3 The Science and Industrial Research Council of Alberta (SIRCA, later to become the Alberta Research Council), was formed in 1921, and given primary responsibility for development of the oil sands. Dr. Karl Clark of SIRCA devised a method for large scale extraction of bitumen from the sands using sodium hydroxide and hot water, which has become the basic process for separating bitumen from sand in the deposits of the area described by Miall (2013a). Clark patented the process in 1929. Between 1930 and the late 1950s, large-scale extraction experiments were undertaken at a site on the Athabasca River called Bitu-mount, 89 km north of Fort McMurray (Humphries 2008). Bitumount is now a provincial historic site. The first large-scale industrial development occurred when the Great Canadian Oil Sands (later to become Suncor) began operating in 1967, producing 12,000 barrels of bitumen a day. It was followed by Syncrude, a consortium of several oil companies, plus the Canadian, Alberta and Ontario governments, in 1978 (Humphries 2008). There is no public record of any substantive concerns about effects on the environment during these early phases of development.

17 One frequent criticism of aquatic monitoring in the oil sands region is that true cumulative effects studies have not been done. Several recent studies have attempted to do so, but have been hampered by the inadequacies in the publicly available data, for reasons outlined above. Squires et al. (2010) and Dubé and Wilson (2013) examined the few reliable long-term data for the river. They found that long-term increases in total phosphorus, conductivity, sulphate and total dissolved nitrogen have occurred in the lower Athabasca River during the period of record, but it is not clear how much of the increases were caused by climate change vs industrial or other human activity. It seems likely that sewage releases from municipalities in the watershed, most notably Fort McMurray (population over 73,000 and growing rapidly), are one important source of phosphorus. Work camps on new oil sands sites under construction contain another 40,000 people. Also, pulp mills in the basin now add nutrients to their effluents to promote removal of biological oxygen demand and decomposition of undesirable chemicals. Because the river is enclosed by ice and snow for about 5 months of the year with low flow volume, oxygen depletion is of some concern for fish populations.

18 The extent that oil sands pollutants have harmed the mainstream Athabasca River remains controversial, but appears to be low, except for the few instances described below. However, continued rapid expansion is predicted to double the impact of the industry in the next 10 years, and the lack of reliable baseline data causes continued concerns. Recent improvements in monitoring are rapidly resolving some of the issues. Given the huge deficiencies in past monitoring described above, paleolimnology will be needed to provide a temporal and spatial record of patterns of past contaminant dispersion in the oil sands region, as exemplified by Kurek et al. (2013), discussed later.

20 Mercury in fish of the Athabasca River is a recognized threat to subsistence consumers. Studies as early as 1975 by Environment Canada showed that mercury in predatory fish of the river and adjacent Lake Athabasca was high even before major oil sands development. Donald et al. (1996) found that 25% of walleye Sander vitreus exceeded consumption guidelines for subsistence consumers, causing Alberta Health to issue a consumption advisory for the species. It is currently recommended that pregnant or nursing women eat no more than 150 g a month, children 1–4 eat less than 75 g a month, and that adults eat no more than 75 g per week of walleye, where 75 g is regarded as an average meal. A recent (2008) data set shows that consumption of northern pike Esox lucius and goldeye Hiodon alosoides should probably be similarly restricted, because the proportion of walleye, goldeye, and northern pike exceeding previous consumption guidelines for subsistence users (0.2 µg/g) was 80%, 72%, and 75%, respectively (Radmanovich 2013). At this point it is not clear whether the higher recent incidence of mercury exceedances for walleye than reported by Donald et al. (1996) is a real increase, or an artifact of methodology. It is under investigation. Fortunately, mercury in the most frequently eaten species, lake whitefish, Coregonus clupeaformis, remains well below consumption guidelines for subsistence users.

21 It is clear that mercury input to the area has increased due to the oil sands industry. The National Pollutant Release Inventory (NPRI) shows a seven-fold increase in upgrader emissions between 2001 and 2010, and mercury concentrations in snow averaged 5.5 fold higher within 50 km of upgraders than it did beyond that radius in 2008 (Kelly et al. 2010; Kirk et al. 2012). Mercury was also significantly higher in river water near or downstream of development, in both tributaries and the Athabasca main-stem, and in invertebrates and fish near to or downstream of development (Kelly et al. 2009; Radmanowich 2013). It is, however, noteworthy that even the most recent reported releases from oil sands upgraders appear not to be as high as from coal-fired power plants near Wabamun Lake, Alberta, (387–732 kg/a from 2000 to 2010) or near the base-metal smelter near Flin Flon, Manitoba, where almost 20 000 kg/a of mercury were emitted before the smelter was closed (CTV News Release, June 18 2010: http://winnipeg.ctvnews.ca/flin-flon-smelting-plant-closure-affects-residents-jobs-and-air-quality-1.524125).

