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TECHNICAL REPORTS

Plant and Environment Interactions

Barley, a Potential Species for Initial Reclamation of Saline Composite Tailings of Oil Sands

^a Department of Botany, 505 Buller Building, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
^b Syncrude Canada Ltd., Edmonton Research Center, 9421-17 Avenue, Edmonton, AB, Canada T6N 1H4
^c Syncrude Canada Ltd., Environmental Center, Fort McMurray, AB, Canada T9H 3H5

^* Corresponding author (renaults{at}cc.umanitoba.ca).

Received for publication December 13, 2002.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
The oil sands industry in Alberta (Canada) has developed the composite tailings (CT) process to reduce the fluid fine tails resulting from the processing of oil sands. This process uses a chemical coagulant (gypsum or alum) to produce aggregated fines (clay), so they are retained with the coarse sand fraction of the extraction tailings to form CT, from which fines-free water is released relatively quickly compared with untreated tailings. The resulting CT and CT waters are saline-sodic, with Na⁺, SO^2-₄, and Cl^- being the dominant ions. When freshly deposited, the CT deposits are too soft for access by reclamation equipment, and the time required for these deposits to remove the water sufficiently to support traffic is uncertain. A greenhouse study was designed to determine the suitability of barley (Hordeum vulgare L.) for reclamation of fresh CT deposits and to evaluate benefits of peat amendments. This study assessed germination, early plant growth, chlorophyll content, and survival of barley growing in alum- and gypsum-treated CT, with and without peat amendment. Ion and trace metal accumulation in the root and shoot tissues of barley was determined. Amendment of CT with peat improved germination, survival, and growth of barley, but did not prevent leaf injury (probably due to Na and Cl and possibly multiple nutrient deficiency). Field studies will be undertaken to validate our greenhouse results suggesting that barley could be used to improve dewatering of the freshly deposited substrates, reduce soil erosion, and facilitate leaching of ions by root penetration into the substrate.

Abbreviations: CT, composite tailings

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
OIL SANDS OPERATORS in the Athabasca oil sands region of Alberta produce large volumes of fluid fine tails during ore extraction (Fine Tailings Fundamentals Consortium, 1995). By the end of the current operations, the volume of fine tails, stored in tailings ponds, could exceed one billion cubic meters. Fine tails (silts and clay minerals) is the fraction of extraction tailings that forms slowly densifying aqueous suspensions within settling basins. As part of the fine tails management strategy to reduce the volume of these tailings, the oil sands industry developed the CT process (Matthews et al., 2002). The CT process is initiated by the addition of a coagulant, calcium sulfate (gypsum) or alternatively aluminum sulfate (alum), to a mixture of fine tails and densified coarse extraction tails (sand-rich fraction from cyclone underflow). The resulting coagulation and aggregation processes lead to the fine particles (clays and silts of less than 44 µm) being retained with the sand fraction during deposition. The produced CT mixture (55–65% solids by weight, with 15–30% fines content) will release water relatively quickly on deposition. The addition of the required inorganic coagulant aid will result in significant changes in the ionic content of the CT and CT release water (MacKinnon et al., 2001). Chemical analysis of the CT mix and its released water has indicated that this material will have a relatively high pH (>7.6) and high concentrations of ions including Na⁺, SO^2-₄, and Cl^- (MacKinnon et al., 2001). Furthermore, with subsequent recycling of release water in processing needs, the salinity of waters contained on the site will further increase. In addition to the salinity of the tailings and associated waters, concerns have been raised regarding impact and availability of trace heavy metals (e.g., Al, B, and Sr) that may be associated with the CT materials.

