Aided phytostabilization using a combination of compost, zerovalent iron grit and coal fly ash (CZA) amendments and revegetation effectively promoted the biological recovery of mining spoils generated at a gold mine in Portugal. Selective dissolution of spoil samples in combination with solid phase characterization using microbeam X-ray absorption near edge structure (μXANES) spectroscopy and microbeam X-ray fluorescence (μXRF) mapping were used to assess As associations in spoils ten years after CZA treatment. The results show that As preferentially associates with poorly crystalline Fe-oxyhydroxides as opposed to crystalline Fe-(oxyhydr)oxide phases. The crystalline Fe(III)-phases dominated in the treated spoil and exceeded those of the untreated spoil three-fold, but only 2.6–6.8% of total As was associated with this fraction. Correlation maps of As:Fe reveal that As in the CZA-treated spoils is primarily contained in surface coatings as precipitates and sorbates. Arsenic binding with poorly crystalline Fe-oxyhydroxides did not inhibit As uptake by plants.

Suspended sediment concentration (SS) is an important indicator of marine environmental changes due to natural causes such as tides, tidal currents, and river discharges, as well as human activities such as construction in coastal regions. In the Saemangeum area on the west coast of Korea, construction of a huge tidal dyke for land reclamation has strongly influenced the coastal environment. This study used remotely sensed data to analyze the SS changes in coastal waters caused by the dyke construction. Landsat and MODIS satellite images were used for the spatial analysis of finer patterns and for the detailed temporal analysis, respectively. Forty Landsat scenes and 105 monthly composite MODIS images observed during 1985–2010 were employed, and four field campaigns (from 2005 to 2006) were performed to verify the image-derived SS. The results of the satellite data analyses showed that the seawater was clear before the dyke construction, with SS values lower than 20g/m³. These values increased continuously as the dyke construction progressed. The maximum SS values appeared just before completion of the fourth dyke. Values decreased to below 5g/m³ after dyke construction. These changes indicated tidal current modification. Some eddies and plumes were observed in the images generated from Landsat data. Landsat and MODIS can reveal that coastal water turbidity was greatly reduced after completion of the construction.

This article assesses the ecological and economic impacts of land reclamation and dredging through consulting recent environmental impact assessment reports. Geographic features of Bahrain during 1963–2008 are produced using Geographical Information System. Extensive but inexpensive shallow coastal areas and tidal flats have been reclaimed particularly from 1997 to 2007 at a high rate of 21km²/year. Formal records show the increase in the original land mass by the year 2008 to be 91km². An estimated total cumulative loss of major habitats resulting from 10 reclamation projects was around 153.58km². Also much larger scale impacts should be considered resulting from the borrow areas used for the extraction of sand or infill materials. A number of key habitats and species are affected in the vicinity of these projects. The study attempts to assign a monetary value to the marine ecosystem functions. There is a need for efficient coastal zone management to regulate a sustainable use of the marine resources.

Fluvial mine tailing deposition has caused extensive riparian damage throughout the western USA. Willows are often used for fluvial mine tailing revegetation, but some accumulate excessive metal concentrations potentially detrimental to browsers. This greenhouse experiment evaluated growth and metal accumulation of Geyer willow (Salix geyeriana Andersson), Drummond’s willow (Salix drummondiana Barratt ex Hook.), diamondleaf willow (Salix planifolia Pursh), Bebb willow (Salix bebbiana Sarg.), thinleaf alder [Alnus incana (L.) Moench spp. tenuifolia (Nutt.) Breitung], water birch (Betula occidentalis Hook.), red-osier dogwood (Cornus sericea L. spp. sericea), and shrubby cinquefoil [(Dasiphora fruticosa (L.) Rydb. ssp. floribunda (Pursh) Kartesz)]. Bare-root shrubs were grown in tailings collected from three acidic, metal-contaminated (i.e., Cd, Cu, Pb, and Zn) fluvial deposits near Leadville, Colorado, USA. Tailings were amended with only lime to raise the soil pH to 7 s.u., or with lime and composted biosolids (224 Mg ha−1). All shrubs survived in the amended tailings; composted biosolids had little effect on plant biomass. Aboveground and belowground biomass increased during the 2-month greenhouse study by 3–9 and 1.5–5 times initial values, respectively. Most shrubs accumulated Pb and Cu in roots, and belowground Pb concentrations in all shrubs were significantly reduced by the addition of composted biosolids. Compared to other species, alder and cinquefoil accumulated Pb in aboveground growth, and concentrations exceeded animal toxicity thresholds, but these shrubs normally comprise a small proportion of animal diets. Dogwood, alder, and cinquefoil contained low Cd concentrations in aboveground new growth, whereas Bebb and Geyer willow contained zootoxic concentrations. Dogwood, alder, and cinquefoil are three good candidates for mine tailing revegetation, especially in fluvial deposits with elevated Cd concentrations.