22 The extent to which the oil sands industrial emissions have contributed to increased mercury in fish of the Athabasca River is not clear. Timoney and Lee (2009) analyzed three earlier studies, and reported increases in mercury in walleye from 0.32 µg/g in 1975 to 0.36 µg/g in 1992, then to 0.41 µg/g in 2005. This conclusion was disputed by Evans and Talbot (2012), who pointed out discrepancies in methods between earlier studies. Evans and Talbot (2012) examined more data sets, including RAMP’s, concluding that there was no significant change in mercury over time, but many small sample sizes, inconsistencies in sampling and analytical protocols between different studies also hindered their analysis. However, Radmanowich (2013) found a mean of only 0.36 µg/g in 20 walleye collected in 2008.

23 Hebert et al. (2011) found that mercury in tern eggs collected on islands near the Athabasca River’s mouth in Lake Athabasca contained 40% higher mercury in 2005 than in 1977. The 2005 eggs also contained high concentrations of naphthalene, which suggests that the source is connected with industrial oil sands development. It seems unlikely that mercury would increase in fish-eating birds if it did not also increase in the fish that birds fed upon. Until results from more comprehensive monitoring are available, the extent to which industrial input has contributed to elevated mercury in fish of the area remains controversial. It is, however, clear that concentrations of mercury in at least three species of fish frequently consumed by First Nations are high enough to warrant concern about subsistence of indigenous people in the area.

24 Despite elevated deposition near the upgraders, less than 4% of mercury emissions reported by NPRI can be accounted for within 50 km of the plant (Kelly et al. 2010). It is well known that long-range transport in the atmosphere causes global dispersal of mercury, and that human activities have increased the global background in the atmosphere by about threefold, with about equal thirds from natural sources, re-emissions of mercury mobilized by humans in earlier times, and annual direct emissions (http://www.epa.gov/hg/control_emis sions/global.htm). Global sources of mercury are still increasing rapidly, particularly in Asia, leading to recent calls for an international treaty to limit emissions (Qiu 2013), which was signed in February 2013.

25 Studies elsewhere have indicated that increasing airborne inputs of mercury will significantly increase concentrations in fish. In a whole water-shed experiment known as METAALICUS, Harris et al. (2007) added a small amount of a distinct stable isotope of mercury to a small lake at the Experimental Lakes Area, northwestern Ontario. The added isotope was reflected in concentrations in fish within a few months. Rapid transfer in the food chain was confirmed by mesocosm experiments in another lake (Orihel et al. 2007). Other distinctive isotopes of the mercury were added to wetlands and uplands in the lake’s catchment. Leakage from wetlands to the lake were very slow, and those from uplands undetectable, although upland mercury has been found to be mobilized during forest fires, which on average only occur once in several decades (Kelly et al. 2006). More recent data from METAALICUS have shown that once mercury inputs to an ecosystem are reduced, concentrations in fish also decrease rapidly, suggesting that the biogeochemical cycle of mercury in aquatic systems is dominated by the past few years of input (J.W.M. Rudd, pers. comm. November 2012). This further suggests that reducing atmospheric mercury will have rapid benefits for fisheries in the Athabasca River, but it is unclear whether reductions must go beyond the oil sands industry. To add to the concern in the oil sands region, Kirk et al. (2012) indicated that part of the particulate-bound mercury in snow of the area is already in methyl mercury form, making it highly susceptible to biological uptake immediately on entering lakes and rivers.

26 Polychlorinated dioxins and furans (PCDDs and PCDFs) were discovered to be unwanted by-products of using chlorine to bleach paper pulp in the 1980s. The compounds biomagnify in food chains, so that even small amounts in water can result in high concentrations in predatory fish. Concentrations in predatory fish in some reaches of the Athabasca River were high enough that a consumption advisory was issued for several species in the early 1990s. Following new federal regulations in 1992 that required pulp mills to use chlorine dioxide instead of free chlorine for bleaching, concentrations in fish of the Athabasca River began to decline. As a result, dioxins and furans have now declined to values where consumption advisories for fish have been lifted (McMaster et al. 2006).

