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Coal and interbedded rocks from the two coalfields in the southern intermontane region of British Columbia, Canada, deposited in fluvial-lacustrine, and lacustrine were examined using reflected lig...

The Permian-Triassic extinction was the most severe in Earth history. The Siberian Traps eruptions are strongly implicated in the global atmospheric changes that likely drove the extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with the oldest dated rocks from the Norilsk section of the Siberian flood basalts. We focused on the voluminous volcaniclastic rocks of the Siberian Traps, relatively unstudied as potential carriers of carbon-bearing gases. Over six field seasons we collected rocks from across the Siberian platform, and we show here the first direct evidence that the earliest eruptions in the southern part of the province burned large volumes of a combination of vegetation and coal. We demonstrate that the volume and composition of organic matter interacting with magmas may explain the global carbon isotope signal and may have significantly driven the extinction.

Thermal maturation is traditionally evaluated based on vitrinite reflectance (VRo) measurements and its relationship to oil and gas generation and diagenetic transformation are ingrained in many basin modeling tools. However, vitrinite derives from higher land plants that evolved in Devonian. In pre-Devonian rocks graptolite reflectance (GR) is the most significant thermal index for establishing thermal maturation. Currently, conversions of GR to VRo equivalent rely on several established linear relationships. This study investigates a continuous thermal evolution of GR during artificial maturation of the Lower Ordovician (Tremadocian) Alum Shale of Estonia. We observe an anomalous breakdown in the gradient of GR versus thermal maturity. The anomaly trend is characterized as a suppressed GR gradient throughout the entire gas window (VRo: 1.0–2.0%). We attribute the suppressed measured GR trend to surface imperfection caused by the generation and evasion of hydrocarbon gases that generate nano-porosity vacuolation of the graptolite tissues. After the gas window, GR resumes its increasing trend with a similar gradient as observed in the pre-gas window, due to continued aromatization and condensation of the organic molecules. The GR anomaly indicates a potential underestimation of thermal maturity up to 0.52%VRo when applying a linear conversion formula between random GR and VRo directly. Therefore, a significant maturity correction should be applied to all legacy GR-based maturity measurements that indicate a gas or post-gas maturity rank.

The Permo-Triassic Extinction was the most severe in Earth history. The Siberian Traps eruptions are strongly implicated in the global atmospheric changes that likely drove the extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with the oldest dated rocks from the Norilsk section of the Siberian flood basalts. The source of this light carbon has been debated for decades.We focused on the voluminous volcaniclastic rocks of the Siberian Traps, relatively unstudied as potential carriers of carbon-bearing gases. Over six field seasons we collected rocks from across the Siberian platform and show the first direct evidence that the earliest eruptions particularly in the southern part of the province burned large volumes of a combination of vegetation and coal. Samples from the Maymecha-Kotuy region, from the Nizhnyaya Tunguska, Podkamennaya Tunguska, and Angara Rivers all show evidence of high-temperature organic matter carbonization and combustion.Field evidence indicates a process in which ascending magmas entrain xenoliths of coal and carbonaceous sediments that are carbonized in the subsurface and also combusted either through reduction of magmas or when exposed to the atmosphere. We demonstrate that the volume and composition of organic matter interactions with magmas may explain the global carbon isotope signal, and have significantly driven the extinction.

Lacustrine oil shale and shale samples of the Tournaisian-age Albert Formation in New Brunswick, Canada, taken from six locations, were analyzed by organic petrology using reflected white and fluorescence light microscopy and by Rock-Eval pyrolysis to determine their depositional environment and hydrocarbon generating potential. Calcium, Th, and Ca contents of the samples were also determined using ICPMS. The results were compared to the Big Marsh lacustrine oil shale of Carboniferous age in Nova Scotia. Organic matter consists mostly of filamentous alginite, bacterial remains, and matrix bituminite, which fluoresce green to dark-yellow. Organic matter was deposited in a lake basin. The regular layering of algal remains and wrapping around mineral particles indicate deposition in a low energy setting below wave base, which resulted in the stratification of the organic matter and the enclosing mineral matrix. There are also fluorescing to non-fluorescing bitumens present in parts of the Albert oil shale. The bitumens were incorporated as a result of hydrocarbon migration during deposition of the oil shales (the two are considered to be syn-sedimentary) because the bitumens are part of the regular rock layering and the fact that the organic matter is wrapped around mineral grains. The bitumens in the Albert oil shales consist of fluorescing wurtzilite and non-fluorescing albertite. The Albert oil shales have lower input of terrestrial sediments containing Th and are carbonate-rich. The variation of Th/U ratio and TOC (wt%) indicates that the Albert oil shales have different mineralogy than those from the Big Marsh ones. There are two types of carbonates particles in the Albert oil shale; a) syngenetic angular particles, which are suspended in the organic matter but may also occur as micrite, and b) rounded to angular and possibly transported particles containing oil inclusions. As a result, variations in Th/U and calcium divided the oil shales into: a low-calcium lacustrine type (which includes the Big Marsh oil shale); the Albert oil shale and shale deposited far from the Albert Mine; and few samples from a deposit close to the Albert Mine that have high calcium content and some of them contained oil inclusions. The higher TOC of samples collected from the bitumen mining area in the Albert Mine is related to bitumen impregnation due to hydrocarbon migration. Variation of HI (mg HC/g/TOC) and authigenic uranium in the Albert oil shale indicates that depositional environment was more anoxic than most of the oil shales in the Big Marsh deposit. Rock-Eval pyrolysis data and accompanying organic petrology analysis indicate that the samples are mostly immature to marginally mature as indicated by %Ro, ran of 0.60–0.68 and variation in the fluorescence Red/Green and Blue/Green and Blue (R/G, B/G, B) quotients. Variations in maturity indicators (such as HI and Tmax) are caused by other factors, such as quantity of organic matter in the samples. The Hydrogen Index (HI) vs. Tmax plot of the oil shales displays a wide range of HI within a narrow Tmax range of 438–442 °C indicating immature to marginally mature Type I kerogen. There is a slight trend of increasing Tmax into the oil window with increasing HI, likely due to the extreme mass of hydrocarbons in these samples, which requires higher energy to breakdown, rather than burial-related thermal maturity. Maturity of the Albert oil shale increases from east to west within the study area as indicated by the westward increase of all three fluorescent quotients of both filamentous algae and matrix bituminite and in the %Ro. The reflectance of the Albert oil shales, measured on vitrinite, is mostly suppressed compared to the nearby Mapleton organic-lean shale in New Brunswick. There is also a correlation between HI and %Ro, ran in the oil shale samples studied; the higher is the HI, the lower is the %Ro. The majority of the oil shale samples have a very high potential for hydrocarbon extraction using the ex-situ methodology (at 30 L/t) and the upper 20% of the samples have the potential for in-situ extraction (at 60 L/t).

The impact of a 120 cm thick dike on dispersed organic matter in the Triassic Marry Harbour (MH) bituminous marl in the Raanes Peninsula, Ellesmere Island, Arctic Canada, was studied using reflected light microscopy and Rock-Eval pyrolysis. Results were compared to a coal seam of similar maturity that was thermally altered by an igneous intrusion. The MH bituminous marl is mature and within the oil window (Ro = 0.94%), whereas the coal is high-volatile B bituminous rank (Ro = 0.80%). Thermal alteration impacted differently the organic-rich marl than the coal seam. Most of the heat generated by the intrusive emplacement in contact with coal is spent transforming coal to coke in the plastic layer/zone, similar to the process that coal undergoes in industrial coking operations. In contrast, the thermal alteration of sedimentary rocks occurs over longer distances as a result of the absence of a plastic layer/zone. The impact zone of the 120 cm thick igneous intrusion was greater in the MH bituminous marl, which became thermally altered (Ro = 2.34%) at 190 cm from the contact with the dike. On the contrary, the coal became thermally altered (%Ro = 5.0%) by a 240 cm alkali-basalt intrusion (twice the thickness of the MH dike) and its impact zone was only 65 cm. Heat and hot volatile matter produced by the thermal decomposition of organic matter and minerals (carbonate, dehydration of clay minerals) in contact with the igneous intrusion body is transferred through the sedimentary rock matrix by convection through fractures. This transformation is evident by the occurrence of the pyrolytic carbon at various distances in the fractured MH marl from contact. The hydrogen index (HI) shows a similar trend to that of the remaining source potential (S2). Both parameters decrease systematically toward the dike, and go through a minimum at 20 cm from the dike contact, as the indigenous organic matter is converted to hydrocarbons or devolatilized. At the dike contact, both S2 and HI have higher values. These trends are similar to those of the volatile elements H and Cl in the intruded coal seam. The free hydrocarbons (S1) showed a slightly different trend than S2 and HI. It increased initially from 300 cm and reached a maximum at about 190 cm from the dike contact before decreasing continually and reaching a minimum at 20 cm from the contact. At the dike contact, the S1 increased slightly, similar to the HI and S2. The presence of oil droplets trapped in carbonate concretions, in combination with the highest value of oil expelled from the source rock (based on S1/TOC) at distance of 190 cm from dike, is an indication of the influence of contact metamorphism on oil generation locally. Furthermore, it indicates that intrusion of igneous dikes into the bituminous MH marl resulted in an increase of organic matter maturation locally and in hydrocarbon generation.

