Rick Pelletier

Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region

Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks.

Dust is the dominant source of "heavy metals" to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta.

Sphagnum fuscum was collected from twenty-five ombrotrophic (rain-fed) peat bogs surrounding open pit mines and upgrading facilities of Athabasca Bituminous Sands (ABS) in northern Alberta (AB) in order to assess the extent of atmospheric contamination by trace elements. As a control, this moss species was also collected at a bog near Utikuma (UTK) in an undeveloped part of AB and 264km SW of the ABS region. For comparison, this moss was also collected in central AB, in the vicinity of the City of Edmonton which is approximately 500km to the south of the ABS region, from the Wagner Wetland which is 22km W of the City, from Seba Beach (ca. 90km W) and from Elk Island National Park (ca. 45km E). All of the moss samples were digested and trace elements concentrations determined using ICP-SMS at a commercial laboratory, with selected samples also analyzed using instrumental neutron activation analysis at the University of Alberta. The mosses from the ABS region yielded lower concentrations of Ag, As, Bi, Cd, Cu, Pb, Sb, Tl, and Zn compared to the moss from the Edmonton area. Concentrations of Ni and Mo in the mosses were comparable in these two regions, but V was more abundant in the ABS samples. Compared with the surface vegetation of eight peat cores collected in recent years from British Columbia, Ontario, Quebec and New Brunswick, the mean concentrations of Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl and Zn in the mosses from the ABS region are generally much lower. In fact, the concentrations of these trace elements in the samples from the ABS region are comparable to the corresponding values in forest moss from remote regions of central and northern Norway. Lithophile element concentrations (Ba, Be, Ga, Ge, Li, Sc, Th, Ti, Zr) explain most of the variation in trace metal concentrations in the moss samples. The mean concentrations of Th and Zr are greatest in the moss samples from the ABS region, reflecting dust inputs to the bogs from open pit mines, aggregate quarries, and gravel roads. Linear regressions of V, Ni, and Mo (elements enriched in bitumen) versus Sc (a conservative, lithophile element) show excellent correlations in the mosses from the ABS region, but this is true also of Ag, Pb, Sb and Tl: thus, most of the variation in the trace metal concentrations can be explained simply by the abundance of dust particles on the plants of this region. Unlike the moss samples from the ABS region and from UTK where Pb/Sc ratios resemble those of crustal rocks, the moss samples from the other regions studied yielded much greater Pb/Sc ratios implying significant anthropogenic Pb contributions at these other sites.

Peat bogs in northern Alberta, Canada reveal decades of declining atmospheric Pb contamination

Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmospheric deposition of Pb, a valuable tracer of human activities. In each profile, the maximum Pb enrichment is found well below the surface. Radiometric age dating using three independent approaches (14C measurements of plant macrofossils combined with the atmospheric bomb pulse curve, plus 210Pb confirmed using the fallout radionuclides 137Cs and 241Am) showed that Pb contamination has been in decline for decades. Today, the surface layers of these bogs are comparable in composition to the “cleanest” peat samples ever found in the Northern Hemisphere, from a Swiss bog ~ 6000 to 9000 years old. The lack of contemporary Pb contamination in the Alberta bogs is testimony to successful international efforts of the past decades to reduce anthropogenic emissions of this potentially toxic metal to the atmosphere.

Higher mortality among remote compared to rural or urban dwelling hemodialysis patients in the United States.

Living far away from specialized care centers is a potential barrier to the delivery of quality health care and has been associated with adverse outcomes. To assess mortality as a function of distance from the closest hemodialysis unit, and as a function of rural rather than urban residence, we analyzed prospectively collected data on 726,347 adults initiating chronic hemodialysis in the United States over a 13-year period. Participants were classified into categories of 0-10 (referent), 11-25, 26-45, 46-100, and remote living over 100 miles from the closest hemodialysis unit. After a median follow-up of 2.7 years (range 0 to 12.7 years), 368,569 patients died. Compared to the referent group, the adjusted hazard ratio of death was 1.01, 0.99, 0.96, and 1.21, respectively. When residence location was classified using rural-urban commuter areas, 16.5, 66.8, and 16.7% of patients lived in urban, micropolitan, and metropolitan areas, respectively. Compared with those living in metropolitan areas, the adjusted hazard ratio of mortality among patients residing in micropolitan and rural communities was 1.02 and 1.01, respectively. Thus, remote but not rural residence was associated with increased mortality among patients initiating chronic hemodialysis treatment in the United States.

