Life cycle assessment of mine tailings management in Canada

The effective management of mine tailings involves the control of several environmental impacts and legal requirements. Six tailings site management and closure scenarios were developed for a copper zinc underground mine located in Quebec (Canada) and compared using life cycle assessment (LCA). Two options are considered for the mine operation: tailings can be sent to the tailings disposal area where they are submerged or they can be partly used for backfilling. For each of these two operation options, three alternatives are presented for mine closure: (a) submerged tailings, (b) partial desulphurization with a cover of desulphurized material and (c) a cover with capillary barrier effects (CCBE) made of natural soils followed by revegetation. The goals of the study were to draw the inventory of these management scenarios from the development to the post-closure phase, to assess and compare their environmental impacts and to determine the importance of the land-use impact category. The potential impacts for each scenario were evaluated using the IMPACT 2002+ LCIA method. The results of the performed LCA indicate that for mine development and operation, scenarios where tailings are partly used as backfill for underground stopes appear to lead to larger impacts in 11 of the 14 midpoint categories since the backfill plant operation consumes a greater amount of material and energy. For a site closure period of 2 years, the CCBE option creates the greatest impacts, since it requires much more effort than the other techniques. The results for the post-closure phase have been analysed separately since they have a larger uncertainty. They appear to modify the comparative assessment results. The various results presented in the paper show the importance of taking land-use impacts into account.     

Leaching and degradation of S-Metolachlor in undisturbed soil cores amended with organic wastes

Environmental Science and Pollution Research - Organic waste (OW) reuse in agriculture is a common practice fostered by benefits in terms of waste recycling and crop production. However, OW...     

New ternary water-soluble support from self-assembly of β-cyclodextrin-ionic liquid and an anionic polymer for a dialysis device

Environmental Science and Pollution Research - We developed a new hybrid material resulting from an innovative supramolecular tripartite association between an ionic liquid covalently immobilized...     

Atmospheric Tracer Techniques and Gas Transport in the Primary Aluminum Industry

The results of 35 Individual SF₆ tracer tests conducted in Norway during 1978 demonstrate the applicability of tracer techniques to the study of a wide variety of pollutant transport problems found in the primary aluminum industry. Tracer methods were employed to determine the efficiency of the pollutant control system over a single reduction cell under a variety of operating conditions. Two tests conducted during normal operation gave efficiencies equal to 100 ±19% and 79 ± 12%, while a test performed during the occurrence of an anode effect yielded an efficiency equal to 66 ± 22%.

Tracer investigations of flow in the wake of a smelter hall indicated that between 1 % and 11 % of secondary, roof-top emissions can become entrained in the recirculation cavity and reenter the hall through the ventilation fresh air supply. These reentry rates were observed for release heights as high as 8 m above the existing roof exhaust duct. Tracer dispersion data collected within 20 building heights of the smelter agreed very well with extrapolations of McEIroy- Pooler dispersion curves for an urban area. Dispersion curves determined from a previous wind tunnel study of flow downwind of an isolated building underestimated dispersion downwind of the vs.melter complex.

The total fluoride mass flow rate measured downwind of a smelter during wet, foggy conditions indicated that wet removal rates of fluorides are in the range 3.2 × 10^?4/s to 6.4 × 10^?4/s. Simulation of the source with several tracer point releases and simultaneous measurement of fluoride and tracer ground-level concentrations downwind of the smelter eliminated the need for measurements of vertical profiles of wind speed and fluoride concentration during the experiment.     

Occurrence of 1,1′-dimethyl-4,4′-bipyridinium (Paraquat) in irrigated soil of the Lake Chad Basin,Niger

Increased use of agrochemical products to improve yields for irrigated crops in sub-Saharan Africa has been accompanied by a significant increase in the risk of environmental contamination. Detailed examples of the fate of pesticides after initial spreading on crop fields are scarce in tropical regions, where safe practices and related health risks are poorly understood by smallholder farmers. In the semi-arid environment of the Lake Chad Basin, SE Niger, both intrinsic properties of pesticides and extrinsic factors such as soil and climate helped to characterize processes leading to an accumulation of pesticides in soils. Analysis by HPLC-UV of a 6 m deep soil profile showed the presence of Paraquat at concentrations from 953?±?102 μg kg^?1 to 3083?±?175 μg kg^?1 at depths between 0.80 and 2.75 m below the land surface. Soil analysis revealed that up to approximately 15 % of the total soil matrix consists of smectites, a clay mineral capable of retaining cationic pesticides such as Paraquat, and a very low content of organic matter (<0.15 wt.% TOC). Paraquat could be stored and not bioavailable in a clayey barrier at approximately 2-m depth and therefore does not represent an immediate risk for populations or environment in this form. However, if the Paraquat application rate remains constant, the clayey barrier could reach a saturation limit within 150–200 years and 180–220 years if we consider a DT50 in soil of ~1,000 days (FAO). Consequently, it could lead to a deeper infiltration and so a pollution of groundwater. Such a scenario can represent a health risk for drinking water and for the Lake Chad, which is a major resource for this densely populated region of semi-arid Africa. Further analyses should focus on deeper layers and groundwater Paraquat contents to validate or invalidate the hypothesis of storage in this clay-rich layer.     

The Crisis Map of the Czech Republic: the nationwide deployment of an Ushahidi application for disasters

Crisis mapping is a legitimate component of both crisis informatics and disaster risk management. It has become an effective tool for humanitarian workers, especially after the earthquake in Haiti in 2010. Ushahidi is among the many mapping platforms on offer in the growing field of crisis mapping, and involves the application of crowdsourcing to create online and interactive maps of areas in turmoil. This paper presents the Crisis Map of the Czech Republic, which is the first such instrument to be deployed nationwide in Central Europe. It describes the methodologies used in the preparatory work phase and details some practices identified during the creation and actual employment of the map. In addition, the paper assesses its structure and technological architecture, as well as its potential possible development in the future. Lastly, it evaluates the utilisation of the Crisis Map during the floods in the Czech Republic in 2013.