Seventeen coal and carbonaceous shale samples taken from eight stratigraphic sections of the Devonian Hecla Bay and Weatherall formations in Arctic Canada, were examined using reflected light microscopy, instrumental neutron activation analysis (INAA), and inductively coupled plasma emission spectroscopy (ICPES). Samples consist of humic coal with 62–79 vol% vitrinite, liptinite-rich humic coal with 42 vol% liptinite, and cannel coal with 52–81 vol% sporinite content. Carbonaceous shale has 46–73 vol% mineral matter and canneloid shale has 30–42 vol% mineral matter as well as 22–38 vol% sporinite content. Most were deposited in areas characterized by minor channel cut-and-abandonment and lake and bay infills peripheral to distributary complexes. A fresh water environment is indicated by Boron (18–71 ppm), low inertinite (0–7.8 wt%), and high sporinite content (30–81 vol%). The ratio of Na/K versus liptinite content shows that coals and associated sediments from the Hecla Bay Formation experienced a more rapid rate of sedimentation than the carbonaceous shales from the Weatherall Formation. The highest total REEs and LREE (La-Gd) was in the liptinite-rich humic coal, followed by humic coal and carbonaceous shale. The concentration of REEs and LREEs in the cannel coals is half of that measured in the liptinite-rich humic coal. The PAAS normalized for oil shales follows two different patterns: 1) the liptinite-rich coal samples display a sharp increase from Nd to Ho, then maintain a similar pattern up to Lu; and 2) samples of other lithologies increase from Nd to Dy, and then maintain a flat trend up to Lu. Hierarchical cluster analysis shows that canneloid and liptinite-rich coal exhibit the greatest similarity with each other whereas humic coal and liptinite-rich coal show the greatest dissimilarity with carbonaceous shale.

The Gordondale Member is a hydrocarbon source rock and potential unconventional reservoir that extends across northeastern British Columbia and central-northwestern Alberta. It is an organic-rich, calcareous, fossiliferous mudstone with a median total organic carbon value of 6.0 wt%. A total of 230 samples were collected from approximately 25 m of Gordondale Member core for organic matter analysis using Rock-Eval 6 analysis and organic petrology. Detailed core logging provides sedimentological context for organic matter characterization. The predominant organic material in the samples is solid bitumen and liptinite with lesser zooclast and inertinite. Most kerogen is Type II, autochthonous marine biomass, with minimal dilution by inert organic carbon. Rock-Eval Tmax values and random reflectance measurements of solid bitumen indicate the samples are within the oil generation window. Solid bitumen contributes a substantial amount of hydrocarbon potential to the interval. A micro-reservoir structure within the core is produced by thin intervals of impermeable displacive calcite that act as barriers to the upward migration of free hydrocarbons. These free hydrocarbon accumulations could make excellent targets for horizontal wells within the Gordondale Member.

The sedimentary succession of 51-m consisting of a thin coal seam (1 m) and oil shale with a marlstone and carbonate-mudstone matrix of the Lower Carboniferous (Visean) Emma Fiord Formation located on the Grinnell Peninsula, Devon Island, Arctic Canada was examined. The techniques used include reflected light microscopy, and instrumental neutron activation analysis (INAA) for elemental concentration, and inductively coupled plasma emission spectrometry (ICPES) for boron concentration. The coal and oil shale was deposited in a lacustrine, freshwater environment. Due to the climatic variation, two types of oil shale were developed based on the amount of precipitation. One with carbonate-mudstone matrix, with high calcite (75%) and low TOC (1.14–1.87%) content. The other a marlstone-dominated matrix with high aluminosilicate (64%) and TOC (16.4–53.6%) content. Oil shale from Emma Fiord experienced a slow rate of sedimentation and terrestrial flux as determined using Th/K/ Na/K, ratios Mn/Ca ratio to Ca respectively, and compared to the oil shale of Carboniferous age deposited in a lacustrine environment with a regular rate of recharge/discharge. The redox conditions for the Emma Fiord oil shale indicate anoxic to dysoxic conditions based on the variation of Cr and V + Ni. Thorium and U systematics indicate that U is more concentrated in oil shale with marlstone matrix and is associated with clay minerals and organic matter (OM), similar to the Carboniferous oil shale from the Big Marsh. The authigenic U is associated with TOC content and is higher for oil shale with the marlstone matrix. The variation of U with TOC indicates both paleo-productivity and preservation and is higher for oil shale with the marlstone matrix. The concentration of rare earth elements (REEs) is 95% due to the presence of light rare earth elements (LREEs) in both oil shale with marlstone and carbonate-mudstone matrices. The REES were normalized to the post-Archean average shale (PAAS). The high volatile bituminous coal at the base of the oil shale sections displays a flat, featureless pattern. The oil shale with a carbonate matrix decreases slightly from light rare earth elements (LREEs) to heavy rare earth elements (HREES). In contrast, the REEs concentration for oil shale with the marlstone matrix decreases more sharply from the LREEs (La-Eu) to HREEs (Tb-Lu). It displays a weak negative Eu anomaly typical of the upper continental crust.

The Lower Silurian Qusaiba Hot Shales (QHS) are proven source rocks for oil within the Paleozoic, and possibly some of the Mesozoic, reservoirs in Saudi Arabia. Moreover, these shales have oil shale potential where they are immature and shallow enough for mining, as well as unconventional shale oil and shale gas potential, in areas where they are within oil-maturity and gas-maturity levels, respectively. The QHS were deposited in relatively shallow marine environments under anoxic water conditions, resulting in accumulation of amorphous kerogen, organic-walled graptolites and acritarchs. Across the Arabian Basin, organic matter quality does not show much variation for the QHS, but the maturity varies greatly as a result of varying burial history. Thermal maturity assessment of shale source rocks that lack vitrinite, such as the Qusaiba Hot shales, continues to be challenging, especially where conflicting measurements are obtained from different sources. This paper presents an integrated assessment of QHS thermal maturity parameters, based on cores from 13 carefully selected boreholes that – based on regional basin models – are believed to cover a wide maturity range (ca. 0.5 to 2.0% Ro). We conducted some analyses on kerogen (maceral petrography, graptolite reflectance, UV-fluorescence, whole rock pyrolysis, Raman spectroscopy of graptolite) and other analyses on bitumen extracts (GC and GC–MS of saturate and aromatic fractions, and FTIR spectroscopy of the asphaltene fraction). We show that using many thermal maturity parameters reduces uncertainty significantly, and we therefore recommend that graptolite reflectance analyses should be conducted in support of other maturity indicators. Proper reflectivity measurements of the graptolites set the reference for comparison of other maturity parameters obtained from petrographic, geochemical, and spectroscopic techniques. Our work provides a template by which Qusaiba thermal maturity can be more accurately estimated when only a limited set of maturity parameters is available.

Important depositional characteristics indicative of climate change has been discovered in 50-m sedimentary succession consisting of oil shales with a marlstone and carbonate matrix of the Visean shales from the Lower Carboniferous Emma Fiord Formation on Devon Island, Canada's Arctic Archipelago. Older Carboniferous (Tournaisian) shales, are however absent from Devon Island, but elsewhere such as Big Marsh, Nova Scotia, Tournaisian shales show no comparable evidence for climate change. The techniques used include reflected light microscopy, RockEval analyses, instrumental neutron activation analysis (INAA) for elemental concentration. Indeed, Visean shales from the Lower part the Emma Fiord Formation from Devon Island have a marlstone matrix with abundant algal matter. The matrix also has low carbonate (32%) and total organic carbon (TOC) content between 33.3%and 55.6%. Moreover, the TOC show a positive correlation with authigenic uranium, and Mo, which suggests a high productivity due to the high rain, deeper water lacustrine depositional environment. Other Visean oil shales from the Emma Fiord Formation on Devon Island have somewhat different characteristics from those with marlstone matrix. Indeed, they have a high (75%) carbonate content with calcified algal matter and low TOC (1.14–17.4%). A very low correlation between TOC and authigenic U, and Mo. Most importantly very high oil generation (98–413 L/t) potential of marlstones as compared to low yield of carbonate mudstones (4.1–17.0 L/t) shows a dramatic climatic shift to low precipitation and much dryer conditions. Such a drastic climatic condition has not been detected for the Tournaisian oil shales.

