Quesnel River Research Articles

Annual pulses of copper-enriched sediment in a North American river downstream of a large lake following the catastrophic failure of a mine tailings storage facility

Failures of mine tailings storage facilities (TSF) can have profound and long-lasting effects on the downstream receiving environment. Virtually all spills to date have been into river systems without large lakes that may buffer downstream impacts. In August 2014, the failure of the Mount Polley copper (Cu)-gold mine TSF in British Columbia, Canada, released ~25 × 106 m3 of water and solids; globally, this is the second largest TSF spill in history. Over 18 × 106 m3 was delivered to Quesnel Lake, which is ~9 km from the TSF and is the third deepest lake in North America, and a crucial habitat for Pacific salmon and trout populations. We determined the sediment-associated Cu concentrations and fluxes in Quesnel River, downstream of the lake, from August 2014 to February 2021 based on the analysis of >400 samples of sediment, mainly collected using a continuous-flow centrifuge. During each winter since the spill, Cu concentrations in the fluvial sediment in the upper reaches of the river (~35 km from the TSF) were elevated relative to regional background concentrations and samples collected before the spill. Maximum Cu concentrations were ~410 mg kg−1 which exceeds Canadian sediment quality guidelines for the protection of aquatic organisms (197 mg kg−1). Monitoring of Quesnel Lake since the spill shows that these annual pulses in the winter are due to resuspension of unconsolidated tailings and sediments at the bottom of Quesnel Lake, during autumnal lake turnover, which become mixed throughout the water column and subsequently flow into Quesnel River. Results show that while large lakes may buffer downstream aquatic systems from contaminated sediment, they may prolong the environmental impact. These findings are crucial in understanding how lake processes may modify the effects of TSF spills on downstream aquatic systems.

Initial Distribution and Interannual Decrease of Suspended Sediment in a Two‐Basin Lake Following a Massive Mine Tailings Spill: Quesnel Lake, BC, Canada

AbstractOn 4 August 2014, a tailings dam failure at Mount Polley Mine in central British Columbia led to the largest short‐term release of mine waste into a lake ever recorded. Once released by the breach, slurry entered the smaller of Quesnel Lake’s two basins, called the West Basin, from which the lake drains northwest into the Quesnel River. An estimated 38,000 ± 11,000 tonnes of fine solids remained suspended in the West Basin on 10 September 2014, 37 days postspill. This decreased to within background levels (<300 tonnes) by June 2015, by which time ∼4,000 tonnes of sediment had flowed from the West Basin into the Quesnel River, and ∼31,000 tonnes had been transported east into the main basin, the direction opposed to the mean hydraulic gradient. Here, we evaluate sediment transport in Quesnel Lake following the Mount Polley tailings dam spill. We apply conservation of mass in two ways: using data collected between 12 August 2014 and 15 October 2020 to estimate suspended sediment mass and mass flows into and out of the West Basin; and using one‐ and two‐basin completely mixed models. Suspended sediment concentrations were highly elevated through the first three seasons postspill, then fluctuated within a gradually decreasing, seasonal cycle. The observed mass trend and an analytical mass balance model of a simplified, two‐basin system suggest that suspended sediment mass will fall to below the median prespill mass by 7 ± 5 years postspill.

River sediment geochemistry and provenance following the Mount Polley mine tailings spill, Canada: The role of hydraulic sorting and sediment dilution processes in contaminant dispersal and remediation

The failure of the Mount Polley tailings storage facility (TSF) in August 2014 was one of the largest magnitude failures on record, and released approximately 25 Mm3 of material, including c. 7.3 Mm3 of tailings into Hazeltine Creek, part of the Quesnel River watershed. This study evaluates the impact of the spill on the geochemistry of river channel and floodplain sediments and utilizes Pb isotope ratios and a multi-variate mixing model to establish sediment provenance. In comparison to sediment quality guidelines and background concentrations, Cu and V were found to be most elevated. Copper in river channel sediments ranged from 88 to 800 mg kg−1, with concentrations in sand-rich and clay/silt-rich sediments being statistically significantly different. Concentrations in river channel were believed to be influenced by hydraulic sorting during the rising and falling limbs of the flood wave caused by the tailings spill. Results highlight the importance of erosive processes, instigated by the failure, in incorporating soils and sediments into the sediment load transported and deposited within Hazeltine Creek. In this instance, these processes diluted tailings with relatively clean material that reduced metal concentrations away from the TSF failure. This does however, highlight environmental risks in similar catchments downstream of TSFs that contain metal-rich sediment within river channels and floodplain that have been contaminated by historical mining.