27 One surprise finding from the NRBS studies was that polychlorinated biphenyls (PCBs) were also elevated near several pulp mill sites. In the nearby Wapiti River, a tributary to the Peace River, a pulp mill was identified as the source of PCBs, but on the Athabasca River, the combined municipal sewage/mill effluent at the town of Hinton, AB, added little to high concentrations found upstream of the effluent, and the source is not known. Concentrations of PCBs did not decline during the NRBS/NREI studies, and remain an issue of concern, although as of 2004, concentrations did not exceed guidelines in any area (McMaster et al. 2006). As in the case of dioxins and furans, biomagnification in food chains can result in high concentrations of PCBs in fish. Several widespread organochlorine pesticides, including toxaphene and DDT, have also been detected in fish, but in trace quantities (McMaster et al. 2006).

28 Polycyclic aromatic compounds (PACs) are currently one of the greatest concerns for chronic pollution in the oil sands, given their prominence in bitumen. The chemistry and toxicity of most PACs is poorly known, and there are hundreds of such compounds formed in both biomass burning and fossil fuel production and consumption. Most familiar are the polycyclic aromatic hydrocarbons (PAHs). A number of well-studied PAH congeners are on the US Environmental Protection Agency’s (EPA) priority pollutant list, because they have carcinogenic, mutagenic or teratogenic properties, cause immunosuppression, and cause a number of other health effects in animal populations (US EPA Fact Sheet: http://www.epa.gov/osw/hazard/wastemin/minimize/factshts/pahs .pdf). The toxicity of most other congeners, and related alkylated PAHs and dibenzothiophenes, both common in oil sands, is unknown. In the oil sands, alkylated PAHs are most prevalent, and the toxicity of this group is particularly poorly known, especially their carcinogenicity to humans (Baird et al. 2007). Also very common in the area and poorly understood are dibenzothiophenes, which have some sulphur atoms within their aromatic structure. Some PACs have been implicated in impairing the cardiac development of fish embryos, as well as a variety of morphological effects and impaired swimming performance (Incardona et al. 2004, 2011; Hicken et al. 2011). Canadian Water Quality Guidelines do not provide guidelines for alkylated PAHs in sediments (CCME 1999).

29 In many boreal areas, including the oil sands, pyrogenic sources (forest fires, products of internal combustion engines, etc.) are difficult to separate from petrogenic (originating in fossil fuels) sources. Most often, values for all congeners are simply summed and reported as ‘Total PAHs.’ Few individual compounds have been tested, despite their having a considerable range of toxicities (Incardona et al. 2004). As a result, it is difficult to make comparisons between sites with different mixtures of compounds, and statements like “total PAHs are higher in urban areas than in the oil sands,” which are popular with industry propagandists, can be highly misleading. Badly needed are studies of the toxicity of single polycyclic compounds, and known mixtures that represent the sources of concern (Baird et al. 2007).

30 We (Kelly et al. 2009) found that PACs, predominantly alkylated PAHs and dibenzothiophenes, were detectable in snow near industrial oil sands development, with concentrations highest near the upgraders that use coke as a fuel. Airborne emissions probably represent a combination of compounds formed in combustion of coke (which is produced on site from bitumen) and chemicals in raw bitumen that are volatile at the high temperatures used to upgrade the bitumen. Concentrations above background values were found in snow for a 50 km radius around the major upgraders near sampling site AR6 (Kelly et al. 2009), with the greatest proportion in particulate, rather than dissolved form. We also found that concentrations of PACs in the Athabasca River and its tributaries were higher near to or downstream of industrial development, including watershed disturbances (Kelly et al. 2009).

31 In lakes isolated from the river system, the degree of industrial contamination has been easy to determine, once sufficiently comprehensive studies were undertaken. Using paleolimnological methods Kurek et al. (2013) studied the long-term record of PAC contaminants in dated sediment cores from six lakes at varying distance from the oil sands upgraders. The six study lakes were in undisturbed, isolated basins, so that the only possible source of increasing contaminants was from airborne industrial emissions. The authors used a multiple chemical ‘fingerprinting’ technique to distinguish petrogenic industrial sources from natural pyrogenic sources such as forest fires. They found that industrial oil sands sources were responsible for increasing concentrations of PACs in sediments in lakes up to 95 km from sources, beginning with development of the oil sands industry. Only one lake had PAC concentrations of concern at present, although with projected rates of oil sands expansion, some have expressed concern that PAC concentrations may be reached in sediments that could exceed guidelines set by the Canadian Council of Ministers of Environment (Hodson 2013). This possibility must be more thoroughly examined. There was no indication of increased toxicity to Daphnia in the fossil record (at least to date), likely due to the greater influence of recent climate change on lake primary production of algae (the food resource of Daphnia). Jautzy et al. (2013) reported similar conclusions on the extent and source of PAH contamination.