The bulk elemental concentration of selected Albert Formation oil shale deposits of Mississippian age from New Brunswick was analyzed using ICP-MS and Prompt Gamma. Results compared to that of the Big Marsh oil shale of similar age from Nova Scotia. Reflected white and fluorescence light was used to determine the characteristic organic matter, and RockEval analyses were used to determine the hydrocarbon potential of oil shale. Both Albert and Big Marsh oil shales were deposited in lacustrine environments, based on geological and sedimentological evidence. The Big Marsh oil shale has low and stable B content (28-54 ppm), which stays almost constant and with the range for freshwater with depth. By contrast, the oil shales from the Albert Formation from New Brunswick have high and were for Albert oil shale. The Big Marsh deposit, in contrast, had stable discharge and recharge with higher aluminosilicate input and limited or no carbonate content. The rate of sedimentation, as determined by Na/K and Th/K ratios indicates that the Albert oil shales deposited at a slower rate as compared to the Big Marsh oil shales. The lower Th/U ratio for Albert oil shale as compared to the Big Marsh is likely due to lower input of weathered and recycled sedimentary terrestrial flux, and allochthonous U content, into the lacustrine setting during their deposition. Albert oil shales deposited in oxic-dysoxic conditions based on their Cr and V/Cr ratio, suggesting a well-oxygenated and uniform, warm temperature upper water level. Variation of Ca/Sr versus Ca/Mn ratios for the Albert oil shale, indicates low Mn/Ca and relatively high Sr/Ca ratio for most of the samples, due to low terrigenous influx and warmer water, which is supported by the mineralogy of the oil shales, which contain low quartz and clay minerals. The presence of higher authigenic U and Mn/Ca ratio for Albert oil shale indicates low terrestrial flux and, therefore Th as compared to Big Marsh oil shales. The Rare Earth element (REEs) content is higher for the Big Marsh oil shales owning to a higher input of aluminosilicate than the Albert oil shale as supported by variation of Y and La and that of Hydrogen index (HI) and Heavy Rare earth (HREEs). The Albert oil shale displays a positive Eu anomaly, typical of a high carbonate environment. By contrast, Big Marsh, which shows a negative Eu anomaly, which is typical of upper continental crust.

The production of coalbed methane (CBM) represents a vital new source of natural gas supply in Western Canada. There are, however, concerns over potential negative environmental impacts on shallow groundwater resources in the hypothetical case that leakage of fluids and gases from CBM operations occurs. This paper compares major ion and isotope geochemistry data for produced fluids or gases from two major coal deposits in Western Canada (Mannville Formation and the Horseshoe Canyon/Belly River Group) with similar data collected for shallow groundwater in south-central Alberta. The objective was to generate comprehensive baseline geochemical data to determine the key geochemical characteristics and differences of produced fluids and gases from two coal deposits and shallow groundwater in Alberta and to find parameters that are suitable for identifying potential leakage of fluids or gases into shallow groundwater. Shallow groundwater had average total dissolved solids (TDS) of 1037 mg/L. Most samples belonged to the Na–HCO3–SO4 water type and average SO 4 2 - concentrations were 185 mg/L. The Horseshoe Canyon/Belly River Group swabbing fluids had average TDS of 5427 mg/L, a Na–HCO3 water type, and average SO 4 2 - concentrations of 47.7 mg/L. The produced fluids from the Mannville Formation had average TDS contents of 74,500 mg/L, negligible SO 4 2 - and a Na–Cl water type. Shallow groundwater and produced fluids from the Horseshoe Canyon Formation and the Mannville group had distinct δ2H and δ18O values and plotting δ18O values versus total dissolved solids was found to be an effective approach to distinguish the waters. Sulfur isotope data revealed the occurrence of bacterial (dissimilatory) SO4 reduction in some shallow groundwater samples and in the produced fluids from the Horseshoe Canyon/Belly River Group. Methane was found in several shallow groundwater samples and its average δ13C (−72.1 ± 6.8‰) and δ2H values (−297 ± 17‰) indicated a biogenic origin predominantly from CO2 reduction. Dissolved gases from the Horseshoe Canyon Formation fluids with average δ13C values of methane of −54.0 ± 4.1‰ and ethane of −36.5 ± 2.4‰ and traces of higher alkanes suggest a mixture of predominantly biogenic and some thermogenic gas. Dissolved hydrocarbon gas from the Mannville Formation had the highest average δ13C values of −49.4 ± 3.6‰ for methane, −28.8 ± 2.1‰ for ethane and −26.9 ± 1.1‰ for propane. The presence of higher alkanes suggests that the Mannville produced fluids contain an appreciable thermogenic gas component. The biogenic gas component in the Horseshoe Canyon and the Mannville Formation was mainly formed via acetate fermentation according to αCO2–CH4 values between 1.02 and 1.07. It is concluded that δ18O values of the fluids in concert with total dissolved solids, and the isotopic compositions of methane and ethane are sufficiently distinct in shallow groundwater and produced fluids from the Horseshoe Canyon and the Mannville Formations that they may serve as tracers for evaluating potential contamination of shallow groundwater with produced fluids or gases.

These have been growing concerns over the environmental impacts of the coal-fired power plants in the western Canadian province of Alberta, which collectively comprise one of the largest point sources of Hg and other trace elements nationally. The overall cumulative impact of the power plants since the beginning of their activities several decades ago has been a critical question for industry, government agencies, and the research community. This paper aims to delineate the cumulative geographic extent of impact by investigating the spatial distribution of mercury and other trace elements of environmental concern in nine freshwater lakes, which cover the large area surrounding the coal-fired power plants in central Alberta, Canada. 210-Lead dating was used in conjunction with physical evidence of deposited fly ash to determine the sediments' age and hence the depths corresponding to the onset of coal-fired power generation in 1956. Total mean concentrations and fluxes of elements of environmental concern with integrated values since 1956 were then determined. The concentration values do not reflect the catastrophic oil spill at Lake Wabamun in 2005. The post-1956 flux rates of As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, V, W, and Zn were generally highest in sediment cores obtained from two lakes adjacent to power plants. However, the variable prevailing wind directions played an important role in determining the aerial distribution of Hg and other trace elements to the southeast and to the west of the power plants. Post-1956 fluxes of most elements declined downwind (westward), consistent with strong easterly winds transporting metal pollution further to the west of the power plants. However, spatial interpolation of the data suggested a major southern extension to the area of maximum metal deposition, which has not been sampled by this or previous studies in the region. An atmospheric model estimate of total Hg flux in 2007 near the Genesee power plant was substantially lower than indicated by the most impacted lake sediments, which have integrated Hg fluxes since 1956. The most likely explanations for the model-sediment difference are either that a sharp spatial gradient of deposition exists in the region, and/or recent technology improvements by the power plants have substantially reduced Hg emissions.

This paper reports mercury (Hg) concentrations and fluxes in precipitation that was collected from 2006 to 2008 at three sites in Canada: sub-Arctic boreal forest, sub-Arctic coast, and southern Alberta, using cold-adapted precipitation collectors which operated reliably at temperatures below −30 °C during the study. The southern Alberta site (Crossfield) may be influenced by Calgary urban air, whereas the sub-Arctic coastal (Churchill, Manitoba) and boreal forest (Fort Vermilion, Alberta) sites are in more remote northern areas. Annual mean Hg concentrations in precipitation (5.0–9.2 ng L −1 ) at the study sites were in the lower half of the range reported for southern Canada and the USA by the Mercury Deposition Network (MDN). But owing to typically low precipitation rates, gross wet Hg fluxes (0.54–2.0 μg m −2 yr −1 ) were among the lowest reported by MDN, with Crossfield having about twice the flux in 2007 of the other two sites. Flux was significantly correlated with precipitation, and thus was highest in summer (June–August) and lowest during winter, a pattern typical of other temperate continental locations. There was no evidence of higher wet Hg fluxes or concentrations in springtime at Churchill where atmospheric mercury depletion events (AMDEs) occur. Measured gross deposition fluxes at the study locations were ∼2–8 times lower than estimated by GEOS-Chem and GRAHM atmospheric models. The largest discrepancy occurred for Churchill, which raises the question of how well Hg deposition from AMDEs is described by current models. Better agreement between measurements and models was obtained from MDN stations in Alberta and Alaska, where wet Hg fluxes were 2–10 times higher than the study sites either because of power plant emissions (Alberta), or because of high precipitation rates (Alaska).