Fukushima-derived radioactivity measurements in Pacific salmon and soil samples collected in British Columbia, Canada

Despite the many studies that have shown minimal health risks to individuals living outside of Japan following the Fukushima Nuclear Accident, there are persisting concerns regarding the consumption of Pacific seafood that may be contaminated with radioactive species from Fukushima. To address these concerns, the activity concentrations of anthropogenic 134Cs and 137Cs, as well as naturally occurring 40K, were measured in Pacific salmon collected from Kilby Provincial Park, British Columbia (BC), in 2013 and from the Quesnel River, BC, in 2014 using low-background gamma-ray spectroscopy. In addition, soil samples and a single roof-debris sample were collected and analysed to provide a record of Fukushima-derived contamination in BC. Cesium-134 was not detected in the salmon samples. Cesium-137 was not detected in any of the sockeye or chum samples, although it was detected in all of the Chinook samples. The weighted average (±1σ) 137Cs activity concentration in the Chinook salmon collected in 2013 and 2014 was 0.23 (3) and 0.20 (3) Bq/kg fresh weight, respectively. A conservative annual dose estimate for an adult who consumes the average Canadian quantity of seafood per year, contaminated with radiocesium at the maximum concentrations measured in this campaign, was calculated to be 0.054 μSv per year. Cesium-134 was detected in all but two of the soil samples. A weak positive correlation was observed between presence of 134Cs and of 7Be suggesting that the 134Cs arrived via atmospheric deposition. Cesium-137 was present in every soil sample, although the total radiocesium activity concentrations measured were significantly less than action levels set by Health Canada.

Red and white Chinook salmon: genetic divergence and mate choice

Chinook salmon (Oncorhynchus tshawytscha) exhibit extreme differences in coloration of skin, eggs and flesh due to genetic polymorphisms affecting carotenoid deposition, where colour can range from white to bright red. A sympatric population of red and white Chinook salmon occurs in the Quesnel River, British Columbia, where frequencies of each phenotype are relatively equal. In our study, we examined evolutionary mechanisms responsible for the maintenance of the morphs, where we first tested whether morphs were reproductively isolated using microsatellite genotyping, and second, using breeding trials in seminatural spawning channels, we tested whether colour assortative mate choice could be operating to maintain the polymorphism in nature. Next, given extreme difference in carotenoid assimilation and the importance of carotenoids to immune function, we examined mate choice and selection between colour morphs at immune genes (major histocompatibility complex genes: MHC I-A1 and MHC II-B1). In our study, red and white individuals were found to interbreed, and under seminatural conditions, some degree of colour assortative mate choice (71% of matings) was observed. We found significant genetic differences at both MHC genes between morphs, but no evidence of MHC II-B1-based mate choice. White individuals were more heterozygous at MHC II-B1 compared with red individuals, and morphs showed significant allele frequency differences at MHC I-A1. Although colour assortative mate choice is likely not a primary mechanism maintaining the polymorphisms in the population, our results suggest that selection is operating differentially at immune genes in red and white Chinook salmon, possibly due to differences in carotenoid utilization.

The impact of a catastrophic mine tailings impoundment spill into one of North America's largest fjord lakes: Quesnel Lake, British Columbia, Canada

AbstractOn 4 August 2014, a catastrophic breach of the Mount Polley mine tailings impoundment released ~25 M m3 of tailings and water and scoured an unknown quantity of overburden into the West Basin of Quesnel Lake. We document Quesnel Lake and Quesnel River observations for 2 months postspill. Breach inflows raised Quesnel Lake by 7.7 cm, equivalent to ~21 M m3. The West Basin hypolimnion was modified immediately, exhibiting increased temperature (~5°C to 6–7.5°C), conductivity (110 to 160 μS/cm), and turbidity (<1 to 200–1000 nephelometric turbidity units (NTU)). Cooscillating seiches moved West Basin hypolimnetic water both westward and eastward contaminating the Main Basin. Postspill, high‐turbidity water propagated eastward (~1 cm/s), introducing a persistent ~20 m thick layer below the thermocline and an ~30 m thick layer at the bottom. The contaminant introduction, mobilization, and bioaccumulation may pose risks to resident and anadromous fish stocks, which support recreational, commercial, and First Nations fisheries.