Before mining activities, the oil sands development area supported a mixed wood boreal forest. The reclamation objective is to produce a self-sustaining ecosystem with no long-term toxicity (Fine Tailings Fundamentals Consortium, 1995). The choice of the reclamation plant species will be influenced by their tolerance to pH, general salinity, and specific ions in these tailings. The results of previous studies (Renault et al., 1998, 1999) have shown that growth and survival of several boreal forest species, including jack pine (Pinus banksiana Lamb.), white spruce [Picea glauca (Moench) Voss], aspen (Populus tremuloides Michx.), and raspberry (Rubus idaeus L.), were affected by the presence of both the tailings substrate and its associated waters. However, the responses and level of tolerance varied depending on the species; for example, red-osier dogwood (Cornus stolonifera Michx.) showed relative tolerance compared with the other boreal species (Renault et al., 2001). Previous results (Renault et al., 2000) have also shown that the structure and the texture of the tailings affected plant growth. They can limit root penetration, modify water-holding capacity, and influence oxygen content of the tailings (Renault et al., 2000). Addition of organic matter, such as peat, could improve tailings texture and structure and buffer some of the chemical impacts, and should help the plant to survive (Oil Sands Vegetation Reclamation Committee, 1998).

Freshly deposited CT is soft (<2 kPa undrained shear strength) and access by traditional reclamation equipment may be limited for some years. Reclamation with grass species that are capable of establishment in the soft deposits would allow for a rapid vegetative cover to reduce wind and water erosion and aid in dewatering the deposit. Vegetation is the most effective long-term stabilizer (Ripley et al., 1996). Over time, grass would also modify substrate properties, improving conditions for the reestablishment via natural succession of a forest ecosystem. Barley was selected for the study due to its relative tolerance to salinity (Greenway and Munns, 1980). In addition, it has been successfully used on tailings sands as a soil stabilizer (Suncor Energy, 2001).

The main objectives of the study were to determine: (i) germination, early plant growth, and survival of barley in both gypsum- and alum-produced CT, with and without peat amendment, and (ii) the effects of ion and trace metal accumulation in barley root and shoot tissues on growth.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Plant Materials
Barley (cv. Bonanza) seeds were provided by the Department of Plant Sciences, University of Manitoba. The experiment was set up in a greenhouse with a (day–night) 25°C–18°C temperature cycle with an 18-h photoperiod, supplemented by 400-W high-pressure sodium lamps (P.L. Light Systems, Beamsville, ON, Canada).

Substrates and Waters
Fresh CT mixes (gypsum CT; alum CT) were produced at Syncrude [alum, 48% solution of Al₂(SO₄)₃·14.3H₂O; gypsum, CaSO₄·2H₂O, dosage 1000 g m^-3]. Release waters (gypsum CT water; alum CT water) were collected from each deposit into polypropylene buckets. Peat (topsoil collected in the area surrounding the mine) and reclamation soil (clayey, sodic mix) representative of the materials used at Syncrude's Mildred Lake site (57°05.95' N, 111°38.90' W) were collected into plastic containers. The properties of the waters and substrates used to prepare the various exposure mixes are summarized in Table 1. Water samples were filtered (0.45-µm filter; Millipore, Bedford, MA) and analyzed by ion chromatography (DI 300; Dionex Corporation, Sunnyvale, CA) for anion composition and by inductively coupled plasma optical emission spectrometry (ICP–OES) (Vista-PRO RL; Varian, Palo Alto, CA) for cations and trace metals following ASTM International (West Conshohocken, PA) methods as modified by Syncrude Canada Ltd. (Franklin et al., 2002). Substrates were analyzed for elemental content by ICP–OES of saturated paste extracts (Redfield et al., 2003). Hydrocarbon content was measured using a soxhlet extraction method using toluene (Syncrude Canada Ltd., personal communication, 2002). The particle size distribution of the mineral solids fraction was determined using the Coulter laser diffraction method at Syncrude's research facility. Soil property determination was based on methods of McKeague (1978). Preparation and analysis of paste saturates (% saturation), soil salinity determination, and calculation of sodium adsorption ratio (SAR = Na/[(Ca + Mg)/2)]^1/2), were conducted by Norwest Labs of Edmonton, Alberta. Saturated pastes of the starting materials and the various test substrates were generally in the 35 to 100% (water/solids by weight) range, with fines (<44 µm) contents in the 15 to 30% range. The SAR values for all starting mineral substrates were greater than 10, while the peat was less than 1 (Table 1).