Bottom ashes collected from ESP and baghouse of seven pulverized coal-fired power plants using subbitumi- nous and bituminous coal and a fluidized bed combustor using crushed bituminous coal were examined for their mineral- ogy and elemental composition. The results presented in this paper are based on the average of three samples collected from each power plant. The mineralogy of each sample was determined using XRD and SEM/EDX; Elemental content was determined using INAA, ICPMS, and CVAAS; and the speciation of As, Cr, and Ni was determined by XANES. Bottom ash from the pulverized power plants consists of granular particles with a minor input of melted glassy fragments, while the bottom ash from the fluidized bed combustor consists entirely of granular particles. The sulphur and carbon con- tents of pulverized bottom ashes range from 0.03 to 2.32 wt % and 0.19 to 6.62 wt %, respectively. For the fluidized bed combustor, the sulphur and carbon contents were 5.27 wt % and 10.72 wt %. The concentrations of As, Cr, Hg, Ni, and Pb in bottom ash are related to sulphur content of coal and are higher for bottom ashes from high sulphur feed coals. Most of the elements associated with S (As, Hg, and Pb) are captured from fluidized bottom ash, more so than by the correspond- ing ESP fly ash. Most of the elements in bottom ash have enrichment (RE) factors of less than 0.7 indicating that they are not enriched in the bottom ashes as compared to the feed coals. Arsenic, Cd, Cr, Ni, and Pb have higher concentrations in granular bottom ash as compared to glassy bottom ash of the same power plant. The feldspars and quartz of feed coal are health hazards and are captured mostly by bottom ash and therefore prevent their emission from stack. The As, Cr, and Ni in form of: non-toxic As +3 , mostly beneficial Cr 3+ , and non-carcinogenic Ni 2+ are in coordination predominantly with oxygen. Mercury and Pb are low and have very little environmental impact.The hazardous elements (As, Cr, Ni, and Pb) are only leached by HCl, indicating that under normal condition they remain immobile and their impact on environment can be considered low.

Fine particles (PM 2.5 ) emitted from the stacks of the coal-fired power plants are of environmental concern since they can easily enter the human respiratory track. The detailed study of the fly ash particles using scanning electron microscope/electron dispersive spectrometry (SEM/EDX) show that fine solid spherical particles (microspheres) are contained by the large cenosphere particles (>50 μm) during the combustion process. The resulting macro particles are known as “plerosphere”, which are typically impregnated by the fine microspheres. The coal-fired power plants’ particle control devices such as the electrostatic precipitators (ESP) and baghouse filters tend to capture the large plerospheres, more efficiently. Therefore, the result of this study suggests that the containment of the microspheres by plerospheres during the coal combustion process can effectively reduce the amount of fine particles and associated elements released into atmosphere.

The production of coalbed methane (CBM) represents a vital new source of natural gas supply in Western Canada. There are, however, concerns over potential negative environmental impacts on groundwater resources caused by potential contamination with fluids and gases from coal-bearing strata. This paper provides a brief description of the geochemistry and a detailed discussion of trace element and rare earth element (REE) concentrations of the produced fluids from two major coal deposits in Western Canada, the Mannville Formation and the Horseshoe Canyon/Belly River Group (HSCN/BRG), and shallow groundwater (SGW) in this region. It evaluates how the depositional environment, redox conditions, and water–rock interactions influence the trace element and rare earth element distributions in the produced fluids and SGW of the study area. Produced waters from the Mannville Formation are a saline Na–Cl type and a high boron content is indicative of a brackish/marine depositional environment. In contrast, the HSCN/BRG produced fluids are a Na–HCO3 water type and have lower total dissolved solids (TDS) and lower boron concentrations. Shallow groundwater has a Na–HCO3 to Na–HCO3–SO4 water type with often high concentrations of sulphate and low TDS. Some groundwater samples, many HSCN/BRG and all Mannville fluids had low sulphate concentrations often with elevated δ34S values indicating that bacterial sulphate reduction had occurred making the redox environment suitable for methanogenesis. Dissolved gas from the Mannville Formation had a notable thermogenic component, whereas dissolved gas from the HSCN/BRG and free gas in shallow groundwater contained methane predominantly or exclusively of biogenic origin. Mannville produced waters are up to 70 times more concentrated in trace elements compared to the HSCN/BRG waters and up to 300 times more concentrated than shallow groundwater. In the Mannville fluids, trace elements, such as As, Se and Pb occurred in concentrations often exceeding drinking water guidelines (5 μg/L, 10 μg/L and 10 μg/L, respectively), whereas most samples in the HSCN/BRG contained only Se above drinking water guidelines, and a few samples contained As and Pb slightly above the maximum allowable concentrations for drinking water. Therefore, the potential risk of trace metal contamination of shallow groundwater with HSCN/BRG swabbing fluids is low because of their comparatively low trace metal content. Rare earth elements in the Mannville produced fluids indicate interaction with silicate dominated host rocks. In contrast, the REEs of the HSCN/BRG produced fluids show interaction with carbonate-rich material. The shallow groundwater shows a similar pattern to the HSCN/BRG, suggesting that REEs are not a suitable parameter to monitor potential contamination of shallow groundwater with CBM fluids from the HSCN/BRG. However, several other geochemical and isotopic parameters are sufficiently distinct between shallow groundwater, HSCN/BRG, and Mannville fluids so that cross-contamination with produced fluids or gases should be identifiable with a suitable geochemical monitoring program.

The Elk Valley coalfield of British Columbia is one of the major coal producing areas in Canada. The coals are of Cretaceous and Jurassic–Cretaceous age and range in rank from high-volatile to low-volatile bituminous (%Romax: 0.8–1.6). Coal seams from outcrops and active mines in this coalfield were analysed for rank and maceral composition using reflected light microscopy, for geochemistry using AAS, INAA, and ICPES, and also by proximate and ultimate analyses. The Elk Valley coal seams contain low average concentrations of hazardous elements such as As, Mo, Pb, and Se. However, there are seams that contain relatively high concentrations of some of these elements, such as 8 mg/kg and 108 mg/kg of arsenic. When the geochemistry of coal seams is compared within the different parts of the coalfield, the elemental composition amongst the seams from various sections located in the central area of the coalfield is similar. Coal seams in the northern area of the coalfield have different geochemistry than coal seams in other areas of the coalfield; seams in the northern area have much higher As, Br, Cr, Cu, Fe, K, and Na content, but contain less Ca.

The particulate organic matter in

Fly ashes produced from Canadian power plants using pulverized coal and fluidized bed combustors were examined for their carbon content to determine their ability to capture mercury. The feed coal used in these power plants were lignite, subbituminous, high and medium volatile bituminous, their blends, and also blends of coal with petroleum coke (Petcoke). The carbon and mercury content of the coals and fly ashes were determined using the ASTM standard method and by the cold vapour atomic absorption spectrometry method. The carbon content of the fly ash was concentrated by strong acid digestion using HCl and HF. The quantitative and qualitative analyses of the carbon concentrate were made by using a reflected light microscope. The results show that the carbon content of fly ash appears to be partially related to depositional environment during coalification and to the rank of the coal. The Hg captured by the fly ash depends on the rank and blend of the feed coals and the type of carbon in the fly ash. The isotropic vitrinitic char is mostly responsible for the capture of most Hg in fly ash. The inadvertent increase in carbon content due to the blending of coal with petroleum coke did not increase the amount Hg captured by the fly ash. The fly ash collected by the hot side electrostatic precipitator has a low Hg content and no relation between the Hg and carbon content of the ash was observed. These results indicate that the quantity of carbon in the fly ash alone does not determine the amount Hg captured. The types of carbon present (isotropic and anisotropic vitrinitic, isotropic inertinitic and anisotropic Petcoke), the halogen content, the types of fly ash control devices, and the temperatures of the fly ash control devices all play major roles in the capture of Hg.