Effects of a small-scale, abandoned gold mine on the geochemistry of fine stream-bed and floodplain sediments in the Horsefly River watershed, British Columbia, Canada

Mining is known to be a major source of metal contamination for fluvial systems worldwide. Monitoring and understanding the effects on downstream water and sediment quality is essential for its management and to mitigate against detrimental environmental impacts. This study aimed to examine the effects of the small-scale, abandoned, hydraulic Black Creek gold mine on the geochemical content of fine (<63 μm) stream bed and floodplain sediment in the Horsefly watershed (British Columbia, Canada), which is a part of the Quesnel River basin. Concentrations of As, Cd, Se and Zn were determined byaqua regiadigestion and the modified BCR (European Community Bureau of Reference) sequential extraction procedure followed by inductively coupled plasma-optical emission spectroscopy or inductively coupled plasma-mass spectrometry. Age-depth models for the floodplain cores were constructed using excess Pb-210 and Cs-137 activity concentration profiles. The results show that the mine caused local As contamination of the Horsefly River floodplain sediment during the first years of operation, but at present the contamination is mainly contained in the Black Creek. Present-day and recent concentrations of Cd, Se and Zn in the Horsefly River are elevated and this is probably derived from other upstream mining activities. The spatial and temporal changes in heavymetal concentrations suggest a slight, but not particularly widespread, mining effect on the finesediment geochemistry in the Horsefly River system.

Individual and cumulative effects of agriculture, forestry and metal mining activities on the metal and phosphorus content of fluvial fine-grained sediment; Quesnel River Basin, British Columbia, Canada

The impact of agriculture, forestry and metal mining on the quality of fine-grained sediment (<63μm) was investigated in the Quesnel River Basin (QRB) (~11,500km2) in British Columbia, Canada. Samples of fine-grained sediment were collected monthly during the snow-free season in 2008 using time-integrated samplers at replicate sites representative of agriculture, forestry and mining activities in the basin (i.e. “impacted” sites). Samples were also collected from replicate reference sites and also from the main stem of the Quesnel River at the downstream confluence with the Fraser River. Generally, metal(loid) and phosphorus (P) concentrations for “impacted” sites were greater than for reference sites. Furthermore, concentrations of copper (forestry and mining sites), manganese (agriculture and forestry sites) and selenium (agriculture, forestry and mining sites) exceeded upper sediment quality guideline (SQG) thresholds. These results suggest that agriculture, forestry and metal mining activities are having an influence on the concentrations of sediment-associated metal(loid)s and P in the Quesnel basin.Metal(loid) and P concentrations of sediment collected from the downstream site were not significantly greater than values for the reference sites, and were typically lower than the values for the impacted sites. This suggests that the cumulative effects of agriculture, forestry and mining activities in the QRB are presently not having a measureable effect at the river basin-scale. The lack of a cumulative effect at the basin-scale is thought to reflect: (i) the relatively recent occurrence of land use disturbances in this basin; (ii) the dominance of sediment contributions from natural forest and agriculture; and (iii) the potential for storage of contaminants on floodplains and other storage elements between the locations of disturbance activities and the downstream sampling site, which may be attenuating the disturbance signal.

