Environmental assessment in the Yukon is multifaceted. The goal of RRMT 238 is to give students a well-rounded perspective on the many players and their roles in the assessment process. This includes the Yukon Environmental and Socio-Economic Assessment Board, the Yukon Water Board, The Yukon Government, First Nations governments, consulting companies, industry proponents, and non-governmental organizations. Students were asked to summarize the role of an organization and discuss the challenges and opportunities of environmental assessment based on information provided during class and by invited speakers. The results are compiled in the following document. In addition, they were challenged to suggest improvements to the environmental assessment process in the Yukon. Improvements suggested by the students include:
- A better integration between YESAB and the Yukon Water Board when it comes to the assessment of impact to water
- Set guidelines to assess the impact of cumulative impacts, including across boundaries
- Improved consultation practices with First Nations people
- Assigning a monetary value on ecosystem components
- Improved dissemination of lessons learned during socio-economic impact assessments
- Give more power to the recommendations that YESAB produces
Passive treatment systems (PTS) present a potential low-cost solution to treating mine-impacted waters (MIW) and impeding release of contaminants, such as metals and sulphate, into receiving waters in remote mine sites in Yukon. Nevertheless, the traditional carbon substrates used to maintain efficient functioning of these systems (i.e., molasses) are not readily available and can be expensive in remote locations. Moreover, the extensive periods of cold temperatures experienced in Yukon may impede the biological functioning of PTS. The goal of this study is to characterize a selection of local organic materials that may be used as complex carbon substrates for PTS and evaluate their potential performance as carbon substrates in the Yukon environment. In the first part of the study, the physiochemical properties of six local complex carbon substrates: willow leaves (Salix sp.), sedges (Carex sp.), peat, peat moss (Sphagnum), poplar (Populus sp.), wood chips, and spruce (Picea sp.) wood chips were characterized. In the second part, bench-scale bioreactors containing organic substrates, were used to evaluate carbon substrate degradation and the performance of bioreactors for sulphate and metal reduction from synthetic mine water at low temperatures for approximately five months. Sulphate reduction in the carex, moss, and willow bioreactors was reduced 100%, and overall, these substrates appear to support microbial-mediated metal sulfide precipitation at low temperatures (<10°C). During the time-frame of the study, spruce was not found to be effective in sulphate reduction. With some exceptions, the overall metal reduction was found to be high in all bioreactors, including controls. Thus, most of the metal removal was attributed to abiotic processes. Basic characterization of substrates, such as carbon content (DOC, TC) and nitrogen (TN) may be indicative of substrate performance, however a more in-depth analysis of the chemical properties of these components is warranted. This study is the first phase of a multiphase research project and is intended to inform future studies.
People that live near or around an operating mine are the most impacted therefore most affected by the operations of the industry. The town of Pelly Crossing is a rural community and has an operating mine nearby, the Minto mine. The members of the First Nation rely deeply on subsistence hunting and gathering of foods near and downstream from the mine site and are very concerned by potential contamination of their environment.
The mine owner intends to use constructed wetlands for long term water treatment for closure. Constructed wetlands have been proposed as a sustainable and cost effective long-term solution to remove heavy metal from water to be discharged in the environment. However, in the Yukon’s rural communities, the complex scientific mechanisms behind the constructed wetlands that are not well understood and there is little known about the positive impacts that constructed wetlands have on the ecosystem. Thus, it is important for the decision makers of Selkirk First Nation (SFN) to be aware of the benefits and concerns of constructed wetlands.
A pilot scale model of a constructed wetland has been built by the students of the Pelly Crossing School and is being used as a tangible, visual learning tool that will enhance and compliment the sciences already being delivered to the students. In the implementation of this project, there has been an attempt to provide a background on the principals of ecological engineering and how it relates to passive water treatment in the north.
Identifying the main stakeholders and building the support for this project has been key to the successful establishment of this project. The authors will present their experience and the outcomes they have seen so far with this project for the community of Pelly Crossing.
Four (4) pilot anaerobic bioreactors were commissioned at the Minto mine site in the summer of 2014 by Amelie Janin, NSERC Industrial Research Chair at Yukon College, and Capstone staff. Installation was completed on August 7th, 2014 and operation started on August 20th,2014. Bioreactor substrate composition varied among the bioreactors and included mixtures of creek sediments, low-grade or river gravel, wood chips or biochar (a coal made out of wood). During the first year the bioreactors were monitored until September 23rd,2014, after which they were dismantled and stored for the winter. In the following year, the bioreactors resumed operation on June 2nd and were monitored between June 20th, 2015 and September 26th, 2015.
