We show that the oil sands industry releases the 13 elements considered priority pollutants (PPE) under the US Environmental Protection Agency's Clean Water Act, via air and water, to the Athabasca River and its watershed. In the 2008 snowpack, all PPE except selenium were greater near oil sands developments than at more remote sites. Bitumen upgraders and local oil sands development were sources of airborne emissions. Concentrations of mercury, nickel, and thallium in winter and all 13 PPE in summer were greater in tributaries with watersheds more disturbed by development than in less disturbed watersheds. In the Athabasca River during summer, concentrations of all PPE were greater near developed areas than upstream of development. At sites downstream of development and within the Athabasca Delta, concentrations of all PPE except beryllium and selenium remained greater than upstream of development. Concentrations of some PPE at one location in Lake Athabasca near Fort Chipewyan were also greater than concentration in the Athabasca River upstream of development. Canada's or Alberta's guidelines for the protection of aquatic life were exceeded for seven PPE-cadmium, copper, lead, mercury, nickel, silver, and zinc-in melted snow and/or water collected near or downstream of development.oil sands mining | oil sands processing | trace metals | airborne deposition | water contamination

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Although the cyanobacterial toxin microcystin has been detected in Canadian fresh waters, little is known about its prevalence on a national scale. Here, we report for the first time on microcystin in 246 water bodies across Canada based on 3474 analyses. Over the last 10 years, microcystins were detected in every province, often exceeding maximum guidelines for potable and recreational water quality. Microcystins were virtually absent from unproductive systems and were increasingly common in nutrient-rich waters. The probable risk of microcystin concentrations exceeding water quality guidelines was greatest when the ratio of nitrogen (N) to phosphorus (P) was low and rapidly decreased at higher N:P ratios. Maximum concentrations of microcystins occurred in hypereutrophic lakes at mass ratios of N:P below 23. Our models may prove to be useful screening tools for identifying potentially toxic “hotspots” or “hot times” of unacceptable microcystin levels. A future scientific challenge will be to determine whether there is any causal link between N:P ratios and microcystin concentrations, as this may have important implications for the management of eutrophied lakes and reservoirs.

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Models were developed for Norway spruce, Sitka spruce, Scots pine, Pedunculate Oak and European Beech to predict the biomass of individual structural roots based on either basal root cross sectional area (rCSA) assessments (basic models) or on rCSA and additional root architectural measurements (multiple models). The material embraces 1257 roots from 337 trees derived from 33 stands. The soil types of the investigation cover sandy podzols, sandy moraine, brown earth, deep peat, and pseudogley, but all species were not represented on all soil types. The models were developed for stands in three dimension classes depending on the average diameter of the stands and for horizontal roots (angle to the surface less than 45°) and vertical roots (angle to the surface greater than or equal to 45°), respectively. Simple models using rCSA near the stump to predict coarse root biomass (logarithmic models) did not account for stand differences in Norway spruce and Sitka spruce. To eliminate these differences, it was necessary to include root taper and vertical root parameters in the models. Variation between stands concerning the regression between rCSA and root biomass was not found for Pedunculate Oak, Scots Pine or European Beech, but the number of stands of these species was also limited compared with Norway spruce and Sitka spruce.

ObjectiveUsing a summary measure of health inequalities, this study evaluated the distribution of adverse birth outcomes (ABO) and related maternal risk factors across area-level socioeconomic status (SES) gradients in urban and rural Alberta, Canada.DesignCross-sectional study using a validated perinatal clinical registry and an area-level SES.SettingThe study was conducted in Alberta, Canada. Data about ABO and related maternal risk factors were obtained from the Alberta Perinatal Health Program between 2006 and 2012. An area-level SES index derived from census data (2006) was linked to the postal code at delivery.ParticipantsWomen (n=3 30 957) having singleton live births with gestational age ≥22 weeks.Primary and secondary outcome measuresWe estimated concentration indexes to assess inequalities across SES gradients in both rural and urban areas (CIdxRand CIdxU, respectively) for spontaneous preterm birth (PTB), small for gestational age (SGA), large for gestational age (LGA), gestational hypertension, gestational diabetes, smoking and substance use during pregnancy and pre-pregnancy weight >91 kg.ResultsThe highest health inequalities disfavouring low SES groups were identified for substance abuse and smoking in rural areas (CIdxR−0.38 and −0.23, respectively). Medium inequalities were identified for LGA (CIdxR−0.08), pre-pregnancy weight >91 kg (CIdxR−0.07), substance use (CIdxU−0.15), smoking (CIdxU−0.14), gestational diabetes (CIdxU−0.10) and SGA (CIdxU−0.07). Low inequalities were identified for PTB (CIdxR−0.05; CIdxU−0.05) and gestational diabetes (CIdxR−0.04). Inequalities disfavouring high SES groups were identified for gestational hypertension (CIdxR+0.04), SGA (CIdxR+0.03) and LGA (CIdxU+0.03).ConclusionsABO and related maternal risk factors were unequally distributed across the socioeconomic gradient in urban–rural settings, with the greatest concentrations in lower SES groups of rural areas. Future research is needed on underlying mechanisms driving SES gradients in perinatal health across the rural–urban spectrum.

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