Flume‐ and field‐based evaluation of a time‐integrated suspended sediment sampler for the analysis of sediment properties

ABSTRACTSuspended sediment has been identified as a vector for nutrient and contaminant transport in the fluvial environment. A time‐integrated sampler (the Phillips sampler), which emerged over a decade ago as a cost‐effective tool for in situ suspended sediment collection, is increasingly being used to collect samples for the analysis of sediment properties such as particle size composition, and nutrient and contaminant concentrations. This study evaluates the sampler under both flume and field conditions for efficiency in the mass and grain size of the suspended sediment collected. The sampler was tested in a flume using both kaolinite and sediment samples (sieved to &lt; 180 µm) collected from the Quesnel River, British Columbia, Canada. In the kaolinite trails, the sampler preferentially collected coarser grain sizes compared to the original sediment, probably due to finer sediment remaining in suspension and therefore passing through the sampler, and also possibly due to flocculation of the kaolinite upon introduction to the flume. Conversely, the sampler collected river sediment that was finer than the original sediment, probably due to some settling of coarser sediment observed at the bottom of the flume. Once allowance was made for these operational issues associated with the flume, maximum sediment mass efficiency for kaolinite and river sediment was 43% and 87%, respectively. Sediment collected by the time‐integrated sampler during field deployment and adjacent channel bed sediment were also compared. The sampler collected sediment with a representative grain size distribution. However, there were differences in the geochemical (arsenic and selenium) concentrations of channel bed sediment and sediment collected by the Phillips sampler which may be a function of differences in the behavior of geochemical elements associated with the two types of sediment. This work suggests that further research is needed to evaluate the role of the Phillips sampler in collecting sediment for contaminant and nutrient analysis. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Testing snow water equivalent retrieval algorithms for passive microwave remote sensing in an alpine watershed of western Canada

Brightness temperatures (TBs) from the special sensor microwave imager (SSM/I) and advanced microwave scanning radiometer (AMSR-E) from 2003 to 2007 are utilized to retrieve and evaluate the snow water equivalent (SWE) over the complex terrain of the Quesnel River Basin (QRB), British Columbia, Canada. Various algorithms including the Environment Canada (EC) algorithms, the spectral polarization difference (SPD) algorithm, and an artificial neural network (ANN) for both SSM/I and AMSR-E are evaluated against in situ SWE observations using several statistical metrics. The results show that the EC algorithms developed specifically for the southern prairies and boreal forest perform poorly across the complex topography and generally deep snow of the QRB. For other frequency combinations of SSM/I and AMSR-E measurements, significant relationships between TB difference and in situ SWE exist only when the snow accumulation is less than a threshold of 250 or 400 mm, which varies at the different in situ stations. Overall, AMSR-E provides better estimates of retrieved SWE than SSM/I. Compared to the algorithms based on TB difference, the ANNs for SSM/I and AMSR-E perform much better. The ANNs trained with all channels of AMSR-E have the best performance in fitting SWE and are able to resolve the temporal variations of SWE at all in situ stations. However, due to the complexity of the topography and vegetation in this mountainous watershed, the ANNs based only on limited in situ stations are not able to retrieve the spatial variations of SWE in this area.

Interrelationships between MODIS/Terra remotely sensed snow cover and the hydrometeorology of the Quesnel River Basin, British Columbia, Canada

Abstract. A spatial filter (SF) method is adopted to reduce the cloud coverage from the Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day snow products (MOD10A2) between 2000–2007 in the Quesnel River Basin (QRB) of British Columbia, Canada. A threshold of k = 2 cm of snow depth measurements at four in-situ observation stations in the QRB are used to evaluate the accuracy of MODIS snow products MOD10A1, MOD10A2, and SF. Using the MOD10A2 and the SF, the relationships between snow ablation, snow cover extent (SCE), snow cover fraction (SCF), streamflow and climate variability are assessed. Based on our results we are able to draw several interesting conclusions. Firstly, the SF method reduces the average cloud coverage in the QRB from 15% for MOD10A2 to 9%. Secondly, the SF increases the overall accuracy (OA) based on the threshold k = 2 cm by about 2% compared to MOD10A2 and by about 10% compared to MOD10A1 at higher elevations. The OA for the four in-situ stations decreases with elevation with 93.1%, 87.9%, 84.0%, and 76.5% at 777 m, 1265 m, 1460 m, and 1670 m, respectively. Thirdly, an aggregated 1°C rise in average air temperature during spring leads to a 10-day advance in reaching 50% SCF (SCF50%) in the QRB. The correlation coefficient between normalized SCE of the SF and normalized streamflow is −0.84 (p&lt;0.001) for snow ablation seasons. There is a 32-day time lag for snow ablation to impact the streamflow the strongest at the basin outlet. The linear correlation coefficient between SCF50% and 50% normalized accumulated runoff (R50%) attains 0.82 (p&lt;0.01). This clearly demonstrates the strong links that exist between the SCF depletion and the hydrology of this sub-boreal, mountainous watershed.

