Athabasca River

The Athabasca deposits have been known since the early 1800s. The first scientific iaterest ia tar sands was taken by the Canadian government ia 1890, and ia 1897—1898, the sands were first drilled at PeHcan Rapids on the Athabasca River. Up until 1960, many small-scale commercial enterprises were attempted but not sustained. Between 1957 and 1967, three extensive pilot-plant operations were conducted ia the Athabasca region, each leading to a proposal for a commercial venture, eg, Suncor and Syncmde. 

The geological stratification of the Athabasca deposit is presented in Figure 2. As with most rivers in this region of Western Canada, the Athabasca River has gouged a deep river valley, exposing the oil sands deposits along its banks. On warm days the bitumen oozes from the river banks and eventually works its way to the water line. Native Indians used this bitumen, mixed with spruce gum, to patch their canoes. 

Distribution Native range was eastern Pacific Ocean and the freshwater, mainly west of the Rocky mountains, from northwest Mexico (including extreme northern Baja California), to the Kuskokwim River, Alaska Probably native in the drainages of the Peace and Athabasca rivers east of the Rocky Mountains. Has been widely introduced throughout North America in suitable localities. Also introduced into New Zealand, Australia and Tasmania, South America, Africa, Japan, southern Asia, Europe, and Hawaii. 

Early use of petroleum or mineral oil, as distinct from animal or plant oils, was achieved by direct harvesting of the crude product from surface seeps and springs. For example, tar obtained from the Pitch Lake (La Brea) area, Trinidad, has been used for the caulking of ships since the Middle Ages and is still marketed to the extent of about 142,000 tonnes per year [1], Tar from the Alberta tar sands was used in the 1700s by Cree Indians of the Athabasca river area to seal their canoes, as recorded by Peter Pond. Also a thick bituminous gum was collected from the soil surface near the St. Clair River in Southern Ontario [2], and from Guanoco Lake, Venezuela [3], and these too were marketed for a range of purposes. 

Thus, tailings disposal requires a larger hole than that from which the tar sand originated or the level of the land will/must be raised at site abandonment. Until a satisfactory means of clay settling can be achieved that will allow reuse of the water, the tailings ponds will grow in size with the life of the plant. Currently, a recycle stream from the tailings ponds produces some 40-60% of the daily water requirements of the tar sand plants the remainder is makeup water from the nearby Athabasca River. 

The main sources of inorganic ions found in tailings water are (1) oil sand connate water (water in the spaces between the sand grains), (2) makeup water taken from the Athabasca River for use in plant processes, and (3) chemicals added during hot water extraction and other processes. These sources contribute ions that accumulate in the pond water that is recycled to oil sands processing. 

Kupchanko, E. E. Preliminary Compatibility Studies of GCOS Sand Tailings Pond Water with Athabasca River Environmental Health Services Division Report Alberta Department of Health Canada, 1968. 

Even the contact between natural waters and exposed oil sands with erosion through the McMurray Formation will result in the release of low background levels into the waters of the area. In Figure 35(a), the results for water samples taken from the main stem Athabasca River (upstream, within and below the main oil sands deposit around Fort McMurray, in northeastern Alberta) and several tributaries in the deposit area, show low but measurable levels of naphthenic acids being observed. When compared to the levels of naphthenates found in the process waters and those influenced by them, the levels present in the process-affected waters are much higher. As one proceeds from the extraction tailings, to the tailings... 

Figure 35. Naphthenic acid concentrations and toxicity (Microtox 1C20) for (a) waters collected along the Athabasca River (from about 100 km upstream of Fort McMurray to the delta of Lake Athabasca), and (b) various waters at Syncrude s Mildred Lake Site. With time, the original toxicity and naphthenic acid levels in the fresh process waters (PW, SP) show a steady decrease when removed from fresh input of tailings (SS, 1, 3, and 5 years). Levels in the Athabasca River represent natural surface waters.

A huge potential source of sulfur in Canada exists in the extensive deposits of bituminous sands along the Athabasca River in Northern Alberta...It is estimated that a 20,000-barrel-per-day bitumen plant would result in the recovery of about 140 tonnes... 

Substantial quantities of hydrocarbons may be released to the environment from natural deposits of oil, heavy oil, shale oil, and bitumen. Although such discharges generally have no detectable effect on residue levels in the oceans, there may be significant accumulation of hydrocarbons in certain fresh waters. One example is the Athabasca River in northern Canada, where oil... 

Figure 7.5. Concentration of oil and grease in the Athabasca River, Alberta, Canada. (From Naquadat, 1976-81.)...

The natural background level of hydrocarbons in sediments is extremely variable, ranging from 1 to >500 mg kg" Low levels are generally found in offshore marine areas while localized hydrocarbon deposits can produce large residues in some fresh waters. For example, Strosher and Peake (1979) reported a maximum concentration of 943 mg kg in the sediments of the Athabasca River upstream of the mining operations. This level is comparable to that found in various estuaries and bays receiving waste from refineries and heavy industry. However, in the aftermath of oil spills, residues have exceeded 5000 mg kg ... 

Strosher, M.T., and E. Peake. 1979. Baseline states of organic constituents in the Athabasca River system upstream of Fort McMurray. Prepared for the Alberta Oil Sands Environmental Research Program by Environmental Sciences Centre (Kananaskis), The University of Calgary. AOSERP Report 53, 71 pp. 

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