Feed coals and fly ashes from two coal-fired power plants burning Alberta subbituminous coal were analyzed for C, Cl, Hg, and S and calorific values (for feed coal only), every week for a period of 33 weeks. The feed coals used in this study were deposited in brackish water and are compared to the coals deposited in a freshwater environment. The Hg and char (unburnt carbon) content of the fly ash was monitored to determine the variation of Hg and its possible relationship to the char types in the fly ash. The feed coals have Hg content of 0.026–0.089 mg/kg and their fly ash contains 0.02–0.243 mg/kg of Hg. The C content of the fly ashes ranges from 0.15% to 0.51%. The carbon/char was separated from the fly ash using HF and HCl. Reactive vitrinitic (formed from woody part of plants) and less reactive inertinitic (natural char) chars were separated by density separations of various specific gravities using ZnBr 2 . The char is mostly reactive vitrinitic (67–80 vol.%). Both stations have similar range of C content for their respective fly ashes. However, station 2 shows a much wider range of Hg in fly ash compared to station 1. In general, the fly ash from coal deposited under brackish water environment (stations 1 and 2) appears to have same or higher Hg content for lower C content compared to the fly ash from coal deposited under fresh water environment. The calculated emitted Hg for the period of 33 weeks for station 1 is estimated to be 64–90% of the total input of Hg with an average of 74%. The calculated emitted Hg shows a more complex pattern for station 2 and falls into two groups; with group (a) showing higher enrichment index for both Hg and S. The calculated emitted Hg for this group is 43–74% with an average of 57%, indicative of more Hg being captured by fly ash, possibly due to interaction between Hg and S. In the second group (b) the emitted Hg is calculated to be 74–95% with an average of 85%. The relative enrichment of both Hg and S in group (b) is low compared to group (a), indicative of possible slight paleo-weathering of the feed coal. The present study indicates that geological parameters such as paleo weathering and also depositional environment of the feed coal may influence the Hg content of fly ash.

Climate warming in the 20th Century has had profound effects on the limnology of High Arctic lakes, including substantial increases in autochthonous primary productivity (APP). Here, we report organic carbon and Hg core profiles from two lakes which support the hypothesis that 20th Century increases in sedimentary Hg at these latitudes were largely driven by APP increases, via Hg scavenging by algae and/or suspended detrital algal matter. Hydrocarbons quantitatively released by thermal cracking of algal-derived organic matter ("S2" carbon) were used to reconstruct past APP. Variation of S2 flux accounted for 87-91% of the variance in total Hg flux in the study lakes since 1854. Mercury and S2 carbon were also associated during the pre-Industrial Period, co-varying by as much as 30% during past warm/cool periods. As a test of the hypothesis, predicted values for 20th Century [Hg] were derived from pre-1900 Hg-S2 relationships. Measured 20th Century [Hg] was on average only 6-11% higher than that predicted in one lake, and 33% higher in the other. S2-normalization of [Hg] in the latter lake suggested that 78% of the average increase in 20th Century [Hg] could be explained by scavenging. These findings suggest that the atmospheric contribution of long-range anthropogenic Hg to High Arctic lakes may have been overestimated by several-fold because of this climate-driven process, and was responsible for no more than 22% of the 20th Century [Hg] increase in the study lakes.

The natural background level of elements in the surface soil of a given area is largely dependent on the geological setting of the region and the underlying soil parent material. Due to the heterogeneity of soil in various environments, it is essential to determine the site-specific natural background levels of elements to quantify the degree of influence of the anthropogenic source(s) within a given study area. This paper discusses the process involved in establishing the natural background level of trace metals and other elements in topsoil for the area surrounding the Teck Cominco zinc–lead smelter in Trail, British Columbia, Canada. The environmental assessment of soil in the Trail region is difficult due to the natural enrichment of metals in surficial material and topsoil as a result of the influence of mineralized bedrock in the region. Detailed examination of the study area based on the deposition data and previously collected soil data led to the selection of presumably the least anthropogenically influenced background sites in the study area, which also reflect the geological diversity of the region. The range of background was defined using the median plus or minus two median absolute deviations [median±(2 × MAD)], after the outliers were excluded. The outliers were identified using the Tukey boxplot concept and the cause of high metal concentrations in the outlier samples is attributed to their proximity to the historical mining sites in the region. The upper limit of the background range was estimated to be (in mg/kg): As, 11.0; Cd, 0.81; Cu, 38.1; Hg, 0.07; Pb, 27.7; Zn, 152. The resulting values are significantly more conservative estimates than would be obtained by other widely used methods (e.g. the mean plus or minus two standard deviations) due to the robust procedure, which prevents any interference by the extreme values in the collected soil background dataset. The upper background thresholds of metals estimated by the 95th percentile resulted in significantly different estimates, especially for As, Hg, Pb and Zn, from the previously reported values. This highlights the need for revision of the risk-based screening levels by environmental regulations in the study area.

This study addresses the physical geochemical aspects of the relationship between Hg and organic matter in recent sediment from eutrophic lakes in central Alberta, Canada. The types of organic matter in the sediment are classified based on their degree of thermal degradation and their petrographical characteristics. This study uniquely applies the methods conventionally used in petroleum geosciences (Rock-Eval® analyses and organic petrology) to investigate the relationship between various types of organic matter and the concentration of Hg in sediment. The results show that the total organic carbon (TOC) in sediment represents the sum of various organic compounds, which may play a completely different role in the distribution and accumulation of Hg. Strong correlations between TOC and the concentration of Hg in the studied sediment arise mainly from the thermally labile portion of organic matter released during pyrolysis under 300 °C. These compounds primarily consist of easily degradable algal-derived lipids and various pigments, which are petrographically described as soluble organic matter (SOM). The preserved SOM in sediment is commonly entrapped within the cell walls of phytoplankton and also appear as surface coating on sediment particles. The strong affinity between Hg and SOM is due not only to its chemical reactivity, but also to the physical characteristic of these labile compounds. The SOM may provide a substrate with enormous surface area by concentrating on the finer sediment size fractions and potentially acting as a “concentrator” for Hg and other organic-associated elements. Lastly, the quantity of the SOM has been calculated as an “elemental concentrator” portion of the TOC, which plays the most important role in the distribution of Hg in sediment.

The distribution of aerially deposited metals, As, Cd, Cu, Hg, Pb and Zn, was studied using passive collection moss monitoring in the vicinity of the smelter in Trail, British Columbia, Canada. The concentrations of metals/metalloids were measured in moss bags exposed to atmospheric deposition for periods of three months. The results show the greatest deposition of metals proximal to the smelter, and a decrease in deposition with increasing distance from the smelter. The pattern of deposition varies with the season, the element under study, and the location of the monitoring station. The depositional pattern around the Trail smelter is controlled mainly by the physiography of the region as related to shape and orientation of the Columbia river valley and direction of the prevailing wind. The results show that the annual aerial deposition of metals is directly related to the quantity of stack-emitted metals and Pb–Zn production levels. The distribution of Pb, Zn and Cd in surface soils around the Trail smelter shows a similar pattern to their deposition at moss-monitoring stations. These soils are characterized by an elevated concentration of metals in the proximity of the smelter, indicating the effect of airborne materials on the geochemistry of the soils in the study area. Such similarity was not found for Hg, Cu and As, indicating that the variation of these elements in soil samples is more likely related to soil chemistry rather than to atmospheric deposition.

Fly ashes were collected from the electrostatic precipitator (ESPs) and/or the baghouse of seven coal-fired power plants. The fly ashes were sampled from power plants that use pulverized subbituminous and bituminous feed coals. Fly ash from bituminous coals and limestone feed coals from fluidized-bed power plant were also sampled. The fly ashes were examined for their mineralogies and elemental compositions. The fly ashes from pulverized low sulfur coals are ferrocalsialic, those from high sulfur coals are ferrosialic and the fly ashes from the fluidized bed coals are ferrocalcic. The concentrations of As, Cd, Hg, Mo, Ni, and Pb in fly ash are related to the S content of the coal. Generally, those feed coals with a high S content contain higher concentrations of these elements. The concentrations of these elements are also greater for baghouse fly ash compared to ESP fly ash for the same station. The S content of fly ash from high S coal is 0.1% for pulverized ESP fly ash and 7% for baghouse fly ash from the fluidized bed, indicating that most of the S is captured by fly ash in the fluidized bed. The baghouse fly ash from the fluidized bed has the highest content of Cd, Hg, Mo, Pb, and Se, indicating that CaO, for the most part, captures them. Arsenic is captured by calcium-bearing minerals and hematite, and forms a stable complex of calcium or a transition metal of iron hydroxy arsenate hydrate [(M 2+ ) 2 Fe 3 (AsO 4 ) 3 (OH) 4 ·10H 2 O] in the fly ash. Most elements in fly ash have enrichment indices of greater than 0.7 indicating that they are more enriched in the fly ash than in the feed coal, except for Hg in all ESP ashes. Mercury is an exception; it is more enriched in baghouse fly ash compared to ESP. Fly ash collected from a station equipped with hot side ESP has a lower concentration of Hg compared to stations equipped with cold side ESP using feed coals of similar rank and mercury content. Fly ash particles from fluidized bed coal are angular and subangular with cores of quartz and calcite. The quartz core is encased in layer(s) of calcium-rich aluminosilicates, and/or calcium/iron oxides. The calcite core is usually encased in an anhydrite shell.