Measurements
Germination (seedling emergence) was recorded over a 25-d period. Three weeks after seeding, chlorophyll analysis and electrolyte leakage were performed on barley plants to estimate the damage caused by the tailings. After eight weeks, survival and injury were recorded and plants were harvested and washed three times with distilled water. Root and shoot fresh weights were recorded, and then the plants were freeze-dried to determine dry weights.

Electrolyte Leakage
To determine the extent of membrane injury, leakage of electrolytes from cells was determined with a portable conductivity meter (Fisher Scientific, Pittsburgh, PA) (Renault et al., 2000). Leaf discs (0.9 cm in diameter) were washed with deionized water and incubated for 1 h at room temperature to rinse the tissues. The solution was then replaced by fresh deionized water and discs were incubated for a further 5 h. Electrical conductivity (ECa) of this solution was measured using the conductivity meter (Renault et al., 2000). To determine total electrolytes, leaf discs were frozen in liquid nitrogen, stored overnight at -85°C, and then incubated for another 5 h at room temperature in deionized water. Electrical conductivity (ECb) of this incubation solution was recorded. The two conductivity values recorded were used to calculate total electrolytes. The following formula was used to calculate the electrolyte leakage as percentages of total electrolytes:

Chlorophyll Determination and Elemental Analysis of Plant Tissues
A 4-cm segment of a fully mature leaf was sectioned at 4 cm from the tip, to avoid collecting necrotic tips. Two plants per replicate (n = 8) for each treatment were used. Leaf chlorophyll content of each leaf segment was determined spectrophotometrically using three methanol extracts (Sestak et al., 1971; Renault et al., 2001).

Freeze-dried root and shoot tissues of five plants per replicate were combined to perform tissue elemental analysis. Major cations and trace metals in plant tissues were measured in 0.45-µm-filter-passing solutions of freeze-dried tissues, after digestion with concentrated HNO₃. The elemental content of this acid digestion was determined by ICP–OES (Varian Vista-PRO RL) (Renault et al., 1999). The major anions, chloride and sulfate, were determined by ion chromatography (Dionex DI-300). A 0.45-µm filtrate of a two-time extraction of the plant tissue with hot (80°C) deionized water (ratio of water to tissue greater than 25:1) was analyzed by ion chromatography with a AS4A-SC 4-mm column and a 3 mM carbonate and 2.4 mM bicarbonate eluant.

Data Analysis
The statistical analysis of the data was performed using a general linear model (GLM) and treatment means were compared using Duncan's multiple range test at the P 0.05 level.

	RESULTS

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Substrate Analysis
The initial pH values in CT substrates were greater than 8 (8.9 and 8.8 for alum CT irrigated with distilled water and alum CT water, respectively, and 8.1 and 8.2 for gypsum CT irrigated with distilled water and gypsum CT water, respectively), while lower values (7.2 and 7.3) were recorded in reclamation soil with peat (Table 2). Amendment of CT substrates with peat caused a decrease in pH, giving a value similar to control substrate (reclamation material with peat). The electrical conductivity was higher in all treatments compared with the control (Table 2) due to, at least in part, the higher concentration of sodium and chloride in the CT treatments. The CT mixes amended with peat showed a reduced level of sodium, chloride, and boron when irrigated with distilled water. Levels of some macronutrients, such as calcium and magnesium, were very low in CT substrates (Table 2).

Germination
Three days after seeding, germination of barley was affected by all CT treatments (CT substrate with and without peat and CT water) (Fig. 1) . However, after four days, only the seeds planted on CT substrates without amendment remained affected by the treatments. Seeds growing in reclamation soil with peat and irrigated with CT water, and CT substrate amended with peat, seemed to have recovered from the initial delay in germination, while seeds growing in CT substrates without peat still exhibited a reduction in germination after 30 days (Fig. 1). Further reduction was observed when CT substrate was irrigated with CT water.

View larger version (33K): [in this window] [in a new window]   Fig. 1. Seedling emergence of barley seeds planted in control and tailing substrates. The * indicates a significant difference from the control for all measurement dates at = 0.05.