Animal Density and Track Counts: Understanding the Nature of Observations Based on Animal Movements

Counting animals to estimate their population sizes is often essential for their management and conservation. Since practitioners frequently rely on indirect observations of animals, it is important to better understand the relationship between such indirect indices and animal abundance. The Formozov-Malyshev-Pereleshin (FMP) formula provides a theoretical foundation for understanding the relationship between animal track counts and the true density of species. Although this analytical method potentially has universal applicability wherever animals are readily detectable by their tracks, it has long been unique to Russia and remains widely underappreciated. In this paper, we provide a test of the FMP formula by isolating the influence of animal travel path tortuosity (i.e., convolutedness) on track counts. We employed simulations using virtual and empirical data, in addition to a field test comparing FMP estimates with independent estimates from line transect distance sampling. We verify that track counts (total intersections between animals and transects) are determined entirely by density and daily movement distances. Hence, the FMP estimator is theoretically robust against potential biases from specific shapes or patterns of animal movement paths if transects are randomly situated with respect to those movements (i.e., the transects do not influence animals’ movements). However, detectability (the detection probability of individual animals) is not determined simply by daily travel distance but also by tortuosity, so ensuring that all intersections with transects are counted regardless of the number of individual animals that made them becomes critical for an accurate density estimate. Additionally, although tortuosity has no bearing on mean track encounter rates, it does affect encounter rate variance and therefore estimate precision. We discuss how these fundamental principles made explicit by the FMP formula have widespread implications for methods of assessing animal abundance that rely on indirect observations.

Characterization of Naphthenic Acids and Other Dissolved Organics in Natural Water from the Athabasca Oil Sands Region, Canada

With growth of the Canadian oil sands industry, concerns have been raised about possible seepage of toxic oil sands process-affected water (OSPW) into the Athabasca River (AR). A sampling campaign in fall 2015 was undertaken to monitor for anthropogenic seepage while also considering natural sources. Naphthenic acids (NAs) and thousands of bitumen-derived organics were characterized in surface water, groundwater, and OSPW using a highly sensitive online solid phase extraction-HPLC-Orbitrap method. Elevated NA concentrations and bitumen-derived organics were detected in McLean Creek (30.1 μg/L) and Beaver Creek (190 μg/L), two tributaries that are physically impacted by tailings structures. This was suggestive of OSPW seepage, but conclusive differentiation of anthropogenic and natural sources remained difficult. High NA concentrations and bitumen-derived organics were also observed in natural water located far north of the industry, including exceedingly high concentrations in AR groundwater (A5w-GW, 2000 μg/L) and elevated concentration in a tributary river (Pierre River, 34.7 μg/L). Despite these evidence for both natural and anthropogenic seepage, no evidence of any bitumen-derived organics was detected at any location in AR mainstem surface water. The chemical significance of any bitumen-derived seepage to the AR was therefore minimal, and focused monitoring in tributaries will be valuable in the future.

Peat Bogs Document Decades of Declining Atmospheric Contamination by Trace Metals in the Athabasca Bituminous Sands Region

Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the Athabasca Bituminous Sands, the largest reservoir of bitumen in the world. Frozen cores were sectioned into 1 cm slices, and trace metals determined in the ultraclean SWAMP lab using ICP-QMS. The uppermost sections of the cores were age-dated with 210Pb using ultralow background gamma spectrometry, and selected plant macrofossils dated using 14C. At each site, trace metal concentrations as well as enrichment factors (calculated relative to the corresponding element/Th ratio of the Upper Continental Crust) reveal maximum values 10 to 40 cm below the surface which shows that the zenith of atmospheric contamination occurred in the past. The age-depth relationships show that atmospheric contamination by trace metals (Ag, Cd, Sb, Tl, but also V, Ni, and Mo which are enriched in bitumen) has been declining in northern Alberta for decades. In fact, the greatest contemporary enrichments of Ag, Cd, Sb, and Tl (in the top layers of the peat cores) are found at the control site (Utikuma) which is 264 km SW, suggesting that long-range atmospheric transport from other sources must be duly considered in any source assessment.

