Bitumen recovery from oil sands in northeastern Alberta, Canada produces large volumes of tailings, which are deposited in mining areas that must be reclaimed upon mine closure. A new technology of non-segregated tailings (NST) developed by Canadian Natural Resources Limited (CNRL) was designed to accelerate the process of oil sands fine tailings consolidation. However, effects of these novel tailings on plants used for the reclamation of oil sands mining areas remain to be determined. In the present study, we investigated the effects of NST on seedlings of three species of plants commonly planted in oil sands reclamation sites including paper birch (Betula papyrifera), white spruce (Picea glauca) and green alder (Alnus viridis). In the controlled-environment study, we grew seedlings directly in NST and in the two types of reclamation soils with and without added NST and we measured seedling growth, gas exchange parameters, as well as tissue concentrations of selected elements and foliar chlorophyll. White spruce seedlings suffered from severe mortality when grown directly in NST and their needles contained high concentrations of Na. The growth and physiological processes were also inhibited by NST in green alder and paper birch. However, the addition of top soil and peat mineral soil mix to NST significantly improved the growth of plants, possibly due to a more balanced nutrient uptake. It appears that NST may offer some advantages in terms of site revegetation compared with the traditional oil sands tailings that were used in the past. The results also suggest that, white spruce may be less suitable for planting at reclamation sites containing NST compared with the two studied deciduous tree species.

Overburden and tailings materials from oil sands production were used as construction materials as part of a novel attempt to create a self-sustaining, peat accumulating fen-upland ecosystem. To evaluate the potential for elemental release from the construction materials, total elemental concentrations in the tailings sand, petroleum coke and peat used to construct a fen ecosystem were determined using microwave-assisted acid digestions and compared to a leaching experiment conducted under environmentally-relevant conditions. A comparison of solid phase to aqueous Na, Ca, S and Mg concentrations showed they were highly leachable in the materials. Given that the concentrations of these elements can affect plant community structure, it is important to understand their leachability and mobility as they migrate between materials used to construct the system. To that end, a mass balance of aqueous Na, Ca, S and Mg was conducted based on leaching experiments and materials analysis coupled with existing data from the constructed system. The data indicate that there is a large pool of leachable Na, Ca, S and Mg in the system, estimated at 27 t of Na, 14 t of Ca, 37.3 t of S and 8.8 t of Mg. Since recharge mainly drives the fen-upland system water regime, and discharge in the fen, evapo-accumulation of these solutes on the surface may occur.

Appalachian USA surface coal mines face public and regulatory pressure to reduce total dissolved solids (TDS) in discharge waters, primarily due to effects on sensitive macroinvertebrates. Specific conductance (SC) is an accurate surrogate for TDS and relatively low levels of SC (300–500 μS cm−1) have been proposed as regulatory benchmarks for instream water quality. Discharge levels of TDS from regional coal mines are frequently >1000 μS cm−1. The primary objectives of this study were to (a) determine the effect of rock type and weathering status on SC leaching potentials for a wide range of regional mine spoils; (b) to relate leachate SC from laboratory columns to actual measured discharge SC from field sites; and (c) determine effective rapid lab analyses for SC prediction of overburden materials. We correlated laboratory unsaturated column leaching results for 39 overburden materials with a range of static lab parameters such as total-S, saturated paste SC, and neutralization potential. We also compared column data with available field leaching and valley fill discharge SC data. Leachate SC is strongly related to rock type and pre-disturbance weathering. Fine-textured and non-weathered strata generally produced higher SC and pose greater TDS risk. High-S black shales produced the highest leachate SC. Lab columns generated similar range and overall SC decay response to field observations within 5–10 leaching cycles, while actual reduction in SC in the field occurs over years to decades. Initial peak SC can be reliably predicted (R2 > 0.850; p < 0.001) by simple lab saturated paste or 1:2 spoil:water SC procedures, but predictions of longer-term SC levels are less reliable and deserve further study. Overall TDS release risk can be accurately predicted by a combination of rock type + S content, weathering extent, and simple rapid SC lab measurements.

Derelict mines pose potential risks to environmental health. Several factors such as soil structure, organic matter, and nutrient content are the greatly affected qualities in mined soils. Soil microbial communities are an important element for successful reclamation because of their major role in nutrient cycling, plant establishment, geochemical transformations, and soil formation. Yet, microorganisms generally remain an undervalued asset in mined sites. The microbial diversity in derelict mine sites consists of diverse species belonging to four key phyla: Proteobacteria, Acidobacteria, Firmicutes, and Bacteroidetes. The activity of plant symbiotic microorganisms including root-colonizing rhizobacteria and ectomycorrhizal fungi of existing vegetation in the mined sites is very high since most of these microbes are extremophiles. This review outlines the importance of microorganisms to soil health and the rehabilitation of derelict mines and how microbial activity and diversity can be exploited to better plan the soil rehabilitation. Besides highlighting the major breakthroughs in the application of microorganisms for mined site reclamation, we provide a critical view on plant−microbiome interactions to improve revegetation at the mined sites. Also, the need has been emphasized for deciphering the molecular mechanisms of adaptation and resistance of rhizosphere and non-rhizosphere microbes in abandoned mine sites, understanding their role in remediation, and subsequent harnessing of their potential to pave the way in future rehabilitation strategies for mined sites.

