Earlier this month, a report came out on how much contaminated water was leaking from the Alberta tar sands. The Green Room reported on the study, as did pretty much every other Canadian media outlet. This was likely because the volumes of the leaks were so big – 11 million litres every day – and the contaminated water was filled with lots of substances that one really shouldn’t drink, such as known carcinogens and toxins like polycyclic aromatic hydrocarbons and copper, zinc and iron.
Anyway, the Green Room was curious about what could be done about this, so we contacted one of Canada’s leading researchers on water pollution, Leslie Warren at McMaster University. Warren has been studying a specific solution – using bacteria to neutralize the tailings ponds. Here are my questions and her answers:-
1) Which of these heavy metals are the most harmful and why?
Most tailings ponds contain a variety of metals – called metal cocktails. While they are all contaminants, they have different health impacts. For example, some metals are neurotoxins, some are carcinogenic, some affect kidney function, allergies, etc. Not surprisingly, metal cocktails are more toxic than individual metals, even at lower levels.
2) How could bacteria help remove some of the toxic metals in tailings ponds?
Bacteria can help by preventing the metals from leaching into the water, or by clumping together the metals into solids. When clumped together, metals are less toxic to the environment, because they don’t leach into the earth as quickly. We know that bacteria are widespread in tailings ponds, which means that they can impact the contaminants -but there’s a lot we still don’t about them.
3) Can bacteria be used to fix all heavy metal pollution or will this only be a partial solution?
Metals do not all behave in the same manner, so there is no one solution to “fix” metal contaminants – it is why metal pollution is so challenging. You need to know which metals are present and then figure out how you can use bacterial processes to immobilize or prevent leaching of these specific contaminants.
I doubt that bacterial treatments will be the whole solution. But given our emerging evidence of how widespread and flexible they are in tailings waters I think they will provide an enormous possibilities as we discover more about them.
4) How long do you think it will take to bring this solution to the field?
I think we will be moving from characterization of bacterial processes into pilot stage application in the field within 5-10 years.
Finally, if you have any more questions for Dr. Warren on this issue, you can post them in the comments section.