Upper Triassic to Middle Jurassic coals from the Alborz region of northern Iran were analyzed by reflected light-fluorescence microscopy and Rock Eval 6® pyrolysis to evaluate their regional rank variation, degree of hydrothermal alteration, and petroleum generative potential. The coal ranks in the region range from a low of 0.69%RoR in the Glanddeh-Rud area to a high of 1.02%RoR in the Gajereh area. Tmax (°C) values (Rock Eval 6 pyrolysis) also increase progressively with increasing vitrinite %Ro values, however Tmax is suppressed lower than would be expected for each rank ranging from 428 °C for the Glandeeh coal to 438 °C for the Gajereh coal. Tmax suppression may be caused by maceral composition and soluble organics within the coal. Moderately high hydrogen indices, persistent and oily exudations from the coals during UV exposure, and traces of hydrocarbon fluid inclusions suggest that liquid petroleum was likely generated within some of the coals.

Particles emitted from three coal-fired power plants burning subbituminous coals from Alberta, Canada were examined for total particulate matter (PM) and size fractions PM >10 , PM 10 , and PM 2.5 . The sampling was carried out following EPA Method 201A, which requires a 6 inch port. Three tests were performed at each station. The rates of emitted particulates from the three power plants are 9.9–53.4 mg/m 3 (dry), 30–90 kg/hr (dry), and 0.039–0.118 kg/MWh, respectively. The emission rates of the various particle sizes for these three power plants are 8.7–39.5 kg/hr of PM >10 , 10.7–40.8 kg/hr of PM 10 , and 9.65–10.7 kg/hr of PM 2.5 . The present results indicate that 29–44% of emitted particles are PM >10 . The total emissions of particulates from two power plants are below the Canadian Guideline for emission from a coal-fired power plant (0.095 kg/MWh), while the third power plant is slightly higher than the Guideline (0.118 kg/MWh). The malfunctioning of control technology may result in unrealistic and wide variation in the measured rates of emitted particles.

Particles emitted from coal-fired power plants burning subbituminous coal from Alberta, Canada were examined for total particulates (PM) and size fractions PM>10, PM10, and PM2.5. The sampling was carried out following EPA Method 201A. Three tests were performed at each station. The emitted particles were examined using SEM/EDX and gravimetric method for the determination of their sizes. The elemental composition of particles was determined using INAA and ICP-MS. The particles emitted from the stack are classified based on their morphologies and chemistries to the following: unburnt carbon, feed-coal minerals such as quartz, and by-products of the dissociation, fractionation, and contamination by minerals in coal. The emitted particles are mostly spherical and their matrices are composed of aluminosilicate minerals containing calcium. The PM>10 fraction contains small plerospheres, fragments of char, and angular quartz and feldspar particles. The PM10 fraction contains solid spheres and cenospheres, gypsum needles, and particles of char. The PM2.5 particle size fraction is mostly composed of solid spherical aluminosilicates with some surface enrichment of elements such as Ba, Ca, and Fe. The composition of emitted particles is ferrocalsialic. Most elements in the particle size fractions are Class I or II, such as Al, Ca, and Fe. Cd, Cu, Mo, and Ti were only detected in PM2.5 fraction.

Feed coals and fly ashes from a coal-fired power station burning Alberta subbituminous coal were examined for a period of thirty-eight weeks to determine the variation in emitted mercury. Feed coal samples were analyzed for proximate, calorific value and Hg content, while fly ash samples were examined for C and Hg contents. The maceral content of the feed coal was also determined. The emitted mercury was calculated and compared to mercury emitted from the stack according to a mass-balance calculation from a previous study for the same station. Mercury contents ranged from 0.029 to 0.066 mg/kg for feed coal, and from 0.069 to 0.112 mg/kg for fly ash. The carbon/char in fly ash was separated into reactive (vitrinitic/bimacerate) and less reactive (inertinitic) chars using ZnBr2 at specific gravities of 1.7, 2.0, and 2.25 to 2.4. The result shows that there is a positive correlation between the carbon and mercury content of the fly ash. The reactive char particles in the fly ash may be responsible for the capture mercury in fly ash. The percentage of estimated captured mercury by fly ash increases with increasing carbon content (%) in fly ash. The percentage of emitted mercury for the period of 38 weeks is estimated to be within the range of 49% to 76% of the total input of mercury.

Summarization: A comparative study related to the concentrations of trace elements especially those of environmental concern, occurring in regular and reclaimed soils on abandoned coal mines as well as on their respective wheat crops has been undertaken in the vicinity of Ptolemais–Amynteon, Greece. The aim was to assess the impact of land reclamation on the crops. The results of elemental analysis show that the concentration of As is 1.5 to 1.7 times higher in the regular soils than in the reclaimed ones, similarly Co is 2.4 to 2.6 times higher, Cr is 1.7 to 2.8 times higher, Ni is 1.9 to3.1 times higher, Pb is 0.8 to 4.6 times higher, and Hg is equal to or 1.7 times higher. Cu, Cd and Se have the same concentration in both kind of soils and Mo and U are 1.7 to 2.0 times lower in the regular soils as compared to the reclaimed soils. Nevertheless, all concentrations are within the reported range for regular soils. Moreover, the concentrations of the studied elements in wheat grains harvested from both types of soils are approximately the same. The reason for the uniform uptake of elements by the plants is the very low solubility of the elements in the soil solutions. This is attributed to the high soil pH and the nature of the occurrence or bonding of the elements in soil minerals. Presented on: International Journal of Coal Geology

This study is related to four Jurassic-age bituminous coal (0.69–1.02 Ro%) samples collected from coal mines from the west, central and east of central, Alborz in northern Iran. Geological settings played key roles in determining the geochemistry and mineralogy of coals from the central Alborz region of northern Iran. The mineralogy of coals from the eastern part of the region is dominated by kaolinite; halloysite; and carbonates such as calcite, dolomite/ankerite, and siderite. The coals were deposited in a lacustrine environment. In the western part of the region, where the depositional setting was also lacustrine with volcanic input and tonstein deposition (glass shards present), the coal primarily contains kaolinite (68%) and fluorapatite (26%). In contrast, coal from the central part of the region, which was deposited in a terrestrial environment and on eroded limestone and dolomite rocks, is dominated by dolomite (98%) with little input by kaolinite. These coals have low sulphur (0.35–0.70 wt.%), which is mostly in the organic form (0.34–0.69 wt.%). Pyritic sulphur is detected only in one coal and in small quantities. The boron contents of these coals range from 9 to 33 mg/kg, indicating that deposition occurred in a fresh water environment. Coal with higher concentrations of Ba, Sr, and P contain fluorapatite and goyazite–gorceixite series [BaAl 3 (PO 4 ) 2 (OH) 5 , H 2 O] minerals, which indicates volcanoclastic input. Compared to world coal averages, these coals exhibit low concentrations of elements of environmental concern, such as As (1.3–5.9 mg/kg), Cd (

Fifty-six samples of stream sediments from 12 creeks in the vicinity of Trail, British Columbia, Canada were examined to determine their origin, characterize their organic matter and their relation to natural/geogenic and anthropogenic sources. The samples were initially screened by Rock-Eval® 6 pyrolysis for their TOC, HI, and OI contents and then examined by both reflected (polarized) and fluorescent light microscopy. It was found that organic matter in stream sediments is mostly from natural/biological sources from local vegetation, such as woody tissue, suberin, spores, and pollen, as well as altered natural/biological input from char formed due to forest fires. Anthropogenic organic matter, mostly coke particles, was also found in the stream sediments. The coke particles have anisotropic properties with medium grained texture formed from medium volatile bituminous coal. The occurrence of coke particles is limited to Ryan Creek located close to an area were some small gold, nickel, and lead smelting operations previously occurred. There is no evidence to indicate that the coke particles found in the creek are emitted from the lead and zinc smelter currently in operation in the area. There are no coal-bearing strata in the area that may have a direct input of coal fragments in any of the creeks.