Chlorophylls and Membrane Leakage
The results showed that chlorophyll a and b content of barley plants growing in reclamation soil, with peat irrigated with CT waters, was not affected by the treatment (Table 4). This is in agreement with injury results that reported no visible damage in this treatment. Chlorophyll a content was reduced in barley growing in CT substrates, with and without peat, while chlorophyll b was decreased only in plants growing in CT substrate, without peat (Table 4). This result is also in agreement with the level of injury in barley seedlings. The chlorophyll a to b ratio was not affected in any treatments, although the level of chlorophyll a was more reduced than the level of chlorophyll b.

Elemental Content of Plant Tissues
Our results showed high amounts of Na, Cl, B, and Mn in plants treated with CT substrates (Tables 5 and 6). Sodium levels in roots and shoots of barley increased significantly in all treatments, with the exception of plants growing in reclamation and peat soil irrigated with CT waters, although there was a trend (Tables 5 and 6). Barley plants growing directly on CT substrates contained very high amounts of Na in their shoots (22.5–27.8 g kg^-1 tissue dry wt.). Chloride levels in both root and shoot tissues were increased in all treatments (Tables 5 and 6), with higher levels (25.5–31.2 g kg^-1 tissue dry wt.) in plants growing directly on CT substrates. In all treatments, the amounts of Na and Cl were higher in shoots than in roots. Calcium, K, and Mg levels decreased in shoot tissues in all treatments (Tables 5 and 6), with values below the critical levels given for barley (3, 15, and 1.5 g kg^-1 tissue dry wt. respectively; Jones et al., 1991) in plants growing in CT substrates, with and without peat amendments. There was no significant change in root tissues, with the exception of K, where a significant reduction was found in a few treatments (Table 5). There was also a decrease in S and P levels in shoots of plants growing directly on CT substrates. However, only P levels were below the critical levels for barley (2 g kg^-1 tissue dry wt.; Jones et al., 1991). In addition, two elements exhibited an increase, Mn levels were higher in roots of plants growing in CT substrates, and B levels were increased in shoot tissues of barley growing in CT substrate with and without peat (Tables 5 and 6). Although Al was present in the alum used to prepare alum–CT, the amount of Al seen in the CT water of the CT substrates was low (Table 1). Within the root and shoot tissues of the plants, exposed to either the alum–CT water or alum-produced CT substrate, the reported concentrations of Al were generally below the detection limit.

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

In addition to water stress, the high accumulation of both Cl and Na in barley tissues is likely to have contributed to injury and growth reduction. An excess of Na and Cl in tissues can cause ion toxicity by interfering with enzyme activities, thus affecting physiological processes (Greenway and Munns, 1980). Our results are in agreement with work of Popova et al. (1995) and have shown a reduction in chlorophyll content of barley leaves. It was suggested that Na could interfere with enzymes involved in chlorophyll synthesis, thus reducing photosynthesis and plant growth. A previous study has shown that barley can take up considerable amounts of Na and Cl, with sensitive varieties accumulating higher amounts than tolerant varieties (Jeschke, 1984). Some salt-tolerant species seem to be able to restrict Na accumulation in shoots (Storey and Wyn Jones, 1978; Al-Karaki, 1997). Also, these ions can contribute to the osmotic adjustment (Matsuda and Riazi, 1981; Storey and Wyn Jones, 1978) that enables barley plants to maintain turgor to a certain extent during water stress.

A third factor that could have contributed to growth reduction is nutrient deficiency. Low levels of K, Mg, Ca, S, and P were found in plants growing on CT substrates compared with control plants. This result could be attributed to competition of Na with Ca, K, and Mg (Ullah et al., 1993). Lynch and Lauchli (1985) found that shoot Ca content of barley was reduced by salinity stress. Calcium plays an important role in maintaining membrane integrity, and is required for communication between cells, while K and Mg play key roles in enzyme regulation (Taiz and Zeiger, 1998). Nutrient deficiency will affect plant growth by disturbing plant metabolism. Plant metabolism can be further altered by the low levels of S, which is an important constituent of natural organic compounds, and P, which is involved in energy storage and structural integrity. These low levels of S and P could be attributed to competition of Cl with NO₃ and H₂PO₄ (Curtin et al., 1993). Although N content was not determined in plant tissues in our study, there is a possibility that this element could have been deficient, as it is known to decrease in presence of NaCl due to competition for uptake between Cl and NO₃ (Grattan and Grieve, 1999). Nutrient deficiency can result from the relatively high pH of the tailings. High pH modifies the availability of elements such as P, K, and Mg that play a major role in plant nutrition (Taiz and Zeiger, 1998). In addition, trace elements are also less available at high pH.

