As of June 2008, 720 million cubic metres of fluid tailings were being stored in Alberta.1
Tailings fluids are toxic to aquatic organisms and pose health concerns for human communities. Napthenic Acids are the major toxicant in oil sands tailings water. Other contaminants in tailings include, arsenic, mercury, polycyclic aromatic hydrocarbons.
Exposure of Naphthenic acid, by mammals, can have significant health impacts (including brain lesions, hemmoraging and liver damage).2 Water affected by processes in the petroleum industries generally contains 40-120 mg /L of Naphthenic acid. ground water is in the range from 0.4 to 51 mg /L which is considered to be in the range of toxicity to human consumption.3 A few mg/L are often observed in surrounding surface waters, un-impacted by process water.4
Incidences of elevated choloride, napthenic acids and ammonia in groundwater monitoring wells suggest current seepage of toxins into water supplies.5
Levels of contamination in surrounding aquatic ecosystems are supported by further assessments that conclude seepage of tailings ponds is occurring. In the most infamous of studies, a University of Waterloo research concluded that as much as 2l/s of pond seepage occurred through the foundation of the Tar Island Dyke pond and as high as 65 l/s seepage of dyke construction water occurred.6 Some estimates have concluded then that as much as 11 million litres/day of toxic, untreated tailings water is leaking into the Athabasca and surrounding tributaries and groundwater sources.7
Beyond regular seepage rates, there have been numerous documented spills of significant volumes tailings water directly into the Athabasca River and or surrounding tributaries (with inevitable impacts for regions groundwater). One such example occurred on September 27, 2007 when a significant spill of 4000 litres of tailings water occurred from the Albian Sands Shell Oil Sands Project.8 To date, there has been no publicized enforcement through Alberta’s Environmental Protection and Enhancement Act (EPEA) for this incident.
In addition to the known toxic contaminants, oil sands operations have consistent exceedences of total suspended solids (TSS) in water discharges. Syncrudes 2007 Waste Water Report to Alberta Environment, for example, reports excedeences of Alberta Environmental Protection and Enhancement Act (EPEA) approval limit at 198 mg/L (50 mg/L is approval limit). No publicly available EPEA Enforcement Action was issued for this incident.
Intensifying Water Quality Concerns in the Lower Athabasca River and Lake.
Given the above evidence of significant toxic leaks into the Athabasca river and tributaries, it is no wonder that downstream communities are becoming increasingly concerned about the health of their aquatic environments - environments that provide their staple food and water needs.
These concerns, however, are not ungrounded. There has been significant evidence of quality impact by the industry surrounding the lower Athabasca river. A few examples include,
The Health Canada general consumer guideline for mercury was exceeded in ~ 30 % of male and ~ 40 % of female walleye. The Health Canada subsistence fisher guideline for mercury was exceeded in all female walleye and ~ 70 % of male walleye. If the more stringent US EPA standards are applied, all walleye, all female whitefish and ~ 90 % of male whitefish exceeded subsistence fisher guidelines. These values constitute a human health concern.9
For example, on 11 June 1980, the concentration of dissolved arsenic in the Athabasca River mainstem near Ft. Mackay was 27 μg/L, 45 times the median arsenic concentration in the river.10 Across Canada, drinking water generally contains fewer than 5 μg/L of arsenic.11
This is by no means exhaustive and a review of the literature, reporting data, and incident data reveals a significant number of cases to elevate concern and require precautionary action for future development approvals in the region.