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Report: Oil Sands Tailing Ponds Leaking Some 11M Liters per Day

Oil sands tailing ponds are leaking more than 11 million liters of contaminated tailings water per day—more than four billion liters (1.056 billion gallons US) per year—into the groundwater in Canada, according to a report derived from industry data by Environmental Defence.

The current leakage rate of contaminated water from Tar Island Dyke into the Athabasca river is estimated to be almost 6 million litres a day. Click to enlarge.

The report, 11 Million Litres a Day: The Tar Sands’ Leaking Legacy, calculates that the addition of new oil sands projects could increase this number to 72 million liters a day, or more than 25 billion liters a year, in the next decade.

Tailings ponds contain toxic contaminants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids. Naphthenic acids in particular break down very slowly and therefore pose a long-term threat to the groundwater of the region. The tailings ponds sit upriver from the Peace-Athabasca Delta, one of the world’s largest inland freshwater deltas and home to Fort Chipewyan, where residents already have serious concerns about pollution and their health.

Tailings ponds are built on bare ground with walls made out of earthen materials. Companies deploy measures to capture some of the leakage from the ponds, but these measures are imperfect, the report says. Company applications for new projects admit that leakage is lost to the groundwater, and these applications were used to arrive at the overall leakage rate.

This study uses industry information to estimate what the overall leakage rate is for tar sands tailings ponds both now and into the future. This information is estimated on a project-specific basis by companies in their project applications, but it has never been publicly put together to come up with an overall leakage rate.

Environmental Defence contracted Pembina Corporate Consulting to calculate the figure. Based on the companies’ own data, Pembina produced several scenarios for leakage rates using different assumptions. Environmental Defence says that it chose a conservative scenario:

  • Wherever it exists, Pembina used the specific company information on leakage rates.

  • Where companies did not provide this information, Pembina applied an average leakage rate calculated using the numbers from the companies that did. These averages were applied on the basis of leakage per barrel of bitumen proposed to be produced.

  • Benefit of the doubt was given that tailings ponds largely “self seal” over time, and it was assumed that all ponds largely self seal after 18 years, but that some leakage still occurs. Pembina estimated that sealed ponds leak 85% less than un-sealed ponds.

  • Due to lack of information, it was assumed that existing ponds have largely “self sealed,” even though this is probably untrue and therefore under-estimates the current leakage rate. Tar Island Dyke, though, is a special case, and Pembina applied the leakage numbers calculated by the University of Waterloo, but assumed that leakage from Tar Island Dyke would reduce to a long term ‘normal’ leakage rate after 5 years.

  • The numbers were added together on an annual basis, using start-up dates and production numbers provided by the companies, and therefore arriving at overall leakage rate by year.

  • The final overall leakage rate is what escapes from the ponds after recovery steps have been taken. In other words, this is the leakage that the companies don’t catch.

Both Alberta and federal legislation prohibits the discharge of toxic materials into the environment, but tailings ponds leakage is sanctioned by the Alberta permitting process. The report calls on the Canadian government to enforce the federal Fisheries Act to end the leakage problem.




Since the calculations are mostly based on producers' (polluters) supplied data, it is fair to conclude that it represents only the tip of the iceberg.

The truth is probably 10 to 20 times that much.

The self sealing claim, in 18 years or less, should also be seriously chalenged. With many toxic ponds very close to the river, leaks are unavoidable and will pollute the river for generations.

What a mess for future generations to attempt to fix.

Fortunately, with the future transition to electrified vehicles + the current long lasting economic turmoils, many new and expansion projects will be delayed or cancelled.


The cost of cleaning up this epic disaster must be added to the basis price of the oil extracted. It would quickly become clear that this is not a viable project, especially at under $50/barrel.

This is a perfect illustration of why true-cost-pricing and mandatory tracking of unpaid externalities is a must for production of all natural resources.

When we figure this out, we'll have seen the last of such environmental disasters (which are really disguised financial boondoggles of the highest order--essentially loans taken out against future generations).

Henry Gibson

There are many places in the world where rain water runs through natural accumulations of petroleum deposits as well as coal deposits. This raises the question if the leakage from the ponds is any less natural or different in content. Many people who are objecting to the oil sands projects continue to use oil and coal either directly or indirectly. The conditions under which the oil that they use is produced is relatively unknown. People can deal only with those companies that operate in a manner that they approve of and pay the price. How about certified organic ethanol for your car?

Absolutely nothing can be done perfectly, and the morbidity on the motorways and from the use of tobacco proves that civilization will tolerate a great deal of imperfection.

A big part of the truth is that people use stuff and they do not scrutenize where it comes from. Yes the oil companies want to make money, but the oil companies sell oil to the public. The public needs cheap energy in order to survive. Is making money by trading in dirivatives "greener" than coal mining.