32 PACs are generally hydrophobic, and those with lower molecular weights tend to be acutely toxic because of their higher water solubility. Their concentrations dissolved in water remain very low, seldom over a few parts per billion for individual congeners, even when input of PACs to the ecosystem is quite high. PACs in solution quickly attach to organic particles. The result has been public confusion caused in part by industry reporting that dissolved concentrations of PACs are very low, not mentioning that 90% and more of the compounds are in the suspended particulate fraction. As a result of their hydrophobic nature, toxicity of PACs to aquatic organisms is often seen first in species that are in contact with bottom sediments, such as the eggs and embryos of fish, and benthic insects, crustaceans and molluscs.

33 While it is widely agreed that erosion of natural bituminous out-crops has been an important source of PACs to sediments of the Athabasca River, some studies have concluded that industrial development has caused significant increases in PAC concentrations in river sediments (Timoney and Lee 2011), while others have concluded the opposite (Hall et al. 2012). However, the latter study was based on the paleolimnology of two lakes well outside the known range of contamination by atmospheric emissions from oil sands sources, and with a variable history of connection to the river. Another problem with detecting increases in contaminants from industrial sources is that the contaminated sediments in rivers are usually deposited in fairly localized areas. If those depositional areas are frequently used by fish, a ‘hotspot’ for contaminant impact occurs (Choy et al. 2008; Fowlie et al. 2008). Unfortunately, due to inadequate monitoring, in the Athabasca River the correspondence between depositional areas for contaminants and fish habitat is still poorly known. Older studies show that concentrations of contaminants in tributary sediments are much higher than in the main stem Athabasca River, which is not surprising given the large upstream areas of the main stem where sediments are not from petroliferous deposits (Headley et al. 2001). Tributaries are key regional fishery spawning areas (Bond and Machniak 1979; Machniak and Bond 1979) and also the areas where water-shed disturbance from mining is highest, making them the most likely sites of industrially caused biological effects. In this regard, studies of fish embryos lead to some interesting hypotheses. It sometimes seems forgotten that the larger tributaries are important sources of fish to the entire Athabasca system, rather than just conduits for water and pollutants. Several thousand fish per year use each of the larger tributaries in the oil sands area (Bond and Mach-niak 1979; Machniak and Bond 1979). As for mercury, resolution of the degree of industrial contribution and its effect on biota must await more detailed study.

34 Several other trace metals are high enough to be of concern in the oil sands area. These include zinc, lead, arsenic copper, cadmium, thallium and vanadium. All are present in bitumen, and all are released in increasing amounts from upgrader emissions (Kelly et al. 2010). However, at present, not enough is known of natural sources or concentrations in biota to indicate whether increased industrial activity will cause problems in the near future. Also of concern is that it is not known whether chronic exposure to the ‘cocktail’ of low concentrations of organic and inorganic contaminants represented by waters in the oil sands area is harmful to fish or other organisms. Hopefully, the proposed improved monitoring program will yield such information quickly.

35 Concerns have been expressed about naphthenic acids (Lo et al. 2006), which are very high in water used for oil sands extraction, and are acutely toxic. Concentrations of concern are not reached outside of tailings ponds, as would be expected from low rates of seepage (Miall 2013b). The main concern would be for a large release to the river, as described below.

36 Several species of fish in the Athabasca River and western Lake Athabasca have high incidences of malformations, including tumours, hematomas, mouth and eye defects, and spinal abnormalities. RAMP has reportedly observed that from 2 to 7 percent of its annual catch has displayed malformations, growths or diseases since 1997 (Globe and Mail News Release, December 2010: http://www.theglobeandmail.com/news/politics/ottawa-kept-in-dark-on-abnormal-fish-found-in-oil-sands-rivers/article1320694/), an incidence reminiscent of industrially contaminated sites in the lower Great Lakes (Smith et al. 1994; Baumann et al. 2000). Indigenous fishermen say that such malformations did not exist in the Athabasca River before the 1980s. This claim receives support from McCart et al. (1982), who examined over 19,000 lake whitefish in the river in 1980, reporting no incidence of malformations, despite one purpose of their study being to record evidence of fish disease (P. McCart, pers. comm. November 2012). Similarly, there is no mention of malformations in reports from AOSERP studies in the late 1970s, where thousands of fish were handled through fish counting fences on tributaries by experienced fisheries biologists. I have personally caught several hundred lake trout, pike and walleye in central Lake Athabasca and interviewed several long-term fishing guides. There is no evidence of malformations or growths except in the western end of the lake near the mouth of the Athabasca River.

