain waters having low pH (<4.5-5) and high values of EC, TDS, SO₄, F, Ca, Mg, Al, Mn, Ni, U, Zn and ²²⁶Ra. The wells located through the ESE-WSE groundwater flow path (1 km down gradient of the mining site) display the most contaminated water. In the summer season, the levels of SO₄, Al, Mn, and U were 50-120 times higher than those registered for uncontaminated waters and exceeded the quality limits for irrigation purposes, presenting soil degradation risks. Nevertheless, this study indicates that groundwater contamination suffered a small decrease from 1999 to 2004. The bioaccumulation of toxic metals such as Al, Mn, and U within the food chain may cause a serious health hazard to the Cunha Baixa village inhabitants.