Another big part of the truth is that there are vast tracts of land that are being farmed. These lands had very few people on them, but the question arises is it damaging of the environment to operate these farms. The answer is yes of course, but the real question is how much damage should be allowed. And who says how much.

Now that oil prices are low there is even less incentive to save the fuel values in the tailings ponds. It is well known that ther are micro-organisms that will eat almost ever chemical found in natural petroleum.

Undeground petroleum spills can be removed by feeding bacterial populations in the soil with a gas like butane until the populations are so large that all hydrocarbons are eaten up.

During the canal building era, the puddling technique was invented to reduce or perhaps mostly eliminate leakage from the canals. This material was some combination of clay and sand worked together. Bentonite is a clay that can expand and stop much leakage.

During the processing phase of bitumen recovery, the sands are heated, and if they are heated to a higher temperature after much of the bitumen is removed, the sand can be exposed to oxygen to oxidize the remaining organics to acetic acid and related compounds. Heat is produced in this process and may be used for other parts of the processing. The acetic acid can then be processed into acetone and other fuels.

It is now the responsibility of Bill Gates and Warren Buffet or others like them to make very good use of the moneys that they amassed. They should build an island beyond the jurisdiction of any US court or buy a small country such as Nauru. It has been proposed that the entire population of Nauru be moved to fertile islands since they destroyed the entire interior with mining.

Nothing would improve the health and prosperity of the children of the world more than building several nuclear reactors in Nauru for the purpose of making fuel and fertiliser. The cost of building the reactors can be quite low and the construction quite fast because there are large companies in the world just right ready for construction without public inteferrence. The first export would be liquid ammonia which can be burned as fuel or used as fertilizer. The next product would be solid ammonium nitrate for fertilizer. It is possible to get carbon dioxide out of ocean water and it could be used with hydrogen to make methanol that can then converted to gasoline.

It is far easier to deal with one pound of fission products than it is to deal with the CO2 and the ash and organics from three million pounds of coal. ..HG..



Alberta could ban expansion of open mining extraction and mandate the 'in situ' method for all future sites. A dozen (or more) nuclear reactors may be required to produce all the heat and electricty needed.

Of course, a very large clean up fund should be set up to clean the existing and future toxic mess.

We all know that Alberta will not do it. $$!!&&$$.

Vehicles progressive but accellerated electrification may be the best way to go. Lead batteries are much too heavy to move around. A decent PHEV would need almost 100 Kg of batteries and BEVs even more.

Advanced future batteries will be 5 to 10 times lighter. Price will come down 5+ folds with mass production and improved design using cheaper materials.



make that 1000 Kg of lead batteries.

Dan A

While in general I'm skeptical of the current generation of nuclear power (mostly in terms of cost), it seems to me that Alberta would be a case where it makes sense IMO, because not only do you have a massive need for electricity, you also have a massive need for heat, and the highest efficency thermal power plants have reached is ~45% (state of the art ultra-supercritical), so they at least 55% of their power is waste heat.

Andrey Levin

Earthed trailing ponds were reasonably allowed when tar sand operations were no more than small-scale and financially risky venture (when price of conventional oil was about 10$).

In last 8 years tar sand operations expanded 10-fold, and are even now quite profitable. Both federal and Provincial environment protection agencies failed miserably to prevent recent proliferation of huge trailing ponds.

As a minimum, all new open pit projects should be mandated to have close to 100% water recycling rate and no trailing ponds. Technology (silt removal) is readily available and it is not prohibitory expensive.



Good possibilities but will Alberta mandate anything that will cost the very rich oil producers more money? They would immediately claim that they have invested too much already and that oil prices are too low etc.

Alberta could even go one step further and mandate recyclying of the current ponds content until they are dry + refill and return the area to forest or agriculture. That would not be that expensive since the oil + chemicals recuperated would almost pay for the operation.

John Taylor

The oil sands projects SEEM profitable when no one is concerned with the cleanup or environmental costs, and shluffs this cost off on future taxpayers.

The real cost of this is a super giveaway to a few oil companies, and a lot of benefiting Americans.
Canada will pay later.


You might be right about the economics of reworking (whose view?), but as long as there are more profitable alternatives , they'll go there first.

Often, I'm thinking generally and specifically - dams and tips - remedial earth works cost many times the cost of the original works. Although I agree that there are specific instances of advantage of previous works being an advantage. Usually when high recovery or asociated minerals find new and profitable markets.

One should not find it hard to think of examples of moneys 'thrown' in the general direction to paper over public concern. These are proclaimed win for the environment. But usually are performed in such a way as to allow the box to be ticked.

I would normally refrain from expressing despair over issues, but in these regards and knowing as we do that as soon as - Hell why wait- the price of oil goes back up and the ice melts a bit more that the speculators will be in for the kill.

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