37 It is likely that the malformations observed in adult fish developed when fish were in embryonic stages. Colavecchia et al. (2004, 2006, 2007) found a high incidence of mortality in embryos of fathead minnows Pimephales promelas and white sucker Catostomus commersoni hatched in the laboratory on sediments rich in oil sands bitumen. Among surviving embryos, a high proportion were malformed, with deformities similar to those found in adult fish from the system. It has generally been assumed that impaired growth and swimming ability will cause decreased probability of survival of embryos, but enough may reach adulthood to be caught by human users.

38 After hatching upstream of Fort McMurray or in suitable tributary reaches, fingerling whitefish and gold-eye migrate downstream to Lake Athabasca, where they do most of their feeding and growing in the lake environment (McCart et al. 1982). It is conceivable that the malformed adult fish do not contain high levels of industrial contaminants, but their grotesque appearance leads indigenous people to avoid eating them.

39 A similar broad range of malformations has been observed in fish of the Gulf of Mexico following the Deepwater Horizon oil spill. A wide variety of laboratory studies suggest that the mechanism may be immune system depression following exposure to PAHs, which leaves fish open to a wide variety of waterborne diseases, of bacterial, fungal and viral origins (James H. Cowan Jr., pers. comm. 5 April 2013).

40 At present, data on fish populations in the Athabasca River and its tributaries are not thorough enough to be able to tell whether there have been long-term declines in fish habitat and production, let alone whether pollutants have caused population-level effects. One period of particular concern is during spring snowmelt, when acids and toxins accumulated for 4–5 months are flushed into tributaries within a few weeks. Melting snow is known to be low in conductivity because of low base cation concentrations, but, industrial emissions can contaminate it with high concentrations of strong acids and toxins (Schindler et al. 1981). The combination of dilution (which probably varies considerably, based on snowpack and speed of melting) and high hydrogen ion input leads to significant acid pulses (Galloway et al. 1987). While data for the oil sands region are few, significant pH depressions of up to two units were recorded already in 1990. At the time, low conductivity indicated that some tributary waters contained up to 80% melted snow (Schindler 1996; Fig. 2). Emissions of sulphur and nitrogen oxides have at least doubled since 1990, when those data were obtained. Significantly, recent studies have shown that melted snow near the oil sands plants is toxic to fish embryos, even when diluted with synthetic river water by 3:1 (Parrott et al. 2012). Our low conductivity data (Fig. 2) show that the proportion of melt-water in tributaries is much higher than this, i.e., conditions are toxic for fish embryos. However, Parrott et al. (2012) reported that the melted snow was not toxic to Gammarus. Gerner et al. (2012) indicated that sensitive benthic organisms declined when PAH load increased in the river system. This conclusion was supported by Shell’s 2012 impact assessment, which reported that sensitive species of benthos had declined in the Muskeg River, from the time of the earlier AOSERP studies on that river (Barton and Wallace 1980). The Muskeg is currently the major tributary most impacted by oil sands mining. It is noteworthy that in the Muskeg River, one of the larger tributaries that is undergoing heavy development in its watershed, grayling Thymallus arcticus were reasonably abundant in the 1970s (Bond and Machniak 1979) but are now rare (Shell Canada 2007).

45 Although recent regional aquatic monitoring studies in the lower Athabasca River area have been greatly improved, not enough results have been reported so far to be able to say conclusively to what extent biota of the river system has been affected or whether there are dangerous trends occurring in the concentrations of chemical toxins. It is essential that a well-designed, modern water-monitoring program be maintained that is capable of detecting trends in pollutants well before damage to the ecosystem has been done, allowing preventive, rather than remedial, action to be taken. In order to regain the trust of indigenous people and other stakeholders, including Canadian citizens, the monitoring must be managed in a transparent science-based, independent manner, as recommended by AEMP (2011) and the subsequent AEMWG (2012). The costs for independent monitoring should be borne by industry, rather than as they are now, by Canadian and Albertan taxpayers. This could easily be accomplished by a surcharge of a few cents on each barrel of oil produced and/or a charge against oil sands leases (AEMWG 2012), which would prevent monitoring from being downgraded at the very time industry is expanding, which has been the case in the past. A good model for this program is the Northern River Basins Study, which was successful in both monitoring and building public trust and consensus in the 1990s (NRBS 1996).