Sodicity of the CT substrates is another factor that could have affected the CT-treated plants, mainly by adverse effects on the physical properties of the CT substrates. The sodium adsorption ratio values (higher than 15) and the high electrical conductivities (higher than 4 dS m^-1) suggest that these CT substrates are not only saline, but also sodic. Sodium can affect the physical properties of such substrates by reducing permeability to water due to swelling of clays and dispersion of soil, resulting in poor soil structure (Sumner and Naidu, 1998). Although small amounts of water (2.5% of irrigation waters) were added from the top to prevent the formation of a crust, CT substrates formed a relatively compact soil over a short time, probably due to the effect of Na on soil particles. As soil porosity affects the amount of water and oxygen present in the soil, this could have resulted in decreased germination. Amendment of CT substrates with peat enabled all plants tested to survive. This is probably due to changes in physical and chemical properties of the substrate, leading to improvement of substrate structure (sodium adsorption ratio values were drastically reduced) and reduction of the toxic compound concentrations.

Our results showed relatively high levels of Mn and B in plants grown directly on CT substrates. Manganese and boron are necessary for plant growth in small amounts; however, a high concentration can cause toxicity (El-Jaoual and Cox, 1998; Mahbooli et al., 2000). A similar increase in Mn level was reported in barley growing in saline soil (Suhayda et al., 1994). Manganese can also lead to Fe and Zn deficiency due to competition for uptake. In our study, Zn levels were higher than 100 mg kg^-1 tissue dry wt. and thus not likely to cause deficiency while Fe levels were lower than 100 mg kg^-1 tissue dry wt. and could have eventually further limited growth (data not shown). The high level of B in plants growing in saline areas has been previously reported in wheat (Grieve and Poss, 2000). Our results suggest that the plants grown on the alum–CT materials will not accumulate significantly higher levels of Al than plants grown in non-alum-treated CT products. This could be due to the fact that at high pH, availability of the Al ion is reduced. This result is encouraging since Al is known to have toxic effects on plants (Cumming and Taylor, 1990; Kinraide et al., 1994) and its presence would pose a challenge for the reclamation of alum CT substrates.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 
Barley plants were relatively tolerant to the CT release waters, both from the gypsum and alum treatments, at least during the eight weeks of treatment. However, the CT substrate from both treatments reduced germination rates and plant survival and caused leaf injury and a reduction in growth. This would be detrimental to the success of the initial reclamation strategy when the tailings were too soft for the easy application of mitigating amendments. As a result, the ability to develop good grass cover over fresh CT deposits without amendment with materials, such as peat, will be limited and this early reclamation strategy is unlikely to be able to play a major role in modifying the fresh CT substrate properties so that the establishment of a viable terrestrial ecosystem in the short term would be possible. These results suggest that CT substrates are not a suitable growth medium for the selected species. Addition of peat to CT substrates improved greatly the germination of the selected species. It also improved survival and minimized growth reduction by decreasing Na and Cl concentration in the substrate. As a result of peat amendment, there was a reduction in the amount of salts absorbed by plants, although some injury still occurred. This suggests that more peat should be added to reclamation substrates to limit the toxic effects of ions. Furthermore, addition of nutrients should be considered in further studies to limit nutrient deficiency.

Our results suggest that barley could be used for phytoremediation, due to its high accumulation of ions in aboveground biomass. However, addition of amendments or a capping layer to materials such as CT will be required. The CT waters did not by themselves lead to poor growth during the time of these experiments. A plant such as barley could be used to remove some of the salts from the ecosystems, and aid in the eventual success of more sensitive woody plant species. This would be a first step in reestablishing a forest ecosystem. In addition, it could improve dewatering of the freshly deposited substrates, reduce soil erosion, and facilitate leaching of ions by root penetration into the substrate. To validate the results of this study, field studies will need to be undertaken.