Topographic control of snow distribution in an alpine watershed of western Canada inferred from spatially-filtered MODIS snow products

Abstract. A spatial filter (SF) is used to reduce cloud coverage in Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day maximum snow cover extent products (MOD10A2) from 2000–2007, which are obtained from MODIS daily snow cover extent products (MOD10A1), to assess the topographic control on snow cover fraction (SCF) and snow cover duration (SCD) in the Quesnel River Basin (QRB) of British Columbia, Canada. Results show that the SF reduces cloud coverage and improves by 2% the accuracy of snow mapping in the QRB. The new product developed using the SF method shows larger SCF and longer SCD than MOD10A2, with higher altitudes experiencing longer snow cover and perennial snow above 2500 m. The gradient of SCF with elevation (d(SCF)/dz) during the snowmelt season is 8% (100 m)−1. The average ablation rates of SCF are similar for different 100 m elevation bands at about 5.5% (8 days)−1 for altitudes &lt;1500 m with decreasing values with elevation to near 0% (8 days)−1 for altitudes &gt;2500 m. Different combinations of slopes and aspects also affect the SCF with a maximum difference of 20.9% at a given time. Correlation coefficients between SCD and elevation attain 0.96 (p&lt;0.001). Mean gradients of SCD with elevation are 3.8, 4.3, and 11.6 days (100 m)−1 for the snow onset season, snowmelt season, and entire year, respectively. The SF decreases the standard deviations of SCDs compared to MOD10A2 with a maximum difference near 0.6 day, 0.9 day, and 1.0 day for the snow onset season, snowmelt season, and entire year, respectively.

Some aspects of the hydroclimatology of the Quesnel River Basin, British Columbia, Canada

AbstractIn conjunction with available climate data, surface runoff is investigated at 12 gauges in the Quesnel watershed of British Columbia to develop its long‐term (1926–2004) hydroclimatology. At Quesnel itself, annual mean values of air temperature, precipitation and runoff are 4·6 °C, 517 and 648 mm, respectively. Climate data reveal increases in precipitation, no significant trend in mean annual air temperature, but an increasing trend in mean minimum temperatures that is greatest in winter. There is some evidence of decreases in winter snow depth. On the water year scale (October–September), a strong positive correlation is found between discharge and precipitation (r = 0·70, p &lt; 0·01) and a weak negative correlation is found between precipitation and temperature (r = − 0·36, p &lt; 0·01). Long‐term trends using the Mann‐Kendall test indicate increasing annual discharge amounts that vary from 8 to 14% (12% for the Quesnel River, p = 0·03), and also a tendency toward an earlier spring freshet. River runoff increases at a rate of 1·26 mm yr−1 m−1 of elevation from west to east along the strong elevation gradient in the basin. Discharge, temperature and precipitation are correlated with the large‐scale climate indices of the Pacific Decadal Oscillation (PDO) and El‐Niño Southern Oscillation (ENSO). Copyright © 2009 John Wiley &amp; Sons, Ltd.

Wind-driven Summertime Upwelling in a Fjord-type Lake and its Impact on Downstream River Conditions: Quesnel Lake and River, British Columbia, Canada