Results during the four months of operation in the succeeding summer and fall in 2015 suggested that:
Bioreactors continued to reduce selenium from the influent which had a concentration close to Minto Mine’s selenium effluent discharge limit, decreasing to below the discharge limit of 0.003 mg/L as set by Minto’s Water Use License;
Steady copper removal was observed in all bioreactors regardless of temperature drop during the fall months;
Chipped wood appeared to release acidity in the effluent along with Total Organic Carbon in the month of operation in 2014 but not during operational period in 2015;
All bioreactors, including two that contained wood chips, met pH requirement of mine discharge limit throughout the 2015 operational period;
The most effective reduction of sulfate was observed in the bioreactors amended with wood chips;
Bioreactors helped to reduce nitrate concentrations to below discharge limits of 7.65 ug/L;
No exceedance of the mine effluent discharge limits were observed for nitrite and ammonia in the bioreactors effluents; and
Elevated levels of phosphate (not regulated) was observed in the effluent of the biochar amended reactor in the first year but absent in the other bioreactors.
Passive water treatment technologies are increasingly being considered for mine site closure in the Yukon and efforts are currently underway to test, compare and contrast passive treatment technologies with conventional technologies. This study aims to provide additional information about the effectiveness of passive treatment technologies for mine water treatment in cold climates. To test the hypothesis that bioreactors can effectively treat mine-impacted water at low temperatures, four bench-scale, continuous flow bioreactors were assessed for their potential to remove As, Se and Sb from mine effluent. The experiment was conducted as part of the work undertaken by the Yukon Mine Research Consortium; an industrial research body which conducts research on remediation and reclamation of Yukon mine sites to further enhance environmental stewardship in the territory.
More specifically, the objectives of this study were to 1) assess the efficiency of removal of As, Sb and Se, three metalloids, from a highly contaminated synthetic drainage in cold conditions as well as from actual leachate collected at the Eagle Gold site, 2) evaluate the impact of using wood chips as part of the composition of the bioreactor and 3) assess the impact of freeze/thaw on the bioreactors’ performance. Four bioreactors in columns were built in the Yukon Research Centre lab and operated for 5 months to treat both synthetic influent and leachate collected at Eagle Gold during summer 2014. Operation was phased as follows: Phase 1) the bioreactors were operated in an environment with uncontrolled temperature in the fall until the bioreactors froze solid; Phase 2) the bioreactors were thawed in a fridge at a stable temperature of 6°C; Phase 3) the bioreactors were operated and monitored at 6°C.
Results show that all bioreactors significantly decreased As, Sb and Se concentrations even when the influent concentration was high (mimicking the “worst case scenario”). However, even though As reduction was efficient, it was not quite enough to bring the concentrations below the discharge limit threshold of 0.15 ug/L. Using drainage produced on site, 38%, 90% and 95% of As, Se and Sb was removed. Using highly contaminated drainage with an average of 5 mg/L As, 0.5 mg/L Se and 0.03 mg/L Sb, the removal efficiencies were recorded at >85% for Sb, >87% for As, and >99% for Se. This study is one of very few studies reported in the literature which demonstrates antimony removal from water by an anaerobic bioreactor.
In addition to the metal removal performance assessment, the results indicate that addition of 20% spruce chips in the composition of the bioreactor substrate improved As removal in the first phase of the study and helped mitigate the impact of freeze/thaw on As, Sb and Se removal. It is thought that the solid substrate provides both an adequate support to either protect and/or favor biofilm growth as well as to provide a surface onto which As can adsorb.
Overall, this study demonstrates the potential application of passive anaerobic bioreactors as a technique to remove As, Sb and Se from mine water effluent. It also suggests that the addition of wood chips to bioreactors may be a suitable amendment in bioreactors built in the Yukon where cold temperatures and freeze/thaw conditions occur.
Constructed wetlands (CWs) have been employed as passive treatment systems for metal contaminated mine drainage in Canada. However, relatively few CWs have been documented in northern environments and further studies are needed to understand the metal removal mechanisms in wetlands operating under cold climates, with short growing seasons. The goal of this study was to evaluate the performance of laboratory-scale CWs for the removal of Cd, Cu, Se and Zn, as well as, to evaluate Cu and Se uptake in two northern plant species (Carex aquatilis and Juncus balticus). Eight laboratory-scale wetlands were constructed using local materials, including locally harvested plant species and microorganisms and operated under northern summer conditions for 10 weeks. The CWs were fed continuously with synthetic influent containing Cd, Cu, Fe, Se and Zn at concentrations predicted at mine closure. Average removal efficiencies of 96%, 99%, 79% and 97% were observed for Cd, Cu, Se and Zn respectively. There were no significant differences in plant establishment or growth between our CW treatments, or any evidence of increasing Cu uptake with increasing contaminant availability in either northern plant species. Increased belowground uptake of Se was observed at the higher influent concentration in the Pit treatment. However, overall our study suggests that uptake of contaminants by these two northern species is very minor (<0.06% Cu and <0.11% Se, except for C.aquatilis in one treatment <0.2% Cu and <0.4 % Se) and likely does not pose a risk to the surrounding environment. We conclude that CWs could operate as successful passive treatment solutions in a northern environment, at least during the summer months, pending further studies on winter treatment. Further studies are required to examine seasonal metal removal rates in relation to rates of sulfate reduction, carbon consumption, metal precipitation and sorption. In addition, potential contaminant uptake and the influence of functional plant characteristics on metal removal in a suite of northern plant species would further assist in the development of large-scale long-term northern CWs.
