Application of fuzzy logic tools for the biogeochemical characterisation of (un)contaminated waters from Aljustrel mining area (South Portugal)

Physico-Chemical Influence of Surface Water Contaminated by Acid Mine Drainage on the Populations of Diatoms in Dams (Iberian Pyrite Belt, SW Spain)

“…thermalis (Kützing) (NTHM), Pinnularia acidophila Hoffman and Krammer (PACI); Pinnularia acoricola Hustedt (PACO); Pinnularia subcapitata Gregory (PSCA) and Pinnularia aljustrelica Luís, Almeida et Ector (PALJ). These species have been found by other authors in similar environments that are characterized by their extreme conditions [10,18,19,20,52]. Thus, species found in these dams fit well with the AMD impact of low pH and high metallic load, which results in the decrease in diatoms diversity, with the spatial variations being more important than the seasonal ones [17].…”

“…This fact added to its low solubility ratio compared to the other metals, is what conditions the respective low % variance (44.4%) shown in Table 1. Temperature showed a low % of variance because the range in temperature from different dams is low (maximum of 5 °C), so it does not very much at the sampling sites, and normally it is not an important variable (e.g., [10,17]). ∑ Sp.…”

“…∑ % Pin is opposite to high pH and to high ∑ Sp., since ∑ % Pin is closely related to metals (As from arsenopyrite, and Cu and Fe from pyrite) and to acidic water [10,11,19]).…”

“…Thus, from an ecological point of view, AMD defines extreme environments (very low pH values, high metal solubility and the presence of iron colloids) (e.g., [10,11,12]) with a deficiency in carbon and inorganic phosphorus, that are crucial to the efficient functioning of biological communities. Lack of these nutrients increase the impact of stress on organisms, and thus (1) impacted communities experience high metal concentrations and very low pH, which lead to a decrease in the diversity of algal species (i.e., [13,14,15,16]) and (2) communities are limited to tolerant organisms that are capable of surviving in these extreme conditions, and are characterized by a simple ecosystem dominated by acidophilic and acid-tolerant organisms [10,17,18,19,20]. These organisms act as important players, ensuring primary production and interfering in the mobility of dissolved chemical species in the aquatic environment [17,19].…”

Assessment of the Environmental Impact of Acid Mine Drainage on Surface Water, Stream Sediments, and Macrophytes Using a Battery of Chemical and Ecotoxicological Indicators

“…The results reported in this study, and in other studies that have assessed the environmental impact in the Aljustrel mining area [2-4,9,22,23] can be used to evaluate the benefits of the remediation measures at the site, documenting the "ground zero" Several studies have documented these impacts in rivers and streams, in Aljustrel [3,9,[22][23][24], and also in other mines from the IPB, both in Portugal, for example, the Lousal mine, affecting the Corona stream [18,25,26], São Domingos, affecting the São Domingos stream, a tributary to the Chança river [10,27] and, in Spain, mainly in Tinto and Odiel river basins, affected by different mines, for example, Rio Tinto, Tharsis, and Sotiel-Coronado [15,17,21,[28][29][30][31][32][33], in the Oraque and Meca rivers (Odiel tributaries), affected by the Tharsis mine [33], also affecting the Chanza and Guadiamar rivers [32]. In fact, in specific hydrogeochemical conditions, the environments affected by AMD can be characterized by extreme conditions, for example, negative pH values [33], similar to those found in the Cobica River basin, affected by AMD-polluted waters coming from the Lagunazo mine and the Herrerias mine, where, in addition to the high concentrations of toxic elements, the mean pH value was negative (pH = −1.56) [34].…”