Oil sands are under heavy development in parts of Canada and the United States. As the name implies, these deposits are comprised in part of sand and petroleum, and are touted by some in the United States as enabling a reduced dependence on other nations for oil.
If it sounds too good to be true, that's because it is. It's very difficult to extract the oil from these deposits; toxic chemicals are shot into the earth to aid extraction, and production is even more polluting than that of "conventional" oil.
The companies profiting from such extraction say that it's safe for the environment, as do government officials. For example, they repeatedly claim that pollutants found in the Athabasca River watershed of Canada (a focus of oil sand extraction) are from natural sources.
Recent research by David Schindler (University of Alberta, Canada) and coworkers has thoroughly debunked this claim. They have found that oil sand extraction has introduced, into the Athabasca River watershed, all thirteen elements considered priority elemental pollutants by the United States Environmental Protection Agency.
Sampling the Athabasca River watershed.
The scientists sampled the Athabasca River watershed in many locations at different times. They collected surface water (water pollution) from 37 sites in February 2008 and 47 sites in June 2008, and sampled the winter snowpack (air pollution) at 31 sites in March 2008.
They chose sites both upstream and downstream of oil sand mining and processing sites. For reference, they also chose other developed and undeveloped sites.
Satellite data was used to assess the extent of land disturbance courtesy of oil sand extraction, and they classified each watershed as more disturbed (greater than 25%) or less disturbed (less than 25%). They focused their detection efforts on the 13 elements designated as priority elemental pollutants by the United States Environmental Protection Agency: antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, thallium, and zinc.
Air pollution.
The scientists found four deposition patterns for dissolved and particulate priority elemental pollutants. Those which decreased exponentially with distance from the site are type 1 (beryllium, lead, mercury, and nickel particulates), while those which also increased locally (due to mining, road dust, land clearing, and other emissions) are type 2 (antimony, arsenic, cadmium, chromium, copper, silver, thallium, and zinc particulates, and dissolved antimony, chromium, copper, nickel, thallium, and zinc).
Type 3 pollutants are those which were deposited locally (dissolved cadmium, lead, and mercury). If a pollutant was detected, yet not in either dissolved or particulate form, it was type 4 (arsenic, beryllium, selenium, and silver).
Oil sand processing facilities are major sources of these pollutants. The average deposition of particulate type 1 and 2 pollutants was up to 30 times that of background levels.
Furthermore, maximum pollution was 120 times above background. The elements arsenic, beryllium, copper, and thallium were only observed near oil sand processing facilities.
Let's have a better idea of how much pollution this is. The scientists report that the approximate total pollution of particulate lead, mercury, and nickel within 50 kilometers of one site was (respectively) 162, 1.1, and 583 kilograms.
The scientists detected particulate type 2 pollutants as much as 85 kilometers away from one oil sand processing facility. Average pollution was 28 times that of background levels, and maximum pollution was 169 times that of background.
Generally, dissolved pollutant levels were less than those of particulates, but were still greater than background levels (up to 5 times for type 2, and up to 18 times for type 3 pollutants). Values above background levels were again observed as much as 85 kilometers away from oil sand processing facilities.
Water pollution: Tributaries.
Pollutant levels increased near oil sand processing facilities and correlated with land disturbance. For example, some pollutants were 8 times as prevalent in more disturbed (greater than 25%) watersheds during the summer than in less disturbed (less than 25%) watersheds.
At all stream mouth and midstream sites, levels of antimony, cadmium, chromium, lead, nickel, silver, and zinc were greater in the winter. Levels of mercury were greater in the summer.
Water pollution: Athabasca delta, Athabasca River, and Lake Athabasca.
Concentrations of antimony, arsenic, chromium, copper, lead, mercury, and nickel, in the summer, immediately downstream of oil sand facilities, were up to 4 times that of upstream. Beryllium, selenium, silver, thallium, and zinc were only detected downstream.
Even as far out as the delta, some pollutants (antimony, arsenic, chromium, copper, lead, mercury, and nickel) were still above upstream levels. In Lake Athabasca, the discharge source of the river, 8 pollutants (antimony, arsenic, cadmium, chromium, copper, lead, mercury, and nickel) were at least twice that of upstream levels.
Implications.
All 13 of the elements designated as priority elemental pollutants by the United States Environmental Protection Agency have been found in the Athabasca River watershed, above background levels. Pollutant levels correlate with land disturbance, and do not uniformly increase over the summer, which is strong collective evidence that the pollutants are from oil sand extraction, not natural sources.
Levels of cadmium, copper, lead, mercury, nickel, silver, and zinc exceed safety limits for aquatic life set by the Canadian government (more often in the summer than in the winter). Especially worrying is that levels were also exceeded during the spring thaw; for example, copper levels are high enough to kill minnow embryos.
Even though none of the pollutant levels exceed drinking water requirements, there is still plenty of reason to be concerned. Metals which are cumulative poisons (e.g. causing kidney failure and cancer) can slowly build up in aquatic life, plant life, as well as within humans.
Oil sand extraction is not safe, as currently practiced. A rigorous, long-term program of monitoring toxic metal pollutants dumped into the environment, and the health of local people, needs to be implemented immediately, in Canada and other locations impacted by oil sand extraction.
NOTE: The scientists' research was funded by The Tides Foundation and the Walter and Duncan Gordon Foundation.
for more information:
Kellya, E. N., Schindlera, D. W., Hodsonb, P. V., Shortc, J. W., Radmanovicha, R., & Nielsena, C. C. (2010). Oil sands development contributes elements toxic at low concentrations to the Athabasca River and its tributaries Proceedings of the National Academy of Sciences : 10.1073/pnas.1008754107