	ACKNOWLEDGMENTS

 
This project was funded by Syncrude Canada Ltd., which has kindly allowed publication of these results. We would like to thank Katherine Zulak and Josie Vitucci (University of Manitoba) and Akiko Ichikawa (University of Alberta) for technical help. The analytical support provided by the Analytical Group at Syncrude Research and the collection of test materials by the Operations Group at the Mildred Lake site are greatly appreciated. We also would like to thank the reviewers of the manuscripts for helpful suggestions.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION CONCLUSIONS REFERENCES

 

• Al-Karaki, G.N. 1997. Barley response to salt stress at varied levels of phosphorus. J. Plant Nutr. 20:1635–1643.
• Al-Niemi, T.S., W.F. Campbell, and M.D. Rumbaugh. 1992. Response of alfalfa cultivars to salinity during germination and post germination growth. Crop Sci. 32:979–980.
• Cumming, J.R., and G.J. Taylor. 1990. Mechanisms of metal tolerance in plants: Physiological adaptations for exclusion of metal ions from the cytoplasm. p. 329–386. In R.G. Alscher and J.R. Cumming (ed.) Stress response in plants: Adaptation and acclimation mechanisms. John Wiley & Sons, New York, NY.
• Curtin, D.H., H. Stepphun, and F. Selles. 1993. Plant responses to sulfate and chloride salinity: Growth and ionic relations. Soil Sci. Soc. Am. J. 57:1304–1310.[Abstract/Free Full Text]
• Dell'Aquila, A., and P. Spada. 1993. The effect of salinity stress upon protein synthesis of germinating wheat embryos. Ann. Bot. (London) 72:97–101.[Abstract/Free Full Text]
• El-Jaoual, T., and D.A. Cox. 1998. Manganese toxicity in plants. J. Plant Nutr. 21:353–386.[ISI]
• Fine Tailings Fundamentals Consortium. 1995. Advances in oil sands tailings research. Volume II: Fine tails and process water reclamation. Alberta Dep. of Energy, Oil Sands and Res. Div., Edmonton, AB, Canada.
• Franklin, J.A., S. Renault, C. Croser, J.J. Zwiazek, and M. MacKinnon. 2002. Jack pine growth and elemental composition are affected by saline tailings water. J. Environ. Qual. 31:648–653.[Abstract/Free Full Text]
• Grattan, S.R., and C.M. Grieve. 1999. Salinity–mineral nutrient relations in horticultural crops. Sci. Hortic. (Amsterdam) 78:127–157.
• Greenway, H., and R. Munns. 1980. Mechanisms of salt tolerance in nonhalophytes. Annu. Rev. Plant Physiol. 31:149–190.
• Grieve, C.M., and J.A. Poss. 2000. Wheat response to interactive effects of boron and salinity. J. Plant Nutr. 23:1217–1226.
• Jacoby, B. 1994 Mechanisms involved in salt tolerance by plants. p. 97–125. In M. Pessakakli (ed.) Handbook of plant and crop stress. Marcel Dekker, New York.
• Jeschke, W.D. 1984. K⁺–Na⁺ exchange at cellular membranes, intracellular compartmentation of cations, and salt tolerance. p. 37–66. In R.C. Staples and G.H. Toenniessen (ed.) Salinity tolerance in plants, strategies for crop improvement. John Wiley & Sons, New York.
• Jones, J.B., B. Wolf, and H.A. Mills. 1991. Plant analysis handbook—A practical sampling, preparation, analysis and interpretation guide. Micro-Macro Publ., Athens, GA.
• Kinraide, T.B., P.R. Ryan, and L.V. Kochian. 1994. Al³⁺–Ca²⁺ interactions in aluminum rhizotoxicity. Planta 192:104–109.[ISI]
• Lynch, J., and A. Lauchli. 1985. Salt stress disturbs the calcium nutrition of barley (Hordeum vulgare L.). New Phytol. 99:345–354.
• MacKinnon, M.D., J.G. Matthews, W.H. Shaw, and R.G. Cuddy. 2001. Water quality issues associated with of composite tailings (CT) technology for managing oil sands tailings. Int. J. Surf. Min. Reclam. Environ. 15:235–256.