Observations and modeling results are presented to explore the response of a multi-basin, fjord-type lake to episodic wind forcing. Field observations show that abrupt cooling and warming events (magnitude greater than 5°C d-1) lasting 3–6 days in a large, salmon-bearing river (Quesnel River) are due to upwelling in its upstream lake (Quesnel Lake) during the summer, stratified season. Within the lake, vertical displacement of isotherms in the vicinity of the river mouth associated with this upwelling is shown to be forced by wind events longer than one quarter of the fundamental seiche period and of sufficient magnitude that the Wedderburn number approaches one. Upwelling occurs nearly-simultaneously throughout a smaller basin adjacent to the outflow (West Basin) that is separated from the Main Basin of Quesnel Lake by a sill and contraction. Wind-driven water fluxes across the sill are estimated using a conceptual model based on volume and heat budgets. These estimates provide an upper bound for flow across the sill and suggest that exchange flow may at times be internally hydraulically controlled, with epilimnetic velocities of up to ∼25 cm/s. Computed fluxes suggest the West Basin hypolimnion has a residence time of 6-8 weeks during the summer stratified period with each upwelling episode irreversibly exchanging 25–30% of the hypolimnetic volume with the rest of the lake. Implications of such events are profound for salmon bearing rivers wherein the thermal habitat is critical to migration success.

Low sludge yield biofilm activated sludge (BAS) upgrade – Quesnel River Pulp

Quesnel River Pulp (QRP) began operating a low sludge yield biofilm activated sludge (BAS) treatment system at its bleached chemithermomechanical (BCTMP) pulp mill at Quesnel, British Columbia, in March 2005. AnoxKaldnes provided the technology. QRP upgraded the anaerobic/activat-ed sludge treatment (AST) system to allow for both increased production rates, as well as production of higher load grades of pulp. The system increased treatment capacity from 110 tons soluble chemical oxygen demand (SCOD)/day to 140 tons SCOD/day with expansion capacity to 170 tons SCOD/day. In addition, the anaerobic system capable of removing 20 tons SCOD/day could be decommissioned since it had a low tolerance for peroxide and sulfur, and high maintenance and operating costs. Results of the upgrade included: 1) meeting all permit limits and effluent is nontoxic to trout under standard test conditions, 2) 80%–85% SCOD removal, 3) stable and reliable operation, 4) sludge yields between 0.12–0.17 net kg total suspended solids (TSS)/kg SCOD removed (compared to previous yields of 0.23 net kg TSS/kg SCOD removed), and 5) ~25% decrease in total effluent treatment costs per ton of pulp, despite a 30% increase in power requirements.

Three-dimensional mapping of a landslide using a multi-geophysical approach: the Quesnel Forks landslide

A landslide located on the Quesnel River in British Columbia, Canada is used as a case study to demonstrate the utility of a multi-geophysical approach to subsurface mapping of unstable slopes. Ground penetrating radar (GPR), direct current (DC) resistivity and seismic reflection and refraction surveys were conducted over the landslide and adjacent terrain. Geophysical data were interpreted based on stratigraphic and geomorphologic observations, including the use of digital terrain models (DTMs), and then integrated into a 3-dimensional model. GPR surveys yielded high-resolution data that were correlated with stratigraphic units to a maximum depth of 25 m. DC electrical resistivity offered limited data on specific units but was effective for resolving stratigraphic relationships between units to a maximum depth of 40 m. Seismic surveys were primarily used to obtain unit boundaries up to a depth of >80 m. Surfaces of rupture and separation were successfully identified by GPR and DC electrical resistivity techniques.

Sulphur Management Strategies in Anaerobic Treatment of a BCTMP/TMP Effluent

Abstract Anaerobic treatment of a bleached chemithermomechanlcal/ thermomechanical BCTMP/TMP (2:1 by volume) effluent obtained from Quesnel River Pulp Co. was studied on a laboratory scale at 35°C. The experimental apparatus consisted of upflow anaerobic sludge bed (UASB) acidogenic reactors followed by hybrid upflow anaerobic sludge bed/fixed-film methanogenic reactors. Under anaerobic conditions, sulphite and sulphate are reduced to sulphide, presenting problems of toxicity, odour, corrosion and reduced methane yields, and treatment efficiencies. The fate of these compounds was examined under various hydraulic retention times and sulphur management strategies, including: (i) pH control; (ii) inhibition of the sulphur reducing bacteria via molybdenum addition; and (iii) stripping hydrogen sulphide dissolved in the reactor liquor by recycling hydrogen sulphide-free off gas. Controlling the pH of the acidogenic reactor from 5.5 (uncontrolled) to 8.0, in order to shift the formed sulphide species to the less toxic ionic form, appeared to be ineffective in promoting wastewater treatment efficiency. Molybdenum addition to the wastewater, tested at levels from 0.1 to 1.0 mM, was effective at 1.0 mM in retarding sulphide formation. Hydrogen sulphide stripping, using scrubbed and recycled off gas, appeared to be the most effective means of sulphur management for this type of wastewater under these conditions.