The chromium species in the feed coals and ash byproducts from seven Canadian coal-fired power plants were examined using Cr X-ray absorption near-edge spectroscopy. Chromium in the Canadian feed coals is always found as Cr{sup 3+} but generally has a dual occurrence, as Cr{sup 3+} is distributed to varying degrees between the clay mineral illite and a poorly crystallized chromium oxyhydroxide phase associated with the organic fraction. In two subbituminous feed coals from Alberta, chromium is present largely as Cr{sup 3+}/illite, whereas in two other such coals, it is present predominantly as CrOOH. Chromium in a low-sulfur bituminous feed coal from Alberta is found mostly as Cr{sup 3+}/illite, whereas for feed coals from Nova Scotia with high sulfur contents, chromium is distributed between both Cr{sup 3+}/illite and CrOOH. Very little chromium was found in the limestone used in a fluidized-bed combustor. The chromium species in most bottom ash samples from all seven combustion units is predominantly, if not entirely, Cr{sup 3+} associated with aluminosilicate phases. Chromium speciation for subbituminous electrostatic precipitator fly ash is mostly Cr{sup 3+}, but in some cases, it is slightly lessand varies by sampling location at the plant. Chromium in fly ash from the combustion ofmore » bituminous feed coals is predominantlyCr{sup 3+}. A unique species of chromium found in one feed coal and an unrelated fly ash is metallic chromium, similar to that in stainless steel. The occurrence of this form of chromium in these materials indicates contamination from machinery, such as the coal milling machine or possibly wearing down of stainless steel parts by the coal or ash. The observation of this unexpected contamination demonstrates the power and usefulness of X-ray absorption fine-structure spectroscopy for speciation determination. 35 refs., 6 figs., 4 tabs.« less

This study characterizes the petrological changes occurring in an organic matter assemblage of Recent lacustrine sediments from Alberta, Canada, during the various steps of Rock-Eval 6® pyrolysis. The results indicate that the organic compounds released during pyrolysis at low temperatures of up to 300 °C (mainly S1-compounds) are most likely derived from a ‘stain-like’ amorphous organic matter, including pigments and oils/lipid products with strong, multicolored VIS fluorescence. The fluid characteristics of the thermally labile S1-compounds possibly account for the significant grain surface coating by the organic matter. Thermal alteration of sediments at 300 °C results in the transformation of some alginite and other macerals into a secondary product of blue–green fluorescing bitumen, which migrates into available free spaces. The release of S2-compounds during high temperature pyrolysis (from 300 to 650 °C) causes severe alterations in the morphology of the liptinitic organic matter. A bright yellow fluorescence that appeared at this stage is likely due to thermal transformation of bitumen produced in S1 pyrolysis and other liptinitic macerals into an “oily-material”, which fills cell lumens and becomes incorporated into the mineral matter. Neither the rapid rate of heating nor the sample residence time during Rock-Eval pyrolysis are sufficient for complete thermal destruction of the secondary hydrocarbon and bitumen products produced in the sample.

The arsenic species in the feed coals and ash byproducts from seven Canadian power plants (including one with a fluidized-bed combustor) that were burning local sub-bituminous and bituminous coals with sulfur contents in the range of 0.30−3.5 wt % have been examined using As X-ray absorption fine structure (XAFS) spectroscopy. The feed coals can be grouped based on their contents of arsenic associated with pyrite (As/pyr) and as As3+ and As5+ (arsenate) species. The arsenic species in sub-bituminous feed coals with low sulfur (0.22−0.38 wt %) and arsenic (1.6−2.2 mg/kg) contents consist of ∼50% As3+ and ∼50% As5+, whereas those with moderate sulfur (0.50 wt %) and arsenic (3.63 mg/kg) contents consist of 84% As/pyr, 7% As3+, and 9% As5+. In bituminous feed coal with low sulfur (0.40 wt %) and arsenic (4.39 mg/kg) contents, the arsenic speciation consists of 34% As/pyr, 12% As3+, and 54% As5+, and for those with high sulfur (2.60−3.56 wt %) and arsenic (54−84 mg/kg) contents, it consists of 77%−82% As/pyr ...

The mercury and maceral content of subbituminous feed coals burned at six Canadian power plants was measured and compared to the mercury and carbon content of corresponding fly ashes. The fly ashes were collected from electrostatic precipitator (ESP) pollution controls used at the power plants. Four feed coals from the Upper Cretaceous to Tertiary age Scollard Formation were deposited in freshwater depositional environment and contain 35–44% inertinite. Two feed coals from the Upper Cretaceous age Horseshoe Canyon Formation were deposited in a brackish water environment and contain 14% inertinite. The data show that abundant inertinite equates to more unburned carbon in ESP fly ash, and to enhanced capture of mercury in cold-side ESP fly ash. This indicates that the inertinite content of a coal seam may be indicative of the percentage of unburned carbon and the percentage of mercury captured by a cold-side ESP.

Western Canadian subbituminous coal is mined using strip-mining methods. The coal is used to feed coal-fired power plants for electricity generation. Parameters that influence the mercury content of these coals include the occurrence and frequency of partings in the seam, weathering, and epigenetic mineralization. Most partings have higher mercury content than the coal layers in the same seam, with the single bentonite bed having the highest Hg content. However, some high ash components, such as sandy siltstone, do not follow this trend. The incorporation of the high mercury partings into the as-mined coal may increase the Hg content in the feed coal. Epigenetic mineralization may also increase the mercury content of coal, depending on the nature of the mineralization. Calculation of the weighted mean of mercury content for various combination of lithological components of a seam illustrates how these components influence the total mercury content of the seam. This approach also suggests how selective mining might be used to reduce mercury in “as-mined” coal. Results of weighted average calculations of mercury indicate that the thin lithological units with moderate mercury may not necessarily influence that overall weighted average of Hg for a seam. However, there can be exception, such as presence of thin (3.5 cm) bentonite parting with high mercury in a 94.5 cm seam that increased the mercury content of seam by 83.4%.

The quantities of six elements (As, Cd, Cu, Hg, Pb, and Zn) were determined in surface soil from 21 stations around the zinc–lead smelter in Trail, British Columbia, Canada. The flux of elements into a unit of soil was then calculated by extrapolating aerial deposition monitoring data obtained from flat square moss bags, which act as traps for airborne particles/elements. The net increase in the quantity of elements in a 10 cm deep by 1 hectare soil unit over a 3-month time interval was estimated as 0.02, 0.65, 0.07, 0.29, 0.22, and 0.65% for As, Cd, Cu, Hg, Pb, and Zn, respectively. The results of this study can be used for elemental inventory of soil in the Trail area and to predict the long-term degree of accumulation of trace elements in the soil. The significant correlation between the deposition rate of Pb, Zn, Cd, and Cu as registered by moss monitoring stations and the quantity of these elements in surface soil indicate the possible effect of airborne material on the geochemistry of the soils in the study area. In contrast, the poor correlation for Hg and As indicates that the variations of these elements in soil samples are likely related to soil chemistry rather than atmospheric deposition. This demonstrates the importance of monitoring for atmospheric deposition of elements since soil is not always a good indicator of the spatial influence of a point source in the study area.

Feed-coals used in some Canadian power plants were examined for their mineralogical and elemental composition. The mode of occurrence of elements (organic/minerals) in these samples were determined using sequential leaching by H 2 O, NH 4 OAc and HCl. Canadian feed-coals examined in this study are subbituminous to bituminous rank (calorific values: 19.62–29.88 MJ/kg). The sulphur content of these coals is 0.32–3.55%. Quartz and aluminosilicates (clay minerals and feldspar) dominate the mineralogy of these samples. The accessory minerals consists of pyrite, sphalerite, barite, calcite, anhydrite, chromite, zircon, biotite, and monazite, which occur as both primary and secondary cell filling types. An interesting mineral found in one of the subbituminous feed-coals is the gorceixite that is normally associated with degraded volcanic ash. The sulphur content of the feed-coals is an indication of their geological setting with feed-coal formed in a fresh water setting containing the least amount of S and those associated with evaporites having the highest S content. The concentrations of Cd, Cr, Cu, Hg, Ni, Se, V, and Zn in these Canadian feed-coals are low compared to world coals. Mercury content of these feed-coals ranges from 0.04 to 0.16 ppm. Mercury is mostly associated with the pyretic portion of coal and has direct correlation to As and S content in these coals. Arsenic in low sulphur coals is mostly associated with coal macerals and in higher sulphur coals with pyrite. About 47% of As in high sulphur coal is removed after leaching by HCl. Water soluble elements consist of Co, Ni and Mn, which are associated only with bituminous feed-coals. The removal of these elements by water is possibly due to an increased acidity of leaching solution and presence of soluble Cl and S. Beryllium and vanadium in low S coals are mostly removed after leaching by HCl, indicating a possible association with clay minerals. Limited Be and V is removed from lower clay mineral content coals; however, in high S content coals, more Be and V are removed. The speciation of As, Cr and Ni indicates that As is mostly present in the less-toxic form As +5 and Cr is present entirely as Cr 3+ , an essential human trace nutrient, found in both subbituminous and bituminous ranked coals. Nickel is present mostly as Ni 2+ in oxygen coordination in these milled coals and carcinogenic compounds of nickel are not present in these feed-coals.