Arsenic occurs in the earth's crust in various chemical forms as a result of both natural and anthropogenic sources. Soil chemical extractions may help understand As availability, as well as the possibility of As entry into the food chain. Phytoextraction has been proposed as a technology for remediation of As-contaminated soils. The study was carried out to assess the bioavailability of As by extractants and to compare the performance of castor bean and sunflower for As removal from soils. Two soils were contaminated with Na2HAsO4.7H2O adding 35 and 150 mg As dm−3 soil. Arsenic availability was assessed using the following extractants: tri-distilled water, ammonium sulfate, ammonium phosphate, ammonium oxalate + oxalic acid, organic acids mixture, Mehlich-1, and United States Environmental Protection Agency 3051. The roots and shoots of 35-day-old plants were collected and dry matter yield as well as As concentration were determined. The accumulation of As in shoot was also calculated in order to evaluate the plants potential for As phytoextraction. The extractants tested were efficient to assess the concentration of available As in soil. Addition of As to the soils did not cause severe toxicity in plants, although the dose 150 mg As dm−3 soil decreased shoot and root yield in both species. Castor bean was less sensitive to As than sunflower, but none of the species had hyperaccumulation characteristics. These species can be used for revegetation of areas contaminated with As up to safe limit of 150 mg As dm−3 soil, as proposed by CONAMA for industrial areas in Brazil.

Reclamation of land disturbed due to mining in arid and semiarid environments occurs across the globe. Large-scale surface mines provide unique opportunities to examine the reclamation process across a landscape. The objectives of this research were to (1) measure infiltration rates in reclaimed surface coal mines and (2) determine the effects of soil properties on ground cover on infiltration rates of surface coal mines. In this study, reclaimed land 10–15 and 20–25 years old, and native reference site (undisturbed) were investigated at two large surface coal mines in Wyoming, USA. Infiltration rates were measured using double-ring infiltrometer method. The soil properties including bulk density, pH, carbonate content, organic carbon content, aggregate stability, electrical conductivity, and soil texture were analyzed using standard methods. The ground cover was estimated visually. Statistical analysis was conducted to determine if any correlations between infiltration rate and soil properties and ground cover exist. Results suggest that at Mine 1, infiltration rates on reclaimed land were found to be significantly higher in the 20–25-year-old reclamation than the 10–15-year-old reclamation and the native site. At Mine 2, the native site had significantly higher infiltration than 20–25-year-old reclamation, which in turn had significantly higher infiltration rates than the 10–15-year-old reclaimed site. Along with infiltration, soil characteristics were examined. Overall, the findings of this study suggest soil texture and plant cover play an important role in controlling infiltration rates in reclaimed surface coal mines.

PURPOSE: To examine (1) the effect of organic (poultry manure) and inorganic (residue mud and phosphogypsum) amendments on nutrient leaching losses from residue sand and (2) whether amendments improve the growth of plants in residue sand. METHODS: Leaching columns were established using residue sand. The phosphogypsum-treated surface layer (0–15 cm) was amended with poultry manure and/or bauxite residue mud and the subsurface layer (15–45 cm) was either left untreated or amended with phosphogypsum. RESULTS: Much of the Na+, K+, Cl− and SO 4 2− was lost during the first four leachings. Additions of phosphogypsum to both surface and subsurface layers resulted in partial neutralization of soluble alkalinity. Mean pH of leachates ranged from 8.0 to 8.4, the major cation leached was Na+ and the major balancing anion was SO 4 2− . Where gypsum was not applied to the subsurface, mean pH of leachates was 10.0–10.9, the main cation leached was still Na+ and the main balancing anions were a combination of SO 4 2− and HCO 3 − /CO 3 2− . At the end of the experiment, concentrations of exchangeable Na+ in the subsurface layers were similar regardless of whether gypsum had been applied to that layer or not. Yields of Acacia saligna were promoted by additions of poultry manure to the surface layer but unaffected by gypsum incorporation into the subsurface layer. CONCLUSIONS: Lack of reaction of phosphogypsum with the subsurface layer is unlikely to be a major factor limiting revegetation of residue sand since in the absence of phosphogypsum the excess Na+ leaches with the residual alkalinity (HCO 3 − /CO 3 2− ) rather than SO 4 2− .