Genetic Control of Juvenile Life History Pattern in Chinook Salmon (Oncorhynchus tshawytscha)

To investigate the genetic basis for the difference in photoperiod responses between juvenile ocean-type and stream-type chinook salmon (Oncorhynchus tshawytscha), we conducted two crossing experiments and exposed the progeny to either a short- or long-day photoperiod for 10 wk from the time of first feeding. The first experiment examined the photoperiod response of pure and reciprocal crosses among red- and white-fleshed Quesnel River (stream-type) chinook salmon. The second experiment tested the photoperiod response of pure and reciprocal crosses between Quesnel River (stream-type) and Conuma River (ocean-type) chinook salmon. In both experiments, Quesnel chinook salmon fry (both red and white fleshed) sustained a high growth rate and developed a high degree of seawater adaptability only when exposed first to a short-day photoperiod for 10 wk and then to a long-day photoperiod. In contrast, the Conuma River chinook salmon grew rapidly and developed the increased seawater adaptability characteristic of smolts when reared on either photoperiod regime. Reciprocal Conuma–Quesnel hybrids displayed the ocean-type pattern of development, indicating that the photoperiod-independent phenotype is dominant and not under maternal control.

Anaerobic Treatment of Bleached TMP and CTMP Effluent in the Biopaq UASB System

The effluents from CTMP mills are on the one hand too dilute for evaporation and recovery, and on the other hand too highly polluted for conventional aerobic secondary treatment. In summer 1986 we therefore started an extensive research program in cooperation with the Ahlström Engineering division in Savonlinna, Finland, and Paques-Lavalin in Toronto, Canada, in order to investigate the anaerobic treatability of CTMP effluent, using UASB technology. This research included fundamental work in the lab, as well as on-site pilot work in Finland and in Canada. As a result, two full-scale plants are in operation. The first plant was started up in October 1988 at Quesnel River Pulp in B.C., Canada, and is treating up to 140 tons of COD per day in two reactors of 3500 m3 each. The second plant was ready for start-up in January 1990 at the Enso-Gutzeit Kotka mill in Finland. The cautious approach for these types of effluents was necessary due to earlier reports on the toxicity of softwood extractives, bleaching agent hydrogen peroxide, complexing agent DTPA and high sulphur levels. Besides this, it was necessary to confirm that granular seed sludge would not deteriorate but would develop normally. The behaviour of hydrogen peroxide was especially interesting and the high redox potential caused could be resolved in a very cost-efficient way without utilising chemicals, enzymes or activated sludge. Resin acids were indentified to be responsible for reducing methanogenic activity considerably. They were eliminated during aerobic post-treatment to very low levels. Lab studies clearly demonstrated how methanogenic activity could be increased by adding dilution water or aerobically treated effluent. The concentration of the resin acids appeared to be associated with raw material (spruce, fir or pine), the season (summer or winter) and with fine fibrous material in the effluent. Sulphur levels in the effluent were relatively high, but resulting sulphide levels were not toxic to methanogens and COD/sulphur ratios were high enough to achieve acceptable removal efficiencies. The paper presents the results from research as well as flow diagrams of the full-scale plants, and results from more than one year full-scale operation at Quesnel River Pulp in B.C. Canada.

Carbonatization and propylitic alteration of fragmental basaltic rocks, Quesnel River gold deposit, Central British Columbia

The Quesnel River gold deposit (1.2 million tonnes grading 5.22 g/t Au in three separate zones) occurs within Takla Group volcanic rocks of Upper Triassic age proximal to an alkalic stock. The deposit occurs in amphibole-augite phyric, fragmental, basaltic rocks. Alteration has produced an assemblage of epidote-chloritetremolite-calcite-quartz with lesser pyrite, chalcopyrite, pyrrhotite, sphalerite, marcasite, galena, arsenopyrite and gold.