• Mahbooli, H., M. Yucel, and H.A. Oktem. 2000. Changes in total protein profiles of barley cultivars in response to toxic boron concentration. J. Plant Nutr. 23:391–399.
• Matsuda, K., and A. Riazi. 1981. Stressed-induced osmotic adjustment in growing regions of barley leaves. Plant Physiol. 68:571–576.[Abstract/Free Full Text]
• Matthews, J.G., W.H. Shaw, M.D. MacKinnon, and R.G. Cuddy. 2002. Development of composite tailings technology at Syncrude Canada. Int. J. Surf. Min. Reclam. Environ. 16:24–39.
• McKeague, J.A. 1978. Manual on soil sampling and methods of analysis. 2nd ed. Subcommittee on Methods of Analysis of Canadian Soil Survey Committee, Ottawa, ON.
• Oil Sands Vegetation Reclamation Committee. 1998. Guidelines for reclamation to forest vegetation in the Athabasca oil sands region. Rep. 99-1. Alberta Environment, Edmonton, AB, Canada.
• Popova, L.P., Z.G. Stoinova, and L.T. Maslenkova. 1995. Involvement of abscisic acid in photosynthetic process in Hordeum vulgare L. during salinity stress. J. Plant Growth Regul. 14:211–218.
• Redfield, E., C. Croser, J.J. Zwiazek, M.D. MacKinnon, and C. Qualizza. 2003. Responses of red-osier dogwood to oil sands tailings treated with gypsum or alum. J. Environ. Qual. 32:1008–1014.[Abstract/Free Full Text]
• Renault, S., C. Croser, J.A. Franklin, J.J. Zwiazek, and M. MacKinnon. 2001. Effects of consolidated tailings on red-osier dogwood (Cornus stolonifera Michx) seedlings. Environ. Pollut. 113:27–33.[Medline]
• Renault, S., C. Lait, J.J. Zwiazek, and M. MacKinnon. 1998. Effect of high salinity tailings waters produced from gypsum treatment of oil sands tailings on plants of the boreal forest. Environ. Pollut. 102:177–184.
• Renault, S., E. Paton, G. Nilsson, J.J. Zwiazek, and M. MacKinnon. 1999. Responses of boreal plants to high salinity oil sands tailings water. J. Environ. Qual. 28:1957–1962.[Abstract/Free Full Text]
• Renault, S., J.J. Zwiazek, M. Fung, and S. Tuttle. 2000. Germination, growth and gas exchange of selected boreal forest seedlings in soil containing oil sands tailings. Environ. Pollut. 107:357–365.
• Ripley, E.A., R.E. Redmann, and A.A. Crowder. 1996. Environmental effects of minings. St. Lucie Press, Boca Raton, FL.
• Sestak, K., J. Catsky, and P.G. Jarvis. 1971. Plant photosynthetic production. W Junk, The Hague, the Netherlands.
• Storey, R., and R.G. Wyn Jones. 1978. Salt stress and comparative physiology in gramineae. I—Ion relations of two salt and water stressed barley cultivars, California Mariout and Arimar. Aust. J. Plant Physiol. 5:801.
• Suhayda, C.G., R.E. Redmann, and X.Y. Wang. 1994. Salinity alters root cell wall properties and trace metal uptake in barley. p. 325–342. In J.A. Manthey, D.E. Crowley, and D.G. Luster (ed.) Biochemistry of metal micronutrients in the rhizosphere. Lewis Publ., Boca Raton, FL.
• Sumner, M.E., and R. Naidu. 1998. Sodic soils. Distribution, properties, management and environmental consequences. Oxford Univ. Press, New York.
• Suncor Energy. 2001. Our journey toward sustainable development. Suncor Energy, Calgary, AB, Canada.
• Taiz, L., and E. Zeiger. 1998. Plant physiology. Sinauer Assoc., Sunderland, MA.
• Ullah, S.M., G. Soja, and M.H. Gerzabek. 1993. Ion uptake, osmoregulation and plant water relations in faba beans (Vicia faba L.) under salt stress. Bodenkultur 44:291–301.

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