Odiel River (SW Spain), a Singular Scenario Affected by Acid Mine Drainage (AMD): Graphical and Statistical Models to Assess Diatoms and Water Hydrogeochemistry Interactions

Abstract

The Odiel River (SW Spain) is one of the most cited rivers in the scientific literature due to its high pollution degree, generated by more than 80 sulphide mines’ (mostly unrestored) contamination in the Iberian Pyritic Belt (IPB), that have been exploited for more than 5000 years. Along the river and its tributaries, the physico-chemical parameters and diatoms, from 15 sampling points, were analyzed in the laboratory. Physico-chemical parameters, water chemical analysis, together with richness and Shannon–Wiener indexes were integrated in a matrix. An initial graphical treatment allowed the definition and proposal of a functioning system model, as well as the establishment of cause–effect relationships between pollution and its effects on biota. Then, the proposed model was statistically validated by factor analysis. For acidic pH waters, high values of Eh, TDS, sulphate, ∑REE and ∑Ficklin were found, while diatomologic indicators took low values. Thus, factor analysis was a very effective tool for graphical treatment validation as well as for pollution–biota interaction models’ formulation, governed by two factors: AMD processes and water balance suffered by the studied river. As a novelty, the cause–effect relationships between high barium concentration and low diversity and richness were demonstrated in the IPB, for the first time.

Sensitivity of Pathogenic Bacteria Strains to Treated Mine Water

“…Due to the fact that the impact of the treated acid mine water on the receiving water will depend on the flow rates/dilution, the chemical measurements are used to assess the quality of the treated acid mine water and some effects of the mine water or effluents discharging on the natural water bodies [ 14 ]. This approach will not describe the overall potentially negative effects; therefore a biological assessment is essential, including the organisms’ tolerance and adaptation-capacity evaluation [ 17 ].…”

Acid Mine Drainage Effects in the Hydrobiology of Freshwater Streams from Three Mining Areas (SW Portugal): A Statistical Approach

“…Further regarding this topic of biogeochemistry of AMD affected waters in all IPB (Spanish and Portuguese parts), this working team has been developing many studies in the last years: [ 40 , 41 , 42 , 43 , 44 ], reinforcing the importance of diatoms as bioindicators, that can assess environmental changes over time, evaluating the contamination impact of these AMD peculiar systems, helping in the decision of the most appropriate intervention, with economic and environmental costs reduction, contributing immediately to the quality improvement of waters. Thus, this type of biogeochemical diagnosis is necessary for the sustainable use of these waters and the prevention of the polluting process, aimed to protect the water ecosystem and its biodiversity from a circular economy perspective that can make possible the reconciliation of mining activity with the use of these waters for non-mining purposes.…”

Factor Analysis of the Physical–Mechanical Properties for Geopolymers Based on Brick Dust and Biomass Bottom Ash as Eco-Friendly Building Materials

“…To attain this, initially, the correlation matrix of variables is obtained from all the data obtained from the test of all the properties. Subsequently, this matrix is analysed in detail, developing the matrix of factors from the r values of the previous matrix [46]. With the matrix of factors, the two main factors that condition the rest of the variables can be obtained, which are subsequently defined from the knowledge of the material and the methodology followed for the geopolymer forming.…”