The atmospheric deposition and regional dispersion pattern of the elements As, Cd, Cu, Hg, Pb and Zn, emitted from Pb-Zn smelters at Trail, British Columbia, Canada, were studied for a period of two years using the passive collection moss-monitoring method. Concentrations of these elements in moss bags, exposed to atmospheric deposition for three months, were first corrected for geogenic input and then site-specific local background level to produce common background elemental concentrations for all monitoring stations. The results of this study indicate that the deposition of these elements is greatest in proximity to the smelter and decreases with an increase in distance. The regional dispersion pattern generally varies seasonally, with the magnitude of variation being dependent on the element under study and the location of the monitoring station. Overall, the deposition of these elements (as registered by moss-monitoring stations) appears to be a complex phenomenon involving various factors such as meteorological conditions (prevailing wind direction and precipitation), physiography (topography, valley shape and orientation) and in-process activities at the smelters (production level, emission control efficiency and the geochemistry of feed). However, the results of this study indicate that, on an annual basis, in-process activities, particularly production levels of Pb and Zn and the quantity of emissions from the stack, are more directly related to the observed deposition of the elements than any of the other factors.

The concentration of As, Cr and Ni and their speciation (As3+;5+, Cr3+;6+ and Ni0;2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP) from a coal fired-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH4OAC and HCI as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCI. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (>90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCI, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.

The geochemistry of Recent sediments from Pigeon Lake, Alberta was studied using Rock-Eval-6 in conjunction with Instrumental Neutron Activation Analyses 137Cs isotope. The results of this study indicate that the variations in Rock-Eval parameters within the sedimentary column are correlated with the concentration of lithophile elements. These variations appear to be controlled by a balance between a number of interrelated processes concerned with both the nature of the deposited biomass and the depositional conditions. Two marker horizons were identified showing an abrupt decrease in Rock-Eval parameters (TOC, S2, and HI) and an increase in concentration of lithophile elements, indicating the clastic nature of the sediments with low autochthonous organic contents. This is attributed to significant natural events such as a storm or flood, which result in a rapid increase in the rate of erosion and subsequently in a high clastic input to the lake. Two cycles showing high organic content were also identified. The first cycle (productivity cycle) corresponds to the increase in algal productivity of the lake due to agricultural activities in the lake’s catchment. In the second cycle (diagenetic cycle), the downward decrease of organic matter is interpreted as the result of selective degradation of organic matter during early diagenesis. The estimated sedimentation rates based on the established marker horizons and 137Cs isotope indicate higher sedimentation in the deeper part of the lake prior to the productivity cycle. However, the sedimentation rates increased towards the littoral zone coinciding with an increase in productivity and subsequently the rise in growth of macrophytes in the near-shore area.

Twenty-five drinking water samples collected from the household property and from the Sydney Regional Municipality well bores and lakes were analyzed to evaluate the various inorganic parameters, level of concentrations of the priority elements and polyaromatic hydrocarbons (PAHs). The pH of the majority of the water samples was below the guidelines adopted by Health and Welfare Canada (1996) , although the drinking waters supplied by the Sydney Regional Municipality were within the guidelines. Only three water samples (13 and 14: Point Aconi area and 16: Port Morien fish plant) have elevated concentrations of various PAHs compared to the detection limit. Eight samples have higher concentrations of manganese and two samples (number 7: Sydney Airport and number 1: RCMP Office; Reserve Mines) have higher concentrations of priority elements (especially lead) than the recommended guidelines (>0.05 mg/l). These priority elements and the PAHs in the drinking water samples may have originated from the leaching of the individual coal seams within that part of the Sydney Basin. Other potential sources of these elements and PAHs (Power Plant disposal, Sydney Tar Pond, metalliferous rocks, hydrocarbon reservoir rocks) are not located close enough to the sampling sites of the water samples. Therefore, they are not considered the source of these elements and PAHs.

Mineralogy and elemental contents were determined on 18 samples from a vertical profile of the No. 2 seam, Genesee mine, AB. The samples analyzed consist of coal, coaly shale, shaly coal, carbonaceous shale, shale, mudstone and siltstone. Proximate analysis was determined on all samples. Elemental analyses were determined by instrumental neutron activation analysis (INAA) for all elements except As, B, Cd, Hg, Mo, Pb, Se (Atomic Absorption) and B, Ba, Be, Co, Cr, Cu, Li, Mn, Nb, Sr and V (inductively coupled plasma-emission spectroscopy, ICP-ES). Samples were low temperature ashed (LTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF) were used to determine quantitative major mineralogy. Accessory mineralogy was determined with Scannining Electron microscope/energy dispersive X-ray analyzer (SEM/EDX) on four samples. In general, the coals in the Genesee mine are within the low end of the range for trace element contents given by Swaine [Swaine, D.J., 1990. Trace Elements in Coal. Butterworths, London, 278 pp.] for most coals. High contents of Cr (9–2620 ppm) and Ni (1–1440 ppm) can be related to an increased amount of a Cr–Ni–Fe oxide (chromite–magnetite?) likely derived from ultrabasic diatremes in the Golden-Columbia Icefields, BC area. The No. 2 seam of the Genesee mine can be divided into two geochemical cycles on the basis of mineralogy, trace element contents and rare earth element (REE) behavior. Cycle I consists of quartz, calcite and kaolinite, lower trace element contents, REE slightly enriched in high rare earth elements (HREE), and thick coal with few partings. Cycle II consists of quartz, calcite, kaolinite, illite, mixed layer and/or expandable lattice clays, feldspar, gypsum, calcium aluminum sulfate hydrate, clinoptilolite, calcite and diopside, higher trace element contents, REE slightly enriched in light rare earth elements (LREE) and thin coal with a greater frequency of partings. The differences between the two geochemical cycles can be accounted for by a decreasing stability of the peat-forming environment resulting from an increasing fluvial influence and volcanogenic input.

This article examines the chemical fractionation (leaching) of elements from the Whitewood Mine subbituminous coals and coal ashes at 120 C, 750 C, and 1000 C. The elements Ba, Zn, and Mn are easily leached from coal by water, ammonium acetate, and hydrochloric acid. Potassium is highly extractable by NH4O acetate but very little with HCl. Hydrochloric acid leaches most of Fe, whereas very small quantities of the element are leached by water or NH4O acetate. Low extractability from coal was noted for Si, Ti, and Cu, an indication of their association with detrital minerals. Extractability of Na from coal was low, which indicates an association with minerals rather than being in the form of exchangeable ions. High leachability for Ca, Sr, and to a certain degree, Mn, Mg, and Na were noted for the 120 C ash samples. Zinc, Ba, S, and P showed a wide variation, reflecting a complex association with carbonate, sulphate, sulphide minerals, and organic matter. Silica, Al, B, Li, Cu, and Mo were completely insolu...

Determining thermal maturity studies in the Ellef Ringnes Island area was complicated by numerous factors, such as the presence of cavings, bitumen staining, and igneous intrusions. Cavings are a problem in certain intervals in Hoodoo H-37, Dome Bay P-36, and Helicopter J-12. Bitumen staining resulting in suppression of reflectance has occurred in the lower part of the Jameson Bay shales in Elve M-40. Thick sills resulted in increase of Ro to 4.0%, whereas thin sills had a minimal impact on reflectance increase. Other features observed include overpressuring caused by hydrocarbon generation in the Schei Point source rocks as well as in the Jameson and Ringnes shales, and a “kinky” Ro profile caused by the presence of low-permeability gas-bearing reservoirs in the Heiberg sandstones in Jackson Bay G-16A. The presence of sapropelic coals with HI up to 329 mg HC/gTOC in Heiberg sandstones in Elve M-40 containing Botryococcus algae should also be noted. Calculated maturation gradients vary from 0.95 ...

The hydrocarbon potential of the Mesozoic succession in the vicinity of King Christian Island in central Sverdrup Basin was evaluated on the basis of maturation parameters and knowledge of the regional geology. The Triassic Schei Point Group, which is the main source rock interval in Sverdrup Basin, is in the mature stage of hydrocarbon generation (Ro>0.60%). The type of organic matter is mainly plank-tonic marine algae and bituminite, deposited in an offshore shelf setting. Rock-Eval Tmax values are in the range 428–444°Q in general agreement with reflectance. Organic richness is indicated by the high hydrogen index (HI) values in the shales (in excess of 300 mg HC/gTOC). Less rich source rocks are found in the Jurassic-age Jameson Bay and Ringnes formations, in accordance with previous studies in the nearby Lougheed and Melville islands. Numerous oil and gas fields have been discovered in King Christian Island to date. Geology shows that the presence or absence of liquid and gaseous hydrocarbon...