11 research outputs found
Fuzzy modelling of acid mine drainage environments using geochemical, ecological and mineralogical indicators
Fuzzy logic was applied to model acid mine
drainage (AMD) and to obtain a classification index of the environmental impact in a contaminated riverine system.
The data set used to develop this fuzzy model (a fuzzy classifier) concerns an abandoned mine in Northern Portugal—
Valdarcas mining site. Here, distinctive drainage environments (spatial patterns) can be observed based on the AMD formed in the sulphide-rich waste-dumps. Such environments were established, as the effluent flows through the mining area, using several kinds of indicators.
These are physical–chemical, ecological and mineralogical parameters, being expressed in a quantitative or qualitative basis. The fuzzy classifier proposed in this paper is a min–
max fuzzy inference system, representing the spatial behaviour of those indicators, using the AMD environments as patterns. As they represent different levels (classes) of contamination, the fuzzy classifier can be used as a tool, allowing a more reasonable approach, compared with classical models, to characterize the environmental impact caused by AMD. In a general way it can be applied
to other sites where sulphide-rich waste-dumps are promoting the pollution of superficial water through the
generation of AMD
Changes in epilithic biomasses and invertebrate community structure over a deposit metal concentration gradient in upland headwater streams
The roles of environmental conditions and spatial factors in controlling stream macroalgal communities
Taxonomic and Biochemical Composition and Digestive Enzyme Activity of Periphyton and Plankton: A Comparative Study
Subsidence from an Underground Coal Mine and Mine Wastewater Discharge Causing Water Pollution and Degradation of Aquatic Ecosystems
The effect of acid mine drainage on the hatching success of branchiopod egg banks from endorheic wetlands in South Africa
Increased Water Pollution After Closure of Australia’s Longest Operating Underground Coal Mine: a 13-Month Study of Mine Drainage, Water Chemistry and River Ecology
Coal Mine Water Pollution and Ecological Impairment of One of Australia’s Most ‘Protected’ High Conservation-Value Rivers
Experimental evaluation of the contribution of acidic pH and Fe concentration to the structure, function and tolerance to metals (Cu and Zn) exposure in fluvial biofilms
An indoor channel system was colonised with fluvial biofilms to study the chronic effects of high Fe and SO4 (2-) concentrations and acidic pH, the water chemistry in the surrounding streams of Aljustrel mining area (Alentejo, Portugal), and their contribution to community (in)tolerance to metal toxicity by short-term experiments with Cu and Zn. Biofilms were subjected to four different treatments during 8 weeks: high Fe and SO4 (2-) concentrations (1 mg Fe l(-1 )+ 700 mg SO 4 (2- ) l(-1)) and acidic pH, high Fe and SO4 (2-) at alkaline pH; lower Fe and SO4 (2-) at acidic pH: and lower Fe and SO4 (2-) concentrations at alkaline pH as negative control. During chronic exposure, acidic pH affected growth negatively, based on low values of algal biomass and the autotrophic index, high values of the antioxidant enzyme activities and low diversity diatom communities, dominated by acidophilic species (Pinnularia aljustrelica) in acidic treatments, being the effects more marked with high Fe and SO4 (2-). Co-tolerance to metals (Cu and Zn) was also shown in biofilms from the acidic treatments, contrasting with the higher sensitivity observed in the alkaline treatments. We can conclude that the Aljustrel mining area acidic environment limits algal growth and exerts a strong selection pressure on the community composition which is in turn, more tolerant to metal exposure
Phytoassessment of acid mine drainage: Lemna gibba bioassay and diatom community structure
An integrated multilevel phytoassessment of an acid mine drainage (AMD, pH range 3.3-6.8) in southern Portugal was performed. A 7-day phytotoxicity bioassay with the duckweed Lemna gibba (chlorosis, necrosis, growth) was carried out, both in the laboratory and in situ, combined with an analysis of the resident epilithic diatom community. The toxicity test was performed with water from the AMD gradient, an unpolluted river control and acidified control water, in order to discriminate potential pH-effects from combined pH- and metal-effects. Diatom communities discriminated well among the sites (alkalophilic species versus halobiontic, acidobiontic and acidophilic species), showing inter-site differences to be larger than intra-site seasonal variations. In L. gibba exposed to AMD, necrosis and growth inhibition were higher in situ compared to the laboratory experiments. L. gibba was more sensitive to AMD than to acidified water. Already after 4 days, growth rate inhibition in L. gibba proved to be a reliable indicator of AMD-stress. Ecotoxicological thresholds obtained with L. gibba corresponded with those obtained previously with animals of intermediate tolerance to AMD. The results were summarised in a multimetric index.CETERAIAV/82/ 00PRAXIS/C/MGS/10200/199