The overall goal of this project was to assess, in three stages, the use of fish otolith microchemistry as a potentially new monitoring tool to be applied around Yukon mine sites. High quality environmental assessments are critical to sound land and water use management as part of all mining development. Improvement of the environmental assessment and prediction of potential impact of land use activities rely on the development of scientific tools and techniques. Fish otolith chemistry integrates information on contaminant exposure and life history of both individual fish and populations. This technique affords a unique opportunity: otoliths consist of a calcium carbonate structures in the inner ear of fish deposited in daily to annual increments. They have been used to determine age and life history events of fish and fish populations. As otoliths are metabolically stable, the contaminant levels within their annular structure can provide a temporal record of exposure of the fish to trace metals and can be used to get baseline data information required for environmental assessments and reconstruct historical exposure for the further protection of aquatic wildlife. As new mining projects are developing in the Yukon, it is believed that Yukon would benefit in establishing a fish otolith chemistry technique and database in the territory with the local population, which in turn gave rise to this project.
The objectives of this study were to:
Complete the fish otolith study at the Keno Hill District site
Engage discussion with the Yukoners and share fish otolith knowledge
Identify the gaps that remain for development and practical use of this technique in Yukon
As a result, otoliths from grayling captured in Cristal creek and Moose creek and sculpins captured in Cristal creek and Haldane creek have been collected and analysed at the University of Manitoba by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometer (LA-ICP-MS). Sculpins show potential to indicate lead presence while lead was not detected in graylings but zinc was. Continued studies with periodic assessment of otoliths providing a retrospective analysis is suggested as a strategy to further define the impact of mining activities on fish otoliths.
All the water quality data, otoliths data and metal data collected have been shared amongst the project partners. In addition, a workshop was hosted in Mayo to discuss the potential application of this technology and discussions were engaged with Yukoners in various organizations.
Four (4) pilot anaerobic bioreactors were commissioned at the Minto mine site, in the summer of 2014 by Amelie Janin, NSERC industrial Research Chair at Yukon College, and Capstone staff (Figure 1). Installation was completed on August 7th, 2014 and operation started on August 20th 2014. Bioreactor substrate composition varied amongst the bioreactors and included mixtures of creek sediments, low-grade or river gravel, wood chips or biochar (a coal made out of wood). Monitoring of the bioreactors stopped on September 23rd 2014 when the bioreactors were dismantled and stored for the winter. Preliminary results obtained during the one month of operation after commissioning suggested that: • Bioreactors were able to reduce selenium below Minto Mine’s effluent discharge limits, as regulated under its water use licence (QZ96-006 Amendment #8); • Copper concentrations were reduced by the bioreactors to a lesser extent than selenium concentrations; • Two out of the four bioreactors affected the pH of the effluent so that the effluent did not meet the mine effluent discharge limits; • Chipped wood seemed to release organic acid in the effluent (lower pH, higher Total Organic Content) in the first month of operation; and • No exceedance of the mine effluent discharge limits were observed for NO3, NO2 and NH3, although high PO4 (not regulated) was observed in the effluent of the biochar amended reactor.
Passive biological treatments have been proposed as an efficient and cost effective treatment of metal bearing water discharged from mine sites after closure. However, concerns are typically expressed around biological treatments and their suitability in northern, colder climates as there are few examples of passive treatment systems operating under cold conditions which have been documented so far. In this study, four laboratory scale anaerobic bioreactors were monitored for over one year for their capacity to reduce metal concentrations at ambient laboratory temperature then at 6°C and 3°C. As, Cd, Cu, Se and Zn concentrations in the effluent were compared and contrasted with discharge limits in application at the Bellekeno Mine, Yukon Territory. Removal efficiencies in the range of 90 to 100% were observed in the four reactors and for the five metals studied, suggesting that sulfate-reducing bacteria native from the Yukon stayed active under cold conditions. In addition, integration of biochar in the composition of a bioreactor had a positive on the treatment efficiencies at the lower temperatures. This finding suggested that addition of a reactive material in the composition of the bioreactor substrate might help reduce the impact of the cold climate on the treatment system by taking advantage of metal adsorption mechanisms, which allows for continued metals removal during changes in temperature.