title: Integrating geochemical (surface waters, stream sediments) and biological (diatoms) approaches to assess AMD environmental impact in a pyritic mining area: Aljustrel (Alentejo, Portugal).
abstract: Aljustrel mines were classified as having high environmental hazard due to their large tailings volume and high metal concentrations in waters and sediments. To assess acid mine drainage impacted systems whose environmental conditions change quickly, the use of biological indicators with short generation time such as diatoms is advantageous. This study combined geochemical and diatom data, whose results were highlighted in 3 groups: Group 1, with low pH (1.9-5.1) and high metal/metalloid (Al, As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn; 0.65-1032 mg/L) and SO4 (405-39124 mg/L) concentrations. An acidophilic species, Pinnularia aljustrelica, was perfectly adapted to the adverse conditions; in contrast, teratological forms of Eunotia exigua were found, showing that metal toxicity affected this species. The low availability of metals/metalloids in sediments of this group indicates that metals/metalloids of the exchangeable fractions had been solubilized, which in fact enables metal/metalloid diatom uptake and consequently the occurrence of teratologies; Group 2, with sites of near neutral pH (5.0-6.8) and intermediate metal/metalloid (0.002-6 mg/L) and SO4 (302-2179 mg/L) concentrations; this enabled the existence of typical species of uncontaminated streams (Brachysira neglectissima, Achnanthidium minutissimum); Group 3, with samples from unimpacted sites, showing low metal/metalloid (0-0.8 mg/L) and SO4 (10-315 mg/L) concentrations, high pH (7.0-8.4) and Cl contents (10-2119 mg/L) and the presence of brackish to marine species (Entomoneis paludosa). For similar conditions of acidity, differences in diversity, abundance and teratologies of diatoms can be explained by the levels of metals/metalloids.
authors.affiliation: University of Aveiro, Department of Geosciences, GeoBioTec - Geobiosciences, Geotechnologies and Geoengineering Research Center, Campus de Santiago, 3810-193 Aveiro, Portugal; University of Aveiro, Department of Biology, GeoBioTec - Geobiosciences, Geotechnologies and Geoengineering Research Center, Campus de Santiago, 3810-193 Aveiro, Portugal; Centro de Ciências do Mar, CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. Electronic address: anatluis@ua.pt.
authors.forename: Ana Teresa
authors.initials: AT
authors.lastname: Luís
authors.affiliation: University of Aveiro, Department of Geosciences, GeoBioTec - Geobiosciences, Geotechnologies and Geoengineering Research Center, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Durães
authors.affiliation: University of Aveiro, Department of Biology, GeoBioTec - Geobiosciences, Geotechnologies and Geoengineering Research Center, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Salomé Fernandes Pinheiro
authors.initials: SFP
authors.lastname: de Almeida
authors.affiliation: University of Aveiro, Department of Geosciences, GeoBioTec - Geobiosciences, Geotechnologies and Geoengineering Research Center, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Eduardo Ferreira
authors.initials: EF
authors.lastname: da Silva
mesh_terms: D017377:Diatoms / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry; D008906:Mining; D011174:Portugal; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical
keywords: AMD; Diatoms; Metals/metalloids; Stream sediments; Surface waters; Teratologies