At a 50-year-old coal mine drainage barrens in central Pennsylvania, USA, we evaluated the biogeochemistry of acidic, Fe(III)oxy(hydr)oxide precipitates in reclaimed plots and compared them to untreated precipitates in control areas. Reclaimed plots supported successional vegetation that became established after a one-time compost and lime treatment in 2006, while control plots supported biological crusts. Precipitates were sampled from moist yet unsaturated surface layers in an area with lateral subsurface flow of mine drainage above a fragipan. Fe(II) concentrations were three- to five-fold higher in reclaimed than control precipitates. Organically bound Fe and amorphous iron oxides, as fractions of total Fe, were also higher in reclaimed than control precipitates. Estimates of Fe-reducing and Fe-oxidizing bacteria were four- to tenfold higher in root-adherent than both types of control precipitates. By scaling up measurements from experimental plots, total Fe losses during the 5-yr following reclamation were estimated at 45 t Fe ha−1 yr−1.

Organic carbon (OC) can help control greenhouse gas emissions by participating in biogeochemical reactions and preventing the migration of contaminants in groundwater systems. The association of OC with Fe (Iron) oxide minerals plays a significant role in stabilizing OC and regulating the biogeochemical cycles of OC on the earth’s surface. Reclaiming farmland from lakes changes an original lake into a wetland, but the destiny of Fe bound-OC in the underlying aquitard during this process has been poorly understood. The mechanisms of migration and transformation of Fe bound-OC were investigated in subsurface aquitard sediments of three typical boreholes in the Chen Lake wetland, central China. The Fe bound-OC content in the natural sedimentary conditions (borehole A), transition area (borehole B), and intensive reclamation area (borehole C) were 0.17–3.87, 0.28–3.98 and 0.13–7.08 mg g⁻¹, respectively. The reclamation changed the redox, water, and infiltration conditions of the surface environment, resulting in a transformation of Fe oxides phases, and then cause the change of content and structure of Fe bound-OC. The fresh organic matter provided by undecomposed crops causes oxygen- and nitrogen-rich compounds to combine with Fe oxides extensively through adsorption, resulting in higher δ¹³C values of Fe bound-OC than non-Fe bound-OC. Fe bound-OC has strong resistance to biodegradation. The Fe bound-OC: total OC ratios generated by adsorption and coprecipitation on the surface layer (0 to −3.5 m) of borehole C was 10.37% and 18.86%, 6.92% and 12.46% higher than those of boreholes A and B, respectively. Coprecipitation has a stronger OC-binding ability and enriches more carboxylates and aromatics, while adsorption gradually assumed a dominant position in OC-Fe interaction in deep aquitard. The reduction dissolution of Fe oxide causes Fe bound-OC to transfer into pore water, leading to an increase of Fe ion and dissolved OC in deep strata.

It was performed the study of the humus forms, quantity and pedochemical characteristics, further the study of plantation growth, and the dynamics in the period of 1994-1999. Negative impacts of the bulldozing were documented, acidification in the period 1994-1999 and the ameliorative role of the birch stand as well

The main aims of the preparatory stands in air pollution areas are growth development, successfull dynamics of the plants and fast creation of the stand microclimate with favourable effect on soil conditions. This process is documented by height and diameter increment. The results confirm different growth dynamics of the particular species. Larch is the species with the best growth dynamics of selected species on experimental plots. On the other hand, beech is the worst species for reforestation in this condition. One of the causes could be damage by frost

The solution for waste disposal being formed in the production of aluminium in Aluminium plant in Ziar nad Hronom is presented. It is namely recultivation of waste pile, it means biological reclamation. Averagely high vegetation is considered the most effective one for the reclamation of devastated areas and for creating natural connection of different components of this environment. Experimental plantations on the pile established in the years 1993-1996 by FRI Zvolen unanimously confirm this finding

The inner 1/3 of Isahaya Bay which is a tributary of Ariake Sea in Japan was shut off from the sea by a dike for the reclamation and disaster prevention in 1997. On the other hand, several environmental and fisheries problems occurred in Ariake Sea after 1990s. Some fishermen insisted that the major reason for the decrease of fishing must be the influence of the dike construction and filed lawsuits. Now the court decision is fixed and Japanese government must open the gates to reintroduce sea water into the reservoir. We made numerical simulations of currents, hydrography and sediment transport to assess the influences of the gate opening. To choose the environmentally wise procedure of gate opening, it is needed to reduce the erosion and deposition of bottom sediments caused by the enhanced tidal current and to minimize the occurrence of hypoxia in the reservoir.