Sphagnum Moss as an Indicator of Contemporary Rates of Atmospheric Dust Deposition in the Athabasca Bituminous Sands Region

Sphagnum moss was collected from ombrotrophic (rain-fed) peat bogs to quantify dust emissions from the open-pit mining and upgrading of Athabasca bituminous sands (ABS). A total of 30 bogs were sampled in the ABS region, and 5 were sampled in central Alberta. Ash was separated into the acid-insoluble ash (AIA) and acid-soluble ash (ASA) fractions using HCl. The AIA concentrations increase toward industry from 0.4 ± 0.5% to 4.7 ± 2.0% over a distance of 30 km; the control site at the Utikuma Region Study Area (URSA) yielded 0.29 ± 0.07% (n = 30). Mass accumulations rates showed similar spatial variation. The morphology and mineralogy of the AIA particles were studied using scanning electron microscopy and energy-dispersive X-ray analysis and the particle size distributions using optical methods. Particle size was more variable in moss closer to industry. Major ions in the ASA fraction showed elevated accumulation rates of Ca, K, Fe, Mg, P, and S, with P being up to 5 times greater in samples nearest industry compared to those in distal locations. Given that P has been regarded as the growth-limiting nutrient in bogs, fertilization of nutrient-poor ecosystems, such as these from fugitive emissions of dusts from open-pit mining, may have long-term ecological ramifications.

Factors Associated with Initiation of Chronic Renal Replacement Therapy for Patients with Kidney Failure

BACKGROUND AND OBJECTIVES Patients with kidney failure sometimes do not receive chronic renal replacement therapy (RRT), even though this may reduce their life expectancy. This study aimed to identify factors associated with initiation of chronic RRT. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This cohort study was conducted with Albertans aged >18 years between May 2002 and March 2009, using linked data from the provincial renal programs, clinical laboratories, and provincial health ministry. This study focused on those who developed kidney failure, defined by an estimated GFR (eGFR) <15 ml/min per 1.73 m(2) at last measurement during follow-up, together with prior CKD (eGFR <60 ml/min per 1.73 m(2) at least 90 days earlier). Multivariable Cox proportional hazards models were used to determine factors significantly associated with initiation of chronic RRT. RESULTS In total, 7901 participants had eGFR <15 ml/min per 1.73 m(2) at last measurement. After adjustment, older participants were less likely to initiate chronic RRT. Remote residence location, dementia, and metastatic cancer also decreased the likelihood of initiating RRT. The cumulative probability of initiating RRT during follow-up was 76.8% for urban-dwelling men aged <50 years without comorbidity, but was only 3.2% among remote-dwelling women aged ≥70 years with dementia and metastatic cancer. In contrast, patients with diabetes and heavy/severe proteinuria were more likely to initiate chronic RRT. CONCLUSIONS There is substantial variability in the likelihood of RRT initiation for patients with eGFR <15 ml/min per 1.73 m(2). Further studies are needed to delineate factors that influence this outcome.

Quality-of-care indicators among remote-dwelling hemodialysis patients: a cohort study.

BACKGROUND We hypothesized that the higher mortality for hemodialysis patients who live farther from the closest attending nephrologist compared with patients living closer might be due to lower quality of care. STUDY DESIGN Population-based longitudinal study. SETTING & PARTICIPANTS All adult maintenance hemodialysis patients with measurements of quality-of-care indicators initiating hemodialysis therapy between January 2001 and June 2010 in Northern Alberta, Canada. PREDICTORS Hemodialysis patients were classified into categories based on the distance by road from their residence to the closest nephrologist: ≤50 (referent), 50.1-150, 150.1-300, and >300 km. OUTCOMES Quality-of-care indicators were based on published guidelines. MEASUREMENTS Quality-of-care indicators at 90 days following initiation of hemodialysis therapy and, in a secondary analysis, at 1 year. RESULTS Measurements were available for 1,784 patients. At baseline, the proportions of patients residing in each category were 69% for ≤50 km to closest nephrologist; 17%, 50.1-150 km; 7%, 150.1-300 km; and 7%, >300 km. Those who lived farther away from the closest nephrologist were less likely to have seen a nephrologist 90 days prior to the initiation of hemodialysis therapy (P for trend = 0.008) and were less likely to receive Kt/V of 1.2 (adjusted OR, 0.50; 95% CI, 0.30-0.84; P for trend = 0.01). Remote location also was associated with suboptimal levels of phosphate control (P for trend = 0.005). There were no differences in the prevalence of arteriovenous fistulas or grafts or hemoglobin levels across distance categories. LIMITATIONS Registry data with limited data for non-guideline-based quality indicators. CONCLUSIONS Although several quality-of-care indicators were less common in remote-dwelling hemodialysis patients, these differences do not appear sufficient to explain the previously noted disparities in clinical outcomes by residence location.